Glibenclamide Nanocrystals in a Biodegradable Chitosan Patch for Transdermal Delivery: Engineering, Formulation, and Evaluation

Chitosan as excellent bio-macromolecule with myriad of anti-activities in biomedical applications - A review

The aim of the study is to explore the myriad of anti-activities of chitosan - deacylated derivative of chitin in biomedical applications. Chitosan consists of reactive residual amino groups, which can be modified chemically to obtain wide range of derivatives. These derivatives exhibit the controlled physicochemical characteristics, which in turn improve its functional properties. Such derivatives find numerous applications in the field of biomedical science, agriculture, tissue engineering, bone regeneration and environmental science. This study presents a comprehensive overview of the multifarious anti-activities of chitosan and its derivatives in the field of biomedical science including anti-microbial, antioxidant, anti-tumor, anti-HIV, anti-fungal, anti- inflammatory, anti-Alzheimer's, anti-hypertensive and anti-diabetic activity. It briefly details these anti-activities with respect to its mode of action, pharmacological effects and potential applications. It also presents the overview of current research exploring novel derivatives of chitosan and its anti- activities in the recent past. Finally, the review projects the prospective potential of chitosan and its derivatives and expects to encourage the readers to develop new drug delivery systems based on such chitosan derivatives and explore its applications in biomedical science for benefit of mankind.

Repaglinide-Solid Lipid Nanoparticles in Chitosan Patches for Transdermal Application: Box-Behnken Design, Characterization, and In Vivo Evaluation

Background

Repaglinide (REP) is an antidiabetic drug with limited oral bioavailability attributable to its low solubility and considerable first-pass hepatic breakdown. This study aimed to develop a biodegradable chitosan-based system loaded with REP-solid lipid nanoparticles (REP-SLNs) for controlled release and bioavailability enhancement via transdermal delivery.

Methods

REP-SLNs were fabricated by ultrasonic hot-melt emulsification. A Box-Behnken design (BBD) was employed to explore and optimize the impacts of processing variables (lipid content, surfactant concentration, and sonication amplitude) on particle size (PS), and entrapment efficiency (EE). The optimized REP-SLN formulation was then incorporated within a chitosan solution to develop a transdermal delivery system (REP-SLN-TDDS) and evaluated for physicochemical properties, drug release, and ex vivo permeation profiles. Pharmacokinetic and pharmacodynamic characteristics were assessed using experimental rats.

Results

The optimized REP-SLNs had a PS of 249±9.8 nm and EE of 78%±2.3%. The developed REP-SLN-TDDS demonstrated acceptable characteristics without significant aggregation of REP-SLNs throughout the casting and drying processes. The REP-SLN-TDDS exhibited a biphasic release pattern, where around 36% of the drug load was released during the first 2 h, then the drug release was sustained at around 80% at 24 h. The computed flux across rat skin for the REP-SLN-TDDS was 2.481±0.22 μg/cm2/h in comparison to 0.696±0.07 μg/cm2/h for the unprocessed REP, with an enhancement ratio of 3.56. The REP-SLN-TDDS was capable of sustaining greater REP plasma levels over a 24 h period (p<0.05). The REP-SLN-TDDS also reduced blood glucose levels compared to unprocessed REP and commercial tablets (p<0.05) in experimental rats.

Conclusion

Our REP-SLN-TDDS can be considered an efficient therapeutic option for REP administration.

Nanostructured Lipid Carrier-Mediated Transdermal Delivery System of Glibenclamide for Gestational Diabetes: Pharmacokinetic and Pharmacodynamic Evaluation

BACKGROUND

Gestational diabetes mellitus (GDM) poses significant risks during pregnancy for both mother and fetus. Adherence to oral antidiabetic medications, like glibenclamide (GB), can be challenging, necessitating novel drug delivery methods. Nanostructured lipid carriers (NLC) offer a promising approach by efficiently permeating the skin due to their small size and lipid-based composition.

