Factorial design approach to fabricate and optimize floating tablets based on combination of natural polymer and rice bran wax

Background The aim of the present research work was to fabricate a novel gastroretentive drug delivery system in the form of tablets using a combination of natural polymer and rice bran wax with an intention to control drug delivery and to enhance the gastric residence time of the model drug Famotidine in the gastrointestinal tract. Results The results of the preliminary trial batches prepared by using the hot melt granulation technique resulting in six different formulations showed good physicochemical characteristics and tablets conformed to the Pharmacopoeial specifications. Gastroretentive tablets containing natural polymer showed prolonged drug release comparable to Methocel. The optimized formulation (C3) using 32 factorial design showed FLT 27 ± 2.47 s, SI 92.68 ± 1.36% and % CDR 98.89 ± 0.39% at 12 h. The stability studies indicated the stability of the formulation during storage. Conclusions It was concluded that the release profile fitted best to zero-order equation with non-Fickian diffusion mechanism of drug release which demonstrates swelling-controlled drug release mechanism. Thus, the formulated tablets have the potential for improved release and gastroretentive properties. Graphical Abstract

Sustained ophthalmic delivery of pH triggered Cromolyn sodium in situ gel

The research study intends to formulate pH triggered in situ gel of Cromolyn sodium composed of Polyacrylic acid (carbopol 934) polymer in combination with Hydroxypropyl Methylcellulose (HPMC K4M) polymer at 1:1, 1.5:1, 2:1 molar ratio by utilizing pH trigger method. Formulations were evaluated for pH, viscosity, gelling capacity, drug content and in vitro drug release. Results of Carbopol 934 and HPMC K4M based in situ gelling systems at 1:1, 1.5:1, 2:1 shown that the formulations were fluid state at room temperature in a formulated pH (pH 4.5) and went through fast progress into the viscous gel phase at the pH of the tear fluid 7.4. The viscosity of formulated pH triggered in situ gel at 2:1 molar ratio shown excellent result compares to 1:1, 1.5:1 molar ratio. The in vitro drug release of the developed in situ gelling formulations at 1:1, 1.5:1, 2:1 molar ratios increases the contact time and showed a non – fickian diffusion type of release behavior with 94.45%, 83.26%, 70.48% respectively over 8 hours periods compared with that of marketed formulation that shows 99.4% over 4 hours. Thus, the developed system at 2:1 molar ratio acts as a viable alternative to conventional eye drops and also prevent the rapid drainage.

Evaluation of the Adsorption and Desorption Dynamics of Beet Juice Red Dye on Alginate Microbeads

The use of alginate microcapsules has often been mentioned as one of the ways to remove dyes from waste solvents, water and materials from the food industry. In addition, alginate can be used as a wall material for the microencapsulation of food dyes and their further application in the food industry. The aims of this study were to: (i) determine the effect of the alginate concentration (1, 2, 3 and 4%) on the ability of the adsorption and desorption of natural beetroot red dye and (ii) evaluate the kinetic parameters of the adsorption and desorption process, as well as the factors affecting and limiting those processes. According to the obtained results, the viscosity of alginate solutions increased with an increase in the alginate concentration. Based on k2 values (the pseudo-second order kinetic rate constant), when a more concentrated solution of alginate was used in the adsorption process, the beads adsorbed a smaller amount of dye. Furthermore, based on the values for n derived from the Korsmeyer–Peppas model, the dye release rates (k) were higher for beads made with lower alginate concentrations, and this release was governed by a pseudo-Fickian diffusion mechanism (n values ranged from 0.2709 to 0.3053).

Effect of Organogelator Concentration on Gelation Kinetics and Drug Release Behaviour of Paracetamol-Loaded Soybean Oleogels

Organogelators induce 3-D networked structures in apolar solvent molecules via cross-linking of non-covalent self-assembled aggregates below the gelation temperature. The objective of the present investigation was to evaluate the effects of different Span 40 concentrations on gelation kinetics and drug release behaviour of topical soybean oleogels. An inversely proportional relationship was observed between gelation time, melt flow index and concentration of Span 40 in soybean oleogels. Gompertz model was employed on gelation kinetics data to determine organogelator and oil parameters which are assumed to be associated with thermal stability and gel flexibility respectively. Formulation OGS2 (18% W/V Span 40) formed less viscous, thermally stable and presumably more flexible oleogel compared to other formulations. Nearly ideal zero-order release of paracetamol was achieved from OGS*2 following Fickian diffusion. However, slow drug release profiles, higher t50 values were observed with oleogels having 20-24% w/v Span 40 which followed Korsmeyer-Peppas kinetics with non-Fickian diffusion.

Towards a Mathematical Model for the Viral Progression in the Pharynx

In this work, a comprehensive model for the viral progression in the pharynx has been developed. This one-dimension model considers both Fickian diffusion and convective flow coupled with chemical reactions, such as virus population growth, infected and uninfected cell accumulation as well as virus clearance. The effect of a sterilizing agent such as an alcoholic solution on the viral progression in the pharynx was taken into account and a parametric analysis for the effect of kinetic rate parameters on virus propagation was made. Moreover, different conditions caused by further medical treatment, such as a decrease in virus yield per infected cell, were examined. It is shown that the infection fails to establish by decreasing the virus yield per infected cell. It is believed that this work could be used to further investigate the medical treatment of viral progression in the pharynx.

