RP-HPLC Method Development and Validation for Simultaneous Estimation of Clarithromycin and Paracetamol

The present work describes a simple, rapid, and reproducible reverse phase high performance liquid chromatography (RP-HPLC) method for the simultaneous estimation of clarithromycin (CLA) and paracetamol (PCM). C18 column (Kromasil ODS, 5？μm, 250 × 4.6？mm) and a mobile phase containing phosphate buffer (0.05？M) along with 1-octane sulphonic acid sodium salt monohydrate (0.005？M) adjusted to pH 3.2: acetonitrile (50？:？50？v/v) mixture was used for the separation and quantification. The flow rate was 1.0？mL/min and the eluents were detected by UV detector at 205？nm. The retention times were found to be 2.21 and 3.73？mins, respectively. The developed method was validated according to ICH guidelines Q2 (R1) and found to be linear within the range of 75–175？μg/mL for both drugs. The developed method was applied successfully for assay of clarithromycin and paracetamol in their combined in-house developed dosage forms and in vitro dissolution studies. 1. Introduction Clarithromycin is a second generation macrolide with broad spectrum of antibiotic activity. It is active against the organisms which are responsible for bacterial exacerbations of lower respiratory tract infections [1]. Clarithromycin (6-O-methyl erythromycin) is synthesized by substituting a methoxy group for the C-6 hydroxyl group of erythromycin. This substitution creates a more acid stable antimicrobial and prevents the degradation of the erythromycin base to the hemiketal intermediate. The increased acid stability of clarithromycin results in improved oral bioavailability and reduced gastrointestinal intolerance [2]. Clarithromycin is characterized by favorable oral bioavailability that achieves 52% to 60%, whereas its antimicrobial activity involves a concentration and time dependent mode of bacteriostatic action [3]. Clarithromycin is metabolized in the liver and in the stomach. Approximately 22% of an oral dose is recovered as parent compound, 18% in the urine and 4% in the faeces. Clearance of clarithromycin decreases with increasing dose, probably because of saturable hepatic metabolism [4] (see Figure 1). Figure 1: Structure of clarithromycin. Paracetamol is a common analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains [5]. Paracetamol is chemically 4-hydroxyacetanilide is a centrally and peripherally acting non-opioid analgesic and antipyretic [6]. Paracetamol lacks many of the side effects of aspirin, unlike other common analgesics such as aspirin and ibuprofen, and has no anti-inflammatory properties, and so it is not a member