Validation of a Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Trimethoprim and Sulfadimethoxine Sodium in Oral Liquid Dosage Form

Mashhour M Ghanem

doi:10.3797/scipharm.1212-30

Abstract

A simple, specific, accurate, and stability-indicating RP-HPLC method was developed and validated for the simultaneous determination of Trimethoprim (TMP) and Sulfadimethoxine sodium (SDMS) in Vetricine® oral solution product. The desired separation was achieved on an ODS column (250×4.6 mm i.d., 5 μm) at room temperature. The optimized mobile phase consisted of an isocratic solvent mixture of water:acetonitrile:triethylamine (700:299:1, v/v/v), adjusted to a pH of 5.7 ± 0.05 with 0.2N acetic acid. The mobile phase was fixed at 0.8 ml/min and the analytes were monitored at 254 nm using a photodiode array detector. The effects of the chromatographic conditions on the peaks USP tailing factor, column efficiency, and resolution were systematically optimized. Forced degradation experiments were carried out by exposing TMP, SDMS standards, and the oral solution formulation to thermal, photolytic, oxidative, and acid-base hydrolytic stress conditions. The degradation products were well-resolved from the main peaks and the excipients, thus proving the reliable stability-indicating method. The method was validated as per ICH and USP guidelines (USP34/NF29) and found to be adequate for the routine quantitative estimation of TMP and SDMS in commercially available Vetricine® oral liquid dosage form.

Highlights

Vetricine® oral solution is a veterinary drug that combines two antibacterial substances, trimethoprim (TMP) and sulfadimethoxine sodium (SDMS)
The overlaid ultraviolet absorption spectra of the two active ingredients TMP and SDMS (0.05 mg/ml each) demonstrated that they shared a wavelength near 254 nm, which was chosen for the entire study
The validated HPLC method developed for the quantitative quality control determination of TMP and SDMS in Vetricine® oral solution was evaluated for system suitability, specificity, sensitivity, linearity, range, accuracy, precision, and robustness

Summary

Introduction

Vetricine® oral solution is a veterinary drug that combines two antibacterial substances, trimethoprim (TMP) and sulfadimethoxine sodium (SDMS). It is a synthetic antimicrobial drug with broad spectrum bactericidal action. It is used for the treatment of infections caused by: Escherichia coli, Salmonella spp., Enterobacter spp., Klebsiella spp., Staphylococcus spp., Vibrio cholerae, Haemophilus influenzae; and other bacteria sensitive to TMP and SDMS especially in poultry and rabbits [1]. TMP is official in BP and USP [2, 3], whereas SDMS is only official in the USP [4]. The combined simultaneous analysis of both drugs has not been adopted in any official pharmacopoeia

Methods

Results

Conclusion