Emerging role of nanosuspensions in drug delivery systems

Carboxymethyl cellulose-based rotigotine nanocrystals-loaded hydrogel for increased transdermal delivery with alleviated skin irritation

Transdermal rotigotine (RTG) therapy is prescribed to manage Parkinson's disease (Neupro® patch). However, its use is suffered from application site reactions. Herein, drug nanocrystalline suspension (NS)-loaded hydrogel (NS-HG) employing polysaccharides simultaneously as suspending agent and hydrogel matrix was constructed for transdermal delivery, with alleviated skin irritation. RTG-loaded NS-HG was prepared using a bead-milling technique, employing sodium carboxylmethyl cellulose (Na.CMC) as nano-suspending agent (molecular weight 90,000 g/mol) and hydrogel matrix (700,000 g/mol), respectively. NS-HG was embodied as follows: drug loading: ≤100 mg/mL; shape: rectangular crystalline; crystal size: <286.7 nm; zeta potential: -61 mV; viscosity: <2.16 Pa·s; and dissolution rate: >90 % within 15 min. Nuclear magnetic resonance analysis revealed that the anionic polymers bind to RTG nanocrystals via charge interaction, affording uniform dispersion in the matrix. Rodent transdermal absorption of RTG from NS-HG was comparable to that from microemulsions, and proportional to drug loading. Moreover, NS-HG was skin-friendly; erythema and epidermal swelling were absent after repeated application. Further, NS-HG was chemically stable; >95 % of the drug was preserved up to 4 weeks under long term (25 °C/RH60%), accelerated (40 °C/RH75%), and stress (50 °C) storage conditions. Therefore, this novel cellulose derivative-based nanoformulation presents a promising approach for effective transdermal RTG delivery with improved tolerability.

Dissolving microarray patches loaded with a rotigotine nanosuspension: A potential alternative to Neupro® patch

Parkinson's disease (PD), affecting about ten million people globally, presents a significant health challenge. Rotigotine (RTG), a dopamine agonist, is currently administered as a transdermal patch (Neupro®) for PD treatment, but the daily application can be burdensome and cause skin irritation. This study introduces a combinatorial approach of dissolving microarray patch (MAP) and nanosuspension (NS) for the transdermal delivery of RTG, offering an alternative to Neupro®. The RTG-NS was formulated using a miniaturized media milling method, resulting in a nano-formulation with a mean particle size of 274.09 ± 7.43 nm, a PDI of 0.17 ± 0.04 and a zeta potential of -15.24 ± 2.86 mV. The in vitro dissolution study revealed an enhanced dissolution rate of the RTG-NS in comparison to the coarse RTG powder, under sink condition. The RTG-NS MAPs, containing a drug layer and a 'drug-free' supporting baseplate, have a drug content of 3.06 ± 0.15 mg/0.5 cm2 and demonstrated greater amount of drug delivered per unit area (∼0.52 mg/0.5 cm2) than Neupro® (∼0.20 mg/1 cm2) in an ex vivo Franz cell study using full-thickness neonatal porcine skin. The in vivo pharmacokinetic studies demonstrated that RTG-NS MAPs, though smaller (2 cm2 for dissolving MAPs and 6 cm2 for Neupro®), delivered drug levels comparable to Neupro®, indicating higher efficiency per unit area. This could potentially avoid unnecessarily high plasma levels after the next dose at 24 h, highlighting the benefits of dissolving MAPs over conventional transdermal patches in PD treatment.

Development and characterization of curcumin nanosuspension-embedded genipin-crosslinked chitosan/polyvinylpyrrolidone hydrogel patch for effective wound healing

This study investigated the development of a genipin-crosslinked chitosan (CS)-based polyvinylpyrrolidone (PVP) hydrogel containing curcumin nanosuspensions (Cur-NSs) to promote wound healing in an excisional wound model. Cur-NSs were prepared, and a simplex centroid mixture design was employed to optimize hydrogel properties for high water absorption, degree of crosslinking, and sufficient toughness. The in vivo wound healing effect was tested in Wistar rats. The optimized hydrogel consisted of a 70:30 ratio of CS:PVP, crosslinked with a 2 % w/w genipin solution. It exhibited high swelling capability (486 %) while maintaining solidity, robustness, and durability. Incorporating 5 % w/w Cur-NSs resulted in a more compact structure, although with a reduction in swelling properties. The release kinetics of Cur from the hydrogel followed the Korsmeyer-Peppas Fickian diffusion model. In vitro biocompatibility studies demonstrated that the hydrogel was non-toxic to skin fibroblast cells. The in vivo experiment revealed a desirable wound healing rate with over 80 % recovery by day 7. Cur-NSs likely aided wound healing by reducing the inflammatory response and stimulating fibroblast proliferation. Additionally, the CS-based hydrogel provided a moist wound environment with hydration and gas transfer, further accelerating wound closure. These findings suggest that the Cur-NS-embedded hydrogel shows promise as a wound dressing material.

High-throughput preparation, scale up and solidification of andrographolide nanosuspension using hummer acoustic resonance technology

The aim of this study was to rapidly develop a sufficiently robust andrographolide nanosuspension (AG-NS) system using hummer acoustic resonance (HAR) technology. The system can effectively improve the dissolution properties of AG, while having high stability and scale-up adaptability. The formulation of AG-NS was optimized in a high-throughput manner using HAR technology and the preparation process was optimized stepwise. Optimal AG-NS with Z-Ave = 223.99 ± 3.16 nm, PDI=0.095 ± 0.007 and zeta potential = -33.20 ± 0.58 mV was successfully prepared with Polyvinylpyrrolidone K30 and Sodium dodecyl sulfate. The optimal prescription was successfully scaled up 100 and 150 times using HAR technology, which was the initial exploration of its commercial scale production. AG-NS was solidified using freeze drying and fluid bed technology, respectively. The optimal AG-NS and its solidified products were exhaustively characterized using various analytical techniques. The high energy input of HAR technology and drying process converted part of the drug into the amorphous state. The in-vitro drug dissolution studies demonstrated relatively higher drug dissolution for AG-NS and its solidified products compared to controls at both the dissolution media (pH 1.2 buffer and pH 6.8 buffer). AG-NS and its solidified products successfully maintained their physical stability in short-term stability and accelerated stability experiments, respectively.

Sorafenib tosylate-loaded nanosuspension: preparation, optimization, and in vitro cytotoxicity study against human HepG2 carcinoma cells

This study aimed to optimize nanosuspension of sorafenib tosylate (an anticancer hydrophobic drug molecule) using a central composite design. Nanosuspension was prepared using a nanoprecipitation-ultrasonication approach. FTIR and DSC analyses demonstrated that the drug and excipients were physicochemically compatible. X-ray powder diffraction analysis confirmed amorphous form of the payload in the formulation. The optimized formulation (batch NSS6) had a zeta potential of -18.1 mV, a polydispersity of 0.302, and a particle size of 97.11 nm. SEM analysis confirmed formation of rod-shaped particles. After 24 h, about 64.45% and 86.37% of the sorafenib tosylate was released in pH 6.8 and pH 1.2, respectively. The MTT assay was performed on HepG2 cell lines. IC50 value of the optimized batch was 39.4 µg/mL. The study concluded that sorafenib tosylate nanosuspension could be a promising approach in the treatment of hepatocellular cancer.

Nanosuspensions in ophthalmology: Overcoming challenges and enhancing drug delivery for eye diseases

This review article provides a comprehensive overview of the advancements in using nanosuspensions for controlled drug delivery in ophthalmology. It highlights the significance of ophthalmic drug delivery due to the prevalence of eye diseases and delves into various aspects of this field. The article explores molecular mechanisms, drugs used, and physiological factors affecting drug absorption. It also addresses challenges in treating both anterior and posterior eye segments and investigates the role of mucus in obstructing micro- and nanosuspensions. Nanosuspensions are presented as a promising approach to enhance drug solubility and absorption, covering formulation, stability, properties, and functionalization. The review discusses the pros and cons of using nanosuspensions for ocular drug delivery and covers their structure, preparation, characterization, and applications. Several graphical representations illustrate their role in treating various eye conditions. Specific drug categories like anti-inflammatory drugs, antihistamines, glucocorticoids, and more are discussed in detail, with relevant studies. The article also addresses current challenges and future directions, emphasizing the need for improved nanosuspension stability and exploring potential technologies. Nanosuspensions have shown substantial potential in advancing ophthalmic drug delivery by enhancing solubility and absorption. This article is a valuable resource for researchers, clinicians, and pharmaceutical professionals in this field, offering insights into recent developments, challenges, and future prospects in nanosuspension use for ocular drug delivery.

