Characterization of Hydrochlorothiazide-Trometamol Mixtures
Formulation of fast release and soluble tablets
Khairy E. Gabr and Thanaa M. E. Borg
Department of Pharmaceutics, Faculty of Pharmacy, Mansoura University, Mansoura (Egypt)
Co-precipitated and physical mixtures of hydrochlorothiazide (HCT) and trometamol (tromethamine, Tris) were examined using Fourier-transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and X-ray diffraction. The solubility of HCT in distilled water was increased in the presence of Tris. Results of the examinations indicated that HCT, co-precipitated with Tris in the solid state, forms complexes. Tablets made from co-precipitates showed improved drug dissolution rates (at constant surface) with a maximum at 30 % HCT (w/w) content. Maximum relative enhancements (10.5 and 5.25) were obtained in distilled water and 0.1 N HCl, respectively. Tablets containing HCT-Tris (3 : 7) co-precipitates exhibited a faster dissolution rate compared to those without Tris. Co-precipitate tablets containing microcrystalline cellulose (Avicel PH101) as diluent gave higher release rates than tablets containing lactose or mannitol. Therefore, Avicel PH101-containing tablets can be used for fast drug release. Co-precipitate tablets containing mannitol or lactose showed high solubility of HCT in distilled water (320 mg/100 ml); one tablet could be dissolved in 10 ml distilled water. These tablets can be used as soluble dosage form for patients unable to swallow tablets.
Key words Fast release tablets Â· Hydrochlorothiazide Â· Soluble tablets Â· Tablet formulations Â· Trometamol, co-precipitates
pharmind 1999, Nr. 3, Seite 281