Preparation and in vitro evaluation of Eudragit microspheres containing acetazolamide

Novel Sustained Release Azithromycin Resinate Fabricated by One-Pot Ion-exchange Performed in Hydro-alcoholic Solution

Drug-resin complexes usually form in the aqueous phase. For poorly water-soluble drugs, low drug loading limits the use of resin in drug formulation. In this study, we used a new method to prepare azithromycin resinates, improving the drug loading rate, shortening the preparation time and simplifying the process. We used hydro-alcoholic solution as the drug loading solvent and the ion exchange resin as the carrier, and this method enabled the resin to adsorb both the retardant and the drug. The sustained release effect of retardant Eudragit RL, RS100 was analyzed. Drug loading efficiency, release profiles, morphology, physicochemical characterization and pharmacokinetic study were assessed. Preparation of drug resinate by batch method resulted in 14% higher drug loading of azithromycin and 3.5 h shorter loading time as compared to pure water for hydroalcoholic solution as drug loading solvent. Raman mappings demonstrated that the retardant with higher molecular weight was more likely to adsorb to the outer layer of the resin compared to the drug. The in vitro release and in vivo pharmacokinetic study of azithromycin resinates showed a sustained release profile with few gastrointestinal adverse effects. Therefore, the addition of ethanol not only improved the efficiency of drug loading but also showed sustained-release effect with one-pot preparation of azithromycin resinates.

Carvacrol nanocapsules as a new antifungal strategy: Characterization and evaluation against fungi important for grape quality and to control the synthesis of ochratoxins

Fungi are a problem for viticulture as they can lead to deterioration of grapes and mycotoxins production. Despite the widespread use of synthetic fungicides to control fungi, their impact on the agricultural ecosystem and human health demand safer and eco-friendly alternatives. This study aimed to produce, characterize and assess the antifungal activity of carvacrol loaded in nanocapsules of Eudragit® and chia mucilage as strategy for controlling Botrytis cinerea, Aspergillus flavus, Aspergillus carbonarius, and Aspergillus niger. Eudragit® and chia mucilage were suitable wall materials, as both favored the encapsulation of carvacrol into nanometric diameter particles. Fourier Transform Infrared Spectroscopy (FTIR) analysis suggested a successful incorporation of carvacrol into both nanocapsules, which was confirmed by presenting a good encapsulation efficiency and loading capacity. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) analyses revealed adequate thermal resistance. All fungi were sensible to carvacrol treatments and B. cinerea was the most sensitive compared to the Aspergillus species. Lower concentrations of encapsulated carvacrol than the unencapsulated form were required to inhibit fungi in the in vitro and grape assays. Additionally, lower levels of carvacrol (unencapsulated or encapsulated) were used to inhibit fungal growth and ochratoxin synthesis on undamaged grapes in comparison to those superficially damaged, highlighting the importance of management practices designed to preserve berry integrity during cultivation, storage or commercialization. When sublethal doses of carvacrol were used, the growth of A. niger and A. carbonarius was suppressed by at least 45 %, and ochratoxins were not found. The nanoencapsulation of carvacrol using Eudragit® and chia mucilage has proven to be an alternative to mitigate the problems with fungi and mycotoxins faced by the grape and wine sector.

Unveiling the potentials of hydrophilic and hydrophobic polymers in microparticle systems: Opportunities and challenges in processing techniques

Conventional drug delivery systems are associated with various shortcomings, including low bioavailability and limited control over release. Biodegradable polymeric microparticles have emerged as versatile carriers in drug delivery systems addressing all these challenges. This comprehensive review explores the dynamic landscape of microparticles, considering the role of hydrophilic and hydrophobic materials. Within the continuously evolving domain of microparticle preparation methods, this review offers valuable insights into the latest advancements and addresses the factors influencing microencapsulation, which is pivotal for harnessing the full potential of microparticles. Exploration of the latest research in this dynamic field unlocks the possibilities of optimizing microencapsulation techniques to produce microparticles of desired characteristics and properties for different applications, which can help contribute to the ongoing evolution in the field of pharmaceutical science.

Development of direct compression Acetazolamide tablet with improved bioavailability in healthy human volunteers enabled by cocrystallization with p-Aminobenzoic acid

Pharmaceutical cocrystallization has been widely used to improve physicochemical properties of APIs. However, developing cocrystal formulation with proven clinical success remains scarce. Successful translation of a cocrystal to suitable dosage forms requires simultaneously improvement of several deficient physicochemical properties over the parent API, without deteriorating other properties critical for successful product development. In the present work, we report the successful development of a direct compression tablet product of acetazolamide (ACZ), using a 1:1 cocrystal of acetazolamide with p-aminobenzoic acid (ACZ-PABA). The ACZ-PABA tablet exhibits superior biopharmaceutical performance against the commercial tablet, DIAMOX® (250 mg), in healthy human volunteers, leading to more than 50 % reduction in the required dose.

Layer-by-Layer Vaginal Films for Acyclovir Controlled Release to Prevent Genital Herpes

Genital herpes is one of the most common sexually transmitted infections worldwide. It mainly affects women, as the rate of sexual transmission from male-to-female is higher than from female-to-male. The application of vaginal antivirals drugs could reduce the prevalence of genital herpes and prevent future infections. Layer-by-layer vaginal films were prepared by the solvent evaporation method using iota-carrageenan, hydroxypropyl methylcellulose and the polymethacrylates Eudragit® RS PO and Eudragit® S100, for the controlled release of acyclovir. The films were characterized by texture analysis and Raman spectroscopy. Swelling, mucoadhesion, and drug release studies were conducted in simulated vaginal fluid. The results show that Layer-by-Layer films exhibited adequate mechanical properties. The structuring of the layer-by-layer films allowed the controlled release of acyclovir and produced a prolonged mucoadhesion residence time of up to 192h. The films formed in layer 2 by the combination of Eudragit® RS PO and S100 showed a controlled release of acyclovir for eight days, and adequate mechanical properties. These promising formulations for the prevention of genital herpes deserve further evaluation.