Fostering the unleashing potential of nanocarriers-mediated delivery of ocular therapeutics

Ocular delivery is the most challenging aspect in the field of pharmaceutical research. The major hurdle for the controlled delivery of drugs to the eye includes the physiological static barriers such as the complex layers of the cornea, sclera and retina which restrict the drug from permeating into the anterior and posterior segments of the eye. Recent years have witnessed inventions in the field of conventional and nanocarrier drug delivery which have shown considerable enhancement in delivering small to large molecules across the eye. The dynamic challenges associated with conventional systems include limited drug contact time and inadequate ocular bioavailability resulting from solution drainage, tear turnover, and dilution or lacrimation. To this end, various bioactive-based nanosized carriers including liposomes, ethosomes, niosomes, dendrimer, nanogel, nanofibers, contact lenses, nanoprobes, selenium nanobells, nanosponge, polymeric micelles, silver nanoparticles, and gold nanoparticles among others have been developed to circumvent the limitations associated with the conventional dosage forms. These nanocarriers have been shown to achieve enhanced drug permeation or retention and prolong drug release in the ocular tissue due to their better tissue adherence. The surface charge and the size of nanocarriers (10-1000 nm) are the important key factors to overcome ocular barriers. Various nanocarriers have been shown to deliver active therapeutic molecules including timolol maleate, ampicillin, natamycin, voriconazole, cyclosporine A, dexamethasone, moxifloxacin, and fluconazole among others for the treatment of anterior and posterior eye diseases. Taken together, in a nutshell, this extensive review provides a comprehensive perspective on the numerous facets of ocular drug delivery with a special focus on bioactive nanocarrier-based approaches, including the difficulties and constraints involved in the fabrication of nanocarriers. This also provides the detailed invention, applications, biodistribution and safety-toxicity of nanocarriers-based therapeutcis for the ophthalmic delivery.

Improving the Antimicrobial Potency of Berberine for Endodontic Canal Irrigation Using Polymeric Nanoparticles

To address the challenges posed by biofilm presence and achieve a substantial reduction in bacterial load within root canals during endodontic treatment, various irrigants, including nanoparticle suspensions, have been recommended. Berberine (BBR), a natural alkaloid derived from various plants, has demonstrated potential applications in dentistry treatments due to its prominent antimicrobial, anti-inflammatory, and antioxidant properties. This study aimed to produce and characterize a novel polymeric nanoparticle of poly (lactic-co-glycolic acid) (PLGA) loaded with berberine and evaluate its antimicrobial activity against relevant endodontic pathogens, Enterococcus faecalis, and Candida albicans. Additionally, its cytocompatibility using gingival fibroblasts was assessed. The polymeric nanoparticle was prepared by the nanoprecipitation method. Physicochemical characterization revealed spheric nanoparticles around 140 nm with ca, -6 mV of surface charge, which was unaffected by the presence of BBR. The alkaloid was successfully incorporated at an encapsulation efficiency of 77% and the designed nanoparticles were stable upon 20 weeks of storage at 4 °C and 25 °C. Free BBR reduced planktonic growth at ≥125 μg/mL. Upon incorporation into PLGA nanoparticles, 20 μg/mL of [BBR]-loaded nanoparticles lead to a significant reduction, after 1 h of contact, of both planktonic bacteria and yeast. Sessile cells within biofilms were also considered. At 30 and 40 μg/mL, [BBR]-loaded PLGA nanoparticles reduced the viability of the sessile endodontic bacteria, upon 24 h of exposure. The cytotoxicity of BBR-loaded nanoparticles to oral fibroblasts was negligible. The novel berberine-loaded polymeric nanoparticles hold potential as a promising supplementary approach in the treatment of endodontic infections.

Transformation of ABT-199 Nanocrystal Suspensions into a Redispersible Drug Product-Impact of Vacuum Drum Drying, Spray Drying and Tableting on Re-Nanodispersibility

The present study compared vacuum drum drying (VDD) and conventional spray drying (SD) for solidifying crystalline ABT-199 nanosuspensions into redispersible oral drug products. The aim was to optimize formulation compositions and process conditions to maintain nanoparticle size after tablet redispersion. The impact of drug load (22%, 33%, 44%) and type of drying protectant (mannitol, mannitol/trehalose mix (1:1), trehalose) on redispersibility and material powder properties were investigated. Moreover, compression analysis was performed assessing the influence of compaction pressure on primary nanocrystal redispersibility and tablet disintegration. Higher drug loads and lower drying protectant levels resulted in particle growth, confirming a drug load dependence on redispersibility behavior. Notably, all drying protectants showed similar protection properties at properly chosen drying process parameters (Tg-dependent), except when VDD was used for mannitol formulations. Differences between the applied drying processes were observed in terms of downstream processing and tabletability: mannitol-containing formulations solidified via VDD showed an improved processability compared to formulations with trehalose. In conclusion, VDD is a promising drying technique that offers advantageous downstream processability compared to SD and represents an attractive novel processing technology for the pharmaceutical industry. As demonstrated in the present study, VDD combines higher yields with a leaner manufacturing process flow. The improved bulk properties provide enhanced tabletability and enable direct compression.

Fabrication and in vitro/vivo evaluation of quercetin nanocrystals stabilized by glycyrrhizic acid for liver targeted drug delivery

The purpose of this study was to design novel drug nanocrystals (NCs) stabilized by glycyrrhizic acid (GL) for achieving liver targeted drug delivery due to the presence of GL receptor in the hepatocytes. Quercetin (QT) exhibits good pharmacological activities for the treatment of liver diseases, including liver steatosis, fatty hepatitis, liver fibrosis, and liver cancer. It was selected as a model drug owing to its poor water solubility. QT NCs stabilized by GL (QT-NCs/GL) were fabricated by wet media milling technique and systemically evaluated. QT-NCs stabilized by poloxamer 188 (QT-NCs/P188) were prepared as a reference for comparison of in vitro and in vivo performance with QT-NCs/GL. QT-NCs/GL and QT-NCs/P188 with similar particle size around 130 nm were successfully fabricated by wet media milling technique. Both of QT-NCs/GL and QT-NCs/P188 showed irregular particles and short rods under SEM. XRPD revealed that QT-NCs/GL and QT-NCs/P188 remained in crystalline state with reduced crystallinity. QT-NCs/GL and QT-NCs/P188 exhibited significant solubility increase and drug release improvement of QT as compared to raw QT. No significant difference for the plasma concentration-time curves and pharmacokinetic parameters of QT were found following intravenous administration of QT-NCs/GL and QT-NCs/P188. However, a significantly higher liver distribution of QT following intravenous administration of QT-NCs/GL was observed in comparison to QT-NCs/P188, indicating QT-NCs stabilized by GL could achieve liver targeted delivery of QT. It could be concluded that GL used as stabilizer of QT NCs have a great potential for liver targeted drug delivery.

Unlocking the Potential of Oleanolic Acid: Integrating Pharmacological Insights and Advancements in Delivery Systems

The growing interest in oleanolic acid (OA) as a triterpenoid with remarkable health benefits prompts an emphasis on its efficient use in pharmaceutical research. OA exhibits a range of pharmacological effects, including antidiabetic, anti-inflammatory, immune-enhancing, gastroprotective, hepatoprotective, antitumor, and antiviral properties. While OA demonstrates diverse pharmacological effects, optimizing its therapeutic potential requires overcoming significant challenges. In the field of pharmaceutical research, the exploration of efficient drug delivery systems is essential to maximizing the therapeutic potential of bioactive compounds. Efficiently delivering OA faces challenges, such as poor aqueous solubility and restricted bioavailability, and to unlock its full therapeutic efficacy, novel formulation strategies are imperative. This discussion thoroughly investigates different approaches and advancements in OA drug delivery systems with the aim of enhancing the biopharmaceutical features and overall efficacy in diverse therapeutic contexts.

Breaking Barriers: Nanomedicine-Based Drug Delivery for Cataract Treatment

Cataract is a leading cause of blindness globally, and its surgical treatment poses a significant burden on global healthcare. Pharmacologic therapies, including antioxidants and protein aggregation reversal agents, have attracted great attention in the treatment of cataracts in recent years. Due to the anatomical and physiological barriers of the eye, the effectiveness of traditional eye drops for delivering drugs topically to the lens is hindered. The advancements in nanomedicine present novel and promising strategies for addressing challenges in drug delivery to the lens, including the development of nanoparticle formulations that can improve drug penetration into the anterior segment and enable sustained release of medications. This review introduces various cutting-edge drug delivery systems for cataract treatment, highlighting their physicochemical properties and surface engineering for optimal design, thus providing impetus for further innovative research and potential clinical applications of anti-cataract drugs.

