ABSTRACT
Ciprofloxacin HCl (CIP) and Metronidazole (MET) are antibacterial drugs used in combination for treatment of mixed aerobic/anaerobic infections. An UPLC-MS/MS method was developed for the simultaneous estimation of CIP and MET in spiked human plasma using sildenafil citrate as an internal standard (IS). Protein precipitation was used for analyte extraction. The chromatographic separation was completed within 6 min using a mobile phase of 0.1% formic acid in water and acetonitrile (70: 30, v/v), Zorbax C18, 100 x 4.6 mm, 3.5 μm analytical column, at a flow rate of 0.5 mL min-1. Multiple reaction monitoring (MRM) transitions were measured in the positive ion mode. Validation of the method showed standard curves to be linear in the range of 10-4000 ng mL-1 for CIP and 30-12000 ng mL-1 for MET with mean correlation coefficient exceeding 0.999. In human plasma, CIP and MET were stable for at least 36 days at –70 ± 5 °C, 6 hours at ambient temperature and after three freeze thaw cycles. After extraction from plasma, the samples were stable in auto sampler at 22 °C for 6 hours. The method was simple, specific, sensitive, precise, accurate and suitable for bioequivalence and pharmacokinetic studies.
ABSTRACT
Aim: The derivatization product of diclofenac (DCL), aceclofenac (ACL), is a non-steroidal anti-inflammatory drug (NSAID) which causes faster and extended action with reduced gastrointestinal (GI) inflammation. The detection of DCL in ACL bulk and pharmaceutical products indicates incomplete synthesis and hydrolysis. In this article we have developed a UPLC-MS/MS method for analysis of ACL and DCL. The method was designed as an at-line monitoring tool for process analytical technology (PAT) application to ACL synthesis. The method was also applied for analysis of ACL and DCL in bulk and tablets. Methodology: Isocratic elution was performed on a UPLC C18 column (2.1 x 50 mm, 1.7 μm) using a mobile phase consisting of acetonitrile, water and formic acid (80:20:0.5, v/v/v). Flow rate was 0.2 mL/min and total run time was 1 min. Auto-sampler temperature was maintained at 5ºC to prevent any further degradation of ACL. Electrospray positive ionization (ESI +Ve) in multiple-reaction monitoring mode (MRM) was used for the simultaneous determination of ACL and DCL. Monitoring was performed at [M+H]+ 354.23: 250.09 and 296.13:250.1 m/z; respectively. The method was validated according to ICH guidelines Q2(R1). Results: The linearity range was 20 – 3000 ng/mL for both drugs. The developed method was accurate and precise (RSD<2%) for the determination of ACL and DCL in single solution (99.65±1.33 and 100.37±1.02 for ACL and DCL; respectively) and laboratory prepared mixtures (101.01±1.07 and 100.45±1.54 for ACL and DCL; respectively). The method was applied to Bristaflam® and Cataflam® tablets and the recovery was 100.95±0.18 and 99.15±0.62; respectively. The average recovery from reaction mixture was101.21±0.06 and 98.89±0.64 for ACL and DCL; respectively. Conclusion: The proposed UPLC-MS/MS method is valid for at-line monitoring of ACL and DCL during PAT application to ACL synthesis and drug determination in bulk and tablets.