Solution-gelation transition of hydroxylpropyl methyl cellulose (HPMC)

• Main Author: Choy, Gincent Jin Sheng.
• Other Authors: Sunil Chandrakant Joshi
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/17205
• Institution: Nanyang Technological University

Many researches have been conducted in the study of controlled drug release matrix tablets and capsules involving synthetic water soluble cellulose modifications. These substances are popular due to their ability to incorporate a large percentage of the drug and still yield a product which is compatible with conventional production techniques. Hydroxypropyl Methyl Cellulose (HPMC) is one such cellulose ethers which are used in a wide variety of applications. In this study, the solution and gelation transition processes of HPMC are investigated using the Micro Differential Scanning Calorimeter. These processes are represented by the degelation and gelation processes respectively. It was found that the enthalpy and entropy changes for the gelation and degelation processes of the same concentration of HPMC did not coincide with each other. This is primarily due to the differences in their mechanisms and the presence of the side groups in the HPMC molecules. It was also found that HPMC is a temperature dependent substance which require multiple scans in order to be stabilized and for the results to achieve a good repeatability. From the studies, it can be observed that the enthalpy and entropy changes for different concentrations of HPMC do not follow a linear relationship. Another interesting observation is the cooling segment of gelation process which exhibit differing rates of cooling with different concentrations. The cooling rates seem to increase with increasing concentration of the HPMC molecules with 1% weight exhibiting a linear relationship.