PLA-Starch Microparticles Containing Clays Focusing Controlled Release of Rifampicin

Abstract

Polymer nanocomposites have been successfully used as excipients in pharmaceutical technology because of the convenient features that make them suitable for many applications, especially in controlled drug delivery therapies. The objective of this work was to prepare and characterize PLA and starch microparticles containing Viscogel B8 organophilic clay as a matrix for controlled release of rifampicin, one of the most spread drugs for tuberculosis treatment. The systems obtained by the spray drying technique were characterized by DRX, FTIR, SEM and low-field NMR. In addition, dissolution tests were performed on simulated gastric fluid. The micrographs indicate that the presence of the drug caused a small change in the shape and size of the particles. In the presence of the drug, the particles were spherical and presented wider size distribution. The XRD assays didn’t show crystalline peaks of rifampicin in the microparticles, which suggests that rifampicin exists in an amorphous solid solution inside the starch-PLA particles. The mathematical model of Baker-Lonsdale was chosen for the treatment of the dissolution data, describing the controlled release of the drug from the matrix by a spherical diffusion process. The results suggest that the proposed release system may be used for the delivery of orally administered drugs, such as rifampicin.