Investigating preparation and characterisation of diphtheria toxoid-loaded on sodium alginate nanoparticles

This paper aims to investigate the preparation and characterisation of the alginate nanoparticles (NPs) as antigen delivery system loaded by diphtheria toxoid (DT). For this purpose, both the loading capacity (LC) and Loading efficiency (LE) of the alginate NPs burdened by DT are evaluated. Moreover, the effects of different concentrations of sodium alginate and calcium chloride on the NPs physicochemical characteristics are surveyed in addition to other physical conditions such as homogenization time and rate. To do so, the NPs are characterised using particle size and distribution, zeta potential, scanning electron microscopy, encapsulation efficiency, in vitro release study and FT‐IR spectroscopy. Subsequently, the effects of homogenization time and rate on the NPs are assessed. At the meantime, the NPs LC and efficiency in several DT concentrations are estimated. The average size of the NPs was 400.7 and 276.6 nm for unloaded and DT loaded, respectively. According to the obtained results, the zeta potential of the blank and DT loaded NPs are estimated as −23.7 mV and −21.2 mV, respectively. Whereas, the LC and LE were >80% and >90%, in that order. Furthermore, 95% of the releasing DT loaded NPs occurs at 140 h in the sustained mode without any bursting release. It can be concluded that the features of NPs such as morphology and particle size are strongly depended on the calcium chloride, sodium alginate concentrations and physicochemical conditions in the NPs formation process. In addition, appropriate concentrations of the sodium alginate and calcium ions would lead to obtaining the desirable NPs formation associated with the advantageous LE, LC (over 80%) and sustained in vitro release profile. Ultimately, the proposed NPs can be employed in vaccine formulation for the targeted delivery, controlled and slow antigen release associated with the improved antigen stability.

Oseltamivir phosphate loaded pegylated-Eudragit nanoparticles for lung cancer therapy: Characterization, prolonged release, cytotoxicity profile, apoptosis pathways and in vivo anti-angiogenic effect by using CAM assay

The target of the current investigation was the delivery of oseltamivir phosphate (OSE) into the lung adenocarcinoma tissues by means of designing nanosized, non-toxic and biocompatible pegylated Eudragit based NPs and investigating their anticancer and antiangiogenic activity. The rationale for this strategy is to provide a novel perspective to cancer treatment with OSE loaded pegylated ERS NPs under favor of smaller particle size, biocompatible feature, cationic characteristic, examining their selective effectiveness on lung cell lines (A549 lung cancer cell line and CCD-19Lu normal cell line) and examining antiangiogenic activity by in vivo CAM analysis. For this purpose, OSE encapsulated pegylated ERS based NPs were developed and investigated for zeta potential, particle size, encapsulation efficiency, morphology, DSC, FT-IR, ¹H NMR analyses. In vitro release, cytotoxicity, determination apoptotic pathways and in vivo CAM assay were carried out. Considering characterizations, NPs showed smaller particle size, cationic zeta potential, relatively higher EE%, nearly spherical shape, amorphous matrix formation and prolonged release pattern (Peppas-Sahlin and Weibull model with Fickian and non-Fickian release mechanisms). Flow cytometry was used to assess the apoptotic pathways using the Annexin V-FITC/PI staining assay, FITC Active Caspase-3 staining assay, and mitochondrial membrane potential detection tests. Activations on caspase-3 pathways made us think that OSE loaded pegylated ERS NPs triggered to apoptosis using intrinsic pathway. As regards to the in vivo studies, OSE loaded pegylated ERS based NPs demonstrated strong and moderate antiangiogenic activity for ERS-OSE 2 and ERS-OSE 3, respectively. With its cationic character, smaller particle size, relative superior EE%, homogenous amorphous polymeric matrix constitution indicated using solid state tests, prolonged release manner, highly selective to the human lung adenocarcinoma cell lines, could trigger apoptosis intrinsically and effectively, possess good in vivo antiangiogenic activity, ERS-OSE 2 formulation is chosen as a promising candidate and a potent drug delivery system to treat lung cancer.

Statistically optimized pentazocine loaded microsphere for the sustained delivery application: Formulation and characterization

Pentazocine (PTZ) is a narcotic analgesic used to manage moderate to severe, acute and chronic pains. In this study, PTZ loaded Ethyl cellulose microsphere has been formulated for sustained release and improved bioavailability of PTZ. These microspheres were fabricated by oil in water emulsion solvent evaporation technique. A three factorial, three levels Box-Behnken design was applied to investigate the influence of different formulation components and process variables on the formulation response using the numeric approach through the design expert^® software. All the formulations were characterized for the morphology, different physicochemical properties and the results were supported with the ANOVA analysis, three dimensional contour graphs and regression equations. The maximum percentage yield was 98.67% with 98% entrapment of PTZ. The mean particle size of the formulations ranges from 50–148μm, which directly relates to the concentration of polymer and inversely proportional to the stirring speed. SEM revealed the spherical shape of PTZ microspheres with porous structures. These are physically, chemically and thermally stable as confirmed through Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD) and thermal gravimetric (TG) analysis respectively. The microspheres provided a sustained release of the PTZ for more than 12 hours, following zero order with fickian and non fickian diffusion. The results indicate that prepared microspheres can be a potential drug delivery system (DDS) for the delivery of PTZ in the management of pains.

