Nanocrystals of Poorly Soluble Drugs: Drug Bioavailability and Physicochemical Stability

Pharmaceutical nanoparticle isolation using CO2-assisted dynamic bed coating

Poor solubility of new chemical entities (NCEs) is a major bottleneck in the pharmaceutical industry which typically leads to poor drug bioavailability and efficacy. Nanotechnologies offer an interesting route to improve the apparent solubility and dissolution rate of pharmaceutical drugs, and processes such as nano-spray drying and supercritical CO₂-assisted spray drying (SASD) provide a route to engineer and produce solid drug nanoparticles. However, dried nanoparticles often show poor rheological properties (e.g. flowability, tabletability) and their isolation using these methods is typically inefficient and leads to poor collection yields. The work presented herein demonstrates a novel production and isolation method for drug nanoparticles using a 'top spray dynamic bed coating' process, which uses CO₂ spray as the fluidizing gas. Nanoparticles of three BCS class II Active Pharmaceutical Ingredients (APIs), namely carbamazepine (CBZ), ketoprofen (KET) and risperidone (RIS), were produced and successfully coated onto micron-sized microcrystalline cellulose (MCC) particles. The size distribution of the API nanoparticles was in the range of 90-490 nm. The stable forms of CBZ (form III), KET (form I), and the metastable form of RIS (form B) were produced and coated onto MCC carrier microparticles. All the isolated solids presented optimal rheological properties along with a 2-6 fold improvement in the dissolution rate of the corresponding APIs. Hence, the 'top spray dynamic bed coater' developed in this work demonstrates to be an efficient approach to produce and coat API nanoparticles onto carrier particles with optimal rheological properties and improved dissolution.

Erythrocyte-mimicking paclitaxel nanoparticles for improving biodistributions of hydrophobic drugs to enhance antitumor efficacy

Recent decades have witnessed several nanocrystal-based hydrophobic drug formulations because of their excellent performance in improving drug loading and controlling drug release as mediate drug forms in tablets or capsules. However, the intravenous administration of drug nanocrystals was usually hampered by their hydrophobic surface properties, causing short half-life time in circulation and low drug distribution in tumor. Here, we proposed to enclose nanocrystals (NC) of hydrophobic drug, such as paclitaxel (PTX) into erythrocyte membrane (EM). By a series of formulation optimizations, spherical PTX nanoparticles (PN) with the particle size of around 280 nm were successfully cloaked in erythrocyte membrane, resulting in a PTX-NP-EM (PNM) system. The PNM could achieve high drug loading of PTX (>60%) and stabilize the particle size significantly compared to PN alone. Besides, the fluorescence-labeling PNM presented better tumor cell uptake, stronger cytotoxicity, and higher drug accumulation in tumor compared to PN. Finally, the PNM was found to be the most effective against tumor growth among all PTX formulations in tumor-bearing mice models, with much lower system toxicity than control formulation. In general, the PNM system with high drug-loading as well as superior bio-distributions in vivo could be served as a promising formulation.

Alginate Nanoformulation: Influence of Process and Selected Variables

Nanocarriers are defined as structures and devices that are constructed using nanomaterials which add functionality to the encapsulants. Being small in size and having a customized surface, improved solubility and multi-functionality, it is envisaged that nanoparticles will continue to create new biomedical applications owing to their stability, solubility, and bioavailability, as well as controlled release of drugs. The type and physiochemical as well as morphological attributes of nanoparticles influence their interaction with living cells and determine the route of administration, clearance, as well as related toxic effects. Over the past decades, biodegradable polymers such as polysaccharides have drowned a great deal of attention in pharmaceutical industry with respect to designing of drug delivery systems. On this note, biodegradable polymeric nanocarrier is deemed to control the release of the drug, stabilize labile molecules from degradation and site-specific drug targeting, with the main aim of reducing the dosing frequency and prolonging the therapeutic outcomes. Thus, it is essential to select the appropriate biopolymer material, e.g., sodium alginate to formulate nanoparticles for controlled drug delivery. Alginate has attracted considerable interest in pharmaceutical and biomedical applications as a matrix material of nanocarriers due to its inherent biological properties, including good biocompatibility and biodegradability. Various techniques have been adopted to synthesize alginate nanoparticles in order to introduce more rational, coherent, efficient and cost-effective properties. This review highlights the most used and recent manufacturing techniques of alginate-based nanoparticulate delivery system, including emulsification/gelation complexation, layer-by-layer, spray drying, electrospray and electrospinning methods. Besides, the effects of the main processing and formulation parameters on alginate nanoparticles are also summarized.

