Physical Characterization of Drug Loaded Microcapsules and Controlled In Vitro Release Study

Microencapsulation of model drug, acetylsalicylic acid into bio-based polymer, alginatepectin matrix and chitosan had been undertaken in this work to characterize the microcapsules based on their composition. Alginate-pectin with the proportion of 40:60 solution was prepared with 0.3 g of drug. This mix was homogenized and atomized using nitrogen gas into 1.0M calcium chloride solution to form sol-gel microcapsules. 0.3 g concentration of the drug solution was prepared with 2% glacial acetic acid and 2 g of chitosan was mixed into that and homogenized using sonicator. Microcapsules were prepared after crosslinking the drug encapsulated chitosan using glutaraldehyde. Drug loaded microcapsules were dried using microwave energy under vacuum at low temperature. Scanning electron microscopy graphs showed that microcapsules have porous and rough surfaces. Fourier Transform Infrared Spectroscopy analysis on the microcapsules confirmed the presence of drug in the polymer matrix. Xray diffraction pattern showed that the microstructure was more like an amorphous pattern. Drug release of the microcapsules was tested in three different pH levels of 1.2, 7.4 and 8.2. Slow and controlled release of drug was observed at all the pH levels. Over all, the drug release percentage was higher in acidic pH and lower in alkali pH.