World Journal of Advance Pharmaceutical Sciences WJAPS, Volume 2, Issue 1, 2025 www.wjaps.com 81 DESIGN AND EVALUATION OF BENZYL- AND DODECYL-BASED QUATERNARY AMMONIUM COMPOUNDS AS POTENTIAL COSMETIC PRESERVATIVES Sejal S. Gaikwad, Shravani R. Veladi, Tanaya R. Thombare, Sanika P. Sawant, A. R. Chaudhari*, V. L. Salode and K. B. Gabhane P. R. Patil Institute of Pharmacy, Talegaon (S.P.), Maharashtra, India. How to cite this Article: Sejal S. Gaikwad, Shravani R. Veladi, Tanaya R. Thombare, Sanika P. Sawant, A. R. Chaudhari, V. L. Salode and K. B. Gabhane (2025). DESIGN AND EVALUATION OF BENZYL- AND DODECYL-BASED QUATERNARY AMMONIUM COMPOUNDS AS POTENTIAL COSMETIC PRESERVATIVES. World Journal of Advance Pharmaceutical Sciences, 2(1), 81-85. Copyright © 2025 A. R. Chaudhari | World Journal of Advance Pharmaceutical Sciences This is an open-access article distributed under creative Commons Attribution-Non Commercial 4.0 International license (CC BY-NC 4.0) 1. INTRODUCTION Cosmetic products are an essential part of daily routines for millions of people worldwide, offering benefits ranging from aesthetic enhancements to hygiene and overall well-being. However, one significant challenge facing the cosmetic industry is microbial contamination, which can lead to product degradation, loss of efficacy, and potential health risks to consumers. Microbial contamination in cosmetics primarily arises during manufacturing processes, storage, or repeated consumer usage, introducing bacteria, fungi, and other microorganisms into the products (Lundov et al., 2009; Geis et al., 2006). Preservatives play a pivotal role in cosmetic formulations by preventing microbial growth, thus ensuring product safety and extending shelf-life. An ideal preservative for cosmetic applications should possess strong antimicrobial efficacy, stability under diverse formulation conditions, minimal interactions with other ingredients, low toxicity, and limited potential for causing allergic reactions or skin irritation (Kabara & Orth, 1997; Elder, 1984). CODEN: WJAPAC Impact Factor: 3.87 ISSN: 3049-3013 World Journal of Advance Pharmaceutical Sciences Volume 2, Issue 1. Page: 81-85 www.wjaps.com Research Article Article Info Article Received: 04 April 2025, Article Revised: 24 April 2025, Article Accepted: 14 May 2025. DOI: https://doi.org/10.5281/zenodo.15442779 ABSTRACT This study presents the synthesis, characterization, and biological evaluation of two novel quaternary ammonium compounds (QACs): Benzyltrimethylammonium chloride (QAC-1) and Dodecyltrimethylammonium bromide (QAC-2), with a focus on their potential as cosmetic preservatives. QAC-1 and QAC-2 were synthesized via alkylation reactions and characterized by FTIR spectroscopy, which confirmed the presence of key functional groups such as C–H stretching and N⁺–CH₃ vibrations. Theoretical and practical yields were calculated, with QAC-1 showing a significantly higher yield (78.08%) compared to QAC-2 (39.99%). Antibacterial activity was assessed using the cup plate method, where QAC-1 exhibited a larger zone of inhibition (4.0 cm) than the standard cetrimide (3.5 cm), while QAC-2 showed moderate activity (3.2 cm). Compatibility studies with common cosmetic excipients revealed good stability of both QACs with hydrophilic substances like glycerin and propylene glycol, whereas lipophilic excipients such as stearic acid and cetyl alcohol led to phase separation or precipitation. These findings highlight QAC-1 as a promising candidate for application as a novel cosmetic preservative, particularly in water-based formulations. Further toxicological and formulation studies are recommended to explore their full potential. KEYWORDS: Quaternary ammonium compounds, cosmetics, antibacterial, preservatives, FTIR, compatibility. *Corresponding author: *A. R. Chaudhari P. R. Patil Institute of Pharmacy, Talegaon (S.P.), Maharashtra, India.