The potential derivatives of caprylic acid were subjected to preservative efficacy testing in Aluminium Hydroxide Gel – USP using Staphylococcus aureus MTCC 2901, Bacillus subtilis MTCC 2063, and Escherichia coli MTCC 1652 as representative challenging microorganisms for antimicrobial effectiveness testing as per USP 2004. The caprylic acid derivative, capryl hydrazide exhibited better preservative efficacy than caprylic acid as well as the standard preservatives, methyl paraben and propyl paraben.