Comparison of ciprofloxacin assays

Area of Science:

• Pharmacokinetics and Drug Monitoring
• Analytical Chemistry
• Microbiology

Background:

• Accurate quantification of ciprofloxacin is crucial for therapeutic drug monitoring and pharmacokinetic studies.
• Existing analytical methods require validation for diverse biological matrices.

Purpose of the Study:

• To compare the efficacy of two independent high-performance liquid chromatography (HPLC) methods against two microbiological assays for ciprofloxacin quantification.
• To evaluate assay performance in serum, saliva, and urine samples from volunteers receiving oral ciprofloxacin.

Main Methods:

• Four distinct bioanalytical methods (2 HPLC, 2 microbiological) were employed.
• Samples (sera, saliva, urine) were collected from four volunteers post-administration of 500 mg oral ciprofloxacin.
• Assay sensitivity and inter-assay variability were assessed using linear regression analysis.

Main Results:

• HPLC methods exhibited high sensitivity (<0.01 µg/mL), while microbiological assays showed limits of 0.02 µg/mL (disc) and 0.06 µg/mL (well).
• Strong correlations were observed between ciprofloxacin concentrations determined by all methods in serum (R=0.90) and urine (R≥0.80).
• Mock unknown samples spiked with known ciprofloxacin amounts were also analyzed.

Conclusions:

• Both high-performance liquid chromatography (HPLC) and microbiological assay methods are suitable for the reliable quantification of ciprofloxacin.
• The validated methods provide accurate ciprofloxacin measurements in biological fluids, supporting clinical and research applications.