A simple, accurate and sensitive spectrophotometric method for the determination of cefadroxil (CXL), cefaclor
(CLR) and cefatoxime (CTXM) in pure, dosage forms, and in the presence of its oxidative degradates is described. The
method is based on the oxidation of the studied drug using cerium(IV) ammonium sulphate and subsequent
determination of the unreacted Ce(IV) by measuring the decrease in absorbance of rhodamine B (RhB) at a suitable
λmax= 540, 541 and 542 nm for CXL, CLR and CTXM, respectively. Regression analysis of Beer/Lambert plots showed
good correlation in the concentration ranges: 1.0-10, 1.0-12 and 2.0-8.0 µg ml−1 for CXL, CLR and CTXM, respectively.
The apparent molar absorptivity, Sandell sensitivity, detection and quantitation limits were calculated. For more accurate
results, Ringbom optimum concentration ranges were 3.0-8.0, 3.0-9.0 and 4.0-7.0 µg ml−1
, respectively. The obtained
results are compared statistically using student's t-test and variance ratio F-test with the official methods. Analyzing
pure and dosage forms containing CXL, CLR and CTXM tested the validity of the proposed method. The relative
standard deviations were ≤ 1.38 with recoveries 98.2-101.2%.