Design and In-Vivo Evaluation of Risperidone Buccal Mucoadhesive Patches of Interpolymer Matrix

The buccal cavity is an alternate route for the administration of the drug. This route gained acceptance as increase in bioavailability is observed due to bypass of first pass metabolism. Solvent casting method was employed for the preparation of the risperidone mucoadhesive patches using different combinations of water soluble and water insoluble polymers using polyvinyl alcohol as a backing layer. Our main objective of this study was to understand the behaviour of water soluble and water insoluble polymers in combination on release pattern. Six different formulations of mucoadhesive patches were evaluated for physicochemical parameters like weight uniformity, content uniformity, thickness uniformity, surface pH, swelling studies, tensile strength, folding endurance, in-vitro drug release, and in-vivo drug absorption. Drug loaded mucoadhesive patches of various polymer bases had shown 35.64 to 72.33% drug release in 30 min in phosphate buffer solution of pH 6.6. In-vitro release data from patches were fit to different equations and kinetic models to explain release profiles. Kinetic models like Hixon-Crowell and Higuchi models were used. The formulation containing HPMC (15Cps) and polyvinyl pyrrolidone was considered as optimized based on the physicochemical and pharmaceutical properties. In-vivo studies in rabbits, carried out with prior permission from IAEC, showed 80.40% of drug release from the optimized patches. In-vivo and in-vitro correlations were found to be good. The drug absorption was found significant from the optimized formulation in healthy rabbits. The structure of the buccal membrane and permeability factors are similar in both human beings and rabbits. Therefore mucoadhesive patches of risperidone may be accepted with the important advantage of reduced risperidone dose.

Enzyme Catalyzed Copolymerization of Lignosulfonates for Hydrophobic Coatings

Enzymatic polymerization of lignin can generate a variety of value-added products concomitantly replacing fossil-based resources. In line with this approach, a laccase from the thermophilic fungus Myceliophthora thermophila (MtL) was used to couple a hydrophobicity enhancing fluorophenol (FP) molecule, namely 4-[4-(trifluoromethyl)phenoxy]phenol (4,4-F3MPP), as a model substrate onto lignosulfonate (LS). During the coupling reaction changes in fluorescence, phenol content, viscosity and molecular weight (size exclusion chromatography; SEC) were monitored. The effects of enzymatic coupling of FP onto LS on hydrophobicity were investigated by the means of water contact angle (WCA) measurement and determination of swelling capacity. Full polymerization of LS resulting in the production of water-insoluble polymers was achieved at a pH of 7 and 33°C. Incorporation of 2% (w/v) of FP led to an increase in WCA by 59.2% while the swelling capacity showed a decrease by 216.8%. Further, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicated successful covalent coupling of the FP molecule onto LS by an emerging peak at 1,320 cm–1 in the FTIR spectrum and the evidence of Fluor in the XPS spectrum. This study shows the ability of laccase to mediate the tailoring of LS properties to produce functional polymers.

The Importance of N186 in the Alpha-1-Antitrypsin Shutter Region Is Revealed by the Novel Bologna Deficiency Variant

Alpha-1-antitrypsin (AAT) deficiency causes pulmonary disease due to decreased levels of circulating AAT and consequently unbalanced protease activity in the lungs. Deposition of specific AAT variants, such as the common Z AAT, within hepatocytes may also result in liver disease. These deposits are comprised of ordered polymers of AAT formed by an inter-molecular domain swap. The discovery and characterization of rare variants of AAT and other serpins have historically played a crucial role in the dissection of the structural mechanisms leading to AAT polymer formation. Here, we report a severely deficient shutter region variant, Bologna AAT (N186Y), which was identified in five unrelated subjects with different geographical origins. We characterized the new variant by expression in cellular models in comparison with known polymerogenic AAT variants. Bologna AAT showed secretion deficiency and intracellular accumulation as detergent-insoluble polymers. Extracellular polymers were detected in both the culture media of cells expressing Bologna AAT and in the plasma of a patient homozygous for this variant. Structural modelling revealed that the mutation disrupts the hydrogen bonding network in the AAT shutter region. These data support a crucial coordinating role for asparagine 186 and the importance of this network in promoting formation of the native structure.

SCREENING OF BIODEGRADABLE POLYMER AND MOST EFFECTIVE VARIABLES IN PREPARATION OF ESSENTIAL OIL LOADED NANO PARTICLES FOR PULMONARY DELIVERY USING TAGUCHI DESIGN

The biodegradability of inhalable nanoparticles (NPs) is an important criterion in prevention of lung toxicity due to NPs which have been taken to cure the condition. Pulmonary inflammation may result due to non-biodegradation or insoluble polymers used to produce NPs. Biodegradable polymers are widely used for manufacturing safe drug-entrapped inhalable NPs for pulmonary delivery. Here in this study, for preparing ajwain essential oil loaded NPs for pulmonary delivery, biodegradable polymers chitosan, gelatin and alginic acid have been evaluated for suitability. Based on the results of trial batches prepared from each polymer, the responses particle size and entrapment efficiency were measured and compared. Out of the three polymers, chitosan was having very good entrapment efficiency, poly dispersive index, drug loading and zeta potential-favorable conditions for pulmonary delivery of essential oils. Further screening of most effective variables in manufacturing nano particles using chitosan, eight batches of nano particles have been prepared as per taguchi orthogonal 2 level array L8 experimental design (Design expert software, version 7.0) where two responses, particle size and entrapment efficiency, have been observed. Based on the results of eight batches, standard effects have been calculated and significant variables identified, for both particle size and entrapment efficiency, for further optimization under design of experiment.

Insoluble Polymers in Solid Dispersions for Improving Bioavailability of Poorly Water-Soluble Drugs

In recent decades, solid dispersions have been demonstrated as an effective approach for improving the bioavailability of poorly water-soluble drugs, as have solid dispersion techniques that include the application of nanotechnology. Many studies have reported on the ability to change drug crystallinity and molecular interactions to enhance the dissolution rate of solid dispersions using hydrophilic carriers. However, numerous studies have indicated that insoluble carriers are also promising excipients in solid dispersions. In this report, an overview of solid dispersion strategies involving insoluble carriers has been provided. In addition to the role of solubility and dissolution enhancement, the perspectives of the use of these polymers in controlled release solid dispersions have been classified and discussed. Moreover, the compatibility between methods and carriers and between drug and carrier is mentioned. In general, this report on solid dispersions using insoluble carriers could provide a specific approach and/or a selection of these polymers for further formulation development and clinical applications.

Hyaluronic Acid: Redefining Its Role

The discovery of several unexpected complex biological roles of hyaluronic acid (HA) has promoted new research impetus for biologists and, the clinical interest in several fields of medicine, such as ophthalmology, articular pathologies, cutaneous repair, skin remodeling, vascular prosthesis, adipose tissue engineering, nerve reconstruction and cancer therapy. In addition, the great potential of HA in medicine has stimulated the interest of pharmaceutical companies which, by means of new technologies can produce HA and several new derivatives in order to increase both the residence time in a variety of human tissues and the anti-inflammatory properties. Minor chemical modifications of the molecule, such as the esterification with benzyl alcohol (Hyaff-11® biomaterials), have made possible the production of water-insoluble polymers that have been manufactured in various forms: membranes, gauzes, nonwoven meshes, gels, tubes. All these biomaterials are used as wound-covering, anti-adhesive devices and as scaffolds for tissue engineering, such as epidermis, dermis, micro-vascularized skin, cartilage and bone. In this review, the essential biological functions of HA and the applications of its derivatives for pharmaceutical and tissue regeneration purposes are reviewed.