Nanoscale strides: exploring innovative therapies for breast cancer treatment

Breast cancer (BC) is a predominant malignancy in women that constitutes approximately 30% of all cancer cases and has a mortality rate of 14% in recent years. The prevailing therapies include surgery, chemotherapy, and radiotherapy, each with its own limitations and challenges. Despite oral or intravenous administration, there are numerous barriers to accessing anti-BC agents before they reach the tumor site, including physical, physiological, and biophysical barriers. The complexity of BC pathogenesis, attributed to a combination of endogenous, chronic, intrinsic, extrinsic and genetic factors, further complicates its management. Due to the limitations of existing cancer treatment approaches, there is a need to explore novel, efficacious solutions. Nanodrug delivery has emerged as a promising avenue in cancer chemotherapy, aiming to enhance drug bioavailability while mitigating adverse effects. In contrast to conventional chemotherapy, cancer nanotechnology leverages improved permeability to achieve comprehensive disruption of cancer cells. This approach also presented superior pharmacokinetic profiles. The application of nanotechnology in cancer therapeutics includes nanotechnological tools, but a comprehensive review cannot cover all facets. Thus, this review concentrates specifically on BC treatment. The focus lies in the successful implementation of systematic nanotherapeutic strategies, demonstrating their superiority over conventional methods in delivering anti-BC agents. Nanotechnology-driven drug delivery holds immense potential in treating BC. By surmounting multiple barriers and capitalizing on improved permeability, nanodrug delivery has demonstrated enhanced efficacy and reduced adverse effects compared to conventional therapies. This review highlights the significance of systematic nanotherapy approaches, emphasizing the evolving landscape of BC management.

Minoxidil Nanosuspension-Loaded Dissolved Microneedles for Hair Regrowth

Minoxidil (MIN) is used topically to treat alopecia. However, its low absorption limits its use, warranting a new strategy to enhance its delivery into skin layers. The objective of this study was to evaluate the dermal delivery of MIN by utilizing dissolved microneedles (MNs) loaded with MIN nanosuspension (MIN-NS) for hair regrowth. MIN-NS was prepared by the solvent-antisolvent precipitation technique. The particle size of MIN-NS was 226.7 ± 9.3 nm with a polydispersity index of 0.29 ± 0.17 and a zeta potential of -29.97 ± 1.23 mV. An optimized formulation of MIN-NS was selected, freeze-dried, and loaded into MNs fabricated with sodium carboxymethyl cellulose (Na CMC) polymeric solutions (MIN-NS-loaded MNs). MNs were evaluated for morphology, dissolution rate, skin insertion, drug content, mechanical properties, ex vivo permeation, in vivo, and stability studies. MNs, prepared with 14% Na CMC, were able to withstand a compression force of 32 N for 30 s, penetrate Parafilm M® sheet at a depth of 374-504 µm, and dissolve completely in the skin within 30 min with MIN %recovery of 95.1 ± 6.5%. The release of MIN from MIN-NS-loaded MNs was controlled for 24 h. MIN-NS-loaded MNs were able to maintain their mechanical properties and chemical stability for 4 weeks, when kept at different storage conditions. The in vivo study of the freeze-dried MIN-NS and MIN-NS-loaded MNs proved hair regrowth on rat skin after 11 and 7 days, respectively. These results showed that MIN-NS-loaded MNs could potentially improve the dermal delivery of MIN through the skin to treat alopecia.

Nasal Delivery to the Brain: Harnessing Nanoparticles for Effective Drug Transport

The nose-to-brain drug-delivery system has emerged as a promising strategy to overcome the challenges associated with conventional drug administration for central nervous system disorders. This emerging field is driven by the anatomical advantages of the nasal route, enabling the direct transport of drugs from the nasal cavity to the brain, thereby circumventing the blood-brain barrier. This review highlights the significance of the anatomical features of the nasal cavity, emphasizing its high permeability and rich blood supply that facilitate rapid drug absorption and onset of action, rendering it a promising domain for neurological therapeutics. Exploring recent developments and innovations in different nanocarriers such as liposomes, polymeric nanoparticles, solid lipid nanoparticles, dendrimers, micelles, nanoemulsions, nanosuspensions, carbon nanotubes, mesoporous silica nanoparticles, and nanogels unveils their diverse functions in improving drug-delivery efficiency and targeting specificity within this system. To minimize the potential risk of nanoparticle-induced toxicity in the nasal mucosa, this article also delves into the latest advancements in the formulation strategies commonly involving surface modifications, incorporating cutting-edge materials, the adjustment of particle properties, and the development of novel formulations to improve drug stability, release kinetics, and targeting specificity. These approaches aim to enhance drug absorption while minimizing adverse effects. These strategies hold the potential to catalyze the advancement of safer and more efficient nose-to-brain drug-delivery systems, consequently revolutionizing treatments for neurological disorders. This review provides a valuable resource for researchers, clinicians, and pharmaceutical-industry professionals seeking to advance the development of effective and safe therapies for central nervous system disorders.

Optimizing Nanosuspension Drug Release and Wound Healing Using a Design of Experiments Approach: Improving the Drug Delivery Potential of NDH-4338 for Treating Chemical Burns

NDH-4338 is a highly lipophilic prodrug comprising indomethacin and an acetylcholinesterase inhibitor. A design of experiments approach was used to synthesize, characterize, and evaluate the wound healing efficacy of optimized NDH-4338 nanosuspensions against nitrogen mustard-induced skin injury. Nanosuspensions were prepared by sonoprecipitation in the presence of a Vitamin E TPGS aqueous stabilizer solution. Critical processing parameters and material attributes were optimized to reduce particle size and determine the effect on dissolution rate and burn healing efficacy. The antisolvent/solvent ratio (A/S), dose concentration (DC), and drug/stabilizer ratio (D/S) were the critical sonoprecipitation factors that control particle size. These factors were subjected to a Box-Behnken design and response surface analysis, and model quality was assessed. Maximize desirability and simulation experiment optimization approaches were used to determine nanosuspension parameters with the smallest size and the lowest defect rate within the 10-50 nm specification limits. Optimized and unoptimized nanosuspensions were prepared and characterized. An established depilatory double-disc mouse model was used to evaluate the healing of nitrogen mustard-induced dermal injuries. Optimized nanosuspensions (A/S = 6.2, DC = 2% w/v, D/S = 2.8) achieved a particle size of 31.46 nm with a narrow size range (PDI = 0.110) and a reduced defect rate (42.2 to 6.1%). The optimized nanosuspensions were stable and re-dispersible, and they showed a ~45% increase in cumulative drug release and significant edema reduction in mice. Optimized NDH-4338 nanosuspensions were smaller with more uniform sizes that led to improved physical stability, faster dissolution, and enhanced burn healing efficacy compared to unoptimized nanosuspensions.

Nanocrystals and nanosuspensions: an exploration from classic formulations to advanced drug delivery systems

Nanocrystals and nanosuspensions have become realistic approaches to overcome the formulation challenges of poorly water-soluble drugs. They also represent a less-known but versatile platform for multiple therapeutic applications. They can be integrated into a broad spectrum of drug delivery systems including tablets, hydrogels, microneedles, microparticles, or even functionalized liposomes. The recent progresses, challenges, and opportunities in this field are gathered originally together with an informative case study concerning an itraconazole nanosuspension-in-hydrogel formulation. The translational aspects, historical and current clinical perspectives are also critically reviewed here to shed light on the incoming generation of nanocrystal formulations.

A comprehensive review on lipid nanocarrier systems for cancer treatment: fabrication, future prospects and clinical trials

Over the last few decades, cancer has been considered a clinical challenge, being among the leading causes of mortality all over the world. Although many treatment approaches have been developed for cancer, chemotherapy is still the most utilized in the clinical setting. However, the available chemotherapeutics-based treatments have several caveats including their lack of specificity, adverse effects as well as cancer relapse and metastasis which mainly explains the low survival rate of patients. Lipid nanoparticles (LNPs) have been utilized as promising nanocarrier systems for chemotherapeutics to overcome the challenges of the currently applied therapeutic strategies for cancer treatment. Loading chemotherapeutic agent(s) into LNPs improves drug delivery at different aspects including specific targeting of tumours, and enhancing the bioavailability of drugs at the tumour site through selective release of their payload, thus reducing their undesired side effects on healthy cells. This review article delineates an overview of the clinical challenges in many cancer treatments as well as depicts the role of LNPs in achieving optimal therapeutic outcomes. Moreover, the review contains a comprehensive description of the many LNPs categories used as nanocarriers in cancer treatment to date, as well as the potential of LNPs for future applications in other areas of medicine and research.