Evaluation of Low Molecular Weight Cross Linked Chitosan Nanoparticles, to Enhance the Bioavailability of 5-Flourouracil

The present study aimed to formulate 5-fluorouracil loaded cross linked chitosan nanoparticles based on chemical cross-linking of low molecular weight chitosan with glutaraldehyde by reverse micelles technique as 5-FU is less hydrophobic, relatively potent, has a shorter half-life, is rapidly metabolized, less tolerated, and has low oral bioavailability; therefore, we aimed to formulate potential nanocarriers of 5-FU for efficient drug delivery to specific targeted areas of action, reduce oral toxicity, improve tolerability and therapeutic outcomes of 5-FU, in a restricted fashion to enhance the bioavailability of 5-FU. Nanoparticles were formulated by the reverse micelle method based on the chemical cross-linking of glutaraldehyde (25% aqueous solution) into a w/o emulsion in different ratios. LMWCH-NPs were characterized for post-formulation parameters by mean particle size, zeta potential, %age yield, loading/entrapment efficiency, Fourier transform infrared spectroscopy (FTIR), DSC/TGA, TEM, PXRD, drug release at pH 1.2, and pH 7.4. 5-FU loaded NPs showed a size range (198 nm-200 nm) and zeta potential (-39mV to -41mV), which ensured mechanical stability and increased retention time in blood vessels by the sustained release properties of biodegradable nanocarrier drug delivery systems. % age yield showed the range 92% to 96% while % LC ranged 2.0% to 3.4% and %EE ranged 40% to 43%. The TEM images showed spherical nanoparticles. FTIR revealed the compatibility between the drug and the cross-linked polymer. DSC/TGA ensured the thermal stability of the drug, while the solid-state stability of the drug-loaded cross-linked chitosan nanoparticles was evaluated by powder X-ray diffraction (PXRD) analysis. Drug release studies were performed using the dialysis bag technique at both pH (1.2 and 7.4) to mimic the gastrointestinal tract. Highly stable NPs displayed targeted release in phosphate buffer pH 7.4 at 37°C. Fickian diffusion was the predominant release with an R2 value of 0.9975-0.9973-and an N value 0.45-0.53. Prepared nanoparticles are inert, biodegradable, and biocompatible drug delivery systems for sustained release of 5-FU with maximum therapeutic efficacy and bioavailability.

Micro-interaction of mucin tear film interface with particles: The inconsistency of pharmacodynamics and precorneal retention of ion-exchange, functionalized, Mt-embedded nano- and microparticles

Physiological reflexes and anatomical barriers render traditional eye drop delivery inefficient. We previously reported that drug-loaded nanoparticles and microspheres prepared from montmorillonite and Eudragit polymers exhibited good sustained-release and lowered intraocular pressure. Here, we compared the performance of optimized formulations to select the most suitable formulation for glaucoma therapy. We found that the microspheres had much higher encapsulation efficiency and drug loading than nanoparticles. Moreover, cytocompatibility experiments demonstrated that nanoparticles showed more severe cytotoxicity than microspheres, probably due to their smaller particles, enhanced cell uptake, and intracellular solubility. Interestingly, the pre-corneal retention time of nanoparticles reflected a clear advantage over microspheres, while the duration of the pharmacological effect of nanoparticles was not as good as that of microspheres: compared with the nanoparticle depressurization duration of only 8 h, the microspheres continuously depressurized for 12 h. The slower release of the microspheres and its micro-interaction mechanism with the discontinuous mucin layer of the tear film led to the inconsistency between duration of pharmacodynamics and fluorescence ocular retention time. In summary, the lower cytotoxicity and longer pharmacological effect of microspheres indicate their potential advantages for glaucoma applications.

Preparation and Biopharmaceutical Evaluation of Novel Polymeric Nanoparticles Containing Etoposide for Targeting Cancer Cells

Objectives

Polymeric nanoparticles are a promising novel drug delivery system and have advantages in cancer therapy. Etoposide is an anticancer agent that is used in the treatment of a variety of malignancies. The aim of the present study was to prepare and evaluate novel polymeric nanoparticles containing etoposide.

Materials and Methods

A 3² full factorial design was used to study the effect of Eudragit EPO and Pluronic F-68 on the characterization of nanoparticle suspensions. The polymeric nanoparticles were prepared by nanoprecipitation technique. The prepared nanoparticles was evaluated by percentage yield, drug polymer compatibility using fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetric (DSC) analysis, drug content, entrapment efficiency, zeta potential, particle size, scanning electron microscopy, X-ray diffraction, in vitro drug release studies, kinetic modeling, stability studies, and in vivo animal studies. Response surface plots were studied, which were generated using PCP dissolution software.

Results

Scanning electron microscopic studies confirmed their porous structure with a number of nanochannels. The FTIR spectra showed the stable character of etoposide in a mixture of polymers and revealed the absence of drug-polymer interactions. The DSC study revealed that the drug was involved in complexation with nanoparticles. The average particle size of etoposide nanoparticles was in the range of 114.4 nm to 136.7 nm. The zeta potential values were attained to ensure good stability of nanosuspensions. In vitro release of the drug from nanoparticles follows the Peppas model and showed controlled release behavior for a period of 24 h. The optimized nanoparticles were subjected to stability studies at 4°C in a refrigerator and the most suitable temperature for storage of etoposide nanoparticles found. The average targeting efficiency of drug-loaded nanoparticles was 41.88±0.030% of the injected dose in the liver, 25.66±0.320% in the spleen 13.82±0.090% in the lungs, 4.52±0.300% in the kidney, and 4.18±0.490% in the brain.