OBJECTIVE

This study aimed to develop and evaluate transdermal patches loaded with glibenclamide NLCs to treat GDM.

METHODS

Glibenclamide NLCs were prepared using hot homogenization with ultrasonication and melt dispersion method. A central composite design was utilized to optimize the formulations. Transdermal patches containing optimized NLCs were developed using HPMC K 100 and Eudragit L polymers. The patches were evaluated for various parameters, and their pharmacokinetic and pharmacodynamic studies were carried out to assess their safety and efficacy.

RESULTS

Optimized NLCs efficiently permeated rat skin. Cell viability studies indicated the nontoxicity of the formulations. NLC-loaded transdermal patches (F2 and F7) showed drug release of 1098 μg/cm2 and 1001.83 μg/cm2 in 24 h, with a 2.5-fold higher flux and permeation coefficient than the GB patch. Pharmacokinetic analysis revealed Tmax of 8 and 10 h and Cmax of 7127 ng/ml and 7960 ng/ml for F2 and F7, respectively, ensuring sustained drug action. AUC0-α was 625681 ng/ml·h and 363625 ng/ml·h for F2 and F7, respectively, indicating improved bioavailability.

CONCLUSION

Transdermal patches incorporating NLCs hold promise for enhancing glibenclamide's therapeutic efficacy in GDM treatment. Improved skin permeation, sustained drug release, and enhanced bioavailability make NLC-based transdermal patches a potential alternative with better patient compliance.

Transdermal Glipizide Delivery System Based on Chitosan-Coated Deformable Liposomes: Development, Ex Vivo, and In Vivo Studies

The current study aimed to develop and evaluate a sustained-release transdermal Glipizide (GLP) film to overcome its oral administration problems. Chitosan (CS)-coated deformable liposomes (DLs) were utilized to enhance the drug transdermal delivery. The formulations were characterized in terms of particle size, zeta potential, entrapment efficiency (EE%), vesicle deformability, morphology, stability, and in vitro release. Transdermal films of chosen formulations were prepared by the solvent casting technique, and an ex vivo study throughout rat skin was also performed. Moreover, a pharmacokinetics (PK) study was carried out and blood glucose levels were estimated. All the liposomes were in the nanometer range and a high EE% was obtained from DLs compared to conventional liposomes (CL). The prepared formulations showed a high stability and the DLs exhibited a high deformability compared to CL. The in vitro release study confirmed the sustained release of GLP from both CL and DL and a more pronounced sustained release of GLP was detected after coating with CS. Moreover, GLP was shown to efficiently permeate through the rat skin from transdermal films by an ex vivo permeation test. The transdermal films showed a promising PK profile in the rat as compared with oral GLP. Most importantly, GLP-CS-DL1 demonstrated a higher hypoglycemic effect, confirming the possibility of systemic action by the local topical delivery of GLP.

The Promising Role of Chitosan-Poloxamer 188 Nanocrystals in Improving Diosmin Dissolution and Therapeutic Efficacy against Ferrous Sulfate-Induced Hepatic Injury in Rats

Diosmin (DSN) exhibits poor water solubility and low bioavailability. Although nanocrystals (NCs) are successful for improving drug solubility, they may undergo crystal growth. Therefore, DSN NCs were prepared, employing sonoprecipitation utilizing different stabilizers. The optimum stabilizer was combined with chitosan (CS) as an electrostatic stabilizer. NCs based on 0.15% w/v poloxamer 188 (PLX188) as a steric stabilizer and 0.04% w/v CS were selected because they showed the smallest diameter (368.93 ± 0.47 nm) and the highest ζ-potential (+40.43 ± 0.15 mV). Mannitol (1% w/v) hindered NC enlargement on lyophilization. FT-IR negated the chemical interaction of NC components. DSC and XRD were performed to verify the crystalline state. DSN dissolution enhancement was attributed to the nanometric rod-shaped NCs, the high surface area, and the improved wettability. CS insolubility and its diffusion layer may explain controlled DSN release from CS-PLX188 NCs. CS-PLX188 NCs were more stable than PLX188 NCs, suggesting the significance of the combined electrostatic and steric stabilization strategies. The superiority of CS-PLX188 NCs was indicated by the significantly regulated biomarkers, pathological alterations, and inducible nitric oxide synthase (iNOS) expression of the hepatic tissue compared to DSN suspension and PLX188 NCs. Permeation, mucoadhesion, and cellular uptake enhancement by CS may explain this superiority.

