Rapid potentiometric and spectrophotometric determination of cefotaxime in pharmaceutical and biological samples

Simple, precise, rapid, and low-cost potentiometric and spectrophotometric methods were developed for the determination of cefotaxime in pure form, pharmaceutical formulations, and biological samples (urine and serum samples). The potentiometric method is based on the direct titration of cefotaxime in an aqueous medium with 0.1 M NaOH at µ = 0.5 NaCl and 25 ± 1.0 ℃ utilizing a combined glass pH electrode. Using the standard addition method based on Gran plot, the lower limits of detection and quantification were found to be 2.89 and 4.0 µg/mL, respectively over a linear concentration range of 4.0 to 65.0 µg/mL of cefotaxime with correlation coefficient of R² = 0.9973 and standard deviation (SD = 0.1) (n = 5). Cefotaxime content in pure solutions, vials, urine, and serum was effectively determined using this approach, yielding satisfactory results. Common components found in the samples analyzed did not cause any interference. Cefotaxime was recovered in a range of 95.0% to 101.6% from various biological fluids and vial dosage forms. Furthermore, the spectrophotometric method was based on the formation of a Prussian Blue (PB) complex. The spectrophotometric detection and determination of cefotaxime were achieved through by interaction between acidic hydrolysis product of cefotaxime (at 70 °C) and a combination of FeCl₃ and hexacyanoferrate (III) ions. The maximum absorbance of the formed complex measured at 700 nm, with 2.50 × 10⁴ Lmol^- 1cm^- 1 molar absorptivity. The Prussian Blue (PB) complex demonstrated excellent stability and sensitivity under ideal conditions, with absorbance rising in direct proportion to the cefotaxime concentration. The quantification limit was determined to be 1.35 µg/mL, and the detection limit was 0.41 µg/mL. The linear calibration, curve within a concentration range of 1.0-6.0 µg/mL, exhibited a standard deviation of 0.004 and a correlation coefficient (R²) of 0.9957 (n = 5). The proposed methods proved to be effective for the determination of cefotaxime in pure form, pharmaceutical formulations and biological samples. The results were in good agreement with those reported in the literature for cefotaxime determination, as well as with those obtained using the proposed potentiometric approach. Furthermore, the environmental impact was assessed using three green evaluation tools: the Analytical Eco-Scale (ESA), the Analytical GREEnness metric (AGREE) and the Green Analytical Procedure Index (GAPI).