No abstract

This study presents the development and validation of UV spectrophotometric methods for the determination of pinaverium bromide (PB) in tablet assay and dissolution studies. The methods were satisfactorily validated according to International Conference on Harmonization guidelines. The response was linear (r2 > 0.99) in the concentration ranges of 2-14 μg/mL at 213 nm and 10-70 μg/mL at 243 nm. The LOD and LOQ were 0.39 and 1.31 μg/mL, respectively, at 213 nm. For the 243 nm method, the LOD and LOQ were 2.93 and 9.77 μg/mL, respectively. Precision was evaluated by RSD, and the obtained results were lower than 2%. Adequate accuracy was also obtained. The methods proved to be robust using a full factorial design evaluation. For PB dissolution studies, the best conditions were achieved using a United States Pharmacopeia Dissolution Apparatus 2 (paddle) at 50 rpm and with 900 mL 0.1 M hydrochloric acid as the dissolution medium, presenting satisfactory results during the validation tests. In addition, the kinetic parameters of drug release were investigated using model-dependent methods, and the dissolution profiles were best described by the first-order model. Therefore, the proposed methods were successfully applied for the assay and dissolution analysis of PB in commercial tablets.

A reversed-phase liquid chromatography (LC) method is validated for the determination of pinaverium bromide (PB) in pharmaceutical dosage forms. The LC method is carried out on a reversed-phase monolithic C18 column (100 x 4.6 mm i.d.), maintained at 45 ºC. The mobile phase consisted of acetonitrile and a solution of triethylamine 0.3% pH 5.0 (50:50; v/v), run at a flow rate of 2.0 mL/min, with photodiode array detector set at 213 nm. The chromatographic separation is obtained with PB retention time of 3.4 min, and it is linear in the range of 5-100 μg/mL (r2 = 0.9991). The limits of detection and quantitation are 1.41 and 4.70 μg/mL, respectively. The specificity and stability-indicating capability of the method are proven through degradation studies, which also showed that there is no interference of the formulation excipients, showing that peak is free from any coeluting peak. The method showed adequate precision, with a relative standard deviation values lower than 1.38%. Excellent values of accuracy were also obtained, with a mean value of 100.68%. Experimental design is used during validation to calculate and prove method robustness. The proposed LC method is applied for the analysis of the PB pharmaceutical dosage forms, contributing to improve the quality control and to assure the therapeutic efficacy.

The present work describes a first-order derivative spectrophotometric (1D-UV) method for determination of dropropizine in commercial oral solutions. The method was developed using ecologically correct solvents and validated according to International Conference on Harmonization (ICH) recommendations. The response was linear in the concentration range of 6–24 μg/mL (r = 0.9997, n = 7) at wavelength 249 nm, which was the zero crossing point of excipient solutions. The detection and quantitation limits were 0.36 and 1.18 μg/mL, respectively. The method showed adequate precision, with a relative standard deviation values lower than 1.41%. Excellent values of accuracy were obtained, with a mean value of 99.44%. The method proved to be robust by a full factorial design evaluation. It is simple, it has low cost, and it has low use of polluting reagents. Minimum environmental hazards observed and the results obtained attest to the reliability of the proposed green method, showing to be specific, linear, precise, accurate and robust. Thus, the validated 1D-UV spectrophotometric method was successfully applied to the quantitative analysis of dropropizine in oral solutions dosage forms, helping to improve quality control and to assure therapeutic efficacy.