Renewable poly(δ-decalactone) based block copolymer micelles as drug delivery vehicle: in vitro and in vivo evaluation

Attenuation of celecoxib cardiac toxicity using Poly(δ-decalactone) based nanoemulsion via oral route

Celecoxib (CLX), a poorly soluble anti-inflammatory drug, requires administration in higher concentrations to produce therapeutic effects, oftentimes resulting in cardiac toxicity. Therefore, in this study, we employed a nanoemulsion technology to improve the solubility of CLX using poly(δ-decalactone) (PDL) polymer as an oil and mPEG-b-PDL as a surfactant. The nanoemulsion (NE) was successfully prepared via the nanoprecipitation method. In vitro characterization was performed for size, drug release, and stability. In vivo studies were performed to establish anti-inflammatory activity, CLX induced cardiac toxicity, and pharmacokinetic profile of NE, post-oral administration. The globular size of less than 100 nm was obtained in NE with high CLX loading. The in vitro drug release studies suggested ∼90% of CLX release from NE within 96 h. A significant anti-inflammatory activity with lowered cardiac marker values was observed for CLX NE compared to a marketed drug formulation. The pharmacokinetic study revealed that the mean retention time of CLX was significantly increased with NE in contrast to the marketed formulation, suggesting the advantage of administering CLX in the form of NE owing to the higher solubility and sustained release pattern. The long-term storage stability study reveals that NE does not show significant changes in terms of size with only a slight decrement in CLX content was observed after 24 months. The obtained results indicate that CLX bioavailability has been considerably improved without being toxic to the heart with the aid of NE and advocate the use of PDL NE for developing oral formulations for poorly soluble drugs.

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.

Exploring the potential of antimalarial nanocarriers as a novel therapeutic approach

Malaria is a life-threatening parasitic disease that affects millions of people worldwide, especially in developing countries. Despite advances in conventional therapies, drug resistance in malaria parasites has become a significant concern. Hence, there is a need for a new therapeutic approach. To combat the disease effectively means eliminating vectors and discovering potent treatments. The nanotechnology research efforts in nanomedicine show promise by exploring the potential use of nanomaterials that can surmount these limitations occurring with antimalarial drugs, which include multidrug resistance or lack of specificity when targeting parasites directly. Utilizing nanomaterials would possess unique advantages over conventional chemotherapy systems by increasing the efficacy levels while reducing side effects significantly by delivering medications precisely within the diseased area. It also provides cheap yet safe measures against Malaria infections worldwide-ultimately improving treatment efficiency holistically without reinventing new methods therapeutically. This review is an effort to provide an overview of the various stages of malaria parasites, pathogenesis, and conventional therapies, as well as the treatment gap existing with available formulations. It explores different types of nanocarriers, such as liposomes, ethosomal cataplasm, solid lipid nanoparticles, nanostructured lipid carriers, polymeric nanocarriers, and metallic nanoparticles, which are frequently employed to boost the efficiency of antimalarial drugs to overcome the challenges and develop effective and safe therapies. The study also highlights the improved pharmacokinetics, enhanced drug bioavailability, and reduced toxicity associated with nanocarriers, making them a promising therapeutic approach for treating malaria.

Recent Progress in Aptamer-Functionalized Metal-Organic Frameworks-Based Optical and Electrochemical Sensors for Detection of Mycotoxins

Mycotoxin contamination in foodstuffs and agricultural products has posed a serious hazard to human health and raised international concern. The progress of cost-effective, facile, rapid and reliable analytical tools for mycotoxin determination is in urgent need. In this regard, the potential utility of metal-organic frameworks (MOFs) as a class of crystalline porous materials has sparked immense attention due to their large specific surface area, adjustable pore size, nanoscale framework structure and good chemical stability. The amalgamation of MOFs with high-affinity aptamers has resulted in the progress of advanced aptasensing methods for clinical and food/water safety diagnosis. Aptamers have many advantages over classical approaches as exceptional molecular recognition constituents for versatile bioassays tools. The excellent sensitivity and selectivity of the MOF-aptamer biocomposite nominate them as efficient lab-on-chip tools for portable, label-free, cost-effective and real-time screening of mycotoxins. Current breakthroughs in the concept, progress and biosensing applications of aptamer functionalized MOFs-derived electrochemical and optical sensors for mycotoxins have been discussed in this study. We first highlighted an overview part, which provides some insights into the functionalization mechanisms of MOFs with aptamers, offering a foundation to create MOFs-based aptasensors. Then, we discuss various strategies to design high-performance MOFs-based aptamer scaffolds, which serve as either signal nanoprobe carriers or signal nanoprobes and their applications. We perceived that applications of optical aptamers are in their infancy in comparison with electrochemical MOFs-derived aptasensors. Finally, current challenges and prospective trends of MOFs-aptamer sensors are discussed.

