Determination of the content of benzocaine and penicillin-g-procaine in combined finished dosage forms using tropaeolin o azo dye

The paper presents the results of developing the method for quantitative determination of benzocaine and penicillin-G-procaine in seven combined medicines and veterinary medicinal products of different dosage forms – ointments, suppositories and tablets. The content of the medicinal substances was determined spectrophotometrically according to the absorbance intensity of the coloured product of diazotized amine azocoupling with the acid monoazo dye tropaeolin O. The presence of other biologically active substances (streptomycin, neomycin, prednisolone, nitrofuran, chloramphenicol, bismuth subgallate, papaverine, extracts of buckthorn and belladonna, vitamin A, menthol, xeroform, and zinc oxide), which are often found in medicines, does not prevent determination of benzocaine and penicillin-G-procaine by of the method developed. The results obtained using the method developed are consistent with those received by the direct UV-spectrophotometry and nitritometric titration after the preliminarily extraction separation of the components.