Preparation of parenteral nanocrystal suspensions of etoposide from the excipient free dry state of the drug to enhance in vivo antitumoral properties

Nanoparticle technology in cancer chemotherapy is a promising approach to enhance active ingredient pharmacology and pharmacodynamics. Indeed, drug nanoparticles display various assets such as extended blood lifespan, high drug loading and reduced cytotoxicity leading to better drug compliance. In this context, organic nanocrystal suspensions for pharmaceutical use have been developed in the past ten years. Nanocrystals offer new possibilities by combining the nanoformulation features with the properties of solid dispersed therapeutic ingredients including (i) high loading of the active ingredient, (ii) its bioavailability improvement, and (iii) reduced drug systemic cytotoxicity. However, surprisingly, no antitumoral drug has been marketed as a nanocrystal suspension until now. Etoposide, which is largely used as an anti-cancerous agent against testicular, ovarian, small cell lung, colon and breast cancer in its liquid dosage form, has been selected to develop injectable nanocrystal suspensions designed to be transferred to the clinic. The aim of the present work is to provide optimized formulations for nanostructured etoposide solutions and validate by means of in vitro and in vivo evaluations the efficiency of this multiphase system. Indeed, the etoposide formulated as a nanosuspension by a bottom-up approach showed higher blood life span, reduced tumor growth and higher tolerance in a murine carcinoma cancer model. The results obtained are promising for future clinical evaluation of these etoposide nanosuspensions.

Ultrasonicated resveratrol loaded starch nanocapsules: Characterization, bioactivity and release behaviour under in-vitro digestion

In this study, the resveratrol was nano-encapsulated in three different sources of starch like Water chestnut Horse chestnut and Lotus stem to safeguard it from gastric conditions and to improve its bioavailability and bioactivity upon digestion. The nano-capsules were prepared using safe and eco-friendly ultra-sonication method and studied for encapsulation-efficiency, particle-size and zeta-potential measurement. These were also characterized by ATR-FTIR, SEM, XRD and DSC. The release behaviour of resveratrol and its activity against anti-diabetic and anti-obesity were also studied. The particle size of HSR, LSR and WSR was found to be 419, 797 and 691 nm with a zeta potential of -16.09, -24.28 and -14.77 and encapsulation efficiency of 81.46, 75.83 and 79.37 %, respectively. The nanoparticles showed porous or film-like structures with decreased crystallinity and higher transition temperatures. The maximum percentage of resveratrol was released in intestinal juice and exhibited higher anti-obesity and anti-diabetic activities than free resveratrol after digestion.

Diclofenac-proline nano-co-crystal development, characterization, in vitro dissolution and diffusion study

Nanotechnology has been widely developed to improve the solubility of active pharmaceutical ingredients. Co-crystal discovery has also taken much attention in drug design and development. A combination of the two techniques generates “nano-co-crystallization”, a new approach to obtaining the superior character of drugs. Previously, a new diclofenac-proline co-crystal (DPC) arrangement has been reported. The present research attempted to develop a nano-diclofenac-proline-co-crystal (NDPC) and to evaluate its formation kinetics, and dissolution-diffusion improvements. Both top-down and bottom-up methods optimized nano-co-crystal production. The top-down technique was used through the wet milling procedure and neat grinding procedures, while the bottom-up technique was performed through the globule inversion phase and fast evaporation assisted microwaving. The NDPCs obtained were then characterized by dynamic light scattering, binocular microscope, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry, powder x-ray diffractometry, and Fourier transform infrared spectrophotometry. The kinetics of NDPC formation was determined based on the difference of microwaving versus the co-crystal yield, which was analyzed using Fourier transform infrared spectroscopy. Dissolution was tested by type 2 apparatus, and diffusion was tested using Franz diffusion cells. The bottom-up method by fast evaporation assisted microwaving provided the best nano-co-crystal with a mean diameter of 598.2 ± 63.2 nm and a polydispersity index of 0.278 ± 0.062. Nano-co-crystal formation kinetic, which was evaluated by FTIR, indicated to follow first order. Finally, NDPC showed the superior dissolution and diffusion profile than conventional-DPC. In this study, we demonstrate a promising alternative for improving the dissolution and diffusion of the drug by nano-co-crystallization.

Use of Spray Flash Evaporation (SFE) technology to improve dissolution of poorly soluble drugs: Case study on furosemide nanocrystals

The poor solubility and related low bioavailability are a major concern for a large number of small molecule drugs, both on the market and in development. Several formulation strategies exist to overcome this issue. Among them, particle engineering is of outmost importance. The aim of this work is to present the potential of Spray Flash Evaporation (SFE), a new technology for drug particle engineering. To assess the potential of SFE, we carried out a case study on the nano-crystallization of furosemide, a BCS class IV drug. A thorough characterization of the obtained nanocrystals is presented along with a study of dissolution which highlights the solubility improvement provided by nanocrystals produced via SFE technology. The obtained results show a particle size reduction when compared to the raw material, as well as an increase of the dissolution rate of 4.5-fold.

