Analysis of creams. V. Application of thin layer chromatography. Part II.

A standard TLC procedure was tested for its applicability in the qualitative analysis of several creams. It was found that in creams of known composition the presence of almost all of the active cream components as well as the excipients can be confirmed. An additional eluent, spray reagent, or a liquid extraction clean-up step sometimes appeared to be necessary.

Analysis of creams. V. Application of thin layer chromatography. Part I.

A standard procedure, consisting of two TLC systems, for the qualitative control of creams is presented. All common cream excipients, except those of very high polarity, are separated in a simple gradient elution system, using diethyl ether as the eluent in a chromatographic chamber saturated with n-pentane. The very polar cream base components are separated using n-butanol-glacial acetic acid-water (20 + 2 + 5) as the eluent.

Analysis of creams. IV. Application of high performance liquid chromatography. Part I.

The possibilities of applying reversed-phase high performance liquid chromatography to the analysis of o/w emulsion type creams without preceding sample clean-up were investigated. The chromatographic behaviour of cream base components and active compounds in reversed phase systems consisting of methanol-water mixtures as the mobile phase and a chemically bonded octadecyl stationary phase, was studied. A number of active compounds and the preservative (sorbic acid) could be determined--often in one chromatographic run--without complications, by simply dissolving the sample in a suitable solvent mixture and injecting an aliquot of the solution into the chromatograph.

The analytical control of the composition of creams.

The analysis without prior sample clean-up of promethazine hydrochloride or clioquinol in commercially available creams has been investigated using UV-spectrophotometry and titrimetric methods. The results were compared with those obtained by GLC and HPLC. Although in some cases the active drug could be determined satisfactorily using the comparatively non-selective UV-absorbance or titrimetric methods, these methods were found to be reliable only when applied to creams for which the qualitative and quantitative composition was completely known.

Analysis of creams. III. Application of gas--liquid chromatography. Part I.

The possibilities of the gas--liquid chromatographic analysis with flame ionization detection of creams of the o/w emulsion type were investigated. Interferences by cream base components in the determination of the active compounds were studied. It appeared to be possible to determine active compounds with a retention index lower than 1900 on ov-17 (e.