OBJECTIVETo prepare the controlled-release delivery gutta-percha points containing metronidazole compound (CDGMC) and to determine its release rate in vitro.

METHODSThe drug points were made by using compound drugs and gutta-percha as a carrier, and CDGMC were prepared followed by enveloping a release membrane outward. The best formula was selected according to the release parameters of the drugs extracted in the release experiments in vitro. The CDGMC were placed into the extracted teeth after root canals were routinely prepared. The non-drug CDGMC was used as the control. The absorbency of the drugs in normal saline (37 degrees C, pH 7.4) was determined timely. The percentage of release and cumulated release of the drugs were calculated according to the concentrations of drugs in medium.

RESULTSThe in vitro experiments showed that this system contained 1,880 micrograms of metronidazole and 267 micrograms of ciprofloxacin. The experiments in healthy single root canal showed that the drug release amounts around the perioapical area were metronidazole 88.54 micrograms/ml and ciprofloxacin 9.05 micrograms/ml in 10 days.

CONCLUSIONCDGMC can continuously release effective drug concentrations more than 10 days and could be considered as an ideal method for clinical application.