Comparação da liberação do fármaco Aciclovir carreado em sistemas microestruturados formados a base de Quitosana

Abstract

Herpes simplex virus (HSV) infections are caused by two types of viruses, type 1 (HSV 1) and type 2 (HSV-2), being endemic worldwide and a frequent public health concern. For treatment, the drug of first choice is Acyclovir, which acts by inhibiting viral DNA polymerase, however, its topical use in the form of ointments requires frequent application to achieve the desired efficacy, as it has low permeation. In this context, the use of biomaterials as a carrier in the controlled release of drugs is an interesting alternative in the health area, to improve permeation and avoid toxic effects. Among the most used biopolymers, chitosan stands out due to its high potential for applications in several areas and for being a selectively permeable material, being a good candidate for the release of topically administered drugs. In this context, in the present work, different microstructures formed based on chitosan were produced and characterized, namely: membranes, capsules and membrane + capsule for encapsulation and release of the drug Acyclovir. The membranes were produced using the casting technique (solvent evaporation) of thin film formation and the capsules were obtained through ionotropic crosslinking, using Sodium Tripolyphosphate (TPP) as a crosslinking agent. The microstructures and/or the starting materials were characterized by infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), mass loss and gain through water absorption tests, mechanical stress versus deformation tests and release tests. The microstructures that showed better stability in drug encapsulation were capsules and the system composed of membrane + capsules. As for the release assay, the microstructure that presented the best result was the one composed of membrane + capsules, modulating the release in 1 hour and 20 minutes, with peak concentration at 2 hours. As for the membrane and capsule systems, both had the same conventional release profile, with the entire drug concentration being released between 15 and 20 minutes.