Self-Assembled Organic Nanomaterials for Drug Delivery, Bioimaging, and Cancer Therapy

Over the past few decades, tremendous progress has been made in the development of engineering nanomaterials, which opened new horizons in the field of diagnosis and treatment of various diseases. In particular, self-assembled organic nanomaterials with intriguing features including delicate structure tailoring, facile processability, low cost, and excellent biocompatibility have shown outstanding potential in biomedical applications because of the enhanced permeability and retention (EPR) effect and multifunctional properties. In this review, we briefly introduce distinctive merits of self-assembled organic nanomaterials for biomedical applications. The main focus will be placed on summarizing recent advances in self-assembled organic nanomedicine for drug delivery, bioimaging, and cancer phototherapy, followed by highlighting a critical perspective on further development of self-assembled organic nanomaterials for future clinical translation. We believe that the above themes will appeal to researchers from different fields, including material, chemical, and biological sciences, as well as pharmaceutics.

Modulating the release of pharmaceuticals from lipid cubic phases using a lipase inhibitor

Lipid cubic phase formulations have gained recognition as potential controlled delivery systems for a range of active pharmaceutical and biological agents on account of their desirable physiochemical properties and ability to encapsulate both hydrophobic and hydrophilic molecules. The most widely studied lipid cubic systems are those of the monoacylglycerol lipid family. These formulations are susceptible to lipolysis by a variety of enzymes, including lipases and esterases, which attack the ester bond present on the lipid chain bridging the oleic acid component to the glycerol backbone. The release of poorly soluble molecules residing in the lipid membrane portions of the phase is limited by the breakdown of the matrix; thus, presenting a potential means for further controlling and sustaining the release of therapeutic agents by targeting the matrix stability and its rate of degradation. The aims of the present study were twofold: to evaluate an approach to regulate the rate of degradation of lipid cubic phase drug delivery systems by targeting the enzyme interactions responsible for their demise; and to study the subsequent drug release profiles from bulk lipid cubic gels using model drugs of contrasting hydrophobicity. Here, hybrid materials consisting of cubic phases with monoacylglycerol lipids of different chain lengths formulated with a potent lipase inhibitor tetrahydrolipstatin were designed. Modulation of the release of a hydrophobic model pharmaceutical, a clofazimine salt, was obtained by exploiting the matrices' enzyme-driven digestion. A stable cubic phase is described, displaying controlled degradation with at least a 4-fold improvement compared to the blank systems shown in inhibitor-containing cubic systems. Sustained release of the model hydrophobic pharmaceutical was studied over 30 days to highlight the advantage of incorporating an inhibitor into the cubic network to achieve tunable lipid release systems. This is done without negatively affecting the structure of the matrix itself, as shown by comprehensive small-angle x-ray scattering experiments.

Dissolution of an ensemble of differently shaped poly-dispersed drug particles undergoing solubility reduction: mathematical modelling

The aim of this theoretical paper is to develop a mathematical model for describing the dissolution process, in a finite liquid environment, of an ensemble of poly-dispersed drug particles, in form of sphere, cylinder and parallelepiped that can undergo solubility reduction due to phase transition induced by dissolution. The main result of this work consists in its simplicity as, whatever the particular particles size distribution, only two ordinary differential equations are needed to describe the dissolution process. This, in turn, reflects in a very powerful and agile theoretical tool that can be easily implemented in electronic sheets, a widespread tool among the research community. Another model advantage lies on the possibility of determining its parameters by means of common independent techniques thus enabling the evaluation of the importance of solid wettability on the dissolution process.

Development and Evaluation of Docetaxel-Phospholipid Complex Loaded Self-Microemulsifying Drug Delivery System: Optimization and In Vitro/Ex Vivo Studies

