Development and Validation of an HPLC Method for Simultaneous Assay of MCI and MI in Shampoos Containing Plant Extracts

Figure 1

Some chromatograms obtained after analyzing placebo spiked with standard of MI and MCI during method development: (a) analysis on C18 column, sample preparation as per 2.4.2–Retention times were long for both analytes, especially MCI (more than 30 minutes); (b) analysis on biphenyl column with chromatographic conditions as per 2.3.1, sample was extracted directly with mixture methanol–0.02 M phosphate buffer solution pH 3.0 (30: 70, v: v) without previous dispersion in isopropyl myristate and cold centrifuging; peak of MI (retention time about 7.7 minutes) was not resolved.

(a)

(b)