Recent developments in the use of nanocrystals to improve bioavailability of APIs

Nanocrystals refer to materials with at least one dimension smaller than 100 nm, composing of atoms arranged in single crystals or polycrystals. Nanocrystals have significant research value as they offer unique advantages over conventional pharmaceutical formulations, such as high bioavailability, enhanced targeting selectivity and controlled release ability and are therefore suitable for the delivery of a wide range of drugs such as insoluble drugs, antitumor drugs and genetic drugs with broad application prospects. In recent years, research on nanocrystals has been progressively refined and new products have been launched or entered the clinical phase of studies. However, issues such as safety and stability still stand that need to be addressed for further development of nanocrystal formulations, and significant gaps do exist in research in various fields in this pharmaceutical arena. This paper presents a systematic overview of the advanced development of nanocrystals, ranging from the preparation approaches of nanocrystals with which the bioavailability of poorly water-soluble drugs is improved, critical properties of nanocrystals and associated characterization techniques, the recent development of nanocrystals with different administration routes, the advantages and associated limitations of nanocrystal formulations, the mechanisms of physical instability, and the enhanced dissolution performance, to the future perspectives, with a final view to shed more light on the future development of nanocrystals as a means of optimizing the bioavailability of drug candidates. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Comparison of the pharmacokinetic characteristics and bioequivalence between two nanosuspension formulations of megestrol acetate in healthy Korean male subjects

Megestrol is commonly used to address appetite loss, cachexia, and significant weight loss in cancer or acquired immune deficiency syndrome patients. This study aimed to assess the pharmacokinetics and determine the bioequivalence of two orally administered megestrol acetate suspensions (625 mg/5 mL) in healthy Korean male subjects. A randomized, open-label, single-dose crossover study was conducted involving fifty-four healthy male subjects who were randomized into two sequence groups. Each subject received either a test or reference drug formulation of 625 mg/5 mL megestrol acetate with a two-week washout period between treatments. Plasma samples were collected before and up to 120 hours after administration, and their plasma drug concentrations were analyzed using validated liquid chromatography-mass spectrometry/mass spectrometry. The pharmacokinetic parameters were calculated, and bioequivalence was confirmed if the 90% confidence intervals of the geometric mean ratios were within the specified bounds of 80.00% to 125.00%. In total, fifty-two subjects completed the study, contributing to the pharmacokinetic analysis. The 90% confidence intervals for the geometric mean ratios of the test formulation compared to the reference formulation were 93.85% to 108.90% for maximum plasma concentration and 91.60% to 101.78% for area under the concentration-time curve from the point of administration to last time point of blood sampling. Throughout the study, no serious or unexpected adverse events were observed. The pharmacokinetic profiles of both formulations of megestrol acetate (625 mg) were comparable and well tolerated in healthy Korean male adult subjects. The test formulation met regulatory criteria for bioequivalence.

Trial Registration

ClinicalTrials.gov Identifier: NCT06147908.

A Review of the Potential of Poly-(lactide-co-glycolide) Nanoparticles as a Delivery System for an Active Antimycobacterial Compound, 7-Methyljuglone

7-Methyljuglone (7-MJ) is a pure compound isolated from the roots of Euclea natalensis A. DC., a shrub indigenous to South Africa. It exhibits significant promise as a potential treatment for the highly communicable disease tuberculosis (TB), owing to its effective antimycobacterial activity against Mycobacterium tuberculosis. Despite its potential therapeutic benefits, 7-MJ has demonstrated in vitro cytotoxicity against various cancerous and non-cancerous cell lines, raising concerns about its safety for consumption by TB patients. Therefore, this review focuses on exploring the potential of poly-(lactide-co-glycolic) acid (PLGA) nanoparticles as a delivery system, which has been shown to decrease in vitro cytotoxicity, and 7-MJ as an effective antimycobacterial compound.

Nanosuspension-Based Drug Delivery Systems for Topical Applications

Nanosuspensions have garnered recent attention as a promising strategy for mitigating the bioavailability challenges of hydrophobic drugs, particularly those characterized by poor solubility in both aqueous and organic environments. Addressing solubility issues associated with poorly water-soluble drugs has largely resolved the need to enhance drug absorption and bioavailability. As mucosal formulations and topical administration progress in the future, nanosuspension drug delivery, straightforward formulation techniques, and versatile applications will continue to be subjects of interest. Nanosuspensions have undergone extensive scrutiny in preparation for topical applications, encompassing ocular, pulmonary, and dermal usage. Among the numerous methods aimed at improving cutaneous application, nanocrystals represent a relatively recent yet profoundly intriguing approach. Despite the increasing availability of various nanosuspension products, primarily designed for oral administration, only a limited number of studies have explored skin permeability and drug accumulation in the context of nanosuspensions. Nevertheless, the scant published research unequivocally underscores the potential of this approach for enhancing cutaneous bioavailability, particularly for active ingredients with low to medium solubility. Nanocrystals exhibit increased skin adhesiveness in addition to heightened saturation solubility and dissolution rate, thereby augmenting cutaneous distribution. The article provides a comprehensive overview of nanosuspensions for topical application. The methodology employed is robust, with a well-defined experimental design; however, the limited sample size raises concerns about the generalizability of the findings. While the results demonstrate promising outcomes in terms of enhanced drug delivery, the discussion falls short of addressing certain limitations. Additionally, the references largely focus on recent studies, but a more diverse inclusion of historical perspectives could offer a more holistic view of the subject.

Intranasal Drug Delivery by Nanotechnology: Advances in and Challenges for Alzheimer's Disease Management

Alzheimer's disease, a progressive neurodegenerative condition, is characterized by a gradual decline in cognitive functions. Current treatment approaches primarily involve the administration of medications through oral, parenteral, and transdermal routes, aiming to improve cognitive function and alleviate symptoms. However, these treatments face limitations, such as low bioavailability and inadequate permeation. Alternative invasive methods, while explored, often entail discomfort and require specialized assistance. Therefore, the development of a non-invasive and efficient delivery system is crucial. Intranasal delivery has emerged as a potential solution, although it is constrained by the unique conditions of the nasal cavity. An innovative approach involves the use of nano-carriers based on nanotechnology for intranasal delivery. This strategy has the potential to overcome current limitations by providing enhanced bioavailability, improved permeation, effective traversal of the blood-brain barrier, extended retention within the body, and precise targeting of the brain. The comprehensive review focuses on the advancements in designing various types of nano-carriers, including polymeric nanoparticles, metal nanoparticles, lipid nanoparticles, liposomes, nanoemulsions, Quantum dots, and dendrimers. These nano-carriers are specifically tailored for the intranasal delivery of therapeutic agents aimed at combatting Alzheimer's disease. In summary, the development and utilization of intranasal delivery systems based on nanotechnology show significant potential in surmounting the constraints of current Alzheimer's disease treatment strategies. Nevertheless, it is essential to acknowledge regulatory as well as toxicity concerns associated with this route; meticulous consideration is required when engineering a carrier. This comprehensive review underscores the potential to revolutionize Alzheimer's disease management and highlights the importance of addressing regulatory considerations for safe and effective implementations. Embracing this strategy could lead to substantial advancements in the field of Alzheimer's disease treatment.

Orodispersible Films: Current Innovations and Emerging Trends

Orodispersible films (ODFs) are thin, mechanically strong, and flexible polymeric films that are designed to dissolve or disintegrate rapidly in the oral cavity for local and/or systemic drug delivery. This review examines various aspects of ODFs and their potential as a drug delivery system. Recent advancements, including the detailed exploration of formulation components, such as polymers and plasticizers, are briefed. The review highlights the versatility of preparation methods, particularly the solvent-casting production process, and novel 3D printing techniques that bring inherent flexibility. Three-dimensional printing technology not only diversifies active compounds but also enables a multilayer approach, effectively segregating incompatible drugs. The integration of nanoparticles into ODF formulations marks a significant breakthrough, thus enhancing the efficiency of oral drug delivery and broadening the scope of the drugs amenable to this route. This review also sheds light on the diverse in vitro evaluation methods utilized to characterize ODFs, ongoing clinical trials, approved marketed products, and recent patents, providing a comprehensive outlook of the evolving landscape of orodispersible drug delivery. Current patient-centric approaches involve developing ODFs with patient-friendly attributes, such as improved taste masking, ease of administration, and enhanced patient compliance, along with the personalization of ODF formulations to meet individual patient needs. Investigating novel functional excipients with the potential to enhance the permeation of high-molecular-weight polar drugs, fragile proteins, and oligonucleotides is crucial for rapid progress in the advancing domain of orodispersible drug delivery.

Novel tetrahydrocurcumin integrated mucoadhesive nanocomposite κ-carrageenan/xanthan gum sponges: a strategy for effective local treatment of oral cancerous and precancerous lesions

Oral cancer is one of the leading causes of death worldwide. Oral precancerous lesions (OPL) are the precursors of oral cancer, with varying degrees of progression. Tetrahydrocurcumin (THC) is a major metabolite of curcumin with superior anticancer properties against various types of cancer. However, THC's clinical outcome is limited by its poor aqueous solubility. Herein, we developed novel mucoadhesive biopolymer-based composite sponges for buccal delivery of THC, exploiting nanotechnology and mucoadhesion for efficient prevention and treatment of oral cancer. Firstly, THC-nanocrystals (THC-NC) were formulated and characterized for subsequent loading into mucoadhesive composite sponges. The anticancer activity of THC-NC was assessed on a human tongue squamous carcinoma cell line (SCC-4). Finally, the chemopreventive activity of THC-NC loaded sponges (THC-NC-S) was examined in DMBA-induced hamster OPL. The selected THC-NC exhibited a particle size of 532.68 ± 13.20 nm and a zeta potential of -46.08 ± 1.12 mV. Moreover, THC-NC enhanced the anticancer effect against SCC-4 with an IC50 value of 80 µg/mL. THC-NC-S exhibited good mucoadhesion properties (0.24 ± 0.02 N) with sustained drug release, where 90% of THC was released over 4 days. Furthermore, THC-NC-S had a magnificent potential for maintaining high chemopreventive activity, as demonstrated by significant regression in the dysplasia degree and a decline in cyclin D1 (control: 40.4 ± 12.5, THC-NC-S: 12.07 ± 5.2), culminating in significant amelioration after 25 days of treatment. Conclusively, novel THC-NC-S represent a promising platform for local therapy of OPL, preventing their malignant transformation into cancer.

