A highly sensitive micelle-enhanced synchronous spectrofluorimetric determination of the recently approved co-formulated drugs, bilastine and montelukast in pharmaceuticals and human plasma at nanogram levels

In this study, the simultaneous determination of bilastine and montelukast, two recently approved co-formulated antihistaminic medications, was accomplished using a quick, sensitive, environmentally friendly, and reasonably priced synchronous fluorescence spectroscopic approach for the first time. Enhancement of the method's sensitivity down to nanogram levels was achieved by the addition of sodium dodecyl sulfate (1.0% w/v) as a micellar system. According to the results, bilastine and montelukast's fluorescence was measured at 255.3 and 355.3 nm, respectively, using Δλ of 40.0 nm and distilled water as a green diluting solvent. With respect to the concentration ranges of bilastine (5.0-300.0 ng/ml) and montelukast (50.0-1000.0 ng/ml), the method showed excellent linearity (r ≥ 0.9998). The results showed that the suggested method is highly sensitive, with detection limits of 1.42 and 13.74 ng/ml for bilastine and montelukast, respectively. Within-run precisions (intra- and interday) per cent relative standard deviations (RSD) for both analytes were <0.59%. With high percentage recoveries and low percentage RSD values, the designed approach was successfully applied for the simultaneous estimation of the cited medications in their dosage form and human plasma samples. To evaluate the green profile of the suggested method, an analytical GREENNESS metric approach (AGREE) and green analytical procedure index (GAPI) metric tools were used. These two methods for evaluating greenness confirmed that the developed method met the highest number of green requirements, recommending its use as a green substitute for the routine analysis of the studied drugs. The proposed approach was validated according to ICHQ2 (R1) guidelines.

Two different synchronous spectrofluorimetric approaches for simultaneous determination of febuxostat and ibuprofen

Two green, simple and sensitive synchronous spectrofluorimetric methods were developed for the first time for the simultaneous estimation of febuxostat (FEB) and ibuprofen (IBU). Method I is constant-wavelength synchronous spectrofluorimetry where FEB and IBU were recorded at 329 and 258 nm, respectively, using Δλ of 40 nm. Method II is constant-energy synchronous spectrofluorimetry using a wavenumber interval of -4000 cm-1. All measurements were carried out in a borate buffer of pH 7 and distilled water for dilution which increased the methods' greenness. The two methods were rectilinear over concentration ranges of 30.0-700.0 ng ml-1 and 0.5-9.0 µg ml-1 in the first method and 20.0-500.0 ng ml-1 and 0.1-8.0 µg ml-1 in the second method for FEB and IBU, respectively. High sensitivity was attained for the two drugs with limits of quantitations (LODs) down to 0.41 and 5.51 ng ml-1 in the first method and 0.25 and 3.32 ng ml-1 in the second method for FEB and IBU, respectively. Recovery percentages were in the range of 97.3-101.9% after extraction from spiked human plasma samples, demonstrating high bioanalytical applicability. The two methods were further applied to tablet dosage forms with good recovery results. The methods' greenness was assessed according to the analytical Eco-Scale and Green Analytical Procedure Index guidelines.

Quantification of Tamsulosin Hydrochloride and Solifenacin Succinate by Discriminative Derivative Synchronous Emission Spectroscopy

OBJECTIVES

The present study was undertaken with the objective to develop and validate a simple spectrofluorimetric method for the simultaneous quantification of tamsulosin hydrochloride and solifenacin succinate.

MATERIALS AND METHODS

First-derivative synchronous spectrofluorimetry was attempted for the simultaneous quantification of the analytes. Tamsulosin hydrochloride was quantified at a wavelength of 322 nm (zero-crossing wavelength point of solifenacin succinate) and solifenacin succinate was measured at 570 nm (zero-crossing wavelength point of tamsulosin hydrochloride).

RESULTS

Calibration plots were constructed over the concentration range of 2-10 µg/mL for tamsulosin hydrochloride and 30-150 µg/mL for solifenacin succinate. The method gave satisfactory results when it is validated for linearity, specificity, accuracy, precision, LOD and LOQ as per the ICH guidelines. The assay values in the commercial formulation were found to be in the percentage range of 95.0 for tamsulosin hydrochloride and 103.5 for solifenacin succinate by the proposed method. These results were well in agreement with their label claim.

CONCLUSION

The proposed synchronous analytical method can be employed for routine quality control analysis of tamsulosin hydrochloride/solifenacin succinate in tablet dose forms.

Liquid chromatographic and spectrofluorimetric assays of empagliflozin: Applied to degradation kinetic study and content uniformity testing

Stability-indicating high-performance liquid chromatography (HPLC) and spectrofluorimetric methods were developed for determination of empagliflozin (EGF). EGF was subjected to oxidation, wet heat, photo-degradation, acid hydrolysis and alkali hydrolysis. The alkaline degradation pathway was subjected to a kinetics study as the major product obtained after stress conditions. Arrhenius plots were constructed and the activation energies of the degradation process were calculated. HPLC was used for the kinetic study as it enabled simultaneous determination of EGF and the degradation product while the spectrofluorimetric assay was applied to content uniformity testing due to its higher sensitivity and lower limit of detection (LOD). Isocratic chromatographic elution was attained for HPLC on a Intersil® C₁₈ column (150 mm × 4 mm, 5 μm), using a mobile phase of acetonitrile-potassium dihydrogen phosphate buffer pH 4, (50:50, v/v) at a flow rate of 1 ml/min with ultraviolet (UV) detection at 225 nm. The relative fluorescence intensity was recorded by spectrofluorimeter applying synchronous mode using ∆λ = 70 nm at 297.6 nm. Linearity ranges were found to be 5-50 μg/ml and 50-1000 ng/ml for HPLC and spectrofluorimetric methods, respectively.

Factorial design optimization of micelle enhanced synchronous spectrofluorimetric assay of Omarigliptin: Applied to content uniformity testing and in vitro drug release

A micelle enhanced spectrofluorimetric method was developed for determination of Omarigliptin (OMG) based on its native fluorescence behavior. The interaction of OMG with surfactants and macromolecules was studied. In aqueous solution, the relative fluorescence intensity (RFI) of OMG was enhanced by 24% in the presence of Tween 80 at pH 3.5. The optimal conditions for the micelle enhanced fluorescence were attained by Minitab® program using Plackett-Burman factorial design. Pareto chart, contour plots and surface plots were used to exclude the insignificant variables and optimize the significant factors. The spectrofluorimeter was operated under synchronous mode using ∆λ = 30 nm and recording the RFI of the intense narrow band at 267 nm for OMG in 0.5% w/v Tween 80 + 0.2 M acetate buffer (pH 3.5) system using water as diluent. Using synchronous scan mode offered many advantages including considerable reduction of spectral overlap and enhanced linearity of the calibrators. Validation parameters were satisfied over the concentration range 0.1-2 μg/ml. The developed method was the first analytical procedure for OMG assay in Marizev® tablets. Moreover, content uniformity testing and in vitro drug release of tablets were performed.