Combination of transdermal patches and solid microneedles for improved transdermal delivery of primaquine

Malaria caused by various types of Plasmodium has become a global health problem. One of the drugs used as the first line of malaria therapy is primaquine (PMQ). PMQ is generally administered through the oral route. However, the use of PMQ orally could potentially cause some side effects and undergo the first-pass metabolism in the liver, reducing its effectiveness. Therefore, it is necessary to develop another drug administration route to avoid this effect. In this study, for the first time, PMQ was formulated into a transdermal patch for transdermal delivery, combined with solid microneedles, Dermaroller®. Following several optimizations, HPMC and glycerin were used as the main polymer and plasticizer, respectively. Specifically, the concentration of PEG 400 as a permeation enhancer was also optimized. The transdermal patches were evaluated for weight uniformity, thickness, surface pH, folding endurance, moisture content, moisture absorption ability, bioadhesive evaluation, and drug content recovery. PMQ release and permeation were also investigated through in vitro and ex vivo tests on rats' skin tissue. Importantly, the safety of the transdermal patch was also evaluated through in vitro hemolytic and in vivo irritation tests which were confirmed by histopathological examinations. The results showed that all formulations showed desired physical and bioadhesive properties with a folding endurance of >300 folds. The results exhibited that 31.31 ± 5.25% and 22.55 ± 4.35% of primaquine were released from transdermal patches following the in vitro and the ex vivo permeation studies. Combined with Dermaroller®, the ex vivo permeation study showed an improved permeation profile with 45.89 ± 5.00% of primaquine permeated after 24 h with a zero-order kinetic during the first 8 h. Hemolysis percentage was found to be <5%, indicating the non-toxic of this approach. Finally, the histopathology study showed that there was no severe tissue damage following the administration of our approach. Further in vivo evaluations should be performed.

Glibenclamide Nanocrystal-Loaded Bioactive Polymeric Scaffolds for Skin Regeneration: In Vitro Characterization and Preclinical Evaluation

Skin restoration following full-thickness injury poses significant clinical challenges including inflammation and scarring. Medicated scaffolds formulated from natural bioactive polymers present an attractive platform for promoting wound healing. Glibenclamide was formulated in collagen/chitosan composite scaffolds to fulfill this aim. Glibenclamide was forged into nanocrystals with optimized colloidal properties (particle size of 352.2 nm, and polydispersity index of 0.29) using Kolliphor as a stabilizer to allow loading into the hydrophilic polymeric matrix. Scaffolds were prepared by the freeze drying method using different total polymer contents (3-6%) and collagen/chitosan ratios (0.25-2). A total polymer content of 3% at a collagen/chitosan ratio of 2:1 (SCGL3-2) was selected based on the results of in vitro characterization including the swelling index (1095.21), porosity (94.08%), mechanical strength, rate of degradation and in vitro drug release. SCGL3-2 was shown to be hemocompatible based on the results of protein binding, blood clotting and percentage hemolysis assays. In vitro cell culture studies on HSF cells demonstrated the biocompatibility of nanocrystals and SCGL3-2. In vivo studies on a rat model of a full-thickness wound presented rapid closure with enhanced histological and immunohistochemical parameters, revealing the success of the scaffold in reducing inflammation and promoting wound healing without scar formation. Hence, SCGL3-2 could be considered a potential dermal substitute for skin regeneration.

