Development and evaluation of buccoadhesive tablet for selegiline hydrochloride based on thiolated polycarbophil

Buccal delivery of small molecules and biologics: Of mucoadhesive polymers, films, and nanoparticles - An update

Buccal delivery of small and large molecules is an attractive route of administration that has been studied extensively over the past few decades. This route bypasses first-pass metabolism and can be used to deliver therapeutics directly to systemic circulation. Moreover, buccal films are efficient dosage forms for drug delivery due to their simplicity, portability, and patient comfort. Films have traditionally been formulated using conventional techniques, including hot-melt extrusion and solvent casting. However, newer methods are now being exploited to improve the delivery of small molecules and biologics. This review discusses recent advances in buccal film manufacturing, using the latest technologies, such as 2D and 3D printing, electrospraying, and electrospinning. This review also focuses on the excipients used in the preparation of these films, with emphasis on mucoadhesive polymers and plasticizers. Along with advances in manufacturing technology, newer analytical tools have also been used for the assessment of permeation of the active agents across the buccal mucosa, the most critical biological barrier and limiting factor of this route. Additionally, preclinical and clinical trial challenges are discussed, and some small molecule products already on the market are explored.

Tablet of Ximenia Americana L. Developed from Mucoadhesive Polymers for Future Use in Oral Treatment of Fungal Infections

The use of biocompatible polymers such as Hydroxypropylmethylcellulose (HPMC), Hydroxyethylcellulose (HEC), Carboxymethylcellulose (CMC), and Carbopol in solid formulations results in mucoadhesive systems capable of promoting the prolonged and localized release of Active Pharmaceutical Ingredients (APIs). This strategy represents a technological innovation that can be applied to improving the treatment of oral infections, such as oral candidiasis. Therefore, the aim of this study was to develop a tablet of Ximenia americana L. from mucoadhesive polymers for use in the treatment of oral candidiasis. An X. americana extract (MIC of 125 μg·mL-1) was obtained by turbolysis at 50% of ethanol, a level that demonstrated activity against Candida albicans. Differential Thermal Analysis and Fourier Transform Infrared Spectroscopy techniques allowed the choice of HPMC as a mucoadhesive agent, besides polyvinylpyrrolidone, magnesium stearate, and mannitol to integrate the formulation of X. americana. These excipients were granulated with an ethanolic solution 70% v/v at PVP 5%, and a mucoadhesive tablet was obtained by compression. Finally, mucoadhesive strength was evaluated, and the results demonstrated good mucoadhesive forces in mucin disk and pig buccal mucosa. Therefore, the study allowed a new alternative to be developed for the treatment of buccal candidiasis, one which overcomes the inconveniences of common treatments, costs little, and facilitates patients' adhesion.

Buccal delivery of small molecules and biologics: of mucoadhesive polymers, films, and nanoparticles

Buccal delivery of macromolecules (biologics) sets a great challenge for researchers. Although several niche small molecule products have been approved as simple sprays, tablets and oral films, it is not simply a case of adapting existing technologies to biologics. Buccal delivery of insulin has reached clinical trials with two approaches: oromucosal sprays of the peptide with permeation enhancers, and embedded gold nanoparticles in a dissolvable film. However, neither of these approaches have led to FDA approvals likely due to poor efficacy, submaximal peptide loading in the dosage form, and to wide intra-subject variability in pharmacokinetics and pharmacodynamics. It is likely however that printed film designs with lower molecular weight stable biotech payloads including lipophilic glucagon-like 1 (GLP-1) agonists and macrocycles with long half-lives will generate greater efficacy than was achieved to date for insulin.

Thiomers--from bench to market

Thiolated polymers or designated thiomers are obtained by immobilization of sulhydryl bearing ligands on the polymeric backbone of well-established polymers such as poly(acrylates) or chitosans. This functionalization leads to significantly improved mucoadhesive properties compared to the corresponding unmodified polymers, as disulfide bonds between thiol groups of thiomers and cysteine-rich glycoproteins of the mucus gel layer are formed. Furthermore, enzyme- and efflux-pump inhibiting as well as improved permeation-enhancing properties are advantages of thiolization. By the covalent attachment of mercaptonicotinamide substructures via disulfide bonds to thiolated polymers these properties are even substantially further improved and stability towards oxidation even in aqueous media can be provided. Meanwhile, more than 50 research groups worldwide are working on thiolated polymers. For certain thiomers the scale up process for industrial production has already been done and GMP material is available. Furthermore, safety of thiolated poly(acrylic acid), thiolated chitosan and thiolated hyaluronic acid could be demonstrated via orientating studies in human volunteers and via various clinical trials. The first product (Lacrimera® eye drops, Croma-Pharma) containing a chitosan-N-acetylcysteine conjugate for treatment of dry eye syndrome will enter the European market this year. It is the only product providing a sustained protective effect on the ocular surface due to its comparatively much more prolonged residence time worldwide. Various further products utilizing, for instance, thiolated hyaluronic acid in ocular surgery are in the pipeline.