In situ forming gel implants is developed continuously in order to reduce pain from the administration. Objective= The purpose of this research is to develop in situ forming gel formulation for implant in periodontitis treatment. Poly(lactic acid-co-glycolic acid)(PLGA) was dissolved in N-methyl pyrrolidone (NMP) and the in situ gel was formed by solvent exchange mechanism. The effect of the ratio of PLGA= NMP was studied at ratio 1=2, 1=3, 1=4, 1=5, 1=10 and 1=15 and the effect of the additives addition such as polyvinylpyrrolidone (PVP), Poloxamer 407® and Poloxamer 188® was also performed. The physical properties, viscosity, gel forming, injectability, and weight loss of polymer were evaluated for all formulations. Results= As the gel forming and viscosity results, it indicated that the selected ratios for later study were PLGA= NMP ratio at 1=3 1=4 and 1=5 because gel was formed within 1 minute. However, the high viscosity was observed with those ratios (11.8033±1.857Pa.s, 2.5760±0.385 Pa.s and 0.9553±0.076 Pa.s, respectively). The reduction of viscosity and injection time and the increasing of polymer weight loss were also observed when the additives were added. It might be due to the internal porous structure. As SEM micrograph, the internal porous structure was observed when the additives were added. Poloxamer addition produced a consistency porous with a thin wall and smooth surface with tiny pore whilst PVP would produce a fluffy texture and a smooth surface with a thick wall and also had different size of porous within structure. Moreover, the polymer weight loss of PLGA/PVP= NMP with ratio at 1=3 was increased dramatically at the first week and the rate of weight loss was increase slowly to plateau since week 2 to 4 of study (% weight loss from week 1 to week 4; 14.37, 19.83, 18.46 and19.18, respectively). Thus it is predictable that the in situ gel from PLGA/PVP might create a slow release until plateau since week 2 of administration. Conclusion= Conclusively, the additives such as Poloxamer or PVP are required for in situ gel forming formulation comprising of PLGA with solvent exchange method to suit for periodontitis treatment application. |