The improvement of routine drug quality control analysis of some antihypertensive drugs using high-performance thin-layer chromatography densitometry method with greenness profile evaluation

The common antihypertensive drugs are B-blockers and diuretics. For the determination of beta-blocker medicines (bisoprolol fumarate and carvedilol) and diuretic drug (Furosemide), new and accurate chromatographic method has been developed. The separation was achieved using a developing system that includes chloroform:methanol:ethyl acetate:ammonia (6:2:2:0.2 by volume) as a mobile phase and the bands were detected at 240 nm. The concentration ranges were 5-25, 1-7, and 1-3.5 μg/band for bisoprolol fumarate, carvedilol, and furosemide, respectively. This chromatographic approach is the first methodology for simultaneously determining bisoprolol fumarate, carvedilol, and furosemide in their pure forms and in their pharmaceutical dosage forms. The advantages of using known analytical procedures are their simplicity, speed, cost effectiveness, lack of laboriousness, and ability to save time as the three tablets are determined in one step and can be used for routine analysis of the investigated combinations in quality control laboratories. According to International Conference of Harmonization guidelines, the established procedures have been validated, and the results were statistically compared to those obtained by the reported reversed-phase-high-performance liquid chromatography methods using Student's t-test and F-test, with no significant difference between them, indicating that the proposed methods can be used for routine drug quality control analysis.

Application of ion pair complexes to design novel potentiometric membrane sensors for direct determination of frusemide in pharmaceuticals

Background

Fabrication of two membrane sensors using two acidic indicators among sulphonthalein dyes, namely bromophenol blue (BPB) and bromocresol green (BCG), and their use as indicative electrodes for the quantification of frusemide (FUR) is presented. The ion pair complexes of FUR with BPB or BCG are used to prepare the membranes in THF solvent, PVC matrix and dibutyl phthalate (DBP) as plasticizer and subsequently to fabricate FUR-BPB (Sensor I) and FUR-BCG (Sensor II) sensors.

Results

Sensors I and II are employable to determine 2.4 × 10-5–2.4 × 10-3 mol/L FUR at operative pH of 3.71. The calibration curve between the potentials against the concentration of FUR yielded the slopes of 58.73 ± 1 and 57.66 ± 1 mV/decade, respectively, using Sensors I and II, and this confirmed the Nernstian behaviour. Satisfactory correlation was obtained between the measured potentials and FUR concentration with the proposed sensors, and this was revealed by regression coefficient values of 0.9987 and 0.9980 for Sensors I and II, respectively. The LOD (limit of detection) values were calculated and reported for both the sensors. The experimental parameters were optimised to yield acceptable characteristics of both the sensors in the context of performance. The role of excipients of tablets and interferences were assessed by standard addition protocol. The obtained results confirmed the ineffective role of excipients of tablets and foreign species used as interferents.

Conclusion

The designed sensors were validated to confirm the accurate, precise, robust and rugged functioning in determining FUR. The mean of recovered FUR, close to 100%, revealed the acceptable and effective functioning of the proposed sensors. Excellent results were obtained by FUR tablets’ analysis using both the sensors.

Development and validation of HPTLC and green HPLC methods for determination of furosemide, spironolactone and canrenone, in pure forms, tablets and spiked human plasma

Two selective and accurate chromatographic methods are presented for simultaneous quantitation of spironolactone (SP) and furosemide (FR) and canrenone (CN), the main degradation product and the main active metabolite of SP. Method A was HPTLC, where separation was completed on silica gel HPTLC F₂₅₄ plates using ethyl acetate-triethylamine-acetic acid (9:0.7:0.5, by volume) as a developing system and UV detection at 254 nm. Method B was a green isocratic RP-HPLC utilizing a C₁₈ (4.6 × 100 mm) column, the mobile phase consisting of ethanol-deionized water (45: 55, v/v) and UV estimation at 254 nm. Adjustment of flow rate at 1 mL/min and pH at 3.5 with glacial acetic acid was done. Regarding the greenness profile, the proposed RP-HPLC method is greener than the reported one. ICH guidelines were followed to validate the developed methods. Successful applications of the developed methods were revealed by simultaneous determination of FR, SP and CN in pure forms and plasma samples in the ranges of 0.2-2, 0.05-2.6 and 0.05-2 μg/band for method A and 5-60, 2-60 and 2-60 μg/mL for method B for FR, SP and CN, respectively.

