Formulation Development and In Vitro Release Studies of Tenofovir-containing Microsponges

Background. Microsponges are intended to carry drugs with minimum dose, while delivering beneficial effects such as better drug stability and reduced adverse effects in recipients. The present investigation was aimed to develop and characterize microsponges containing tenofovir (TNF). Methods. Quasi-emulsion diffusion technique was used to prepare TNF-containing microsponges. Eudragit L-100 was used as a polymer, whereas glycerol and dibutylphthalates were used as plasticizers. Drug and polymer were experimented in five formulations (F1-F5) of different ratios such as 1:1, 1:2, 1:3, 1:4, and 1:5. They were characterized for various physical parameters such as size, crystallinity, and interactions. Results. Fourier-transform infrared spectroscopic results showed that there was no incompatibility between the drug and excipients. Drug entrapment efficacy was found between 47% and 67%, and the particle size ranges were between 4.52 μm and 8.98 μm. Cumulative drug diffusion of formulation F2 (drug:polymer ratio = 1:2) was found to be 84.15% in 180 min for an X-ray diffraction studies of pure drug and microsponges formulation clearly indicated the reduction in the crystallinity of the drug which could be the reason for the improved solubility of the drug. Scanning electron microscopy analysis results indicated that the formulations have excellent structure and almost all formulations exhibited in spherical shape. Conclusion. Based on all the evaluation parameters, formulation F2 was concluded as the best formulation, and it is an alternative approach for conventional therapy with better patient compliance.