Effect of Heating Rate on the Accuracy of Paracetamol Melting Point Determination Using a Stuart SMP3 Apparatus
Keywords:
paracetamol, melting point, heating rate, thermal lag, melting range, Stuart SMP3Abstract
Melting-point determination is an important analytical technique for the identification of crystalline pharmaceutical substances and the assessment of their purity. This study aimed to investigate the effect of heating rate on the measured melting point of paracetamol using a Stuart SMP3 melting-point apparatus. Three commercially available paracetamol products collected from the local market in Tobruk, Libya, were coded as Brand A, Brand B, and Brand C and analyzed. Melting points were determined using the capillary method in accordance with British Pharmacopoeia (BP) and United States Pharmacopeia (USP) procedures. Three replicate measurements were performed for each brand at different controlled heating rates, and the onset and completion temperatures of melting were recorded. the results were expressed as Mean ± Standard Deviation (SD), and One-way Analysis of Variance (ANOVA) was used to evaluate differences among the different heating rates. The measured melting points were compared with the reference melting range of paracetamol (approximately 168–172°C). The results showed that increasing the heating rate generally increased the observed melting temperatures and broadened the melting range, particularly at the highest heating rate of 10°C/min. Lower heating rates produced melting-point values closer to the reference range and generally showed better measurement consistency. these findings indicate that heating rate is an important experimental factor affecting the determination of paracetamol melting point using the Stuart SMP3 apparatus. therefore, an appropriate heating rate is recommended to achieve a balance between analytical efficiency, accuracy, and reproducibility in routine melting-point determination and pharmaceutical quality-control testing.
References
-Ahmad, I.; Shaikh, R. H. Effect of temperature and humidity on hardness and friability of packaged paracetamol tablet formulations. Pak. J. Pharm. Sci. 1993, 7 (2), 69–78.
-Akasha., A, Ahdeya., E, Bsebsu ., Z . (2019) Comparative study between five brands of metformin hydrochloride available in Libyan drug market. Mintage Journal of Pharmaceutical and Medical Sciences. 8 (3) 37-41
-Acetaminophen capsules. (2019). In United States Pharmacopeia Convention Committee of Revision (Ed.), United States Pharmacopeia - National Formulary (41st ed., p. 8). United States Pharmacopeial Convention.
-Boldyreva, E. V., Drebushchak, T. N., Paukov, I. E., Kovalevskaya, Y. A., & Drebushchak, V. A. (2004). DSC and adiabatic calorimetry study of the polymorphs of paracetamol: An old problem revisited. Journal of Thermal Analysis and Calorimetry, 77, 607–623.
-British Pharmacopoeia , (2017) and beyond. European Pharm Rev. 2017 ; 22:14-6 tablets, the Stationery Office...
-Council of Europe. European Pharmacopoeia. 6th ed. Strasbourg: Council of Europe; 2007. Paracetamol; p. 2611.
-European Pharmacopoeia. Paracetamol, Monograph 0049. European Directorate for the Quality of Medicines & HealthCare (EDQM), Council of Europe
-Espeau, P., Ceolin, R., Roblès, R., & others. (2005). Polymorphism of paracetamol: Relative stabilities of the monoclinic and orthorhombic phases inferred from topological pressure-temperature and temperature-volume phase diagrams. Journal of Pharmaceutical Sciences, 94(3), 524–539.
-Gunatilake, S. K., Samaratunga, S. S., Adekola, F.A. ( 2016). Effects of binder on the physico-chemical properties and the quality of paracetamol tablets. Der Pharm Chem. 8, 237-42
-Global Surveillance and Monitoring System for Substandard and Falsified Medical Products. World Health Organization: Geneva, 2017.
-Gaisford, S., Buanz, A. B. M., & Jethwa, N. (2010). Characterisation of paracetamol form III with rapid-heating DSC. Journal of Pharmaceutical and Biomedical Analysis, 53(3), 366–370.
`12-Khan AD, Baranwal PK, Ali MA, Kumar S, Sharma S (2019) Comparative quality evaluation of two brands of paracetamol tablets obtained from the market. International Journal of Pharmaceutical Education and Research. 1 (1): 14-18.
-Reem . ,A, Syed ., N , Muhammad .M ., (2021) Quality assessment of nine paracetamol 500 mg tablet brands marketed in Saudi Arabia. BMC Res Notes. 2021; 14: 254-258.
-Ruwida., K , Entesar., E , Asma .,E. (2024). Physical and Chemical Evaluation of Different Brands of Paracetamol Tablets, journal Alqalam Med App Sci. 2024;7(2), 257-260.
-Rassat, M., Ouandji, I., Guiblin, N., & Espeau, P. (2024). Obtaining two polymorphic forms of paracetamol within the phase diagram with PEG 1500. European Journal of Pharmaceutics and Biopharmaceutics, 195.
-Stuart Equipment. SMP3 Melting Point Apparatus: Operating Instructions. Stuart/Barloworld Scientific .
-Some, I.T., Bogaerts, P., Hanus, R., Hanocq, M., Dubois, J. (2001). Stability parameter estimation at ambient temperature from studies at elevated temperatures. Journal of pharmaceutical sciences. 90(11):1759-1766.
-U.S. Food and Drug Administration (FDA). (2024). Q2(R2) Validation of Analytical Procedures: Guidance for Industry.
-Mukesh, P. Ratnaparkhi, Shilpa P. Chaudhari, Suresh B. Dhiwar RRG. Marketed Formulations: Quality Evaluation of Conventional Release Paracetamol Tablet. Res J Pharm Tech. 2012, 5 (3), 390–392 .
- Qi, S., Avalle, P., Saklatvala, R., & Craig, D. (2008). An investigation into the effects of thermal history on the crystallisation behaviour of amorphous paracetamol. European Journal of Pharmaceutics.
