Effect of size on degradation and different fabrication methods for nano particles

• Main Author: Loh, Eugenia Mei Ting.
• Other Authors: Loo Say Chye Joachim
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Materials::Biomaterials
• Online Access: http://hdl.handle.net/10356/18991
• Institution: Nanyang Technological University

Poly (lactic-co-glycolic acid), also known as PLGA, is commonly used to encapsulate drugs for drug delivery purpose in the form of micro size particles as well as nano order particles. The objective of this report is to study the effect of the size of PLGA particles during degradation and relating factors that contributes to the degradation rate. Different methods of fabricating nano particles were discussed in this report as well. The solvent evaporation method was employed to fabricate micro particles while a modified solvent evaporation method was used for the fabrication of the nano particles. 7 weeks in vitro study was also carried out on the micro particles and a 3 weeks in vitro study on the nano particles. Scanning electron microscope (SEM) and the field transmission scanning microscope (FESEM) were employed to study the morphology and size of the micro and nano particles respectively. Their images showed morphological changes during the timeline of degradation. This proves that the PLGA microspheres were undergoing bulk degradation as there was low mass loss at the early stage and therefore no significant change in physical appearance. Degradation rate for lidocaine loaded microspheres was faster than that of the microspheres that do not contain lidocaine. Base on the GPC plotted graph, it can be determined that PLGA has undergone random scission of internal bonds. Mass loss of the degraded products was also calculated as supporting evidence that degradation had taken place. It has also been determined that factors like size, microspheres containing Lidocaine and amount of surfactant contribute to the rate of degradation. Lidocaine loaded microspheres were proven to have a faster degradation rate as compared to those without Lidocaine because Lidocaine acted as a base catalyst. It had been observed also that the larger microspheres studied had a faster degradation rate. A higher amount of surfactant is required to fabricate smaller particles and this acted as a barrier for water to penetrate into the particles. However, since nano particles have higher surface area, the degradation rate will speed up. Therefore, the degradation rate of the smaller particles will have to depend on the dominating factor which could either be the surfactant concentration or the surface area of the particles.