Conclusion

Etoposide loaded nanoparticles was found to be effective in sustained release.

Polymeric Nanocapsules as Nanotechnological Alternative for Drug Delivery System: Current Status, Challenges and Opportunities

Polymer-based nanocapsules have been widely studied as a potential drug delivery system in recent years. Nanocapsules-as one of kind nanoparticle-provide a unique nanostructure, consisting of a liquid/solid core with a polymeric shell. This is of increasing interest in drug delivery applications. In this review, nanocapsules delivery systems studied in last decade are reviewed, along with nanocapsule formulation, characterizations of physical/chemical/biologic properties and applications. Furthermore, the challenges and opportunities of nanocapsules applications are also proposed.

Identification of a previously unreported co-crystal form of acetazolamide: a combination of multiple experimental and virtual screening methods

In this work, we demonstrate an approach of trying multiple methods in a more comprehensive search for co-crystals of acetazolamide.

Targeted Release of Probiotics from Enteric Microparticulated Formulations

The development of advanced probiotic delivery systems, which preserve bacteria from degradation of the gastrointestinal tract and achieve a targeted release mediated by pH-independent swelling, is of great interest to improve the efficient delivery of probiotic bacteria to the target tissue. Gram-positive and Gram-negative bacteria models (Lactobacillus acidophilus (Moro) Hansen and Mocquot (ATCC® 4356™) and Escherichia coli S17, respectively) have been successfully encapsulated for the first time in pH-independent microparticulate polymethacrylates (i.e., Eudraguard biotic) used for the targeted delivery of nutraceuticals to the colon. These bacteria have also been encapsulated within the mucoadhesive polymethacrylate Eudragit RS 100 widely used as targeted release formulation for active pharmaceutical ingredients. The enteric microparticles remained unaltered under simulated gastric conditions and released the contained viable microbial cargo under simulated intestinal conditions. Buoyancies of 90.2% and 57.3% for Eudragit and Eudraguard microparticles, respectively, and long-term stability (5 months) for the encapsulated microorganisms were found. Cytotoxicity of the microparticles formulated with both polymers was evaluated (0.5-20 mg/mL) on Caco-2 cells, showing high cytocompatibility. These results underline the suitability of the synthesized materials for the successful delivery of probiotic formulations to the target organ, highlighting for the first time the potential use of Eudraguard biotic as an effective enteric coating for the targeted delivery of probiotics.

Zein-alpha lipoic acid-loaded nanoparticles to enhance the oral bioavailability of dapoxetine: optimization and clinical pharmacokinetic evaluation

Background

Premature ejaculation (PE) is the most common type of male sexual disorder with important psychological consequences. Dapoxetine (DPX), a recently approved drug for the treatment of PE, suffers from low bioavailability with large variability that ranges from 15–76% (mean 42%) after oral administration. The objective of this study is to optimize the parameters for the preparation of DPX-Zein-alpha lipoic acid (ALA) nanoparticles (NPs) to improve the bioavailability of DPX and consequently decrease therapeutic dose and adverse effect, leading to patient satisfaction and compliance.

Methods

We investigated the effect of ALA concentration, PVA concentration and stirring rate on nanoparticle size (Y₁), zeta potential (Y₂), initial DPX release (Y₃) and cumulative DPX release (Y₄). In addition, in vivo pharmacokinetic study was performed for the optimized DPX formulation on human healthy volunteers compared with marketed DPX tablet.

Results

The optimized DPX-loaded NPs showed Y₁, Y₂, Y₃, and Y₄ of 159.24 nm, 19.14 mV, 25.31% and 95.9 %, respectively. A single oral dose of 30 mg of optimized DPX-loaded NPs to human volunteers resulted in 2-fold improvement of AUC (1376.145±339.592 vs 709.178±146.307 in DPX), 4-fold increase in t_max (2.5±0.314 vs 0.583±0.144), prolongation of MRT (7.637±1.373 compared to 6.031±1.826 h), but with reduction in t_1/2 (5.283±1.077 vs 8.452±2.813).

Conclusion

The clinical findings suggest 194% enhancement of relative bioavailability of the optimized DPX-loaded NPs, potentially leading to a decrease in therapeutic dose and associated side effects in the treatment of PE.

Enhanced antibacterial activity of Egyptian local insects' chitosan-based nanoparticles loaded with ciprofloxacin-HCl

Chitosan (CS), possess enormous properties, being biodegradable, biocompatible, and antimicrobial. CS could be formulated and casted into different forms including 2D films, hydrogels, and nanoparticles. Chitosan-based nanoparticles (CSNPs) showed countless interest as polymeric drug delivery system (DDS) with its improved bioavailability, and stability when compared with traditional DDS. Ciprofloxacin is a prescribed antibiotic for many diseases, but its efficiency was affected by antibacterial resistance. Therefore, in this study, CSNPs loaded with ciprofloxacin (Cipro/CSNPs) were prepared from CS isolated from desert locusts, beetles, honey bee exoskeletons, and shrimp shells were used as a standard control. CSNPs were formulated by ionic crosslinking method, then loaded with ciprofloxacin HCl, and characterized using particle size distribution, zeta potential, and drug entrapment efficiency. The release of ciprofloxacin from CSNPs was evaluated and its kinetic modelling was performed. Antibacterial activity of CSNPs was evaluated against Escherichia coli, Bacillus thuringiensis, Methicillin-resistant Staphylococcus aureus (MRSA) and, Pseudomonas aeruginosa. Minimum inhibitory concentrations (MIC) were determined and compared between chitosan sources. The Cipro/CSNPs results indicate that the highest antibacterial activity against E. coli and MRSA with MIC varying from 0.0043 to 0.01 μg/ml and from 0.07 to 0.14 μg/ml, respectively. In addition, CSNPs enhanced drug delivery, and allowed its controlled release.

