Thermal analysis of ascorbic acid and its compatibility with excipients by using DSC and tg/dtg methods / Hendrawati Mohd Sapuan

The physical-chemical properties and compatibilities of several commonly used pharmaceutical excipients with ascorbic acid were evaluated using thermal method. Differential scanning calorimetry (DSC) was used as a screening technique for assessing the compatibility of ascorbic acid with some currently employed pharmaceutical excipients such as avicel, magnesium stearate and lactose. The influence of different storage temperature on the drug stability in binary mixture after one month was also evaluated. On the basis of DSC result, ascorbic acid was found to be compatible with lactose and PEG 4000. Some drug-excipient interaction was observed with avicel and magnesium stearate. Result shows that, decomposition of ascorbic acid in binary mixtures is higher as the storage temperature is increase except for mixture containing lactose. Thermogravimetry (TG) was of help in interpreting the DSC results.