Freeze dried chitosan/ poly-(glutamic acid) microparticles for intestinal delivery of lansoprazole

Lansoprazole sodium is a proton pump inhibitor used in treating gastroesophageal reflux disease (GERD). It is highly acid-labile and presents many formulation challenges. Therefore, this drug needs to be protected from the harsh environment in the stomach. In order to achieve this, a pH-sensitive microparticle system composed of chitosan and γ- poly-(glutamic acid) was prepared and loaded with Lansoprazole. The prepared microparticles were not stable in gastric pH. To overcome this problem microparticles were freez-dried and filled in an enteric-coated capsule. Upon oral administration, the enteric-coated capsule remained intact in the acidic environment of the stomach, but dissolved rapidly in the distal segment of the GIT. Consequently, all the microparticles loaded in the capsule were brought into the intestine, thus enhancing the intestinal absorption of drug. Drug encapsulation efficiency of formulation F3 was found to be 82.82 % and in vitro release of prepared formulation F3 was found to be 94% after 8 h of dissolution in 7.4 pH phosphate buffer. FTIR and DSC studies showed no interaction between the drug and polymer. The formulation showed good swelling property. SEM photographs showed that microparticles are spherical and lies in size range of 300-400 μm. From the above, it can be concluded that the prepared chitosan/ γ-poly-(glutamic acid) microparticles can be used as carriers for the intestinal delivery of acid liable drugs such as lansoprazole.