Efficacy of a Eudragit L30D-55 encapsulated oral vaccine containing inactivated bacteria (Lactococcus garvieae/Streptococcus iniae) in rainbow trout (Oncorhynchus mykiss)

The efficacy of a Eudragit L30D-55 encapsulated vaccine against Lactococcus garvieae and Streptococcus iniae was investigated in rainbow trout. Fish were divided into four groups and fed the different experimental feeds. Groups were: A) fish immunized by Eudragit-coated pellets containing vaccine, B) fish immunized by vaccine-coated pellets without Eudragit, C) fish fed Eudragit-coated pellets without vaccine and D) fish fed pellets without vaccine orEudragit (control group). In groups A and B, the vaccination was conducted for 14 days. Similar to groups A and B, fish of group C were fed 14 days with pellets coated with Eudragit and afterwards they were fed control diet. Serum samples were taken on day 0, 20, 40 and 60 of the experiment. After 60 days, fish were challenged with L. garvieae and S. iniae. In almost all groups, innate immunity components including alternative complement activity, lysozyme activity, bactericidal activity, IgM and total protein showed no significant changes during the 60 days that the experiment lasted. However, the blood respiratory burst activity and lysozyme activity showed a significant increase on day 20 of experiment in groups B and D respectively (P < 0.05). The relative expression of immune-related genes including IL-6 and IgM genes was higher in vaccinated fish, with the highest expression in those immunized by Eudragit-coated pellets (Group A). In addition, the relative expression of IL-6 and IgM peaked on day 20 but decreased on day 60 in vaccinated groups. The ELISA antibody titer against L. garvieae increased from day 20 and peaked on day 60 of experiment (P < 0.05). Also, the antibody titer against L. garvieae was higher in fish immunized by Eudragit-coated pellets (Group A) compared to fish of group C and control. After bacterial challenge, a survival percentages of % 85 ± 7.07% (challenged with S. iniae) and % 72.21 ± 7.8% (challenged with L. garvieae) were observed respectively in groups immunized with pellets coated with Eudragit L30D-55 (Group A), which were higher than survival percentages obtained in other experimental groups (P < 0.05). The results of the present study demonstrate that the oral administration of Eudragit L30D-55-encapsulated vaccine appropriately protects rainbow trout against Lactococcus garvieae and Streptococcus iniae.

Gemcitabine hydrochloride microspheres used for intravesical treatment of superficial bladder cancer: a comprehensive in vitro/ex vivo/in vivo evaluation

INTRODUCTION

Bladder cancer is responsible for more than 130,000 deaths annually worldwide. Intravesical delivery of chemotherapeutic agents provides effective drug localization to the target area to reduce toxicity and increase efficacy. This study aimed to develop an intravesical delivery system of gemcitabine HCl (Gem-HCl) to provide a sustained-release profile, to prolong residence time, and to enhance its efficiency in the treatment of bladder cancer.

MATERIALS AND METHODS

For this purpose, bioadhesive microspheres were successfully prepared with average particle size, encapsulation efficiency, and loading capacity of 98.4 µm, 82.657%±5.817%, and 12.501±0.881 mg, respectively. For intravesical administration, bioadhesive microspheres were dispersed in mucoadhesive chitosan or in situ poloxamer gels and characterized in terms of gelation temperature, viscosity, mechanical, syringeability, and bioadhesive and rheological properties. The cytotoxic effects of Gem-HCl solution, Gem-HCl microspheres, and Gem-HCl microsphere-loaded gel formulations were evaluated in two different bladder cancer cell lines: T24 (ATCC HTB4TM) and RT4 (ATCC HTB2TM).

RESULTS

According to cell-culture studies, Gem-HCl microsphere-loaded poloxamer gel was more cytotoxic than Gem-HCl microsphere-loaded chitosan gel. Antitumor efficacy of newly developed formulations were investigated by in vivo studies using bladder-tumor-induced rats.

CONCLUSION

According to in vivo studies, Gem-HCl microsphere-loaded poloxamer gel was found to be an effective and promising alternative for current intravesical delivery-system therapies.

Controlled drug delivery for glaucoma therapy using montmorillonite/Eudragit microspheres as an ion-exchange carrier

Background

Glaucoma is a serious eye disease that can lead to loss of vision. Unfortunately, effective treatments are limited by poor bioavailability of antiglaucoma medicine due to short residence time on the preocular surface.

Materials and methods

To solve this, we successfully prepared novel controlled-release ion-exchange microparticles to deliver betaxolol hydrochloride (BH). Montmorillonite/BH complex (Mt-BH) was prepared by acidification-intercalation, and this complex was encapsulated in microspheres (Mt-BH encapsulated microspheres [BMEMs]) by oil-in-oil emulsion-solvent evaporation method. The BH loaded into ion-exchange Mt was 47.45%±0.54%. After the encapsulation of Mt-BH into Eudragit microspheres, the encapsulation efficiency of BH into Eudragit microspheres was 94.35%±1.01% and BH loaded into Eudragit microspheres was 14.31%±0.47%.