Docetaxel (DTX) has clinical efficacy in the treatment of breast cancer, but it is difficult to develop a product for oral administration, due to low solubility and permeability. This study focused on preparing a self-microemulsifying drug delivery system (SME) loaded with DTX-phospholipid complex (DTX@PLC), to improve the dissolution and gastrointestinal (GI) permeability of DTX. A dual technique combining the phospholipid complexation and SME formulation described as improving upon the disadvantages of DTX has been proposed. We hypothesized that the complexation of DTX with phospholipids can improve the lipophilicity of DTX, thereby increasing the affinity of the drug to the cell lipid membrane, and simultaneously improving permeability through the GI barrier. Meanwhile, DTX@PLC-loaded SME (DTX@PLC-SME) increases the dissolution and surface area of DTX by forming a microemulsion in the intestinal fluid, providing sufficient opportunity for the drug to contact the GI membrane. First, we prepared DTX@PLC-SME by combining dual technologies, which are advantages for oral absorption. Next, we optimized DTX@PLC-SME with nanosized droplets (117.1 nm), low precipitation (8.9%), and high solubility (33.0 mg/g), which formed a homogeneous microemulsion in the aqueous phase. Dissolution and cellular uptake studies demonstrated that DTX@PLC-SME showed 5.6-fold higher dissolution and 2.3-fold higher DTX uptake in Caco-2 cells than raw material. In addition, an ex vivo gut sac study confirmed that DTX@PLC-SME improved GI permeability of DTX by 2.6-fold compared to raw material. These results suggested that DTX@PLC-SME can significantly overcome the disadvantages of anticancer agents, such as low solubility and permeability.

Recent advances in long-acting nanoformulations for delivery of antiretroviral drugs

In spite of introduction of combination antiretroviral therapy (cART) against human immunodeficiency virus (HIV) infection; inaccessibility and poor adherence to oral cART costs 10 in 100,000 death worldwide. Failure in adherence leads to viral rebound, emergence of drug resistance and anticipated HIV infection in high risk individuals. Various Long-acting antiretroviral (LA ARV) nanoformulations including nano-prodrug, solid drug nanoparticles (SDN), nanocrystals, aspherical nanoparticles, polymeric and lipidic nanoparticles have shown plasma/tissue drug concentration in the therapeutic range for several weeks during pre-clinical evaluation. LA ARV nanoformulations therefore have replaced cART as better alternative for the treatment of HIV infection. Cabenuva™ is recently approved by Health Canada containing LA cabotegravir+LA rilpivirine nanocrystals (ViiV healthcare) for once monthly administration by intramuscular route. The LA nanoformulation due to its nanosize insist on better stability, delivery to lymphatic, slow release into systemic circulation via lymphatic-circulatory system conjoint and secondary drug depot within infiltered immune cells at site of administration and systemic circulation in contrast to conventional drugs. However, the pharmacokinetic, biodistribution and efficacy of LA nanoformulations hinge onto physicochemical properties of the drugs and route of administration. Therefore, current review emphasizes on these contradistinctive factors that affects the reproducibility, safety, efficacy and toxicity of LA anti-HIV nanoformulations. Moreover, it expatiates on application of profuse nanoformulations for long-acting effect with promising preclinical discoveries and two clinical leads. To add on, utilization of physiology-based and mechanism-based pharmacokinetic modelling and in vivo animal models which could lead to enhanced safety and efficacy of LA ARV nanoformulations in humans have been included.

Nanotechnology as a tool to overcome the bariatric surgery malabsorption

Obesity is a metabolic disease that affects all ages; it is considered life-threatening condition as it leads to fatal complications such as; cardiovascular diseases and diabetes. The therapeutic options include; life-style modifications, pharmacotherapy intervention, and surgical intervention. Bariatric surgery (BS) is considered as the most effective option among the others for its rapid weight loss, maintaining the lost mass, and improving the quality of life of the patients. Nevertheless, BS leads to severe changes in the bioavailability of medications, especially for chronic diseases, which may reach to limit where the patient's life endangers. Recently, pharmaceutical formulations had developed several methods to improve the drug bioavailability of drugs though the implying of nanotechnology. Nonotechnology is responsible for reducing the size of the drugs to the nano range (<1000 nm), which increase the drug surface area, dissolution, absorption, and, most importantly, the bioavailability of these drugs. It is believed that BS malabsorption and drugs bioavailability problems can be solved using nanotechnology for its advantages in overcoming BS complications.

Modification of the zeta potential of montmorillonite to achieve high active pharmaceutical ingredient nanoparticle loading and stabilization with optimum dissolution properties

