Preparation,Characterization and Solubility Investigation of Hydrochlorothiazide-flucytosine Cocrystal
A cocrystal of hydrochlorothiazide(1)and flucytosine(2)was prepared to improve the solubility of 1 and the hygroscopicity of 2.The 1-2 cocrystal was characterized by single-crystal X-ray diffraction,powder X-ray diffraction,Fourier transform infrared spectroscopy,thermogravimetry,and differential scanning calorimetry.The solubility and hygroscopicity of the 1-2 cocrystal were also examined.Compared with 1,the equilibrium solubility and intrinsic dissolution rate of 1 in the 1-2 cocrystal in hydrochloric acid(pH 1.2),phosphate buffer(pH 6.8),and pure water(pH 7.0)were increased.Meanwhile,the weight of 1-2 cocrystal did not increase under the conditions of 25 ℃ and relative humidity of 95%.These results indicated that the solubility of 1 was increased and the hygroscopicity of 2 was weakened by forming a cocrystal of 1 and 2,which provided a reference for the research on improving the solubility of poorly water-soluble drugs.