Biocellulose nanofibers: a new generation of materials for applications in drug delivery

Abstract

Pharmaceutical excipients are high importance substances in the composition of dosage forms, since among its various functions it can be employed for the temporal and/or spatial control of drug delivery, ensuring to the patient a better quality of life due to reduction of side effects and administrations throughout the day. The search for new excipients that allow the improvement of the bioavailability and the therapeutic efficacy of existing drugs have been subject of intense research during the past few years, emerging in this scenario an important alternative to the traditional excipients: the use of bacterial cellulose nanofibers. These have nanometric scale, high crystallinity, and high amount of hydroxyl groups on the surface, so that the key factor to its use as excipient is the fact of after the removal of water by the spray-drying process, a very entangled and dense network of nanofiber is formed by establishing of interactions among neighboring fibers by hydrogen bonds, which represents an irreversible process and which should contribute significantly to the effective entrapment of the drug in the matrix and control of the release rate for a prolonged period of time. At phase 1, the excipients (powders) and microcapsules (containing hydrophilic or hydrophobic drugs) based on biocellulose nanofibers will be produced at laboratory level from the production of bacterial cellulose by biotechnological route employing Acetobacter xylinum, which will be submitted to the defibrillation in high-energy homogenizer and Grinder, subsequently dried by the spray drying technique, and evaluated by physicochemical and performance methods to prove its effectiveness. From this initial phase, it is expected to get a new, promising and multifunctional pharmaceutical excipient for the design of different types of systems, including microparticles, nanoparticles, matrix tablets, drug-loaded films, transdermal systems, among others, with excellent mechanical properties, barrier as well as high potential mucoadhesive. (AU)