Nanoparticles (NPs) of three poorly water-soluble BCS class II active pharmaceutical ingredients (APIs) (clozapine (CLO), curcumin (CUR) and carbamazepine (CBMZ) with zeta potentials -28.5 ± 2.5, -33 ± 1.5 and -13 ± 1.5 mV respectively) were produced, stabilized and isolated into the solid state with the help of Montmorillonite (MMT) clay carrier particles. The nanoparticles of clozapine (27 nm), curcumin (170 nm) and carbamazepine (30 nm) were produced and stabilized in suspension using a reverse antisolvent precipitation technique in the presence of 'as received' MMT carrier particles (∼30 μm) and/or MMT carrier particles whose surface had been slightly modified with a cationic protein, protamine sulphate salt (PA). The resulting nanoparticle carrier composites were isolated directly from suspension into a solid state form by simple filtration followed by air-drying. The API dissolution rates from these dried NP-carrier composites were comparable with those of the respective stabilized API nanoparticles in suspension up to maximum CLO, CUR and CBMZ loadings of 23%, 21.8% and 33.3% (w/w) respectively, although surface modification of the MMT carrier particles with PA was needed for the CLO and CUR NP-carrier composites in order to preserve the fast API nanosuspension-like dissolution rates at higher API loadings. For both of these APIs, the optimal loading of PA on MMT was around 4 mg/g, which likely helped to limit aggregation of the API nanoparticles at the higher API loadings. Interestingly, no MMT surface modification was needed to preserve fast API dissolution rates at higher API loadings in the case of the CBMZ NP-carrier composites. This discrimination among the three APIs for carrier particle surface modification was previously observed in reported studies by our group for three other APIs, namely valsartan, fenofibrate and dalcetrapib. When examined together, the data for all six APIs suggest a general trend whereby API nanoparticles with zeta potentials more positive than around -25 mV do not require carrier particle surface modification with PA in order to preserve their fast dissolution rates from NP-carrier composites at higher API loadings. Thus, this study offers a potentially effective means of transforming poorly water soluble BCS Class II APIs into fast dissolving solid dosage NP-carrier composites, whereby the surface properties of the carrier particle can be tuned with prior knowledge of the zeta potential of the API nanoparticles.

Pure Trans-Resveratrol Nanoparticles Prepared by A Supercritical Antisolvent Process Using Alcohol and Dichloromethane Mixtures: Effect of Particle Size on Dissolution and Bioavailability in Rats

The aim of this study was to prepare pure trans-resveratrol nanoparticles without additives (surfactants, polymers, and sugars) using a supercritical antisolvent (SAS) process with alcohol (methanol or ethanol) and dichloromethane mixtures. In addition, in order to investigate the effect of particle size on the dissolution and oral bioavailability of the trans-resveratrol, two microparticles with different sizes (1.94 μm and 18.75 μm) were prepared using two different milling processes, and compared to trans-resveratrol nanoparticles prepared by the SAS process. The solid-state properties of pure trans-resveratrol particles were characterized. By increasing the percentage of dichloromethane in the solvent mixtures, the mean particle size of trans-resveratrol was decreased, whereas its specific surface area was increased. The particle size could thus be controlled by solvent composition. Trans-resveratrol nanoparticle with a mean particle size of 0.17 μm was prepared by the SAS process using the ethanol/dichloromethane mixture at a ratio of 25/75 (w/w). The in vitro dissolution rate of trans-resveratrol in fasted state-simulated gastric fluid was significantly improved by the reduction of particle size, resulting in enhanced oral bioavailability in rats. The absolute bioavailability of trans-resveratrol nanoparticles was 25.2%. The maximum plasma concentration values were well correlated with the in vitro dissolution rate. These findings clearly indicate that the oral bioavailability of trans-resveratrol can be enhanced by preparing pure trans-resveratrol nanoparticles without additives (surfactants, polymers, and sugars) by the SAS process. These pure trans-resveratrol nanoparticles can be applied as an active ingredient for the development of health supplements, pharmaceutical products, and cosmetic products.

Development and evaluation of TPGS/PVA-based nanosuspension for enhancing dissolution and oral bioavailability of ticagrelor

In this study, we developed ticagrelor-dispersed nanosuspension (TCG-NSP) to enhance the dissolution and oral bioavailability of ticagrelor (TCG) through a statistical design approach. TCG, a reversible P2Y₁₂ receptor antagonist, is classified as a biopharmaceutics classification system (BCS) class IV drug with low solubility and permeability, resulting in low oral bioavailability. Nanosuspension (NSP) is an efficient pharmaceutical technique for overcoming the disadvantages. First, we optimized TCG-NSP consisting of D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) and polyvinyl alcohol (PVA), which exhibited homogeneously dispersed TCG particle (233 nm) and low precipitation (3%). Characterization studies demonstrated that TCG-NSP provided amorphous TCG particles and supersaturation effect, resulting in higher dissolution than a commercial product. In addition, everted gut sac and pharmacokinetic studies confirmed that TCG-NSP improved the gastrointestinal permeation of TCG by 2.8-fold compared to commercial product, thereby enhancing the oral bioavailability (2.2-fold). These results suggested that TCG-NSP could be successfully used as an efficient pharmaceutical formulation to achieve the enhanced dissolution and oral bioavailability of TCG.