Herpetetrone nanosuspensions enhance drug solubility and bioavailability to improve anti-hepatic fibrosis effects

The aim of this study was to enhance the dissolution rate and oral bioavailability of herpetetrone (HPT) by preparing nanosuspensions (NSs) and evaluate the changes in its anti-hepatic fibrosis effect. Herpetetrone nanosuspension (HPT-NS) was prepared using the ultrasound-precipitation technique, and characterised on the basis of mean diameter, zeta potential (ZP), encapsulation efficiency percent (EE%), scanning electron microscopy (SEM), and X-ray powder diffraction (XRPD). In addition, the pharmacokinetics and anti-hepatic fibrosis activity were evaluated. HPT-NS prepared with the optimised formulation was found to be spherical with mean diameter of 177.48 ± 6.13 nm, polydispersity index (PDI) of 0.108 ± 0.002 and ZP of -17.28 ± 2.02 mV. The EE (m/m, %) was 83.25 ± 0.27. XRPD analyses confirmed that the amorphous state of HPT in HPT-NS remained unchanged. The dissolution rate of HPT-NS was significantly higher than that of HPT coarse suspensions (HPT-CSs). Following oral administration, Cmax and AUC0-t of HPT-NS showed a significant increase (p < 0.05). In vitro, HPT inhibited the proliferation of HSC-T6 cells and induced apoptosis by up-regulating the expression of Bax proteins and down-regulating the expression of Bcl-2 and TGF-β1 proteins. Compared with HPT-CS, HPT-NS exhibited a more pronounced anti-fibrotic effect. HPT-NS, as a new drug formulation designed to improve the solubility and bioavailability of the drug, shows promising potential in enhancing the anti-liver fibrosis effect.

Impact of Additives on Drug Particles during Liquid Antisolvent Crystallization and Subsequent Freeze-Drying

The impact of single or combinations of additives on the generation of nanosuspensions of two poorly water-soluble active pharmaceutical ingredients (APIs), fenofibrate (FF) and dalcetrapib (DCP), and their isolation to the dry state via antisolvent (AS) crystallization followed by freeze-drying was explored in this work. Combinations of polymeric and surfactant additives such as poly(vinyl alcohol) or hydroxypropyl methyl cellulose and sodium docusate were required to stabilize nanoparticles (∼200-300 nm) of both APIs in suspension before isolation to dryness. For both FF and DCP, multiple additives generated the narrowest, most-stable particle size distribution, with the smallest particles in suspension, compared with using a single additive. An industrially recognized freeze-drying process was used for the isolation of these nanoparticles to dryness. When processed by the liquid AS crystallization followed by freeze-drying in the presence of multiple additives, a purer monomorphic powder for FF resulted than when processed in the absence of any additive or in the presence of a single additive. It was noted that all nanoparticles freeze-dried in the presence of additives had a flat, flaky habit resulting in large surface areas. Agglomeration occurred during freeze-drying, resulting in micron-size particles. However, after freeze-drying, powders produced with single or multiple additives showed similar dissolution profiles, irrespective of aging time before drying, thus attenuating the advantage of multiple additives in terms of size observed before the freeze-drying process.

Nanotechnology-Based Drug Delivery Systems for Honokiol: Enhancing Therapeutic Potential and Overcoming Limitations

Honokiol (HNK) is a small-molecule polyphenol that has garnered considerable attention due to its diverse pharmacological properties, including antitumor, anti-inflammatory, anti-bacterial, and anti-obesity effects. However, its clinical application is restricted by challenges such as low solubility, poor bioavailability, and rapid metabolism. To overcome these limitations, researchers have developed a variety of nano-formulations for HNK delivery. These nano-formulations offer advantages such as enhanced solubility, improved bioavailability, extended circulation time, and targeted drug delivery. However, existing reviews of HNK primarily focus on its clinical and pharmacological features, leaving a gap in the comprehensive evaluation of HNK delivery systems based on nanotechnology. This paper aims to bridge this gap by comprehensively reviewing different types of nanomaterials used for HNK delivery over the past 15 years. These materials encompass vesicle delivery systems, nanoparticles, polymer micelles, nanogels, and various other nanocarriers. The paper details various HNK nano-delivery strategies and summarizes their latest applications, development prospects, and future challenges. To compile this review, we conducted an extensive search using keywords such as "honokiol", "nanotechnology", and "drug delivery system" on reputable databases, including PubMed, Scopus, and Web of Science, covering the period from 2008 to 2023. Through this search, we identified and selected approximately 90 articles that met our specific criteria.

Oral bioavailability enhancement of doxazosin mesylate: Nanosuspension versus self-nanoemulsifying drug delivery systems

Background and purpose

Doxazosin mesylate (DOX) is an antihypertensive drug that possesses poor water solubility and, hence, poor release properties. Both nanosuspensions and self-nanoemulsifying drug delivery systems (SNEDDS) are becoming nanotechnology techniques for the enhancement of water solubility of different drugs.

Experimental approach

The study's goal was to identify the best drug delivery system able to enhance the release and antihypertensive effect of DOX by comparing the physical characteristics such as particle size, zeta potential, entrapment efficiency, release rate, and main arterial blood pressure of DOX-loaded nanosuspensions and SNEDDS in liquid and solid form.

Key results

DOX nanosuspension preparation had a particle size of 385±13 nm, poly-dispersity index of 0.049±3, zeta potential of 50 ± 4 mV and drug release after 20 min (91±0.43 %). Liquid SNEDDS had a droplet size of 224±15 nm, poly-dispersity index of (0.470±0.01), zeta potential of -5±0.10 mV and DR20min of 93±4 %. Solid SEDDS showed particle size of 79±14 nm, poly-dispersity index of 1±0.00, a zeta potential of -18 ±0.26 mv and DR20min of 100 ±2.72 %.

Conclusion

Finally, in terms of the mean arterial blood pressure lowering, solid SNEDDS performed better effect than both liquid SNEDDS and nanosuspension (P >0.05).

Overview of Recent Advances in Nano-Based Ocular Drug Delivery

Ocular diseases profoundly impact patients' vision and overall quality of life globally. However, effective ocular drug delivery presents formidable challenges within clinical pharmacology and biomaterial science, primarily due to the intricate anatomical and physiological barriers unique to the eye. In this comprehensive review, we aim to shed light on the anatomical and physiological features of the eye, emphasizing the natural barriers it presents to drug administration. Our goal is to provide a thorough overview of various characteristics inherent to each nano-based drug delivery system. These encompass nanomicelles, nanoparticles, nanosuspensions, nanoemulsions, microemulsions, nanofibers, dendrimers, liposomes, niosomes, nanowafers, contact lenses, hydrogels, microneedles, and innovative gene therapy approaches employing nano-based ocular delivery techniques. We delve into the biology and methodology of these systems, introducing their clinical applications over the past decade. Furthermore, we discuss the advantages and challenges illuminated by recent studies. While nano-based drug delivery systems for ophthalmic formulations are gaining increasing attention, further research is imperative to address potential safety and toxicity concerns.

Glucose-conjugated glutenin nanoparticles for selective targeting and delivery of camptothecin into breast cancer cells

Receptor-mediated drug delivery systems are a promising tool for targeting malignant cells to suppress/inhibit the malignancy without disturbing healthy cells. Protein-based nanocarrier systems possess numerous advantages for the delivery of variety of chemotherapeutics, including therapeutic peptides and genes. In the present work, glucose-conjugated camptothecin-loaded glutenin nanoparticles (Glu-CPT-glutenin NPs) were fabricated to deliver camptothecin to MCF-7 cells via GLUT-1 transporter protein. Initially, Glu-conjugated glutenin polymer was successfully synthesized through reductive amination reaction, and this was confirmed by FTIR and 13C-NMR. Then, camptothecin (CPT) was loaded into Glu-conjugated glutenin polymer forming Glu-CPT-glutenin NPs. The nanoparticles were studied for their drug releasing capacity, morphological shape, size, physical nature, and zeta potential. The fabricated Glu-CPT-glutenin NPs were found to be spherical in shape and amorphous in nature with 200-nm size range and a zeta potential of - 30 mV. Furthermore, MTT assay using Glu-CPT-glutenin NPs confirmed concentration-dependent cytotoxicity against MCF-7 cells after 24-h treatment, and IC50 was found to be 18.23 μg mL-1. In vitro cellular uptake study demonstrated that the Glu-CPT-glutenin NPs had enhanced endocytosis and delivered CPT in MCF-7 cells. A typical apoptotic morphological change of condensed nuclei and distorted membrane bodies was found after treatment with IC50 concentration of NPs. The released CPT from NPs also targeted mitochondria of MCF-7 cells, significantly increasing the level of reactive oxygen species and causing the damage of mitochondrial membrane integrity. These outcomes confirmed that the wheat glutenin can positively serve as a significant delivery vehicle and enhance the anticancer potential of this drug.