Results

Both Fourier transform infrared spectra and X-ray diffraction patterns indicated that BH was successfully intercalated into acid-Mt to form Mt-BH and then Mt-BH was encapsulated into Eudragit microspheres to obtain BMEMs. Interestingly, in vitro release duration of the prepared BMEMs was extended to 12 hours, which is longer than both of the BH solution (2.5 hours) and the conventional BH microspheres (5 hours). Moreover, BMEM exhibited lower toxicity than that of BH solution as shown by the results of cytotoxicity tests, chorioallantoic membrane-trypan blue staining, and Draize rabbit eye test. In addition, both in vivo and in vitro preocular retention capacity study of BMEMs showed a prolonged retention time. The pharmacodynamics showed that BMEMs could extend the drug duration of action.

Conclusion

The developed BMEMs have the potential to be further applied as ocular drug delivery systems for the treatment of glaucoma.

Synthesis and Swelling Behavior of pH-Sensitive Semi-IPN Superabsorbent Hydrogels Based on Poly(acrylic acid) Reinforced with Cellulose Nanocrystals

pH-sensitive poly(acrylic acid) (PAA) hydrogel reinforced with cellulose nanocrystals (CNC) was prepared. Acrylic acid (AA) was subjected to chemical cross-linking using the cross-linking agent MBA (N,N-methylenebisacrylamide) with CNC entrapped in the PAA matrix. The quantity of CNC was varied between 0, 5, 10, 15, 20, and 25 wt %. X-ray diffraction (XRD) data showed an increase in crystallinity with the addition of CNC, while rheology tests demonstrated a significant increase in the storage modulus of the hydrogel with an increase in CNC content. It was found that the hydrogel reached maximum swelling at pH 7. The potential of the resulting hydrogels to act as drug carriers was then evaluated by means of the drug encapsulation efficiency test using theophylline as a model drug. It was observed that 15% CNC/PAA hydrogel showed the potential to be used as drug carrier system.

Development of Eudragit RS 100 Microparticles Loaded with Ropinirole: Optimization and In Vitro Evaluation Studies

The current study aimed to develop novel pH independent microparticles loaded with ropinirole (ROP) for sustained drug release. Eudragit RS 100 was used as release retardant and microparticles were fabricated by oil-in-oil emulsion solvent evaporation method. A three-factor three-level Box-Behnken design using Design-Expert software was employed to optimize formulation variables. Ropinirole loaded microparticles were evaluated with respect to morphology, particle size, encapsulation efficiency, and in vitro release profile. Optical microscopy and SEM micrographs indicated spherical shape with smooth surface and well-defined boundary. The particle size was in the range of 98.86 to 236.29 μm, being significantly increased with increasing polymer concentration. Higher polymer load also increased the thickness of internal polymer network, which led to reduced drug loss and higher entrapment efficiency (89%). The cumulative in vitro release was found to be in the range of 54.96 to 99.36% during the release studies (12 h) following zero order release kinetics and non-Fickian diffusion pattern. The developed microparticles have the potential to sustain the release of ropinirole, which may lead to a reduction in its adverse effects and improved management of Parkinson's disease.

Synthesis of xanthan gum graft copolymer and its application for controlled release of highly water soluble Levofloxacin drug in aqueous medium

Graft copolymers (XG-g-PNVP-1 to XG-g-PNVP-5) of xanthan gum (XG) and poly(N-vinyl-2-pyrrolidone) (PNVP) was synthesized by free radical polymerization using peroxymonosulphate/thiourea redox pair. The synthesized graft copolymers were well characterized by ¹H NMR, FTIR, XRD, SEM, TGA/DTA and AFM analyses. The optimum conditions for maximum grafting were determined by varying the concentrations of N-vinyl-2-pyrrolidone (NVP) from 10×10^-2 to 18×10^-2moldm^-3; the grafting ratios increases up to 14×10^-2moldm^-3, while thereafter decreased. Graft copolymer (XG-g-PNVP-D) hybrid was prepared to load levofloxacin drug, about 15mg drug was loaded; and its release was studied in phosphate buffer solution (PBS) at pH 7.4 on 37±0.1°C; About 80% drug was released in 36h.

Comparison of Different Nanosuspensions as Potential Ophthalmic Delivery Systems for Ketotifen Fumarate

Purpose: The objective of this study was to develop, characterize, and comparatively investigate the ketotifen fumarate (KF) nanosuspensions (NS_S) to enhance the permeability of KF. Methods: In the present work, the NS_P and NS_E were prepared by double-emulsion solvent evaporation/nanoprecipitation methods with poly (D,Llactide-co-glycolide) and Eudragit RL100 polymers, respectively. The loading efficiency, particle size, and polydispersity index of prepared different NSs were evaluated with scanning electron microscopy (SEM), X-ray diffraction, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and in vitro release and transcorneal permeation . NSs were also compared on the basis of particle size and polydispersity index. Results: Particle size, polydispersity index, and loading efficiency of NS_P1 and NS_E3 showed the best value (158 nm, 117 nm, 0.21, 0.43 and 43%, 95.23%, respectively). SEM showed spherical globules and DSC results showed the reduction in crystallinity. The NS_E3 formulations demonstrated significantly (p<0.05) higher drug release rates than the NS_P1 due to increases in the surface area. Comparative studies showed that NS_E release and permeability are higher than NS_P. Conclusion: It is concluded that both NS_P and NS_E provide a useful dosage form for the ocular drug delivery which can enhance the permeability of KF.

