Papain wound dressings obtained from poly(vinyl alcohol)/calcium alginate blends as new pharmaceutical dosage form: Preparation and preliminary evaluation.

Transparent, soft, flexible, mechanically resistant films, which are ideal for use as wound dressings were prepared in the presence of 2% papain, a proteolytic enzyme that can play a role in the chemical debridement of the skin and can accelerate the healing process. The films, based on poly(vinyl alcohol):calcium alginate blends with increasing concentrations of polysaccharide (10, 20, and 30% v/v), were obtained by casting method. FTIR and DSC analyses were performed to assess the composition and miscibility of blends. Mechanical properties such as tensile strength, elasticity modulus, and elongation at breakpoint were evaluated. The influence of different concentrations of calcium alginate on physical attributes of films like wettability, swelling capacity and mechanical properties was determined. The stability of papain in the films was assessed indirectly by hemolytic activity assay employing direct contact method and confirmed by technique based on blood agar diffusion. Preliminary cytotoxicity was evaluated with the XTT method. The results showed that at the polymer concentrations tested, the blends were miscible. The increase in the content of the calcium alginate increased the wettability and swelling capacity of the films, which is desirable in wound dressings. On the other hand, mechanical resistance decreased without causing breakage of the films during the swelling tests. The hemolytic activity of the films was maintained during the studied period, suggesting the stability of papain in the proposed formulations. Cellular viability indicated that the films were non-toxic. The analysis of the results showed that it is possible to prepare interactive and bioactive wound dressing containing papain from blends of PVA and calcium alginate polymers.

Design, characterization and preliminary in vitro evaluation of a mucoadhesive polymer based on modified pectin and acrylic monomers with potential use as a pharmaceutical excipient.

Bio-based polymers have been reported to have applications in biomedical and pharmaceutical areas. Polysaccharides, especially prepared from plant sources, have served a variety of uses. This work aims to prepare a polymer for use as a pharmaceutical excipient containing a functionalized carbohydrate (pectin) and acrylic monomers (methyl methacrylate, butyl methacrylate and ethyl acrylate) via an emulsion polymerization technique. Carbon double bonds were incorporated into the pectin by reacting this natural polymer with glycidyl methacrylate. The methacrylated pectin was then polymerized with acrylic monomers by emulsion polymerization. The mucoadhesive performance of the materials was investigated by in vitro preliminary assays based on viscometric studies, texture analysis and film wettability. The obtained results showed that the synergistic viscosity increase with greater concentrations of modified pectin. The contact angle decreased, suggesting an increase in the wettability for polymers with large amounts of methacrylated pectin. The addition of mucin in lattices caused an increase in the intermolecular forces and in the work of adhesion. This corroborates the use of pectin as a mucoadhesive excipient for mucoadhesive drug delivery systems.

Design of prolonged release tablets using new solid acrylic excipients for direct compression.

The design of new excipients that extend the release of drugs from tablets over prolonged periods is essential in reaching enhanced therapeutic performances. In this sense, the objective of this study was to develop new excipients, based on acrylic monomers (ethyl acrylate, methyl methacrylate, and butyl methacrylate) for use in direct compression (DC). The polymeric excipients were prepared by suspension and emulsion polymerization reactions and were characterized by FTIR to confirm the polymerization reaction. For the success of direct compression, excipients must present good flow and compactability properties. Therefore, excipients were submitted to analysis of morphology (SEM), particle size and size distribution by laser diffraction, and powder density (bulk density and tapped density). The Carr index, Hausner ratio, flow ratio, and cotangent of the angle α were determined. Thereafter, the polymeric excipients were used to prepare inert matrices by DC using propranolol hydrochloride (PHCl) as a model drug. The tablets were evaluated for average weight, breaking force, and friability tests. The release profiles were determined, and the dissolution kinetics was studied. The results indicated that matrices prepared from excipients obtained by suspension polymerization (NWCB and PECB) presented a release of PHCl for a period exceeding 12h, most likely due to the higher micromeritic properties. The results suggested that the increase in the percentage of polymers, as well as in the compression time, resulted in a higher hardness of the matrix with a reduced rate release of the PHCl. Finally, in vitro preliminary tests showed that the polymeric excipients produced were non-toxic for the gingival fibroblasts.

Pharmaceutical acrylic beads obtained by suspension polymerization containing cellulose nanowhiskers as excipient for drug delivery.

Direct compression is one of the most popular techniques to prepare tablets but only a few commercial excipients are well adapted for this process into controlled release formulations. In the last years, the introduction of new materials for drug delivery matrix tablets has become more important. This paper evaluated the physicochemical and flow properties of new polymeric excipient of ethyl acrylate, methyl methacrylate and butyl metacrylate, synthesized by suspension polymerization using cellulose nanowhiskers as co-stabilizer, to be used as direct compression for modified release tablets. Infrared spectroscopy (FTIR) confirmed the success of the copolymerization reaction. Scanning electron microscopy (SEM) showed that excipient was obtained how spherical beads. Thermal properties of the beads were characterized by thermogravimetric (TG) analysis. Particle size analysis of the beads with cellulose nanowhiskers (CNWB) indicated that the presence of the nanowhiskers led to a reduction of particle size and to a narrower size distribution. In vitro test showed that the nanowhiskers and beads produced are nontoxic. Parameters such as Hausner ratio, Carr's index and cotangent of angle α were employed to characterize the flow properties of CNWB beads. Furthermore, the beads are used to produce tablets by direct compression contained propranolol hydrochloride as model drug. Dissolution tests performed suggested that beads could be used as excipient in matrix tablets with a potential use in drug controlled release.