Novel Meta-iodobenzylguanidine and Etoposide Complex: Physicochemical Characterization and Mathematical Modeling of Anticancer Activity

It is hypothesized that meta-iodobenzylguanidine (MIBG) complexation with etoposide (VP-16) will improve drug solubility and specificity towards BE(2)C neuroblastoma (NB) cells, 90% of which are known to be MIBG avid. After MIBG and VP-16 interaction, the dry complex was analyzed for crystalline structure, surface morphology, solubility, and size distribution by X-ray powder diffraction (P-XRD), scanning electron microscopy (SEM), infrared (FTIR) and UV spectroscopy, and dynamic light scattering. After exposure to the complex, the cell viability and decay rates were assessed by the MTS assay and estimated using exponential decay models (EDM). Multi-factorial ANOVA and an independent t-test were used to assess for cell viability and solubility data, respectively. The resulting (1: 3 w/w) VP-16: MIBG complex had a mean diameter and zeta potential of 458.5 nm and 0.951 mV, respectively. It dramatically increased the drug apparent water solubility (~ 12-folds). This was ascribed to the formation of a VP-16/MIBG nanocrystalline state mainly governed by cation-π interactions, evidenced by FTIR, SEM, and P-XRD data following the complexation. The EDM relating percent cell viability to drug concentration yielded an excellent fit (r2 > 0.95) and enabled to estimate the IC50 values of both native drug and its complex: 6.2 μM and 5.23 μM, respectively (indicating a conservation of drug anticancer activity). The statistical results were consistent with those of the exponential decay models, indicating that MIBG does not inhibit the anticancer activity of VP-16. This study indicates that the VP-16/MIBG complexation improves VP-16 solubility without antagonizing its anticancer activity. Moreover, the efficiency of the EDM for drug IC50 estimation provides alternative mathematical method for such in vitro cytotoxicity studies.

Formulation and Characterization of Ursodeoxycholic Acid Nanosuspension Based on Bottom-Up Technology and Box-Behnken Design Optimization

BACKGROUND

Ursodeoxycholic acid (UDCA) is a therapeutic agent used for the treatment of cholestatic hepatobiliary diseases in pediatric patients. It is a bile acid that presents high lipophilicity, and it belongs to Class II of the Biopharmaceutical Classification System (BCS), which exhibits low water solubility and high intestinal permeability, which leads to poor oral absorption. The objective of this work was to design and optimize UDCA nanosuspensions by means of the precipitation-ultrasonication method to improve the solubility, dissolution, and oral bioavailability of UDCA.

METHODS

A three-level, three-factor Box-Behnken design was used to optimize formulation variables and obtain uniform, small-particle-size UDCA nanosuspensions. The independent variables were: stabilizer percentage (X1), amplitude (X2), and sonication time (X3), and the dependent variable was the particle size (Y1). In the precipitation-ultrasonication method, UDCA was dissolved in acetone:PEG 400 (1:1 v/v) and quickly incorporated into the antisolvent (pre-cooled aqueous dispersion of HPMC E-15 0.3%), by means of intense sonication at 50 W for 5 min, controlling temperature through an ice water bath. The lyophilization efficacy was evaluated by means of a cryoprotective efficacy test, working with 10% maltose at -80 °C. The nanosuspensions were characterized by dynamic light scattering (DLS), X-ray diffraction, and scanning electron microscopy (SEM). The physicochemical stability was determined at 25 °C and 4 °C at 7, 14, 30, and 60 days, and the UDCA content was analyzed via HPLC-UV. An in vitro dissolution assay and an oral bioavailability study were performed in male Wistar rats.

RESULTS

A significant impact was achieved in the optimized nanosuspension with 0.3% (stabilizer), 50 W (amplitude), and 5 min (sonication time), with a particle size of 352.4 nm, PDI of 0.11, and zeta potential of -4.30 mV. It presented adequate physicochemical stability throughout the study and the UDCA content was between 90% and 110%. In total, 86% of UDCA was dissolved in the in vitro dissolution test. The relative oral bioavailability was similar without significant statistical differences when comparing the lyophilized nanosuspension and the commercial tablet, the latter presenting a more erratic behavior. The pharmacokinetic parameters of the nanosuspension and the commercial tablet were Tmax (1.0 ± 0.9 h vs. 2.0 ± 0.8 h, respectively), Cmax (0.558 ± 0.118 vs. 0.366 ± 0.113 µM, respectively), ΔCmax (0.309 ± 0.099 vs. 0.232 ± 0.056, respectively), AUC (4.326 ± 0.471 vs. 2.188 ± 0.353 µg/mL.h, respectively, p < 0.02), and IAUC0-24h (2.261 ± 0.187 µg/mL.h vs. 1.924 ± 0.440 µg/mL.h, respectively).

CONCLUSIONS

The developed nanosuspension presents an appropriate dosage and administration for pediatric patients. On the other hand, it exhibits an adequate absorption and UDCA oral bioavailability.

Nanotechnology-based ocular drug delivery systems: recent advances and future prospects

Ocular drug delivery has constantly challenged ophthalmologists and drug delivery scientists due to various anatomical and physiological barriers. Static and dynamic ocular barriers prevent the entry of exogenous substances and impede therapeutic agents' active absorption. This review elaborates on the anatomy of the eye and the associated constraints. Followed by an illustration of some common ocular diseases, including glaucoma and their current clinical therapies, emphasizing the significance of drug therapy in treating ocular diseases. Subsequently, advances in ocular drug delivery modalities, especially nanotechnology-based ocular drug delivery systems, are recommended, and some typical research is highlighted. Based on the related research, systematic and comprehensive characterizations of the nanocarriers are summarized, hoping to assist with future research. Besides, we summarize the nanotechnology-based ophthalmic drugs currently on the market or still in clinical trials and the recent patents of nanocarriers. Finally, inspired by current trends and therapeutic concepts, we provide an insight into the challenges faced by novel ocular drug delivery systems and further put forward directions for future research. We hope this review can provide inspiration and motivation for better design and development of novel ophthalmic formulations.

Developing Nanosuspension Loaded with Azelastine for Potential Nasal Drug Delivery: Determination of Proinflammatory Interleukin IL-4 mRNA Expression and Industrial Scale-Up Strategy

In order to increase bioavailability and intranasal absorbance, the current work set out to create azelastine nasal spray based on nanosuspension. Chondroitin was utilized as a polymer to prepare azelastine nanosuspension through the precipitation procedure. A size of 500 nm and a polydispersity index of 0.276 with a negative potential (-20 mV) were achieved. X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, thermal analysis including differential scanning calorimetry and thermogravimetric analysis, in vitro release, and diffusion studies were used to characterize the optimized nanosuspension. MTT assay was used to assess the viability of the cells, and hemolysis assay was used to assess the blood compatibility. Using RNA extraction and reverse transcription polymerase chain reaction, the levels of the anti-inflammatory cytokine IL-4, which is most closely related to cytokines in allergic rhinitis, were measured in mouse lungs. The drug dissolution and diffusion study indicated 2.0-fold increase compared to pure reference sample. Therefore, the azelastine nanosuspension could be suggested as a practical and simple nanosystem for intranasal delivery with improved permeability and bioavailability. The outcome obtained in this study indicated that azelastine nanosuspension has great potential to treat allergic rhinitis as intranasal treatment.

Intravenous nanocrystals: fabrication, solidification, in vivo fate, and applications for cancer therapy

INTRODUCTION

Intravenous nanocrystals (INCs) have shown intrinsic advantages in antitumor applications, particularly their properties of high drug loading, low toxicity, and controllable size. Therefore, it has a very bright application prospect as a drug delivery system.

AREAS COVERED

The ideal formulation design principles, fabrication, solidification, in vivo fate of INCs, the applications in drug delivery system (DDS) and the novel applications are covered in this review.

EXPERT OPINION

It is vital to select a suitable formulation and fabrication method to produce a stable and sterile INCs. Besides, the type of stabilizers and physical characteristics can also influence the in vivo fate of INCs, which is worthy of further studying. Based on wide researches about applications of INCs in cancer, biomimetic INCs are concerned increasingly for its favorable compatibility. The output of these studies suggested that INCs-based drug delivery could be a novel strategy for addressing the delivery of the drug that faces solubility, bioavailability, and toxicity problems.

The application of nanomedicine in clinical settings

As nanotechnology develops in the fields of mechanical engineering, electrical engineering, information and communication, and medical care, it has shown great promises. In recent years, medical nanorobots have made significant progress in terms of the selection of materials, fabrication methods, driving force sources, and clinical applications, such as nanomedicine. It involves bypassing biological tissues and delivering drugs directly to lesions and target cells using nanorobots, thus increasing concentration. It has also proved useful for monitoring disease progression, complementary diagnosis, and minimally invasive surgery. Also, we examine the development of nanomedicine and its applications in medicine, focusing on the use of nanomedicine in the treatment of various major diseases, including how they are generalized and how they are modified. The purpose of this review is to provide a summary and discussion of current research for the future development in nanomedicine.