Functional block copolymer micelles based on poly (jasmine lactone) for improving the loading efficiency of weakly basic drugs

Functionalization of polymers is an attractive approach to introduce specific molecular forces that can enhance drug–polymer interaction to achieve higher drug loading when used as drug delivery systems. The novel amphiphilic block copolymer of methoxy poly(ethylene glycol) and poly(jasmine lactone) i.e., mPEG-b-PJL, derived from renewable jasmine lactone provides free allyl groups on the backbone thus, allowing flexible and facile post-synthesis functionalization. In this study, mPEG-b-PJL and its carboxyl functionalized polymer mPEG-b-PJL-COOH were utilised to explore the effect of ionic interactions on the drug–polymer behaviour. Various drugs with different pK_a values were employed to prepare drug-loaded polymeric micelles (PMs) of mPEG-b-PJL, mPEG-b-PJL-COOH and Soluplus® (polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer) via a nanoprecipitation method. Electrostatic interactions between the COOH pendant on mPEG-b-PJL-COOH and the basic drugs were shown to influence the entrapment efficiency. Additionally, molecular dynamics (MD) simulations were employed to understand the polymer–drug interactions at the molecular level and how polymer functionalization influenced these interactions. The release kinetics of the anti-cancer drug sunitinib from mPEG-b-PJL and mPEG-b-PJL-COOH was assessed, and it demonstrated a sustainable drug release pattern, which depended on both pH and temperature. Furthermore, the cytotoxicity of sunitinib-loaded micelles on cancer cells was evaluated. The drug-loaded micelles exhibited dose-dependent toxicity. Also, haemolysis capacity of these polymers was investigated. In summary, polymer functionalization seems a promising approach to overcome challenges that hinder the application of polymer-based drug delivery systems such as low drug loading degree.

Block copolymer micelles with a functional core have been synthesized and evaluated for their drug delivery capability. High drug loading was observed due to strong ionic interactions, while cytotoxicity of polymers was found to be low.

Synthesis of copolyesters based on substituted and non-substituted lactones towards the control of their crystallinity and their potential effect on hydrolytic degradation in the design of soft medical devices

ROP synthesis of polyesters at different molar ratios of monomers ε-caprolactone (ε-CL) in combination with alkyl substituted lactones δ-decalactone (δ-DL), ε-decalactone (ε-DL) and δ-dodecalactone (δ-DD), as well copolymers based on ε-DL and δ-DD.

Combined Ultrasound Treatment with Transferrin-Coupled Nanoparticles Improves Active Targeting of 4T1 Mammary Carcinoma Cells

Objective: Conventional chemotherapy remains the mainstay treatment for many breast cancer patients, but its effectiveness is limited by toxic side effects. Incorporating drugs such as docetaxel into nanoparticle medicines can reduce toxicity but further improvements are required. To facilitate more active tumor targeting, we prepared transferrin-docetaxel-loaded pegylated-albumin nanoparticles (Tf-PEG-DANPS). Methods: The growth inhibitory effects and the ability of unmodified DANPS or PEG-DANPS to induce apoptosis in 4T1 mouse mammary cancers were compared to Tf-PEG-DANPS treatment using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry. These experiments were extended in vivo to the intravenous treatment of 4T1 tumors where PEG-DANPS was compared to Tf-PEG-DANPS alone or Tf-PEG-DANPS combined with ultrasound (US + Tf-PEG-DANPS). Histological assessments using hematoxylin and eosin (HE) sections were performed to examine antitumor activity, metastasis to lung and liver, and body weight measurements taken as an indicator of toxicity. Results: MTT experiments show that, in the normal and low concentration interval, the inhibition ability of the Tf-PEG-DANPS is higher than that of other drug-giving groups, and the flow cytometry show that the proportion of induced apoptosis in each given group is 2.88%, 42.95%, 48.23%, and 57.89%, indicating that the Tf-PEG-DANPS group has more significant ability to induce apoptosis than other drug-giving groups. From the pathological HE staining and semiquantitative analysis, US+Tf-PEG-DANPS can effectively inhibit the growth of breast cancer transplanted tumors and suppress metastases, it also has smaller toxic side effects on mice. Conclusion: The antitumor effect of US+Tf-PEG-DANPS represents an effective combination that exhibits increased antitumor activity and metastasis reduction with an improved side-effect profile.

