HPLC ANALYSIS OF BACTERIOSTATS 167 Inject A Triclosan B Triclosan Figure 1. Chromatograms of (a) reference triclosan standard, and (b) that of a deodorant stick. cate injections of reference standard solutions of triclosan and TCC in a single day, and over a period of three to four days. Chromatographic response precision data are shown in Table III. Data indicate that precision of the procedure is very good. Accuracy of the procedure was tested by addition of known amounts of triclosan and TCC to deodorant sticks and deodorant soaps, respectively. For this study triclosan was added to a deodorant stick placebo sample, whereas TCC was added to a deodorant soap sample which was previously assayed. The data are presented in Table IV.

168 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Inject A •dTCC Iniect B Figure 2. Chromatograms of (a) reference TCC standard, and (b) that of a deodorant soap. The recovery data indicate that the accuracy of the •rocedure is excellent. The precision of the assay procedure was further determined by analyzing a commercial deodorant stick for triclosan and a deodorant soap for TCC. For five replicate assays the coefficient of variation for triclosan was + 3% and that for TCC was 0.38%. SPECIFICITY OF THE ASSAY PROCEDURE Although it was established that the procedure is capable of discriminating the bacteriostats from the inactive matrix, perfumes, etc., it was necessary to show that the procedure has the capability of discriminating the bacteriostats from the degradation products of the bacteriostats and from those of the perfumes or any other ingredient present in the deodorants. Table III Reproducibility Data of Chromatographic Responses • Within-Run (n = 6) Between-Run (n = 4) Retention time Area Retention Time Area Triclosan 483 _+ 8.1 572,870 _+ 10,983 496 _+ 18 548,166 _+ 24,654 % CV 0.84 0.96 1.8 4.5 TCC 468 _+ 2.4 at 340,877 _+ 1,811 473 _+ 9.8 365,393 + 29,748 % CV 0.26 0.27 1.04 8.1 •Retention time and area are expressed in seconds and electronic counts, respectively. The amounts of triclosan and TCC injected were 1.26 and 0.258/zg respectively.