Research progress on the preparation and application of flavonoid nanocrystals

Flavonoids have been reported to possess significant pharmacological activities,such as antioxidant, anti-inflammatory and anticancer effects. However, the low solubility and low bioavailability limits their clinical application. Nanocrystal technology can solve the delivery problems of flavonoids by reducing particle size, increasing the solubility of insoluble drugs and improving their bioavailability. This article summaries nanosuspension preparation methods and the stabilizers for flavonoid nanocrystals, and reviews the drug delivery routes including oral, Injection and transdermal of flavonoid nanocrystals, to provide information for further research on nanocrystal delivery system of flavonoids.

A study on puerarin in situ gel eye drops: Formulation optimization and pharmacokinetics on rabbits by microdialysis

Puerarin (PUE), an isoflavonoid isolated from Pueraria lobata (Willd) Ohwi root, is a β-adrenergic receptor inhibitor used in treating glaucoma. The concentration range of gellan gum was determined based on the formulation viscosity and gelling capacity. PVP-K30 and gellan gum were used as variables, with the viscosity of formulation: STF = 40: 21, the 4 h permeation rate of rabbit isolated sclera, and 2 h in vitro release rate as response values. The JMP software was used to optimize the results, presenting that gellan gum was the main factor influencing viscosity. The in vitro release and permeation rate were primarily influenced by PVP-K30. The optimal prescription was 0.45% gellan gum and 6.0% PVP-K30. The in vitro release and permeation characteristics of puerarin in situ gel (PUE-ISG) were investigated using PUE solution as a control. The dialysis bag method results indicated that the release of the solution group leveled off after 4 h, while the PUE-ISG group had been continuously releasing. However, the cumulative release rates of the two were no longer significantly different at 10 h. The cumulative permeation rates of the ISG and solution groups were not significantly different (P > 0.05) in the rabbit isolated sclera. The apparent permeability Papp and steady-state flux Jss of PUE-ISG were 0.950 ± 0.059 cm·h^-1 and 9.504 ± 0.587 mg·cm^-2·h^-1, respectively. A sensitive and stable HPLC-MS/MS analytical method for quantifying aqueous humor concentrations of PUE was validated. A microdialysis technique was successfully used in the aqueous humor pharmacokinetics study to sample aqueous humor from rabbit eye continuously. The results revealed that PUE-ISG significantly increased the drug concentration in the aqueous humor, with C_max and AUC_(0-t) 3.77 and 4.40 times higher than those of the solution group, respectively. T_max was also significantly prolonged, indicating good prospects for clinical application. The developed PUE-ISG preparation has the characteristics of rapid drug release and sustained permeation, and increase the drug concentration in aqueous humor, with all inactive ingredients remaining within the maximum allowable limits recommended by the FDA guideline.

Nanocarriers for ocular drug delivery: Recent advances and future opportunities

Topical route of administration is very important and the most commonly used method of drug delivery for treatment of ocular diseases. However, due to unique anatomical and physiological barriers of eye, it is difficult to achieve the therapeutic concentration in the targeted tissue within the eye. To overcome the effect of these barriers in absorption and to provide targeted and sustained drug delivery, various advances have been made in developing safe and efficient drug delivery systems. Various formulation strategies for ocular drug delivery are used, like basic formulation techniques for improving availability of drugs, viscosity enhancers, and use of mucoadhesives for drug retention and penetration enhancers to promote drug transport to the eye. In this review, we present a summary of the current literature to understand the anatomical and physiological limitations in achieving adequate ocular bioavailability and targeted drug delivery of topically applied drugs and use of new techniques in formulating dosage forms in overcoming these limitations. The recent and future advances in nanocarrier-mediated drug delivery may have the potential to provide patient-friendly and noninvasive techniques for the treatment of diseases related to the anterior and posterior segments of the eye.

Three Dimensional Printing and Its Applications Focusing on Microneedles for Drug Delivery

Microneedles (MNs) are considered to be a novel smart injection system that causes significantly low skin invasion upon puncturing, due to the micron-sized dimensions that pierce into the skin painlessly. This allows transdermal delivery of numerous therapeutic molecules, such as insulin and vaccines. The fabrication of MNs is carried out through conventional old methods such as molding, as well as through newer and more sophisticated technologies, such as three-dimensional (3D) printing, which is considered to be a superior, more accurate, and more time- and production-efficient method than conventional methods. Three-dimensional printing is becoming an innovative method that is used in education through building intricate models, as well as being employed in the synthesis of fabrics, medical devices, medical implants, and orthoses/prostheses. Moreover, it has revolutionary applications in the pharmaceutical, cosmeceutical, and medical fields. Having the capacity to design patient-tailored devices according to their dimensions, along with specified dosage forms, has allowed 3D printing to stand out in the medical field. The different techniques of 3D printing allow for the production of many types of needles with different materials, such as hollow MNs and solid MNs. This review covers the benefits and drawbacks of 3D printing, methods used in 3D printing, types of 3D-printed MNs, characterization of 3D-printed MNs, general applications of 3D printing, and transdermal delivery using 3D-printed MNs.

Impact of nanotechnology on the oral delivery of phyto-bioactive compounds

Nanotechnology is an advanced field that has remarkable nutraceutical and food applications. Phyto-bioactive compounds (PBCs) play critical roles in promoting health and disease treatment. However, PBCs generally encounter several limitations that delay their widespread application. For example, most PBCs have low aqueous solubility, poor biostability, poor bioavailability, and a lack of target specificity. Moreover, the high concentrations of effective PBC doses also limit their application. As a result, encapsulating PBCs into an appropriate nanocarrier may increase their solubility and biostability and protect them from premature degradation. Moreover, nanoencapsulation could improve absorption and prolong circulation with a high opportunity for targeted delivery that may decrease unwanted toxicity. This review addresses the main parameters, variables, and barriers that control and affect oral PBC delivery. Moreover, this review discusses the potential role of biocompatible and biodegradable nanocarriers in improving the water solubility, chemical stability, bioavailability, and specificity/selectivity of PBCs.

Formulation Strategies of Nanosuspensions for Various Administration Routes

Nanosuspensions (NSs), which are nanosized colloidal particle systems, have recently become one of the most interesting substances in nanopharmaceuticals. NSs have high commercial potential because they provide the enhanced solubility and dissolution of low-water-soluble drugs by means of their small particle sizes and large surface areas. In addition, they can alter the pharmacokinetics of the drug and, thus, improve its efficacy and safety. These advantages can be used to enhance the bioavailability of poorly soluble drugs in oral, dermal, parenteral, pulmonary, ocular, or nasal routes for systemic or local effects. Although NSs often consist mainly of pure drugs in aqueous media, they can also contain stabilizers, organic solvents, surfactants, co-surfactants, cryoprotectants, osmogents, and other components. The selection of stabilizer types, such as surfactants or/and polymers, and their ratio are the most critical factors in NS formulations. NSs can be prepared both with top-down methods (wet milling, dry milling, high-pressure homogenization, and co-grinding) and with bottom-up methods (anti-solvent precipitation, liquid emulsion, and sono-precipitation) by research laboratories and pharmaceutical professionals. Nowadays, techniques combining these two technologies are also frequently encountered. NSs can be presented to patients in liquid dosage forms, or post-production processes (freeze drying, spray drying, or spray freezing) can also be applied to transform the liquid state into the solid state for the preparation of different dosage forms such as powders, pellets, tablets, capsules, films, or gels. Thus, in the development of NS formulations, the components/amounts, preparation methods, process parameters/levels, administration routes, and dosage forms must be defined. Moreover, those factors that are the most effective for the intended use should be determined and optimized. This review discusses the effect of the formulation and process parameters on the properties of NSs and highlights the recent advances, novel strategies, and practical considerations relevant to the application of NSs to various administration routes.

Biochemical, structural characterization and in-vitro evaluation of antioxidant, antibacterial, cytotoxic, and antidiabetic activities of nanosuspensions of Cinnamomum zeylanicum bark extract

Cinnamomum zeylanicum is a traditional medicinal plant known for its anti-inflammatory, antidiabetic, antimicrobial, anticancer, and antioxidant properties. Its therapeutic efficacy using nanosuspensions is still unclear for treating infectious diseases. This study was designed to evaluate the bioactivities, biochemical characterization, and bioavailability of freshly prepared nanosuspensions of C. zeylanicum. Structural and biochemical characterization of C. zeylanicum and its biological activities, such as antioxidants, antimicrobials, antiglycation, α-amylase inhibition, and cytotoxicity was performed using Fourier-transform infrared (FTIR) spectroscopy and High-Performance Liquid Chromatography (HPLC). C. zeylanicum extract and nanosuspensions showed TPCs values of 341.88 and 39.51 mg GAE/100 g while showing TFCs as 429.19 and 239.26 mg CE/100g, respectively. DPPH inhibition potential of C. zeylanicum extract and nanosuspension was 27.3% and 10.6%, respectively. Biofilm inhibition activity revealed that bark extract and nanosuspension showed excessive growth restraint against Escherichia coli, reaching 67.11% and 66.09%, respectively. The α-amylase inhibition assay of extract and nanosuspension was 39.3% and 6.3%, while the antiglycation activity of nanosuspension and extract was 42.14% and 53.76%, respectively. Extracts and nanosuspensions showed maximum hemolysis at 54.78% and 19.89%, respectively. Results indicated that nanosuspensions possessed antidiabetic, antimicrobial, anticancer, and antioxidant properties. Further study, however, is needed to assess the clinical studies for the therapeutic use of nanosuspensions.