Local drug delivery systems for inflammatory diseases: Status quo, challenges, and opportunities

Inflammation that is not resolved in due course becomes a chronic disease. The treatment of chronic inflammatory diseases involves a long-term use of anti-inflammatory drugs such as corticosteroids and nonsteroidal anti-inflammatory drugs, often accompanied by dose-dependent side effects. Local drug delivery systems have been widely explored to reduce their off-target side effects and the medication frequency, with several products making to the market or in development over the years. However, numerous challenges remain, and drug delivery technology is underutilized in some applications. This review showcases local drug delivery systems in different inflammatory diseases, including the targets well-known to drug delivery scientists (e.g., joints, eyes, and teeth) and other applications with untapped opportunities (e.g., sinus, bladder, and colon). In each section, we start with a brief description of the disease and commonly used therapy, introduce local drug delivery systems currently on the market or in the development stage, focusing on polymeric systems, and discuss the remaining challenges and opportunities in future product development.

Assessment of Intracellular Delivery Potential of Novel Sustainable Poly(δ-decalactone)-Based Micelles

Biodegradable polymers from renewable resources have attracted much attention in recent years within the biomedical field. Lately, poly(δ-decalactone) based copolymer micelles have emerged as a potential drug delivery carrier material as a sustainable alternative to fossil-based polymers. However, their intracellular drug delivery potential is not yet investigated and therefore, in this work, we report on the synthesis and cellular uptake efficiency of poly(δ-decalactone) based micelles with or without a targeting ligand. Folic acid was chosen as a model targeting ligand and Rhodamine B as a fluorescent tracer to demonstrate the straightforward functionalisation aspect of copolymers. The synthesis of block copolymers was accomplished by a combination of facile ring-opening polymerisation and click chemistry to retain the structure uniformity. The presence of folic acid on the surface of micelles with diameter ~150 nm upsurge the uptake efficiency by 1.6 fold on folate receptor overexpressing MDA-MB-231 cells indicating the attainment of targeting using ligand functionality. The drug delivery capability of these carriers was ascertained by using docetaxel as a model drug, whereby the in vitro cytotoxicity of the drug was significantly increased after incorporation in micelles 48 h post incubation. We have also investigated the possible endocytosis route of non-targeted micelles and found that caveolae-mediated endocytosis was the preferred route of uptake. This work strengthens the prospect of using novel bio-based poly(δ-decalactone) micelles as efficient multifunctional drug delivery nanocarriers towards medical applications.

Novel Intranasal Drug Delivery: Geraniol Charged Polymeric Mixed Micelles for Targeting Cerebral Insult as a Result of Ischaemia/Reperfusion

Brain damage caused by cerebral ischaemia/reperfusion (I/R) can lead to handicapping. So, the present study aims to evaluate the prophylactic and therapeutic effects of geraniol in the form of intranasal polymeric mixed micelle (PMM) on the central nervous system in cerebral ischaemia/reperfusion (I/R) injury. A 3² factorial design was used to prepare and optimize geraniol PMM to investigate polymer and stabilizer different concentrations on particle size (PS) and percent entrapment efficiency (%EE). F3 possessing the highest desirability value (0.96), with a PS value of 32.46  ±  0.64 nm, EE of 97.85  ±  1.90%, and release efficiency of 59.66  ±  0.64%, was selected for further pharmacological and histopathological studies. In the prophylactic study, animals were classified into a sham-operated group, a positive control group for which I/R was done without treatment, and treated groups that received vehicle (plain micelles), geraniol oil, and geraniol micelles intranasally before and after I/R. In the therapeutic study, treated rats received geraniol oil and micelles after I/R. Evaluation of the effect of geraniol on behavior was done by activity cage and rotarod and the analgesic effect tested by hot plate. Anti-inflammatory activity was assessed by measuring interleukin β6, cyclooxygenase-2, hydrogen peroxide, and inducible nitric oxide synthase. Histopathogical examination of cerebral cortices was also done to confirm the results of a biochemical assay. Geraniol nanostructured polymeric mixed micelles showed an enhanced neuro-protective effect compared to geraniol oil, confirming that PMM via intranasal route could be an efficient approach for delivering geraniol directly to the brain through crossing the blood-brain barrier.

Nanodrug Delivery Systems for the Treatment of Ovarian Cancer

Despite advances achieved in medicine, chemotherapeutics still has detrimental side effects with ovarian cancer (OC), accounting for numerous deaths among females. The provision of safe, early detection and active treatment of OC remains a challenge, in spite of improvements in new antineoplastic discovery. Nanosystems have shown remarkable progress with impact in diagnosis and chemotherapy of various cancers, due to their ideal size; improved drug encapsulation within its interior core; potential to minimize drug degradation; improve in vivo drug release kinetics; and prolong blood circulation times. However, nanodrug delivery systems have few limitations regarding its accuracy of tumour targeting and the ability to provide sustained drug release. Hence, a cogent and strategic approach has focused on nanosystem functionalization with antibody-based ligands to selectively enhance cellular uptake of antineoplastics. Antibody functionalized nanosystems are (advanced) synthetic candidates, with a broad range of efficiency in specific tumour targeting, whilst leaving normal cells unaffected. This article comprehensively reviews the present status of nanosystems, with particular emphasis on nanomicelles for molecular diagnosis and treatment of OC. In addition, biomarkers of nanosystems provide important prospects as chemotherapeutic strategies to upsurge the survival rate of patients with OC.

