A study of paracetamol tablet decomposition by thermogravimetry

• Main Author: Mislang, Ma. Glenda T.
• Format: text
• Language: English
• Published: Animo Repository 1997
• Subjects: Acetaminophen; Analgesics; Drugs > Analysis; Thermal analysis; Thermogravimetry; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/1802
• Institution: De La Salle University

The conventional way of assessing the thermal stability and self-life of drug products is by storing the samples at accelerated temperature conditions and determining the remaining potency after an elapsed time. This research was conducted to obtain kinetic data on the decomposition of two types of Paracetamol tablets, in the hope of finding an alternative method of evaluating the thermal stability and predicting the shelf-lives of the drug products. The thermal decomposition of the tablets was studied by thermogravimetric analysis. The effect of aging was studied by analyzing the thermogravimetric and the derivative of the thermogravimetric curves (TG/DTG), as well as the resulting kinetic parameters of samples stored in ovens maintained at 40, 50 and 60 degrees Centigrade for certain periods of time. This non-isothermal (dynamic) technique of thermogravimetry was compared with the conventional, isothermal method of accelerated stability studies of pharmaceutical products. The effect of particle size and various heating rates were likewise investigated. The TG and DTG profiles were recorded and the thermogravimetric data were analyzed using the Coats and Redfern Equation. The Ozawa method was also employed in calculating the kinetic parameters of the decomposition using four different heating rates. Results showed that the weight-loss data fit a zero-order reaction with the kinetic parameters (activation energy and frequency factor) heavily dependent on the particle size and heating rate. The TG and DTG profiles of the samples stored at elevated temperature conditions showed no remarkable change in appearance. The obtained kinetic data had no large deviation which supports the laboratory assay data showing the samples to be fairly stable at the studied conditions. However, no meaningful comparisons can be made between the conventional and the thermogravimetric methods as to the use of the calculated kinetic parameters in shelf-life prediction.