Advancement in Solubilization Approaches: A Step towards Bioavailability Enhancement of Poorly Soluble Drugs

A drug's aqueous solubility is defined as the ability to dissolve in a particular solvent, and it is currently a major hurdle in bringing new drug molecules to the market. According to some estimates, up to 40% of commercialized products and 70-90% of drug candidates in the development stage are poorly soluble, which results in low bioavailability, diminished therapeutic effects, and dosage escalation. Because of this, solubility must be taken into consideration when developing and fabricating pharmaceutical products. To date, a number of approaches have been investigated to address the problem of poor solubility. This review article attempts to summarize several conventional methods utilized to increase the solubility of poorly soluble drugs. These methods include the principles of physical and chemical approaches such as particle size reduction, solid dispersion, supercritical fluid technology, cryogenic technology, inclusion complex formation techniques, and floating granules. It includes structural modification (i.e., prodrug, salt formation, co-crystallization, use of co-solvents, hydrotrophy, polymorphs, amorphous solid dispersions, and pH variation). Various nanotechnological approaches such as liposomes, nanoparticles, dendrimers, micelles, metal organic frameworks, nanogels, nanoemulsions, nanosuspension, carbon nanotubes, and so forth have also been widely investigated for solubility enhancement. All these approaches have brought forward the enhancement of the bioavailability of orally administered drugs by improving the solubility of poorly water-soluble drugs. However, the solubility issues have not been completely resolved, owing to several challenges associated with current approaches, such as reproducibility in large scale production. Considering that there is no universal approach for solving solubility issues, more research is needed to simplify the existing technologies, which could increase the number of commercially available products employing these techniques.

Superior possibilities and upcoming horizons for nanoscience in COVID-19: noteworthy approach for effective diagnostics and management of SARS-CoV-2 outbreak

The outbreak of COVID-19 has caused great havoc and affected many parts of the world. It has imposed a great challenge to the medical and health fraternity with its ability to continue mutating and increasing the transmission rate. Some challenges include the availability of current knowledge of active drugs against the virus, mode of delivery of the medicaments, its diagnosis, which are relatively limited and do not suffice for further prognosis. One recently developed drug delivery system called nanoparticles is currently being utilized in combating COVID-19. This article highlights the existing methods for diagnosis of COVID-19 such as computed tomography scan, reverse transcription-polymerase chain reaction, nucleic acid sequencing, immunoassay, point-of-care test, detection from breath, nanotechnology-based bio-sensors, viral antigen detection, microfluidic device, magnetic nanosensor, magnetic resonance platform and internet-of-things biosensors. The latest detection strategy based on nanotechnology, biosensor, is said to produce satisfactory results in recognizing SARS-CoV-2 virus. It also highlights the successes in the research and development of COVID-19 treatments and vaccines that are already in use. In addition, there are a number of nanovaccines and nanomedicines currently in clinical trials that have the potential to target COVID-19.

Overcoming Treatment Challenges in Posterior Segment Diseases with Biodegradable Nano-Based Drug Delivery Systems

Posterior segment eye diseases present a challenge in treatment due to the complex structures in the eye that serve as robust static and dynamic barriers, limiting the penetration, residence time, and bioavailability of topical and intraocular medications. This hinders effective treatment and requires frequent dosing, such as the regular use of eye drops or visits to the ophthalmologist for intravitreal injections, to manage the disease. Moreover, the drugs must be biodegradable to minimize toxicity and adverse reactions, as well as small enough to not affect the visual axis. The development of biodegradable nano-based drug delivery systems (DDSs) can be the solution to these challenges. First, they can stay in ocular tissues for longer periods of time, reducing the frequency of drug administration. Second, they can pass through ocular barriers, offering higher bioavailability to targeted tissues that are otherwise inaccessible. Third, they can be made up of polymers that are biodegradable and nanosized. Hence, therapeutic innovations in biodegradable nanosized DDS have been widely explored for ophthalmic drug delivery applications. In this review, we will present a concise overview of DDSs utilized in the treatment of ocular diseases. We will then examine the current therapeutic challenges faced in the management of posterior segment diseases and explore how various types of biodegradable nanocarriers can enhance our therapeutic arsenal. A literature review of the pre-clinical and clinical studies published between 2017 and 2023 was conducted. Through the advances in biodegradable materials, combined with a better understanding of ocular pharmacology, the nano-based DDSs have rapidly evolved, showing great promise to overcome challenges currently encountered by clinicians.

Nanomedicine strategies to improve therapeutic agents for the prevention and treatment of preterm birth and future directions

The World Health Organisation (WHO) estimates 15 million babies worldwide are born preterm each year, with 1 million infant mortalities and long-term morbidity in survivors. Whilst the past 40 years have provided some understanding in the causes of preterm birth, along with development of a range of therapeutic options, notably prophylactic use of progesterone or uterine contraction suppressants (tocolytics), the number of preterm births continues to rise. Existing therapeutics used to control uterine contractions are restricted in their clinical use due to pharmacological drawbacks such as poor potency, transfer of drugs to the fetus across the placenta and maternal side effects from activity in other maternal systems. This review focuses on addressing the urgent need for the development of alternative therapeutic systems with improved efficacy and safety for the treatment of preterm birth. We discuss the application of nanomedicine as a viable opportunity to engineer pre-existing tocolytic agents and progestogens into nanoformulations, to improve their efficacy and address current drawbacks to their use. We review different nanomedicines including liposomes, lipid-based carriers, polymers and nanosuspensions highlighting where possible, where these technologies have already been exploited e.g. liposomes, and their significance in improving the properties of pre-existing therapeutic agents within the field of obstetrics. We also highlight where active pharmaceutical agents (APIs) with tocolytic properties have been used for other clinical indications and how these could inform the design of future therapeutics or be repurposed to diversify their application such as for use in preterm birth. Finally we outline and discuss the future challenges.

Physical stability and dissolution of ketoprofen nanosuspension formulation: Polyvinylpyrrolidone and Tween 80 as stabilizers

This study was conducted to improve the dissolution of ketoprofen in nanosuspensions. Ketoprofen nanosuspensions were prepared by a solvent evaporation method using polyvinylpyrrolidone (PVP) and Tween 80 as stabilizers at varied ratios with ketoprofen. Ethanol was used as a solvent for ketoprofen. Physical stability and dissolution of the produced ketoprofen nanosuspensions and conventional suspension were analyzed and compared. The parameters evaluated for their stability for a three-month period were pH, appearance, odor, color, particle size, zeta potential, polydispersity index (PI), and dissolution compared with ketoprofen suspension. Ketoprofen and PVP ratios of 1:1 and 1:1.5 had nano-scale particle sizes of 78.47±0.61 and 156.9±1.55, respectively. These nanosuspensions had stable pH, appearance, odor, color, particle size, and PI at room temperature. The dissolution rates of ketoprofen nanosuspensions were higher compared to that of ketoprofen conventional suspension. PVP and Tween 80 improved ketoprofen nanosuspension dissolution and was stable at room temperature for three months.

Breaking Barriers in Eye Treatment: Polymeric Nano-Based Drug-Delivery System for Anterior Segment Diseases and Glaucoma

The eye has anatomical structures that function as robust static and dynamic barriers, limiting the penetration, residence time, and bioavailability of medications administered topically. The development of polymeric nano-based drug-delivery systems (DDS) could be the solution to these challenges: it can pass through ocular barriers, offering higher bioavailability of administered drugs to targeted tissues that are otherwise inaccessible; it can stay in ocular tissues for longer periods of time, requiring fewer drug administrations; and it can be made up of polymers that are biodegradable and nano-sized, minimizing the undesirable effects of the administered molecules. Therefore, therapeutic innovations in polymeric nano-based DDS have been widely explored for ophthalmic drug-delivery applications. In this review, we will give a comprehensive overview of polymeric nano-based drug-delivery systems (DDS) used in the treatment of ocular diseases. We will then examine the current therapeutic challenges of various ocular diseases and analyze how different types of biopolymers can potentially enhance our therapeutic options. A literature review of the preclinical and clinical studies published between 2017 and 2022 was conducted. Thanks to the advances in polymer science, the ocular DDS has rapidly evolved, showing great promise to help clinicians better manage patients.