Effects of citrate based additives on the viscosity profile of hydroxypropylmethylcellulose solution / Azreen Suzyliana Zabidi

AIM: This study sets to investigate the effects of citrate based additives on the viscosity profile of hydroxypropylmethylcellulose (HPMC) solution.
METHOD: The HPMC solution, with or without the incorporation of additives, was subjected to viscosity test using a rotatory viscometer and at a solution temperatures of 30 to 60°C unless otherwise stated. The additives used were trisodium citrate, citric acid, triethylcitrate and triacetin.
RESULT: The viscosity of aqueous HPMC solutions was reduced when appropriate amounts of trisodium citrate, citric acid, triethylcitrate and triacetin were added. Using 1% w/w HPMC solution, triethylcitrate demonstrated the best viscosity lowering effect when solution temperature of 30 to 50°C were concerned while trisodium citrate exhibited a marked viscosity lowering property at 60°C. Using 1.5% w/w HPMC solution, smaller additive such as citric acid gave rise to the most prominent viscosity lowering property.
CONCLUSION: Trisodium citrate, citric acid, triethylcitrate and triacetin exhibited viscosity lowering property in HPMC solution.