Surfactant-Free Glibenclamide Nanoparticles: Formulation, Characterization and Evaluation of Interactions with Biological Barriers

PURPOSE

The aim of this work was to formulate and characterize surfactant-free glibenclamide nanoparticles using Eudragit RLPO and polyethylene glycol as sole stabilizer.

METHODS

Glibenclamide nanoparticles were obtained by nanoprecipitation and evaluated in terms of drug content, encapsulation efficiency, apparent saturation solubility, drug release profile, solid state and storage stability. The influence of different stirring speed on the particle size, size distribution and zeta potential of the nanoparticles was investigated. The nanoparticle biocompatibility and permeability were analyzed in vitro on Caco-2 cell line (clone HTB-37) and its interaction with mucin was also investigated.

RESULTS

It was found that increasing the molecular weight of polyethylene glycol from 400 to 6000 decreased drug encapsulation, whereas the aqueous solubility and dissolution rate of the drug increased. Particle size of the nanoformulations, with and without polyethylene glycol, were between 140 and 460 nm. Stability studies confirmed that glibenclamide nanoparticles were stable, in terms of particle size, after 120 days at 4°C. In vitro studies indicated minimal interactions of glibenclamide nanoparticles and mucin glycoproteins suggesting favorable properties to address the intestinal mucus barrier. Cell viability studies confirmed the safety profile of these nanoparticles and showed an increased permeation through epithelial cells.

CONCLUSION

Taking into consideration these findings, polyethylene glycol is a useful polymer for stabilizing these surfactant-free glibenclamide nanoparticles and represent a promising alternative to improve the treatment of non-insulin dependent diabetes.

Formulation optimization and characterization of transdermal film of curcumin by response surface methodology

Objective

India is referred as goldmine of herbal drugs but still lack of optimization of herbal drugs, which has kept us on the back foot. The rationale of the study is to prepare optimized transdermal drug delivery system of curcumin employing response surface methodology to study the collective effect of independent variables like concentration of ethyl cellulose, hydroxyl propyl methyl cellulose and dibutyl phthalate which significantly influenced characteristics like percentage elongation and in vitro drug release.

Method

Twenty formulations containing varying concentrations of polymers and permeation enhancer were prepared using solvent casting technique.

Result

The study revealed that the effect of dibutyl phthalate (DBP) concentration was the highest on percentage elongation (P < 0.0001), while hydroxy propyl methyl cellulose (HPMC) concentration exhibited pronounced effect on drug release (P < 0.0001) through dialysis membrane. Linear model fitted the best for curcumin release and elongation for all formulations. According to Derringer’s desirability prediction tool, the composition of optimized film was found to be 242.14% of HPMC, 109.59% of ethyl cellulose (EC), and 1.03% of DBP. Under these conditions, the optimized patch exhibited a predicted value of %elongation and in vitro drug release of 94.35% and 80.0306%, respectively, which was comparable to the actual values of percent elongation and in vitro drug release i.e. 95.02% and 81.03% respectively. FTIR and thermal studies were also performed which revealed no interaction or complexation between drug and excipients. The ex vivo study performed using rat skin showed that the cumulative drug release from the optimized patch showed flux of (30.68 ± 18) µg/cm²/h.

Conclusion

It can be concluded that in future if proper optimization of herbal formulations is carried out, they can become the first choice for patients as compare to synthetic drugs.

Nano Encapsulated Curcumin: And Its Potential for Biomedical Applications

Curcumin, a yellow-colored polyphenol extracted from the rhizome of turmeric root, is commonly used as a spice and nutritional supplement. It exhibits many pharmacological activities such as anti-inflammatory, anti-bacterial, anti-cancer, anti-Alzheimer, and anti-fungal. However, the therapeutic application of curcumin is limited by its extremely low solubility in aqueous buffer, instability in body fluids, and rapid metabolism. Nano delivery system has shown excellent potential to improve the solubility, biocompatibility and therapeutic effect of curcumin. In this review, we focus on the recent development of nano encapsulated curcumin and its potential for biomedical applications.

