Central Composite Design and Optimization of Polylactic Acid (PLA) Microspheres for Controlled Azithromycin Release

The growing demand for long-lasting drug delivery has inspired researchers to develop and optimize the size of microspheres, ensuring the release of the drug in a predetermined quantity. Uncontrollable release of the drug creates several clinical challenges, such as toxic effects, and the drug delivery system fails to release a drug in the therapeutic window. To overcome these issues, microspheres are rapidly gaining acceptance in modern healthcare. Polylactic acid (PLA) microspheres deliver medicine to designated tissue due to their biocompatibility and biodegradability. The present work focuses on fabricating PLA microspheres by the double emulsion (w1-o-w2) solvent evaporation method by using the central composite design (CCD) of response surface methodology. This study aims to investigate the impact of formulation parameters, specifically stirring speed and surfactant concentration during solvent evaporation, on the size of PLA microspheres. The azithromycin (AZM)-loaded microspheres were prepared using the optimal process variables, and their morphology and size were assessed using a high-resolution scanning electron microscope (SEM). The results demonstrate that the optimal formulation of AZM-loaded PLA microspheres derived from CCD facilitated a sustained release profile of AZM from PLA microspheres.