The Synthesis And Analysis Of Procaine

Procaine is one of the ester-type local anesthetics,which is oldest and widely used quick action local anesthetics with less toxicity. It has been widely used in the fields of the clinical medicine in the world as the prior local anesthetic drug for ninety years.In this paper synthetical methods and the analytical methods as well as the developing foreground had summarized.The appropriate synthetical methods were developed to reduce the environment contamination and shorten the reaction time. p-Toluene sulphonic acid was found superior to sulfuric acid as the catalyst for the esterifying p-nitrobenzoic acid in butanol to get butyl p-nitrobenzoate. Followed by catalytically hydrogenating the resulting butyl p-nitrobenzoate in situation and,after distilling off the majority of excess butanol,reacting the hydrogenation solution with diethylaminoethanol in the presence of an alkali alcoholate during 85 to 90℃ while removing the liberated butanol in vacuum. The nitro ester was catalytically hydrogenated without intermediate isolation. The toxicity solvents such as the benzene and dimethylbenzene were not used. The raw material ratio, catalyst dosage, reaction time and reaction temperature were discussed to obtain the optimal reaction conditions. The potentiometry titration was used to analyze butyl p-aminobenzoate.For the purification of the procaine from the aqueous procaine-containing solution, the pH was adjust to about 8. The solution was treated with 1% weight activated carbon to remove impurities. n-Butyl acetate was used to extract procaine and hydrochloric acid as used to reverse extract procaine to water phase. Sodium hydroxide was used to adjust pH11 to precipitate the procaine in the form of its free base.The methods of HPLC and the spectrophotometry developed in this study for the determination of procaine have the advantage of simplicity, precision, and accuracy. The procaine hydrochloride reacted with p-dimethylaminobenzalhyde in glacial acetic acid to form an Schiff base, which was a yellow compound. Its maximum absorption wavelength is at 452nm, the recovery of the method was from 95.2 to 100.5%.A first derivative spectrometric method was developed for the determination of the para aminobenzoic acid (PABA). The calibration graph is A=0.0021C+0.0005, with the linear regression correlative coefficient is 0.9986 and the relative standard deviation (RSD) of 1.21%.