THE EFFECT OF pH CONTROL ON THE SOLUBILITY AND PARTITION COEEFICIENT OF TRANDOLAPRIL

Mbah J Chika; Enwereji O Prisilla

Authors

Mbah J Chika Author
Enwereji O Prisilla Author

Keywords:

Trandolapril, solubilty, partition coefficient, pH control

Abstract

The objective of the present study was to investigate the effect of pH control on the aqueous solubility and partition coefficient of trandolapril respectively. The aqueous solubility was determined at 25 ° C using pH values of 1.0,2.0,4.0,5.0,5.4,5.8, 6.4, 8.0 and 9.0 respectively. The aqueous solubility of the drug was also studied at 35 ° C and 45 ° C respectively. The partition coefficient of trandolapril was determined at 25 ° C between chloroform and aqueous buffer solutions using pH values of 2.0, 4.4, 5.0, 5.4, 5.8, 6.4, 7.4 and 9.0 respectively. The pH-solubility profile of trandolapril showed an intrinsic solubility of

3.524 ´ 10^-2 mg/ml at 25 ±1° C. The pH-dependency of the apparent chloroform-water partition coefficient of trandolapril gave a partition coefficient of 58.88 for free trandolapril. The results of the study allowed the dissociation constant of the drug to be calculated. The physicochemical data obtained at alkaline pH (³ 9.0) can be useful in the development of pharmaceutical liquid dosage forms of the drug.