Role of wetting agents and disintegrants in development of danazol nanocrystalline tablets

Poor wetting and/or particle aggregation are the shortcomings of the dried nanocrystalline suspensions, which subsequently might hinder the superior dissolution performance of the nano-crystalline suspensions. The objective of this study was to evaluate the effect of wetting agents and disintegrants on the dissolution performance of dried nanocrystals of an active pharmaceutical ingredient (API) with poor wetting property. Danazol, a BCS Class II compound with high LogP and low polar surface area, was chosen as a model compound for this study. Danazol nanocrystalline suspension was prepared by wet-media milling and converted into powder via spray granulation either with mannitol or microcrystalline cellulose as carriers at a drug: carrier ratio of 1:9 w/w. Danazol nanocrystalline suspension showed a superior dissolution performance compared to an un-milled danazol suspension. Dried danazol nanocrystals suffered from poor wetting leading to hindered dissolution performance i.e. ~ 40% and ~ 15% drug dissolution within 15 min for the mannitol and microcrystalline cellulose-based granules, respectively. Addition of a lipophilic surfactant (i.e. docusate sodium) at a surfactant: drug ratio of 0.015: 1 w/w during granulation helped in retaining the superior drug dissolution rates i.e. more than 80% drug dissolution within 15 min for mannitol-based granules by enhancing the wettability of dried danazol nanocrystals when compared to a hydrophilic surfactant (i.e. poloxamer 188) or disintegrant (i.e. sodium starch glycolate or croscarmellose sodium). The fast-dissolving mannitol-based granules containing danazol nanocrystals and docusate sodium were compressed into a tablet dosage form. The tablets containing danazol nanocrystals with docusate sodium showed a superior dissolution performance compared to a tablet containing un-milled danazol with docusate sodium.

Advanced modification of drug nanocrystals by using novel fabrication and downstream approaches for tailor-made drug delivery

Drug nanosuspensions/nanocrystals have been recognized as one useful and successful approach for drug delivery. Drug nanocrystals could be further decorated to possess extended functions (such as controlled release) and designed for special in vivo applications (such as drug tracking), which make best use of the advantages of drug nanocrystals. A lot of novel and advanced size reduction methods have been invented recently for special drug deliveries. In addition, some novel downstream processes have been combined with nanosuspensions, which have highly broadened its application areas (such as targeting) besides traditional routes. A large number of recent research publication regarding as nanocrystals focuses on above mentioned aspects, which have widely attracted attention. This review will focus on the recent development of nanocrystals and give an overview of regarding modification of nanocrystal by some new approaches for tailor-made drug delivery.

Emerging role of nanosuspensions in drug delivery systems

Rapid advancement in drug discovery process is leading to a number of potential new drug candidates having excellent drug efficacy but limited aqueous solubility. By virtue of the submicron particle size and distinct physicochemical properties, nanosuspension has the potential ability to tackle many formulation and drug delivery issues typically associated with poorly water and lipid soluble drugs. Conventional size reduction equipment such as media mill and high-pressure homogenizers and formulation approaches such as precipitation, emulsion-solvent evaporation, solvent diffusion and microemulsion techniques can be successfully implemented to prepare and scale-up nanosuspensions. Maintaining the stability in solution as well as in solid state, resuspendability without aggregation are the key factors to be considered for the successful production and scale-up of nanosuspensions. Due to the considerable enhancement of bioavailability, adaptability for surface modification and mucoadhesion for drug targeting have significantly expanded the scope of this novel formulation strategy. The application of nanosuspensions in different drug delivery systems such as oral, ocular, brain, topical, buccal, nasal and transdermal routes are currently undergoing extensive research. Oral drug delivery of nanosuspension with receptor mediated endocytosis has the promising ability to resolve most permeability limited absorption and hepatic first-pass metabolism related issues adversely affecting bioavailability. Advancement of enabling technologies such as nanosuspension can solve many formulation challenges currently faced among protein and peptide-based pharmaceuticals.

Nanodelivery of Natural Antioxidants: An Anti-aging Perspective

The aging process is known to be associated with heightened oxidative stress and related systemic inflammation. Therefore, antioxidant supplementation is regarded as a promising strategy to combat aging and associated pathological conditions. Food-grade antioxidants from plant-derived extracts are the most common ingredients of these supplements. Phyto-bioactive compounds such as curcumin, resveratrol, catechins, quercetin are among the most commonly applied natural compounds used as potential modulators of the free radical-induced cellular damages. The therapeutic potential of these compounds is, however, restricted by their low bioavailability related to poor solubility, stability, and absorbance in gastrointestinal tract. Recently, novel nanotechnology-based systems were developed for therapeutic delivery of natural antioxidants with improved bioavailability and, consequently, efficacy in clinical practice. Such systems have provided many benefits in preclinical research over the conventional preparations, including superior solubility and stability, extended half-life, improved epithelium permeability and bioavailability, enhanced tissue targeting, and minimized side effects. The present review summarizes recent developments in nanodelivery of natural antioxidants and its application to combat pathological conditions associated with oxidative stress.

