Determination of Procaine Hydrochloride by Two Spectrophotometric Methods in its Pharmaceutical Preparation and Human Blood Serum.

Two methods of high sensitivity and simplicity, based on spectrophotometry, have been proposed for the quantitative analysis of local anesthetic drug procaine hydrochloride (PROC-HCl) in its pure state as well as within pharmaceutical formulations and human blood serum. The first methodology is predicated on the diazotization of PROC-HCl to its corresponding diazotized form, employing sodium nitrite under ambient conditions in the presence of acetic acid. Subsequently, coupling with the 2,5-dimethylphenol reagent to produce an intense yellow-orange colored azo dye. Importantly, this dye exhibits a maximum absorption peak at a wavelength of 466 nm. Beer's law was found to be applicable within a concentration range from 1 to 15 g/ml, yielding a determination coefficient of 0.9997, and molar absorptivity of 2.193x104 l/mol.cm, Sandell's sensitivity 0.0124 g/cm2 limit of detection 0.105 g/ml, and limit of quantification 0.352 g/ml. The stoichiometric ratio for the reaction involving coupling diazotized procaine with 2,5-dimethylphenol was established at 1:1. Employing the suggested method for the determination of procaine in its dosage form (injection) and serum sample produced analytical results that were deemed acceptable within scholarly standards. The second method depended on the same route of reaction but instead read absorbance measuring the area under the peak, with a fixing range of wavelengths 460-480 nm. Beers law was applicable in the concentration range of 0.25 to 20 g/ml, with a determination coefficient of 0.9990. Finally, the method was applied to the injection form of procaine, giving a better recovery. As a comparison between the two methods, in the second method the extent of the linear relationship decreased to concentration lower than the minimum concentration in the first method, and the recovery by the second method was about 100%.