Study on "Signal" Constituents for the Evaluation of Animal Crude Drugs. II. Organic Acids

An analytical method of determining organic acids in animal crude drugs using selective and sensitive postcolumn-pH buffered electroconductivity detection HPLC was established and the organic acid contents in 10 drugs were determined. Nine organic acids : acetic acid, butylic acid, formic acid, isobutylic acid, lactic acid, malic acid, propionic acid, pyroglutamic acid and succinic acid were found. Lactic acid content in Lumbricus varied greatly among the samples from 0.83 to 13.08mg/g, and the contents of acetic acid, butylic acid, isobutylic acid and propionic acid in Cervi Parvum Cornu also showed large variation. Contents of the organic acids in other animal crude drugs did not vary greatly among the samples. These contents were believed to change during the time course of preservation and distribution on the market, so the content in animal crude drugs stored under various conditions, and the appearance, Loss on drying and pH were also studied. No change was observed in any of these factors in any drug stored in tightly closed containers, except for the lactic acid content in Amydae Carapax which showed a slight increase. However, various changes in the factors were observed in all crude drugs stored in 40°C-75% relative humidity (RH) open containers.