Comparative chemical and biological analysis of coal tar-based therapeutic agents to other coal-derived materials

In this study, methodologies developed for the analysis of synthetic fuel products were applied to the coal tar fractions isolated from coal tar‐based pharmaceutical products. A pharmaceutical stock solution of 20% coal tar in alcohol, a 50% coal tar bath emulsion and a 4.3% coal tar shampoo were studied. The toxicology and chemical composition of the coal tar fractions isolated from these materials were compared with an industrial coal tar and with a direct‐liquefaction coal liquid product. The coal tars and coal liquid product were fractionated into chemical classes by alumina column chromatography and individual components were identified and quantitated by high‐resolution gas chromatography. The microbial mutagenicity of these materials was measured against S. typhimurium, TA 98. In addition, the industrial coal tar, coal‐liquid product, and coal tar isolate from the 20% coal tar in alcohol solution were tested for initiating activity in an initiation/promotion mouse skin painting assay for carcinogenicity. The chemical compositions of the coal tar‐based therapeutic agents, the industrial coal tar and direct‐liquefaction coal liquid were similar. With the exception of the 50% bath emulsion, the microbial mutagenicity and tumor‐initiating activity in mouse skin for those materials tested were also similar.