Optimization and in-vitro evaluation of poly (lactic acid)/mesalazine microspheres as drug carriers

Abstract

Purpose: The present study is intended to the preparation and optimization of controlled drug release microparticles based on polylactic acid and Mesalazine. This active ingredient is usually used in the therapy of intestine inflammatory diseases, particularly the Crohn’s disease and hemorrhagic recto colitis. Methods: Microencapsulation by simple O/W emulsion solvent evaporation method was used to prepare these formulations. Some of the process variables such as the emulsifier concentration, the polymer concentration, the drug: polymer ratio and stirring speed were varied and the obtained biodegradable microparticles were characterized by FTIR spectroscopy, X-ray diffraction, DSC method and optical microscopy. The drug release was established both in simulated intestinal fluid and distilled water and the data analysis and the release mechanism were investigated on the basis of Higuchi and Korsmeyer-Peppas models. Results: The microparticles’ size i.e. the number mean diameter (d10) ranged from 127 to 744 µm and the drug content varied from 12 to 27%. The effect of the selected variables on the microparticles’ characteristics (size, morphology and drug release) were exhaustively discussed for the PLA/mesalazine microparticles’ optimization. Conclusion: This study showed that the microparticles’ morphology depended strongly on the emulsifier concentration and the drug entrapment is related to the initial drug:polymer ratio and polymer concentration.