New ecological first derivative synchronous spectrofluorimetric method for simultaneous quantification of carvedilol and ivabradine in tablets

A new, rapid, selective, green, and highly sensitive method has been established to determine ivabradine and carvedilol simultaneously. The first derivative synchronous spectrofluorimetric approach was applied for the determination of the studied drugs. Assessment of the first derivative amplitude of carvedilol and ivabradine has been done at 339 nm and 298 nm respectively which are the zero crossing points of each other. The method validation is estimated and was found to be consistent with International Conference on Harmonization guidelines. Linearity was found to be in the range of 10.0 to 90.0 ng/mL for carvedilol and from 80.0 to140.0 ng/mL for ivabradine. The detection limits were found to be 1.2 ng/ mL and 3.3 ng/mL and the quantitation limits were 3.7 ng / mL and 10.0 ng /mL for carvedilol and ivabradine, respectively. The method was effectively applied for the determination of both drugs in their synthetic mixture in different ratios and in their prepared co-formulated tablets. The results were compared with those of comparison HPLC methods. Ethanol was used as a green solvent. The proposed method is suitable for the determination of ivabradine and carvedilol with satisfactory accuracy and precision. The greenness of the method was evaluated using four assessment tools, i.e. NEMI, GAPI, Eco-scale, and AGREE. The proposed method is simple with a low cost compared to HPLC methods.

Hollow fiber based liquid phase microextraction with high performance liquid chromatography for the determination of trace carvedilol (β-blocker) in biological fluids

A hollow-fiber liquid-phase microextraction (HF-LPME), followed by high-performance liquid chromatography–ultraviolet (HPLC–UV) method for the trace determination of carvedilol (β-blocker) in biological fluids, has been described. The separation was achieved using Inertsil ODS-3 C18 (250 mm × 4.6 mm, 3 μm) column with a mobile phase composition of 10 mM phosphate buffer (pH 4.0)–acetonitrile (50:50, v/v) at a flow rate of 1.0 mL/min, under isocratic elution. Several parameters (i.e., type of organic solvent, donor phase pH, concentration of acceptor phase (AP), stirring rate, extraction time, and salt addition) that affect the extraction efficiency were investigated. The optimum HF-LPME conditions were as follows: dihexyl ether as an organic solvent; donor phase pH, 10.7; 0.1 M HCl (AP); 1100-rpm stirring rate; 60-min extraction time; and no salt addition. These parameters have been confirmed using design of experiments. Under these conditions, an enrichment factor of 273-fold was achieved. Good linearity and correlation coefficient were obtained over the range 5–1000 ng/mL (r2 = 0.9994). Limits of detection and quantitation were 1.2 and 3.7 ng/mL, respectively. The relative standard deviation at 3 different concentration levels (5, 500, and 1000 ng/mL) were less than 13.2%. Recoveries for spiked urine and plasma were in the range 80.7–114%. The proposed method is simple, sensitive, and suitable for the determination of carvedilol in biological fluids.

Development and validation of a new spectrofluorimetric method for the determination of some beta-blockers through fluorescence quenching of eosin Y. Application to content uniformity test

A simple, rapid, sensitive and economic spectrofluorimetric method has been developed and validated for determination of some β-adrenergic blocking agents namely; betaxolol hydrochloride (BTX), carvedilol (CAR), labetalol hydrochloride (LBT), nebivolol hydrochloride (NEB) and propranolol hydrochloride (PRO). The method is based on the quenching effect of the cited drugs on the fluorescence intensity of eosin Y at pH 3.4 (acetate buffer). The fluorescence quenching is due to the formation of an ion-pair complex and was measured without extraction at 545 nm (λex. 301.5 nm). The factors affecting the formation of the ion-pair complex were carefully studied and optimized. Under the optimal conditions, the linear ranges for the relationship between the fluorescence quenching value and the concentration of the investigated drugs were 100-2500, 150-2500 and 50-2250 ng mL-1 for (BTX, CAR), (LBT, NEB) and (PRO) respectively. The method was validated according to ICH guidelines and was applied for determination of the cited drugs in pharmaceutical dosage forms with excellent recoveries. In addition, content uniformity testing of some commercial dosage forms was checked by the proposed method.