Thermal decomposition kinetics and compatibility studies of primaquine under isothermal and non-isothermal conditions
Primaquine (PQ) is the drug of choice for the radical cure of Plasmodium vivax malaria, and currently being administered in solid dosage form. In this study, the compatibility studies were carried out using differential scanning calorimetry (DSC), thermogravimetry (TG), and fourier transformed infrared (FT-IR). Non-isothermal and isothermal methods were employed to investigate kinetic parameters under nitrogen and air atmospheres using TG. The DSC investigations obtained by physical mixtures showed slight alterations in the melting temperatures of PQ with some excipients. The FT-IR confirmed the possible interactions obtained by DSC for the physical mixtures with PQ and lactose, magnesium stearate and mannitol. The results showed that the thermal decomposition followed a zero order kinetic in both atmospheres in non-isothermal method. The activation energy in both methods using nitrogen atmosphere was similar, and in air atmosphere the activation energy decreased.
KeywordsThermoanalysis Primaquine Compatibility Kinetics TG DSC
- 7.Jackson K, Young D, Pant S. Drug-excipient interaction and their affect on absorption. Res Focus. 2000;3:336–45.Google Scholar
- 10.Nunes RS, Semaan FS, Riga AT, Cavalheiro ETG. Thermal behavior of verapamil hydrocholide and its association with excipients. J Therm Anal Calorim; 2009. doi: 10.1007/s10973-009-0072-x.
- 11.Giron D. Contribution of thermal methods and related techniques to the rational development of pharmaceuticals, Part 1. PSTT. 1998;1:191–9.Google Scholar
- 12.Giron D. Contribution of thermal methods and related techniques to the rational development of pharmaceuticals, Part 2. PSTT. 1998;1:262–8.Google Scholar
- 16.Gennaro AR. Remington’s the pharmaceutical sciences and practice of pharmacy. Philadelphia: Lippincott, Williams & Wilkins; 2004.Google Scholar
- 24.British Pharmacopoeia. 3ed. London; 1999.Google Scholar