Optimized and validated HPLC methods for compendial quality assessment. IV. Non-chiral and chiral purity tests for solanaceous (tropane) alkaloids

The main alkaloids of certain plants of the Solanacea family, such as atrop ine and scopolamine, together with the synthetic homatropine and methylhoma tropine, are routinely used medicinal agents and have their monographs in t he modern pharmacopeias. In these monographs, non selective chemical reacti ons and/or TLC serve for the detection of "foreign alkaloids, related subst ances, etc." impurities. In the present paper selective HPLC methods for the compendial purity contr ol of these alkaloids are published. The methods allow the detection of 0.0 5 mu g (= 0.1 %) and the quantitation of 0.05 - 5.0 mu g of tropic acid or mandelic acid as hydrolytic degradation product impurities (chromatographic system : C-18 / methanol - phosphate buffer pH 5 - 5.5). The limit of dete ction is 0.025 mu g. Also, HPLC for the separation of tropane alkaloid enan tiomers (chromatographic system : Chiralcel OD / n-hexane - isopropanol - m ethanol - triethylamine) is presented. Procedure for the enantiomeric purit y control of S - ( -) - hyoscyamine, the detection of R - ( +) - distomer i s suggested.