Organocatalyzed ring opening polymerization of regio-isomeric lactones: reactivity and thermodynamics considerations

Study of the kinetics and thermodynamics of the organocatalyzed ring opening polymerization of a regio-isomeric mixture of β,δ-trimethyl-ε-caprolactones (TMCL).

Facile methodology of nanoemulsion preparation using oily polymer for the delivery of poorly soluble drugs

Aqueous solubility of an active pharmaceutical ingredient (API) is a determining factor that has a direct impact on formulation strategies and overall bioavailability. Fabrication of nanoemulsions of poorly soluble drugs is one of the widely utilized approaches to overcome this problem. However, thermodynamic instability and tedious manufacturing processes of nanoemulsions limit their clinical translation. Therefore, this study was focused on circumventing the abovementioned hurdles by utilizing the polymer as an oil phase, instead of conventional oils. The nanoemulsion was prepared via a facile low-energy nanoprecipitation method using renewable poly(δ-decalactone) (PDL), as an oil phase and Pluronic F-68 as surfactant. The prepared nanoemulsions were characterized in terms of size, drug encapsulation efficiency, stability, and toxicity. Five different hydrophobic drugs were utilized to evaluate the drug delivery capability of the PDL nanoemulsion. The prepared nanoemulsions with sizes less than 200 nm were capable to enhance the aqueous solubility of the drugs by 3 to 10 times compared with the well-established Pluronic F-68 micelles. No phase separation or significant changes in size and drug content was observed with PDL nanoemulsions after high-speed centrifugation and 3 months of storage at two different temperatures (20 °C and 50 °C). PDL nanoemulsions were found to be non-heamolytic up to concentrations of 1 mg/mL, and the cell cytotoxicity studies on MDA-MB-231 and MEF cells suggest a concentration and time-dependent toxicity, where the PDL polymer itself induced no cytotoxicity. The results from this study clearly indicate that the PDL polymer has a tremendous potential to be utilized as an oil phase to prepare stable nanoemulsions via a facile methodology, ultimately favouring clinical translations.

Graphical abstract

Triamcinolone acetonide-loaded PLA/PEG-PDL microparticles for effective intra-articular delivery: synthesis, optimization, in vitro and in vivo evaluation

Nowadays the use of sustainable polymers as poly-lactic acid (PLA) and poly-δ-decalactone (PDL) in drug delivery is advantageous compared to polymers derived from fossil fuels. The present work aimed to produce microparticles (MPs) derived from novel sustainable polymers, loaded with triamcinolone acetonide (TA) for treatment of rheumatoid arthritis via intra-articular (IA) delivery. PDL was synthesized from green δ-decalactone monomers and co-polymerized with methoxy-polyethylene glycol (mPEG) forming PEG-PDL with different molecular weights. The Hansen's solubility parameters were applied to select the most compatible polymer with the drug. An o/w emulsion/solvent evaporation technique was used for MPs fabrication, using 3 [3] full factorial design. Selection of the optimized MPs was performed using Expert Design® software's desirability function. The optimized formulations were characterized using scanning electron microscope, powder X-ray diffraction, differential scanning calorimetry, infrared spectroscopy and in vitro release studies. The inhibition percents of inflammation and histopathological studies were assessed in complete Freund's adjuvant-induced rats' knee joints evaluating the effect of IA injections of selected MPs compared to the free drug suspension. Solubility studies revealed high compatibility and miscibility between TA and PEG-PDL₁₇₀₀, which was blended with PLA for convenient MPs formation. The in vitro characterization studies confirmed the formation of drug-copolymer co-crystals. The in vivo studies ensured the superiority of the newly designed composite MPs in inflammation suppression, compared to the free drug suspension and PLA MPs as well. The present study proved the advantage of using sustainable polymers in a novel combination for effective drug delivery and suggesting its usefulness in designing versatile platforms for therapeutic applications.

Solid Lipid Nanoparticles: Emerging Colloidal Nano Drug Delivery Systems

Solid lipid nanoparticles (SLNs) are nanocarriers developed as substitute colloidal drug delivery systems parallel to liposomes, lipid emulsions, polymeric nanoparticles, and so forth. Owing to their unique size dependent properties and ability to incorporate drugs, SLNs present an opportunity to build up new therapeutic prototypes for drug delivery and targeting. SLNs hold great potential for attaining the goal of targeted and controlled drug delivery, which currently draws the interest of researchers worldwide. The present review sheds light on different aspects of SLNs including fabrication and characterization techniques, formulation variables, routes of administration, surface modifications, toxicity, and biomedical applications.