OBJECTIVETo study the effects of Zuojin Pill and Fanzuojin Pill (ZJP and FZJP) on the growth metabolism of enterobacteria from the biothermodynamic viewpoint, and to objectively validate the difference between the two drugs for investigating a new way in congener Chinese drugs research.

METHODSThe growth metabolism power-time curves of enterobacteria affected by ZJP and FZJP in different concentrations were obtained by microcalorimetry. And the activities of the two drugs were assessed depending some related characteristic parameters, including growth rate constant (k), maximum output power (P(max)), peak time (T(p)) , maximum heat-output (Q1), and bacteria inhibition rate (I).

RESULTSWith the drugs' concentration increasing, T(p) was prolonged, k value reduced in enterobacteria, i.e. , the two drugs both inhibited the growth of enterobacteria in different extents. Comparison of inhibiting rates showed that the bacteriostasis activity of ZJP was greater than that of FZJP.

CONCLUSIONSThere was objective difference in activities of inhibiting enterobacteria between ZJP and FZJP. Microcalorimetry could express the features at real-time, on-line and sensitively. It was able to determine the activity of drugs accurately and quickly in appraising congener Chinese drugs, like ZJP and FZJP, by microcalorimetry.