Stability-Indicating Method for the Determination of Some Cephalosporines in the Prescence of Degradation Products

Abstract

A rapid and convenient spectrophotometric method is described for the quantitative determination of some of Cephalosporines Cefadroxil, I Cephradine II and Cefaclor III. The proposed method depends upon the conversion of these compounds to the corresponding piperazine-2,5 dione derivatives by heating in an alkaline sorbitol-zinc ion solution for 10—25 minutes at 90°C and subsequent treatment of these derivatives with 0.1 N sodium hydroxide to obtain highly absorbing products with λ_max at 345 nm for I & II and at 334 nm for III using zero order absorption curve. Using first derivative spectrum (D₁) for III the λ_max is at 362 nm. The method was found to be free of the interference from polymerization and other degradation products. Its application to assess the stability of the Cephalosporines was demonstrated. Verification of Beer's Law showed lincarity at concentrations of 12.5-87.5 μg ml⁻¹, 12.5-125 μg ml^−l and 6.7-66.7 μg ml⁻¹ for I, II and III respectively with mean accuracies 100.37 ± 0.72%, 100.45 ± 0.87% and 99.63 ± 1.97% when using zero order absorption curve. Using D1 for III gave linearity at concentration range 42-114 μg.ml⁻¹ with mean accuracy of 99.54 ± 0.77%.

The proposed method is applied successfully for the determination of Cephalospnnes in bulk powder and in pharmaceutical preparations. The results obtained by the proposed method are statistically analysed and compared with hose obtained by applying the USP XXII method.

Several methods have been reported for the determination of I including colorimetric [l-3], HPLC [4], TLC [5] and differential pulse polarography [6].

Fluoremetric [7], derivative Spectrophotometric [8], UV absorptiometric [9], Colorimetric [10,11] and HPLC [12] methods have been reported for the determination of II.

Some analytical methods have been reported for the determination of III. These include HPLC [13-151, Colorimetric [16,17]. TLC [5] and UV absorptiomemc [18] methods.

The purpose of this manuscript is to determine the previously mentioned drugs in the presence of their degradation products by a selective method.

Key Words:

• Spectrophotometry
• pharmaceutical analysis
• stability indicating method
• determination of Cephalosprines
• drug formulation