Formulation, characterization and evaluation of the effect of polymer concentration on the release behavior of insulin-loaded Eudragit(®)-entrapped mucoadhesive microspheres

Introduction:

The aim of this study was to use Eudragit^® RL 100 (pH-independent polymer) and magnesium stearate (a hydrophobic droplet stabilizer) in combination to improve the controlled release effect of insulin-loaded Eudragit^® entrapped microspheres prepared by the emulsification-coacervation technique.

Materials and Methods:

Mucoadhesive insulin-loaded microspheres containing magnesium stearate and varying proportions of Eudragit^® RL 100 were prepared by the emulsification-coacervation technique and evaluated for thermal properties, physicochemical performance, and in vitro dissolution in acidic and subsequently basic media.

Results:

Stable, spherical, brownish, discrete, free-flowing and mucoadhesive insulin-loaded microspheres with size range of 14.20 ± 0.30-19.80 ± 0.60 μm and loading efficiency of 74.55 ± 1.05-75.90 ± 1.94% were formed. After 3 h, microspheres prepared with insulin: Eudragit^® RL 100 ratios of 1:4, 1:6, and 1:8 released 73.40 ± 1.38, 66.20 ± 1.59, and 71.30 ± 1.27 (%) of insulin, respectively.

Conclusion:

The physicochemical and physico-technical properties of the microspheres developed in this study demonstrated the effectiveness of the Eudragit^® RL entrapped mucoadhesive microspheres (prepared by the emulsification-coacervation technique using varying polymer concentration) as a carrier system for oral insulin delivery.

Maximizing the encapsulation efficiency and the bioavailability of controlled-release cetirizine microspheres using Draper-Lin small composite design

This study was aimed at developing a controlled-release cetirizine hydrochloride (CTZ)-loaded polymethacrylate microsphere by optimization technique using software-based response surface methodology. The emulsion solvent evaporation method was utilized in the preparation of microspheres. Four process variables were selected, namely, Eudragit RLPO loading percentage in total polymer, the emulsifier hydrophilic lipophilic balance (HLB), the antitacking percentage, and the dispersed phase volume. The desired responses were particle size, angle of repose, production yield, encapsulation efficiency, loading capacity, initial drug release, and the time for 85% of drug release from the microspheres. Optimization was carried out by fitting the experimental data to the software program (Statgraphics Centurion XV). Moreover, 18 batches were subjected to various characterization tests required for the production of dosage form. The pharmacokinetic parameters were evaluated after the oral administration of 10 mg CTZ in both optimized formulation and commercial product on healthy human volunteers using a double-blind, randomized, cross-over design. The optimized formulation showed satisfactory yield (84.43%) and drug encapsulation efficiency (87.1%). Microspheres were of spherical shape, smooth surface, and good flowability with an average size of 142.3 μm. The developed optimized batch of microspheres ensured 28.87% initial release after 2 hours, and the release of CTZ extended for >12 hours. In addition, the relative bioavailability of the optimized formulation was 165.5% with respect to the marketed CTZ tablets indicating a significant enhancement of CTZ bioavailability. Thus, there is an expectation to decrease the administered dose and the frequency of administration, and subsequently minimize the adverse effects that are faced by the patient during the treatment.

Metrodidazole In Situ Forming Eudragit RS Gel Comprising Different Solvents

In situforming gel with solvent exchange mechanism is one of drug delivery systems for periodontitis treatment. The system is injected into the desired site then transforms into a gel state when the solvent diffuses out and aqueous diffuses in. Thein situforming Eudragit RSgels loading 1, 5 and 10%w/w metronidazole (MT) were developed in this study usingN-methyl pyrrolidone (NMP), 2-pyrrolidone and dimethyl sulfoxide (DMSO) as solvent. The viscosity of the gel systems in all solvents were increased as drug or polymer amount was increased with Newtonian flow behavior. Transformation into gel was evident after initiated the systems in phosphate buffer pH 6.8. NMP systems exhibited the lowest work of syringeability through 18 G syringe. Drug release from dialysis tube of DMSO systems was slower than that of NMP and 2-pyrrolidone systems, respectively. Antimicrobial activity againstStaphylococcus aureusof the systems comprising MT using NMP as solvent was greater than that using 2-pyrrolidone and DMSO, respectively, which the antimicrobial activity was increased as the drug amount was increased. Therefore, the solvent type affected the viscosity, gel formation, syringeability, drug release and antimicrobial activity of Eudragit RS systems. These developed systems sustained the drug release and inhibited the bacterial growth hence they were interesting systems for periodontitis treatment.

