Spectrophotometric determination of etidocaine in pharmaceutical (dental) formulation.

A spectrophotometric method was developed for the determination of etidocaine hydrochloride (EH) in injectable pharmaceutical preparation. The proposal of this work was to develop a rapid, simple, inexpensive, precise and accurate visible spectrophotometric method. The method is based on the formation of the ion-pair complex by the EH reaction with bromocresol green in the pH 4.6 which after chloroform extraction gives a yellow color that in basic medium change to blue color and exhibits a maximum absorbance at 625 nm. The calibration graph was linear over the range 2.0-6.0 microg ml(-1) EH calculated on the final yellow solution. The R.S.D. of the slope of the four lines was 0.73%. This method can be applied to injectable pharmaceutical preparation dosage studied.