Successive ratio subtraction as a novel manipulation of ratio spectra for quantitative determination of a mixture of furosemide, spironolactone and canrenone

Furosemide and spironolactone are commonly prescribed antihypertensive drugs. Canrenone is the main degradation product and main metabolite of spironolactone. Ratio subtraction and extended ratio subtraction spectrophotometric methods were previously applied for quantitation of only binary mixtures. An extension of the above mentioned methods; successive ratio subtraction, is introduced in the presented work for quantitative determination of ternary mixtures exemplified by furosemide, spironolactone and canrenone. Manipulating the ratio spectra of the ternary mixture allowed their determination at 273.6nm, 285nm and 240nm and in the concentration ranges of (2-16μgmL^-1), (4-32μgmL^-1) and (1-18μgmL^-1) for furosemide, spironolactone and canrenone, respectively. Method specificity was ensured by the application to laboratory prepared mixtures. The introduced method was ensured to be accurate and precise. Validation of the developed method was done with respect to ICH guidelines and its validity was further ensured by the application to the pharmaceutical formulation. Statistical comparison between the obtained results and those obtained from the reported HPLC method was achieved concerning student's t-test and F ratio test where no significant difference was observed.

Rapid determination of furosemide in drug and blood plasma of wrestlers by a carboxyl-MWCNT sensor

A novel method is developed for the quantification of furosemide in biological fluids. The method is based on the electro-reduction of Zn(II)-furosemide complex at carboxyl-MWCNT modified glassy carbon electrode. It is shown that, in Britton-Robinson buffer (pH5.7) the reduction peak of Zn(II)-furosemide complex formed at -1.0 V (versus, Ag/AgCl). The increment of current signal obtained from the reduction peak current of the Zn(II)-furosemide complex was rectilinear with furosemide concentration in the range of 0.03 to 140.0 μg ml(-1), with a detection limit of 0.007 μg ml(-1). The drug recovery ranged between 97.8% and 100.8% and the mean drug recovery was 98.89%. The accuracies (relative error% and RSD%) were less than 15% and are acceptable according to the US FDA guideline for bioanalytical method validation. The sensor was used for quantification of furosemide in drug and biological fluid samples. The data of drug analysis were compared with the standard method.

Use of a diazocoupling reaction for sensitive and selective spectrophotometeric determination of furosemide in spiked human urine and pharmaceuticals

Two simple, sensitive, and selective spectrophotometric methods for the determination of 5-(aminosulfonyl)-4-chloro-2-((2-furanylmethyl)amino)benzoic acid (furosemide, FUR) are described. The methods are based on acid hydrolysis of FUR to free primary aromatic amine and diazotization followed by coupling with N-1-napthylethylene diamine (NEDA) (method A) or 4,5-dihydroxynaphthalene-2,7-disulfonic acid (chromotropic acid, CTA) (method B). The colored reaction product can be measured spectrophotometrically at 520 nm (method A) or 500 nm (method B). Beer’s law is obeyed over the ranges of 1.75–21.0 μg mL−1 and 2.5–30.0 μg mL−1, for method A and method B, respectively. Apparent molar absorptivities and Sandell’s sensitivities (in L mol−1 cm−1 and μg cm−2 per 0.001 absorbance unit, respectively) were 1.34 × 104 and 0.0253 using NEDA as the coupling agent, and 8.5 × 103 and 0.0389 using CTA for the same purpose. Analysis of solutions containing seven different concentrations of FUR gave a correlation coefficient of 0.9979 using NEDA and 0.9984 using CTA, while the slope and the correlation coefficient of the regression equation were calculated. The reaction stoichiometry in both methods was evaluated by the limiting logarithmic method and was found to be 1: 1 (diazotized FUR: NEDA or diazotized FUR: CTA). The methods were successfully applied to the determination of FUR in spiked human urine and in pharmaceutical formulations. The recovery of FUR from spiked urine was satisfactory resulting in the values of (109.4 ± 4.37) % using NEDA and (113.0 ± 4.74) % using CTA. Results of the analysis of pharmaceuticals demonstrated that the proposed procedures are at least as accurate and precise as the official method while a statistical analysis indicated that there was no significant difference between the results obtained by the proposed methods and those of the official method.