Surface stabilized atorvastatin nanocrystals with improved bioavailability, safety and antihyperlipidemic potential

Atorvastatin, a favored option for hyperlipidemia exhibits the problem of poor gastric solubility and low absolute bioavailability (12%) along with higher pre-systemic clearance (>80%). Therefore, to circumvent these limitations, atorvastatin nanocrystals were prepared using poloxamer-188 as stabilizer via high pressure homogenization technique followed by lyophilization. Various variables like drug to poloxamer-188 ratio, homogenization cycle, homogenization pressure, type and concentration of cryoprotectant were optimized to achieve uniform nanosized crystals with good dispersibility. Solid state characterization by ATR-FTIR and DSC revealed no incompatible physicochemical interaction between drug and excipients in formulation while DSC and PXRD collectively corroborated the reduced crystallinity of drug in nanocrystals. Size analysis and SEM confirmed nanometric size range of nanocrystals (225.43 ± 24.36 nm). Substantial improvement in gastric solubility (~40 folds) and dissolution rate of drug in nanocrystals was observed. Pharmacokinetic study in wistar rats revealed significant improvement in oral bioavailability (~2.66 folds) with atorvastatin nanocrystals compared to pure drug. Furthermore, reduction in serum total lipid cholesterol, LDL and triglyceride content justified the effectiveness of formulation at 50% less dose of atorvastatin along with improved plasma safety profile in comparison of pure drug. In conclusion, atorvastatin nanocrystals are safe and efficacious drug delivery system confirming potent competence in treatment of hyperlipidemic conditions with ease of scalability for commercialization.

Formulation and characterization of glibenclamide and quercetin-loaded chitosan nanogels targeting skin permeation

Aim: Our aim was to develop and characterize a nanogel formulation containing both glibenclamide and quercetin and to explore the permeation profile of this combination. Methods: Drug-loaded nanogel was prepared by ionic gelation. In addition, optimum encapsulation efficiencies of glibenclamide and quercetin were also obtained. The average nanoparticle size at optimum conditions was determined by Zetasizer. Results: The particle size of the nanogel was found to be 370.4 ± 4.78 nm with a polydispersity index of 0.528 ± 0.04, while the λ potential was positive in a range of 17.6 to 24.8 mV. The percentage cumulative drug release also showed favorable findings. Conclusion: The chitosan nanogel could be a potential alternative for delivering glibenclamide and quercetin through skin.

Engineering of solidified glyburide nanocrystals for tablet formulation via loading of carriers: downstream processing, characterization, and bioavailability

INTRODUCTION

Presenting poorly water-soluble drugs as nanoparticles has shown to be an effective technique in enhancing drug dissolution rate, intrinsic solubility, and thus oral bioavailability. Nevertheless, working with nanoparticles introduces many challenges, one of which is their physical instability. Formulating nanoparticles into a solid dosage form may overcome such challenges and thus unlock the potential benefits of nanosizing.

METHODS

The current work investigates the possibility of developing a novel solid dosage form, with enhanced dissolution rate, whereby nanocrystals (~400 nm) of the class II Biopharmaceutical Classification System drug, glyburide (GBD) were fabricated through combined precipitation and homogenization procedures. Using a novel, but scalable, spraying technique, GBD nanocrystals were loaded onto commonly used tablet fillers, water-soluble lactose monohydrate (LAC), and water insoluble microcrystalline cellulose (MCC). Conventional tableting processes were then used to convert the powders generated into a tablet dosage form.

RESULTS

Studies of redispersibility showed considerable preservation of size characteristics of GBD nanocrystals during downstream processing with redispersibility indices of 105 and 118 for GBD-LAC and GBD-MCC, respectively. Characterization by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy showed that the powders generated powders contained nanosized crystals of GBD which adhered to carrier surfaces. Powder flowability was characterized using Hausner ratio (HR) and Carr's index (CI). GBD-LAC-loaded particles exhibited poor flowability with CI and HR of 37.5% and 1.60, respectively, whilst GBD-MCC particles showed a slightly improved flowability with CI and HR of 26.47% and 1.36, respectively. The novel tablet dosage form met US Pharmacopeia specifications, including drug content, hardness, and friability.

