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Coating of chitosan-Ibuprofen microspheres with a pH-depending interpolymer complex

Abstract:

Introduction: The irritating effect on the gastric mucosa caused by non-steroidal anti-inflammatory drugs is one of the main adverse reactions. Their encapsulation in polymer matrices with enteric properties is a technological alternative to solve the problem. Objective: to obtain ibuprofen-loaded chitosan microparticles coated with a pH dependent interpolymer complex based on poly(acrylic acid)/poly(N-vinyl-2-pyrrolidone). Methods: Ibuprofen-loaded chitosan microparticles were prepared through the spray drying technique; the yield and the efficiency of encapsulation were evaluated. Microparticles were coated with a pH-dependent interpolymer complex based on poly(acrylic acid)/poly(N-vinyl-2-pyrrolidone) using the emulsion/solvent evaporation technique. The complex formation was verified by Fourier transform infrared spectroscopy and the morphological evaluation was made with the electronic scanning microscopy. Release studies used simulated gastric (SGF, pH= 1.2) and intestinal (SIF, pH= 6.8) fluids. Results: in the process of obtaining the chitosan and chitosan-ibuprofen microparticles, the yield rates amounted to 69 ± 1 % and 54.4 ± 0.8 % respectively were obtained. The encapsulation efficiency was 46.8 ± 0.7 %. The coated microparticles presented rough surface. Complex formation was confirmed by changes in the position of the absorption bands of the functional groups involved in hydrogen bonding. The release of ibuprofen from uncoated microparticles in simulated gastrointestinal fluid reached 40 % whereas it was neglectable in the coated microparticles during the study interval. Conclusions: the results show the potential of poly(acrylic acid)/poly(N-vinyl-2-pyrrolidone) interpolymer complex as pH dependent cover for use as enteric coating to reduce the side effects on the gastric mucosa of medications such as non-steroidal anti-inflammatory drugs.