Formulation and in vitro characterization of poly(dl-lactide-co-glycolide)/Eudragit RLPO or RS30D nanoparticles as an oral carrier of levofloxacin hemihydrate

The main objective of this study was to design positively charged Levofloxacin Hemihydrate (Levo-h)-loaded nanoparticles with improved entrapment efficiency and antibacterial activity. PLGA alone or in combinations with Eudragit® RLPO or RS30D with or without positively charged inducing agent; 1,2-dioleoyl-3-trimethylammonium-propane, chloride salt (DOTAP); were used for preparation of nanoparticles. Blending between PLGA and Eudragit® RLPO or RS30D with inclusion of DOTAP caused a marked increase in entrapment efficiency and switched zeta potential from negative to positive. Nanoparticle formulations; NR3 (Levo-h:PLGA:Eudragit® RLPO; 1:1:1 w/w with DOTAP) and NS3 (Levo-h:PLGA:Eudragit® RS30D; 1:1:1 w/w with DOTAP) that possess high positive zeta potential (59.3 ± 7.5 and 55.1 ± 8.2 mV, respectively) and Efficient Levo-h entrapment (89.54 ± 1.5 and 77.65 ± 1.8%, respectively) were selected for further examinations; in vitro release, physical stability and microbiological study. NR3 and NS3 showed significant sustained release of Levo-h. NR3 and NS3 exhibited good stability after storage at room temperature. Microbiological assay showed strengthened antibacterial activity of NR3 against both types of gram-negative bacteria (E. coli, Ps. aeruginosa) and of NS3 against Ps. aeruginosa compared to free Levo-h solution. NR3 and NS3 appear to be promising oral delivery system for Levo-h.

Extended Release of Timolol from Ethyl Cellulose Microparticles Laden Hydrogel Contact Lenses

Glaucoma is a second leading cause of blindness globally after cataract, which is managed through eye drops, which are highly inefficient due to a low bioavailability of less than 1-5%. Frequent administration of eye drops leads to incompliance in patients, so there is a great need for medical device such as contact lenses to treat glaucoma. The objective of research was to provide sustained ocular delivery of timolol via prototype poly (hydroxyethyl methacrylate) hydrogel contact lenses which may improve bioavailability due to increase in ocular residence time of drug. The present work was to encapsulate drug in ethylcellulose microparticles, and to entrap these microparticles in the hydrogel. Microparticles were prepared by spray drying method using different ratios of drug to ethylcellulose. The solid state characterization studies of drug loaded microparticles revealed the transformation of drug to an amorphous state. The hydrogels were characterized by studying their optical and physical properties to determine their suitability as extended wear contact lenses. Microparticles laden hydrogels were compared with direct drug loaded hydrogels. The study of microparticles laden hydrogels showed reduction in optical and physical properties and the impact was proportional to the amount of microparticles in hydrogels. The results suggest the application of optimization and nanotechnology. In vitro drug release study revealed that direct loading batch delivers drug for 22 hours with high drug loading of 150 µg, while microparticles laden hydrogel deliver drug up to 48 hours (zero order kinetics) with low drug loading of 50 µg. The hydrogels appeared safe in the cytotoxicity study. The study demonstrated the promising potential of loading the ethyl cellulose microparticles into hydrogels to serve as a good platform for sustained ophthalmic drug delivery.

Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: selective targeting to diseased versus healthy tissue

Colon targeted drug delivery is an active area of research for local diseases affecting the colon, as it improves the efficacy of therapeutics and enables localized treatment, which reduces systemic toxicity. Targeted delivery of therapeutics to the colon is particularly advantageous for the treatment of inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease. Advances in oral drug delivery design have significantly improved the bioavailability of drugs to the colon; however in order for a drug to have therapeutic efficacy during disease, considerations must be made for the altered physiology of the gastrointestinal (GI) tract that is associated with GI inflammation. Nanotechnology has been used in oral dosage formulation design as strategies to further enhance uptake into diseased tissue within the colon. This review will describe some of the physiological challenges faced by orally administered delivery systems in IBD, the important developments in orally administered nano-delivery systems for colon targeting, and the future advances of this research.

FROM THE CLINICAL EDITOR

Inflammatory Bowel Disease (IBD) poses a significant problem for a large number of patients worldwide. Current medical therapy mostly aims at suppressing the active inflammatory episodes. In this review article, the authors described and discussed the various approaches current nano-delivery systems can offer in overcoming the limitations of conventional drug formulations.

Long-term controlled release of PLGA microparticles containing antidepressant mirtazapine

The aim of the study was to prepare PLGA microparticles for prolonged release of mirtazapine by o/w solvent evaporation method and to evaluate effects of PVA concentration and organic solvent choice on microparticles characteristics (encapsulation efficiency, drug loading, burst effect, microparticle morphology). Also in vitro drug release tests were performed and the results were correlated with kinetic model equations to approximate drug release mechanism. It was found that dichloromethane provided microparticles with better qualities (encapsulation efficiency 64.2%, yield 79.7%). Interaction between organic solvent effect and effect of PVA concentration was revealed. The prepared samples released the drug for 5 days with kinetics very close to that of zero order (R(2 )= 0.9549 - 0.9816). According to the correlations, the drug was probably released by a combination of diffusion and surface erosion, enhanced by polymer swelling and chain relaxation.

Development and characterization of novel site specific hollow floating microspheres bearing 5-Fu for stomach targeting

Multiple-unit-type oral floating hollow microspheres of 5-fluorouracil (5-Fu) were developed using modified solvent evaporation technique to prolong gastric residence time, to target stomach cancer, and to increase drug bioavailability. The prepared microspheres were characterized for micromeritic properties, floating behavior, entrapment efficiency, and scanning electron microscopy (SEM). The in vitro drug release and floating behavior were studied in simulated gastric fluid (SGF) at pH 1.2. The yield of microspheres was obtained up to 84.46 ± 6.47%. Microspheres showed passable flow properties. Based on optical microscopy, particle size was found to be ranging from 158.65 ± 12.02 to 198.67 ± 17.45 μm. SEM confirmed spherical size, perforated smooth surface, and a hollow cavity inside the microspheres. Different kinetic models for drug release were also applied on selected batches.