Ahmed Najim Abood , Zainab Najim Abdul-nabi

College of Pharmacy, University of Basrah, Basrah, Iraq;

For correspondence:-  Ahmed Abood   Email: ahmed.abood@uobasrah.edu.iq

Received: 2 February 2025        Accepted: 19 March 2026        Published: 30 March 2026

Citation: Abood AN, Abdul-nabi ZN. Impact of lipophilic carriers on metronidazole lipophilicity. Trop J Pharm Res 2026; 25(3):307-314 doi: https://dx.doi.org/10.4314/tjpr.v25i3.3

© 2026 The authors.
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Abstract

Purpose: To optimize the lipophilicity of metronidazole using two lipophilic carriers (stearic acid and cholesterol). Methods: The partition coefficient of compounds was determined using the shake flask method. The classical method included shaking a sample in a flask to equilibrate it between an aqueous phase and an organic phase. The concentration of the analyte of interest was determined in both phases using spectrophotometry. Two lipophilic substances, stearic acid (SA) and cholesterol (CH), were included at varying concentrations. Specifically, stearic acid was incorporated at 0.25 % and 0.5 %, while cholesterol was incorporated at 0.1 and 0.25 %. A full factorial design with 4 base formulas was utilized to provide a comprehensive analysis of both the main and interaction effects of the two additives on metronidazole lipophilicity. Results: Statistical model portrayed that both SA and CH significantly affected Log P values (SA: p = 0.003, CH: p = 0.006). Notably, interaction between SA and CH was highly significant and of a negative interaction coefficient (p = 0.000, Coef = -0.04209), indicating that higher cholesterol levels reduce the lipophilicity-enhancing effect of stearic acid. Conclusions: Lipophilicity of metronidazole may be optimized using optimum amounts of stearic acid and cholesterol. This could offer new formulation strategies for the purpose of enhanced drug delivery.

Keywords: Lipophilicity, Full Factorial Design, Metronidazole

Impact Factor
Thompson Reuters (ISI): 0.6 (2023)
H-5 index (Google Scholar): 49 (2023)