New Sensitive Spectrophotometric Methods for the Determination of Raloxifene Hydrochloride in Pharmaceuticals Using Bromate‐Bromide,Methyl Orange and Indigo Carmine

Abstract

Abstract:Two new sensitive spectrophotometric methods are proposed for the determination of raloxifene hydrochloride (RLX) using bromate-bromide mixture and two dyes, methyl orange and indigocarmine, as reagents. The methods entail the addition of a known excess of bromate-bromide mixture to RLX in hydrochloric acid medium followed by determination of residual bromine by reacting with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (Method A) or indigo carmine and measuring the absorbance at 610 nm (Method B). In both methods, the amount of bromine reacted corresponds to the amount of RLX. The absorbance is found to increase linearly with concentration of RLX. Under the optimum conditions, RLX could be assayed in the concentration range 0.1-2.0 and 0.5-6.0 µg mL -1 by method A and method B, respectively. The apparent molar absorptivities are calculated to be 1.9x10 5 and 4.5x10 4 L mol -1 cm -1 for method A and method B, respectively, and the corresponding Sandell sensitivity values are 0.003 and 0.011 µg cm -2 . The limits of detection and quantification are also reported for both methods. Intra-day and inter-day precision and accuracy of the developed methods were evaluated as per the current ICH guidelines. The methods were successfully applied to the assay of RLX in its tablet formulation and the results were compared with those of a reference method by calculating the Student's t-value and F-value. No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained by recovery experiments via standard-addition procedure.

Adsorptive stripping voltammetry determination of the hormone therapy Raloxifene HCl in formulation and human serum

“…But, because of the typical plasma Vitamins (C and E), paracetamol, aspirin, ibuprofen and terfenadine stripping voltammetry methods (LS-AdCSV and SW-AdCSV) were described for the determination of RLX in bulk form and pharmaceutical formulations. The two methods are much more sensitive compared to the reported methods [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] for determination of RLX. Moreover, both methods are free from such experimental variables as heating, extraction step, reduction, oxidation or complexation reactions for formation of colored chromogens prior to the analysis.…”

“…However, a limit of quantification (LOQ) of 0.10 ng mL −1 RLX 6,7 in both males and postmenopausal females was reported. 6,7 Va r i o u s a n a l y t i c a l m e t h o d s i n c l u d i n g high-performance liquid chromatography (HPLC), [9][10][11][12][13][14][15] spectrophotometry [16][17][18][19][20][21][22][23][24] and capillary electrophoresis 25 have been reported in the literature for the determination of RLX in bulk samples as well as pharmaceutical preparations. The HPLC methods reported [9][10][11][12][13][14][15] necessitate sample pretreatment and time-consuming extraction steps prior to analysis of the drug.…”

“…On the other hand, the spectrophotometric methods reported for the assay of RLX were based on redox and complexation reactions for formation of colored chromogens prior to the analysis. [16][17][18][19][20][21][22][23][24] Determination of RLX by these methods was also not sensitive enough (LOQ = 0.08 to 16.00 µg mL -1 ), complex, or at least required time-consuming steps, which may lead to significant analytical errors. Determination of RLX in its formulations with a method based on measurement of the intensity of resonance Rayleigh scattering of the ion association complex of RLX with Evans blue was reported 26 (LOQ = 60.0 ng mL -1 ) but it requires an expensive instrumental set up.…”

“…29 However, LC-MS/MS methods involve expensive solid phase extraction steps prior to the analysis which are time-consuming and not economically feasible for routine analysis (as such equipment and techniques are not available in most of the laboratories). Moreover, most of the methods reported [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] are considered not efficient enough for the assay of RLX in human plasma and at different therapeutic dose levels for pharmacokinetic studies as well as therapeutic drug monitoring. Therefore, a simple and sensitive procedure is desired for determination of RLX in human plasma.…”

Utilization of oxidation-reduction reaction of Folin-Ciocalteu’s phenol reagent in colorimetric determination of amlodipine in pharmaceutical dosage form

“…Some of these methods use spectrofluorometry [15,16]. Spectrophotometry has been used for determination of many drugs including AMO in pharmaceuticals preparations [17][18][19][20][21][22]. Electrochemical techniques also have been used [23][24][25][26].…”