Highly Porous Composite Scaffolds Endowed with Antibacterial Activity for Multifunctional Grafts in Bone Repair

The present study deals with the development of multifunctional biphasic calcium phosphate (BCP) scaffolds coated with biopolymers—poly(ε-caprolactone) (PCL) or poly(ester urea) (PEU)—loaded with an antibiotic drug, Rifampicin (RFP). The amounts of RFP incorporated into the PCL and PEU-coated scaffolds were 0.55 ± 0.04 and 0.45 ± 0.02 wt%, respectively. The in vitro drug release profiles in phosphate buffered saline over 6 days were characterized by a burst release within the first 8h, followed by a sustained release. The Korsmeyer–Peppas model showed that RFP release was controlled by polymer-specific non-Fickian diffusion. A faster burst release (67.33 ± 1.48%) was observed for the PCL-coated samples, in comparison to that measured (47.23 ± 0.31%) for the PEU-coated samples. The growth inhibitory activity against Escherichia coli and Staphylococcus aureus was evaluated. Although the RFP-loaded scaffolds were effective in reducing bacterial growth for both strains, their effectiveness depends on the particular bacterial strain, as well as on the type of polymer coating, since it rules the drug release behavior. The low antibacterial activity demonstrated by the BCP-PEU-RFP scaffold against E. coli could be a consequence of the lower amount of RFP that is released from this scaffold, when compared with BCP-PCL-RFP. In vitro studies showed excellent cytocompatibility, adherence, and proliferation of human mesenchymal stem cells on the BCP-PEU-RFP scaffold surface. The fabricated highly porous scaffolds that could act as an antibiotic delivery system have great potential for applications in bone regeneration and tissue engineering, while preventing bacterial infections.

Cellulose/Exosome Nanocarrier for Improved Prolonged Release of 5-Fluorouracil: Preparation, Characterization, Drug Release Behavior and Cytotoxicity

Designing of nanoparticle drug delivery systems and improving the efficacy of anticancer drugs are a great deal of effort in the recent years. In this study, a novel biocompatible nanocarrier based on bacterial cellulose (BC) in presence of exosome (Exo) was prepared to controlled release of 5-fluorouracil (5-FU), (5-FU.Exo@BC). The physicochemical properties of 5-FU.Exo@BC was characterized using field emission scanning electron microscopy (FESEM), Differential Scanning Calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and X-ray Diffraction (XRD) techniques that confirmed the successful preparation of 5-FU.Exo@BC. The release behavior of 5-FU.Exo@BC compared to 5-FU and 5-FU@BC demonstrated a significant sustained release during 162 h. The release mechanism of the above three systems followed Korsmeyer-peppas with non-Fickian diffusion for 5-FU@BC and 5-FU.Exo@BC. In addition, the viability of HT-29 cells (human colon cancer cell line), towards BC, 5-FU@BC and 5-FU.Exo@BC indicated the promising efficacy of 5-FU into 5-FU.Exo@BC. Subsequently, the prepared bio-nanocomposite could be proposed as a potential drug delivery system with effective controlled-release function.

Formulation and in-vitro Evaluation of Carvedilol Gastroretentive Capsule as (Superporous Hydrogel)

The preferred route of drug administration is the oral route, but drugs with narrow absorption window in the gastrointestinal tract are still challenging. The ability to extend and monitor the gastric emptying time is a valuable tool for processes remaining in the stomach longer than other traditional dosage forms. The purpose of this study was to formulate and evaluate gastroretentive superporous hydrogel (SPH) of carvedilol with view to improve its solubility and increase gastric residence time in order to get sustained release formulas via utilization of various kinds and concentrations of hydrophilic polymers then after, incorporate the best prepared formula into capsules. Sixteenth formulae of SPH hybrid were prepared by gas blowing technique from the following materials; monomers (Poly vinyl alcohol, and Acrylamide), cross-linkers (Methylene bisacrylamide, and glutaraldehyde), hybrid agent (Chitosan), foaming agent (NaHCO3) and foam stabilizer (Tween 80). Different amounts or concentrations of these materials were utilized to investigate their effect on SPH properties (density, porosity, floating, drug content, drug release, swelling time, and swelling ratio). The soaking procedure was utilized for loading of carvedilol into SPH hybrid (6.25mg/2.5g SPH). After analysis the results statistically and application the similarity factor (f2) equation, formula F8 was selected as the best formula and incorporated into capsules. The drug release data were applied to different mathematical kinetics and the results were shown to be fitted to Higuchi model and the release mechanism was (non fickian) diffusion. The overall results suggested that the proposed SPH hybrid drug delivery system is encouraging for carvedilol specific delivery to the stomach.

Development of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers of Loteprednol Etabonate: Physicochemical Characterization and Ex Vivo Permeation Studies

Purpose Loteprednol etabonate (LE) is a new generation corticosteroid that is used for the treatment of inflammatory and allergic conditions of the eye, and management of seasonal allergic rhinitis nasally. LE which is a poorly soluble drug with insufficient bioavailability, has a high binding affinity to steroid receptors. Sophisticated colloidal drug delivery systems of LE could present an alternative for treatment of inflammatory and allergic conditions of the skin. For this purpose, solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) were attempted to improve for transdermal LE delivery for the first time. Methods SLN and NLC were produced by hot homogenization and ultrasonication technique. Formulations were characterized by dynamic light scattering, scanning electron microscopy, fourier transform infrared spectroscopy and differential scanning calorimetry. Their physical stability was monitored for 3 months of storage. Drug release profiles and permeation properties of SLN and NLC through the porcine skin were investigated. Results It was determined that SLN and NLC below 150 nm particle size had a homogeneous particle size distribution as well as high drug loading capacities. They were found to be stable both physically and chemically at room temperature for 90 days. In terms of release kinetics, it was determined that they released from SLN and NLC in accordance with Fickian diffusion release. Formulations prepared in this study were seen to significantly increase drug penetration through pig skin compared to the control group (p ≤ 0.05). Conclusion SLN and NLC formulations of LE can be stated among the systems that can be an alternative to conventional systems with less side-effect profile in the treatment of inflammatory problems on the skin.