A spectrophotometric reliable, rapid and sensitive methods have been developed and validated for the determination of fexofenadine hydrochloride. A method was described for the determination of fexofenadine hydrochloride in pure form or pharmaceutical formulations using bromophenol blue (BPB) bromothymol blue (BTB), bromocresol green (BCG) and bromocresol purple (BCP). This method involved the formation of colored chloroform (CHCl3) extractable ion-associate complexes with BPB, BTB, BCG and BCP in acidic medium. All variables affecting the reaction have been investigated and the conditions were optimized. The extracted complexes showed absorbance maximum at λmax 411, 414, 409, and 411 nm, respectively. The reagents form a chloroform – soluble colored ion association complex with fexofenadine hydrochloride at pH 2.4, 2.4, 2.2 and 2.4 using BPB, BCG, BTB and BCP respectively. Regression analysis of Beer –Lambert plots showed good correlation in the concentration ranges 1.0 – 6.0, 0.5 – 9.0, 1.0 – 8.0 and 0.5 – 6.0 μg mL–1, respectively. The apparent molar absorptivity. Sandell sensitivity, detection and Quantitation limits were calculated. Applications of the proposed methods to representative pharmaceutical formulations are successfully presented. |
