Chromatographic separation and spectroscopic characterization of the E/Z isomers of acrivastine.

A reverse phase high performance liquid chromatography (HPLC) method has been developed for the separation of two geometric isomers of Acrivastine using crude reaction mixture. The resolution between two isomers was found more than 2.9. The geometric isomers have been isolated by preparative HPLC and characterized by spectroscopic techniques, such as NMR, infrared, and MS. The developed method has been validated for the determination of Z-isomer in Acrivastine. The limit of detection and limit of quantification of the Z-isomer were 0.05 and 0.2 µg/ml, respectively. The developed method is precise, linear, accurate, rugged and robust for its intended use.

Microbial transformation of the antihistaminic drug triprolidine hydrochloride.

The production of a known mammalian metabolite of the antihistamine triprolidine through fungal metabolic transformation has been demonstrated. The filamentous fungus Cunninghamella elegans ATCC 9245 was grown in Sabouraud dextrose broth containing triprolidine hydrochloride monohydrate. One major metabolite was extracted with methylene chloride, isolated by high-performance liquid chromatography, and identified by its proton-nuclear magnetic resonance and desorption chemical ionization mass spectral properties as hydroxymethyl triprolidine (2-[1-(4-hydroxymethylphenyl)-3-(1-pyrrolidinyl-1-propenyl)] pyridine). After 240 h of incubation, the hydroxymethyl derivative represented approximately 55.0% of the initial dose. Fungal oxidation of hydroxymethyl triprolidine to the corresponding carboxylic acid triprolidine derivative (also a known mammalian triprolidine metabolite) was not observed. No mutagenic activity was observed for triprolidine and hydroxymethyl triprolidine by reversion of Salmonella typhimurium strains TA97, TA98, TA100, and TA104 at concentrations up to 1000 and 200 micrograms/plate, respectively. These results suggest that the fungal metabolism of triprolidine to the hydroxymethyl derivative occurs predominantly through pathways which do not result in mutagenic activation. Incubation of C. elegans with triprolidine under an 18O2 atmosphere and subsequent electron impact mass spectral analysis of the hydroxymethyl triprolidine formed indicate that molecular oxygen was incorporated into the methyl group and suggest a mono-oxygenase catalyzed reaction. This study parallels previous studies on the mammalian metabolism of triprolidine and clearly indicates that the microbial transformation of triprolidine is a useful alternative for the synthesis of potential mammalian metabolites.