Insight into the Formation of Glimepiride Nanocrystals by Wet Media Milling

Nanocrystal formation for the dissolution enhancement of glimepiride was attempted by wet media milling. Different stabilizers were tested and the obtained nanosuspensions were solidified by spray drying in presence of mannitol, and characterized regarding their redispersibility by dynamic light scattering, physicochemical properties by differential scanning calorimetry (DSC), FT-IR spectroscopy, powder X-ray diffraction (PXRD), and scanning electron microcopy (SEM), as well as dissolution rate. Lattice energy frameworks combined with topology analysis were used in order to gain insight into the mechanisms of particle fracture. It was found that nanosuspensions with narrow size distribution can be obtained in presence of poloxamer 188, HPC-SL and Pharmacoat^® 603 stabilizers, with poloxamer giving poor redispersibility due to melting and sticking of nanocrystals during spray drying. DSC and FT-IR studies showed that glimepiride does not undergo polymorphic transformations during processing, and that the milling process induces changes in the hydrogen bonding patterns of glimepiride crystals. Lattice energy framework and topology analysis revealed the existence of a possible slip plane on the (101) surface, which was experimentally verified by PXRD analysis. Dissolution testing proved the superior performance of nanocrystals, and emphasized the important influence of the stabilizer on the dissolution rate of the nanocrystals.

The Polymorphism of Drugs: New Approaches to the Synthesis of Nanostructured Polymorphs

Among the significant problems of modern pharmacology are the low solubility and bioavailability of drugs. One way to resolve this problem is to obtain new polymorphic forms of drugs with improved physicochemical properties. Various approaches have been developed with this aim, including the preparation of co-crystals, the use of nanoparticles, or the use of compounds in the form of a salt. A promising direction in pharmacology concerns the production of new stable polymorphic structures. In this mini-review, we consider certain aspects of drug polymorphism, methods for the synthesis of polymorphs, and the stability, size, and transformation of crystalline polymorphs. Moreover, we summarize our results from several studies demonstrating the problems associated with the synthesis of new polymorphous modifications based on inert gases and cryotemperatures. The results indicate that the problems specific to drug polymorphisms have only been partly resolved, are of current interest, and require further development.

Fabrication of Second Generation Smarter PLGA Based Nanocrystal Carriers for Improvement of Drug Delivery and Therapeutic Efficacy of Gliclazide in Type-2 Diabetes Rat Model

Drug delivery and therapeutic challenges of gliclazide, a BCS class II drug used in type 2 diabetes mellitus (T2DM) can be overcome by exploring smarter carriers of second-generation nanocrystals (SGNCs). A combined method of emulsion diffusion, high-pressure homogenization and solvent evaporation method were employed in the preparation of gliclazide loaded poly (D, L-lactide-co-glycolide) (PLGA) SGNCs. Taguchi experimental design was adopted in fabrication of Gliclazide SGNc using Gliclazide -PLGA ratio at 1:0.5, 1:0.75, 1:1 with stabilizer (Poloxamer-188, PEG 4000, HPMC E15 at 0.5, 0.75, 1% w/v). The formulated gliclazide of SGNCs were investigated for physicochemical properties, in vitro drug release, and in vivo performance studies using type-2 diabetes rat model. The formulation (SGNCF1) with Drug: PLGA 1: 0.5 ratio with 0.5% w/v Poloxamer-188 produced optimized gliclazide SGNCs. SGNCF1 showed spherical shape, small particle size (106.3 ± 2.69 nm), good zeta potential (−18.2 ± 1.30 mV), small PDI (0.222 ± 0.104) and high entrapment efficiency (86.27 ± 0.222%). The solubility, dissolution rate and bioavailability of gliclazide SGNCs were significantly improved compared to pure gliclazide. The findings emphasize gliclazide SGNCs produce faster release initially, followed by delayed release with improved bioavailability, facilitate efficient delivery of gliclazide in T2DM with better therapeutic effect.

Nanodelivery of phytobioactive compounds for treating aging-associated disorders

Aging population presents a major challenge for many countries in the world and has made the development of efficient means for healthspan extension a priority task for researchers and clinicians worldwide. Anti-aging properties including antioxidant, anti-inflammatory, anti-tumor, and cardioprotective activities have been reported for various phytobioactive compounds (PBCs) including resveratrol, quercetin, curcumin, catechin, etc. However, the therapeutic potential of orally administered PBCs is limited by their poor stability, bioavailability, and solubility in the gastrointestinal tract. Recently, innovative nanotechnology-based approaches have been developed to improve the bioactivity of PBCs and enhance their potential in preventing and/or treating age-associated disorders, primarily those caused by aging-related chronic inflammation. PBC-loaded nanoparticles designed for oral administration provide many benefits over conventional formulations, including enhanced stability and solubility, prolonged half-life, improved epithelium permeability and bioavailability, enhanced tissue targeting, and minimized side effects. The present review summarizes recent advances in this rapidly developing research area.

