Archives of Pharmacal Research
- Volume 7 Issue 1
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- Pages.47-52
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- 1984
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- 0253-6269(pISSN)
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- 1976-3786(eISSN)
Pharmaceutical studies on the polymorphism of hydrochlorothiazide
- Kim, Bong-Hee (Department of Pharmacy, Chung-Nam National University) ;
- Kim, Johng-Kap (College of Pharmacy, Chung Ang University)
- Published : 1984.06.01
Abstract
Four polymorphic forms (I, II, III and IV) of hydrochlorothiazide have been characterized on the basis of x-ray diffractometry and differential thermal analysis. Form I was obtained by crystallization from N, N-dimethylformamide and Form II was crystallized from hot methanol. Form III was precipitated from sodium hydroxide aqueous solution by treatment with hydrochloric acid and Form IV was crystallized from 50% methanol. The metastable form I was a most stable form among four polymorphs, which was stable more than ten months at room temperature. The thermodynamic parameters such as heat of solution, enthalpy, entropy, free energy difference and transition temperature were determined by the measurement of intrinsic dissolution rate. The transition temperature and the heat of transition between the metastable Form I an Form II were determined to be
Keywords
- Hydrochlorothiazide;
- Polymorphs;
- Differential thermal analysis;
- x-Ray powder diffractometry Transition temperature;
- Heat of transition