CONCLUSION

Higher dissolution rates were observed from the nanocrystal-based tablets compared to the microsized and commercial drug formulations. Moreover, the novel nanocrystal tablet dosage forms showed enhanced in vivo performance with area under the plasma concentration- time curve in the first 24 hours values 1.97 and 2.24 times greater than that of marketed tablets.

Role of Nanotechnology in Diabetic Management

BACKGROUND

Diabetes Mellitus (DM) has emerged as an epidemic that has affected millions of people worldwide in the last few decades. Nanotechnology is a discipline that is concerned with material characteristics at nanoscale and offers novel techniques for disease detection, management and prevention.

OBJECTIVE

Diabetes mellitus is an epidemic disease that has affected millions of people globally. Nanotechnology has greatly enhanced the health status by providing non-obtrusive techniques for the management and treatment of diabetic patients.

METHOD

In diabetes research, the nanotechnology has encouraged the advancement of novel glucose monitoring and several modalities for insulin delivery holding possibilities to enhance the personal satisfaction and life quality for diabetic patients.

RESULT

Nanoparticles hold a great potential in the areas of drug delivery and are explored as vehicles for orally administered insulin formulations. Glucose biosensors equipped with nanoscale materials such as Quantum Dots (QDs), Carbon Nanotubes (CNTs), Magnetic Nanoparticles (MNPs) etc. have shown greater sensitivity. Nanotechnology in diabetic research is heading towards the novel techniques which can provide continuous glucose monitoring offering accurate information and improving patient's compliance.

CONCLUSION

The present review addresses the different aspects of nanoparticles and recent patents related to diabetic management based on nanotechnology.

Nanoparticulate-based drug delivery systems for small molecule anti-diabetic drugs: An emerging paradigm for effective therapy

Emergence of nanoparticulate drug delivery systems in diabetes has facilitated improved delivery of small molecule drugs which could dramatically improve the quality of life for diabetics. Conventional dosage forms of the anti-diabetic drugs exhibit variable/less bioavailability and short half-life, demanding frequent dosing and causing increased side-effects resulting in ineffectiveness of therapy and non-compliance with the patients. Considering the chronic nature of diabetes, nanotechnology-based approaches are more promising in terms of providing site-specific delivery of drugs with higher bioavailability and reduced dosage regimen. Nanomedicines act at the cellular and molecular levels to enhance the uptake of the drug into the cells or block the efflux mechanisms thus retaining the drug inside the cell for a longer duration of time. Many studies have hinted at the possibility of administering peptide drugs like glucagon like peptides orally by encapsulation into nanoparticles. Nanoparticles also allow further modifications including their encapsulation into microparticles, polyethylene glycol (PEG)-PEGylation- or functionalization with ligands for active targeting. Nevertheless, such remarkable benefits are fraught with their long-term safety concerns, regulatory hurdles, limitations of scale-up and ineffective patent protection which have hindered their commercialization. This review summarizes the latest advances in the area of nanoformulations as applied to the delivery of anti-diabetics. STATEMENT OF SIGNIFICANCE: The present work describes the latest advancements in the area of nanoformulations for anti-diabetic therapy along with highlighting the advantages that these nanoformulations offer at molecular level for diabetes. Although several potent orally active anti-hyperglycemic agents are available, the current challenges in efficient management of diabetes include optimization of the present therapies to ensure an optimum and stable level of glucose, and also to reduce the occurrence of long term complications associated with diabetes. Nanoformulations because of their high surface area to volume ratio provide improved efficacy, targeting their delivery to the desired site of action tends to minimize adverse effects and administration of peptide drugs by oral route is also possible by encapsulating them in nanoparticles. As we reflect on the success and failures of latest research on nanoformulations for the treatment of diabetes, it is important not to dwell on lack of FDA approvals but rather define future directions that guarantee more effective anti-diabetic treatment. In proposed review we have explored the latest advancement in anti-diabetic nanotechnology based formulations.