Nanotherapeutic silibinin: An insight of phytomedicine in healthcare reformation

Most of the herbal origin drugs possess water insoluble active constituents which lower the bioavailability and increase systemic clearance after administration of repeated or higher dose of drug. Silymarin is extracted from the seeds and fruits of milk thistle plant Silybum marianum which consists of main biologically active component as silibinin. However, the clinical applications of silibinin show some limitations due to low aqueous solubility, poor penetration into the epithelial cells of intestine, high metabolism and rapid systemic elimination. But nanotechnology-based drug delivery system explores great potential for phytochemicals to enhance the aqueous solubility and bioavailability of BCS class II and IV drugs, improve stability and modify the pharmacological activity. This review focuses on the therapeutic properties of silibinin and discusses the benefits, challenges and applications of silibinin nanoformulations. Such nanotherapeutic system as a regular medicine will be an attractive approach to reduce the adverse events and toxicities of current therapies.

The Effects of Vinegar Processing on the Changes in the Physical Properties of Frankincense Related to the Absorption of the Main Boswellic Acids

Boswellic acids (BAs), as the main components of frankincense, exhibit notable anti-inflammatory properties. However, their pharmaceutical development has been severely limited by their poor oral bioavailability. Traditional Chinese medicinal processing, called Pao Zhi, is believed to improve bioavailability, yet the mechanism is still completely unclear. Previous research suggested that the bioavailability of a drug can be influenced by physical properties. This paper was designed to investigate the physical properties of frankincense and processed frankincense, including the surface morphology, particle size, polydispersity index (PDI), zeta potential (ZP), specific surface area, porosity, and viscosity. The differences in the intestinal absorption characteristics and equilibrium solubilities between frankincense and processed frankincense were determined by an ultra-high-performance liquid chromatography coupled with a triple quadrupole electrospray tandem mass spectrometry (UHPLC-TQ-MS) analysis method. The results showed that vinegar processing can alter the surface morphology, decrease the particle size and PDI, raise the absolute values of the ZP, specific surface area and porosity, and drop the viscosity of frankincense. Meanwhile, the rates of absorption and dissolution of the main BAs were increased after the processing of frankincense. The present study proves that the physical properties were changed after processing, in which case the bioavailability of frankincense was enhanced.

Synthesis of a long acting nanoformulated emtricitabine ProTide

While antiretroviral therapy (ART) has revolutionized treatment and prevention of human immunodeficiency virus type one (HIV-1) infection, regimen adherence, viral mutations, drug toxicities and access stigma and fatigue are treatment limitations. These have led to new opportunities for the development of long acting (LA) ART including implantable devices and chemical drug modifications. Herein, medicinal and formulation chemistry were used to develop LA prodrug nanoformulations of emtricitabine (FTC). A potent lipophilic FTC phosphoramidate prodrug (M2FTC) was synthesized then encapsulated into a poloxamer surfactant (NM2FTC). These modifications extended the biology, apparent drug half-life and antiretroviral activities of the formulations. NM2FTC demonstrated a >30-fold increase in macrophage and CD4+ T cell drug uptake with efficient conversion to triphosphates (FTC-TP). Intracellular FTC-TP protected macrophages against an HIV-1 challenge for 30 days. A single intramuscular injection of NM2FTC, at 45 mg/kg native drug equivalents, into Sprague Dawley rats resulted in sustained prodrug levels in blood, liver, spleen and lymph nodes and FTC-TP in lymph node and spleen cells at one month. In contrast, native FTC-TPs was present for one day. These results are an advance in the transformation of FTC into a LA agent.

How to assess orodispersible film quality? A review of applied methods and their modifications

In recent years, there has been a tendency toward creating innovative, easy to use and patient-friendly drug delivery systems suitable for every consumer profile, which would ensure safety, stability and acceptability of a drug. One of the relatively novel and promising approaches is the manufacture of orodispersible films (ODFs), which is an upcoming area of interest in drug delivery. They are defined as polymer thin films that disintegrate in the oral cavity within seconds, without drinking water or chewing, and eliminate the risk of choking. Gaining special usefulness in therapies of children and the elderly, ODFs seem to fill the gap in the range of preparations available for these groups of patients. As no detailed monography of ODFs including testing methods and uniform requirements has been presented in any of the pharmacopoeias to date, the aim of this article is to give an overview of the applied testing methods, their modifications and innovative approaches related to ODF quality assessment.