Sensitive bromatometric assay methods for finasteride in pharmaceuticals

Abstract

Three sensitive spectrophotometric methods are presented for the determination of finasteride in bulk and in tablets. The methods rely on the use of bromate-bromide reagent and three dyes namely, methyl orange, indigocarmine and thymol blue as reagents. They involve the addition of a measured excess of bromate-bromide reagent to finasteride in acid medium, and after the bromination reaction is judged to be complete, the unreacted bromine is determined by reacting with a fixed amount of either methylorange and measuring the absorbance at 520 nm (method A) or indigocarmine and measuring the absorbance at 610 nm (method B) or thymol blue and measuring the absorbance at 550 nm (method C). In all the methods, the amount of insitu generated bromine reacted corresponds to the amount of finasteride. The absorbance measured at the respective wavelength is found increase linearly with the concentration of finasteride. Beer's law is obeyed in the ranges 0.25-2.0, 0.5-6.0 and 1-12 µg mL-1 for method A, method B and method C, respectively. The calculated molar absorptivity values are 5.7x10 4 , 3.12x10 4 and 1.77x10 4 L mol-1 cm-1 respectively, for method A, method B and method C, and the corresponding Sandell sensitivity values are 0.0065, 0.012 and 0.021 µg cm-2. The limits of detection (LOD) and quantification (LOQ) are also reported for all the methods. Accuracy and, intraday and inter-day precisions of the methods were established according to the current ICH guidelines. The methods were successfully applied to the determination of finasteride in commercially available tablets and the results were found to closely agree with the label claim. The results of the methods were statistically compared with those of a reference method by applying Student's t-test and F-test. The accuracy and reliability of the methods were further confirmed by performing recovery tests via standard addition procedure.

Cerimetric determination of simvastatin in pharmaceuticals based on redox and complex formation reactions

“…A number of oxidisable pharmaceutical substances have earlier been assayed using cerium (IV) sulphate by several workers [32][33][34][35][36][37][38][39][40][41][42][43][44][45] based on several reaction schemes. The present methods entail adding a known excess of cerium (IV) sulphate to SMT in acid medium followed by the determination of unreacted oxidant by two reaction schemes involving the use of ferroin, and iron (II) and thiocyanate as reagents.…”

Ratio - First Order Derivative - Zero Crossing UV-Visible Spectrophotometric Method for Analysis of Amoxicillin, Levofloxacin and Lansoprazole Mixture

“…Therefore, the simultaneous determination method of Lanso together with antibiotics is important. UV-Vis absorption spectrophotometry [10][11][12][13][14][15], spectrofluorimetry [16,17], HPLC [18][19][20][21][22], thin-layer chromatography (TLC) [23], electrochemical [24][25][26][27][28][29] and LC-MS/MS [30] methods have been used for the determination of Amox, Levo and Lanso. Among these methods, UV-Vis absorption spectrophotometry is a widespread used analytical method and UV-Vis spectrophotometers are available basic instrument in every analytical laboratory.…”

Stability-Indicating Micellar Elektrokinetic Chromatography Method for Determination of Finasteride in Pharmaceutical Preparations

“…[8] Metabolic profile of a drug can be introduced by stability studies. [9] Several methods have been reported for the analysis of finasteride by using HPLC, [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] spectrophotometry, [26][27][28][29] voltammetry, [30] and HPTLC. [31][32] There is no report available for MEKC analysis of FIN in the literature.…”