Pramipexole nanocrystals for transdermal permeation: Characterization and its enhancement micro-mechanism

The purpose of the study was to improve transdermal delivery of pramipexole via nanocrystals and investigate the enhancement micro-mechanism. Pramipexole nanocrystals were prepared using wet media milling method and incorporated into carbomer gel. In vitro permeation studies through rabbit ear skin indicated that the cumulative permeation amount of pramipexole from nanocrystals in 24 h was 2.75 times more than that from coarse suspension. Investigations of selective follicular closing technique indicated that approximately 33.88% of the total permeation from nanocrystals was contributed to the follicular pathway, which was confirmed by scanning electron microscopy images. In vitro permeation and in vivo pharmacokinetic studies indicated that pramipexole from nanocrystal gel showed a higher permeation profile than that from coarse suspension gel. Overall, nanocrystals could improve transdermal delivery of pramipexole through transepidermal and transfollicular pathways by the nanosized particles.

Biomaterials for drug delivery patches

The limited efficiency of conventional drugs has been instigated the development of new and more effective drug delivery systems (DDS). Transdermal DDS, are associated with numerous advantages such its painless application and less frequent replacement and greater flexibility of dosing, features that triggered the research and development of such devices. Such systems have been produced using either biopolymer; or synthetic polymers. Although the first ones are safer, biocompatible and present a controlled degradation by human enzymes or water, the second ones are the most currently available in the market due to their greater mechanical resistance and flexibility, and non-degradation over time. This review highlights the most recent advances (mainly in the last five years) of patches aimed for transdermal drug delivery, focusing on the different materials (natural, synthetic and blends) and latest designs for the development of such devices, emphasizing also their combination with drug carriers that enable enhanced drug solubility and a more controlled release of the drug over the time. The benefits and limitations of different patches formulations are considered with reference to their appliance to transdermal drug delivery. Furthermore, a record of the currently available patches on the market is given, featuring their most relevant characteristics. Finally, a list of most recent/ongoing clinical trials regarding the use of patches for skin disorders is detailed and critical insights on the current state of patches for transdermal drug delivery are also provided.

Stabilizing ability of surfactant on physicochemical properties of drug nanoparticles generated from solid dispersions

This study was aimed to examine the nanoparticle formation from redispersion of binary and ternary solid dispersions. Binary systems are composed of various ratios of glibenclamide (GBM) and polyvinylpyrrolidone K30 (PVP-K30), whereas a constant amount at 2.5%w/w of a surfactant, sodium lauryl sulfate (SLS) or Gelucire44/14 (GLC), was added to create ternary systems. GBM nanoparticles were collected after the systems were dispersed in water for 15 min. The obtained nanoparticles were characterized for size distribution, crystallinity, thermal behavior, molecular structure, and dissolution properties. The results indicated that GBM nanoparticles could be formed when the drug content of the systems was lower than 30%w/w in binary systems and ternary systems containing SLS. The particle size ranged from 200 to 500 nm in diameter with narrow size distribution. The particle size was increased with increasing drug content in the systems. The obtained nanoparticles were spherical and showed the amorphous state. Furthermore, because of being amorphous form and reduced particle size, the dissolution of the generated nanoparticles was markedly improved compared with the GBM powder. In contrast, all the ternary solid dispersions prepared with GLC anomalously provided the crystalline particles with the size ranging over 5 µm and irregular shape. Interestingly, this was irrelevant to the drug content in the systems. These results indicated the ability of GLC to destabilize the polymer network surrounding the particles during particle precipitation. Therefore, this study suggested that drug content, quantity, and type of surfactant incorporated in solid dispersions drastically affected the physicochemical properties of the precipitated particles.