Clésio Soldatelli Paim

Validation of UV Spectrophotometric Method for Quantitative Determination of Entacapone in Tablets Using Experimental Design of Plackett‐Burman for Robustness Evaluation and Comparison with HPLC

Abstract Validation of UV spectrophotometric method for quantitative determination of entacapone in tablets using acetonitrile as solvent. The validation of analytic method was realized through the study of the following analytic parameters: specify linearity, precision, accuracy, and robustness. The excipients of the formulation did not interfere at 305 nm, demonstrating the specificity of the method. The method was linear (r=0.99996) at concentrations ranging from 3.0 to 20.0 µg ml−1, precise (repeatability and intermediated precision), exact (method of standard addition), and robust. The results confirmed that the method is valid and useful to the routine quality control of entacapone in coated tablets. The method was compared to a high‐performance liquid chromatography (HPLC) method, which was previously developed and validated to the same drug. There was not a significant difference between the methods for entacapone quantitation.

Development of a simple, rapid and validated spectrophotometric method for nitazoxanide in pharmaceutical formulations and comparison with HPLC

A rapid, economical, reproducible, and simple direct spectrophotometric method was developed and validated for the assay of nitazoxanide in pharmaceutical formulations. Nitazoxanide concentration was estimated in water at 345 nm and pH 4.5. The method was suitable and validated for specificity, linearity, precision, and accuracy. There was no interference of the excipients in the determination of the active pharmaceutical ingredient. The proposed method was successfully applied in the determination of nitazoxanide in coated tablets and in powders for oral suspension. This method was compared to a previously developed and validated method for liquid chromatography to the same drug. There was no significative difference between these methods for nitazoxanide quantitation.

SIMULTANEOUS DETERMINATION OF DELAPRIL AND MANIDIPINE IN A PHARMACEUTICAL FORMULATION BY A STABILITY-INDICATING RP-LC METHOD

Simple, precise, and stability-indicating reversed-phase liquid chromatography (RP-LC) method was developed and validated for simultaneous determination of delapril (DEL) and manidipine (MAN) in pharmaceutical dosage form, using the Plackett-Burman experimental design for robustness evaluation. The LC method was carried out on a C8 column (250 mm × 4.6 mm i.d., 5 µm), maintained at 35°C. The mobile-phase consisted of acetonitrile and a solution of triethylamine 0.3% pH 3.0 (adjusted with phosphoric acid) (55:45; v/v), run at a flow rate of 1.2 mL · min−1 and using photodiode array (PDA) detection at 220 nm. The chromatographic separation was obtained within 7 min and was linear in the range of 3–120 µg · mL−1 (r2 = 0.9997) for DEL and 1–40 µg · mL−1 (r2 = 0.9998) for MAN. Validation parameters such as the specificity, linearity, precision, accuracy, and robustness were evaluated, giving results within the acceptable range. Stress studies were carried out and no interference of the degradation products was detected. The proposed method was successfully applied for the simultaneous quantitative analysis of DEL and MAN in the tablet dosage form, contributing to improve the quality control and to assure the therapeutic efficacy.

Development of a dissolution test for lamotrigine in tablet form using an ultraviolet method

A finalidade deste estudo foi desenvolver e validar um metodo de dissolucao para o farmaco lamotrigina na forma farmaceutica comprimido. Este metodo tambem foi utilizado para comparar o perfil de dissolucao entre o Neural® e o produto de referencia Lamictal®. O procedimento analitico foi realizado utilizando-se espectrofotometria de absorcao no ultravioleta (267 nm) como forma de quantificacao do farmaco. Apos a determinacao da solubilidade e das condicoes sink, os parâmetros selecionados foram: pas (50 rpm), 900 mL de acido cloridrico 0.01 M e o tempo de 30 minutos (unico ponto). Este metodo foi validado atraves da especificidade, linearidade, exatidao, precisao e robustez. A estabilidade da lamotrigina tambem foi avaliada no meio de dissolucao.

STABILITY-INDICATING CZE METHOD AND STRESS DEGRADATION STUDIES OF NITAZOXANIDE

A new, simple, and effective stability-indicating CZE method was developed and validated for the determination of nitazoxanide in pharmaceutical formulations, using nimesulide as an internal standard. The optimum separation was carried out on a fused silica capillary (48.5 cm × 75 μm i.d., effective length 40 cm) maintained at 25°C, and a running electrolyte containing sodium acetate buffer (pH 5.2; 30 mM)-acetonitrile (80:20, v/v). The injections of the samples were performed using the pressure mode at 50 mbar for 5 s, with detection at 360 nm using a photo-diode array detector. The method was suitably validated for specificity, linearity, precision, accuracy, limit of detection and quantitation, and robustness. The high sensitivity of the method was proven with the limit of detection (0.05 μg mL−1) and quantitation (0.2 μg mL−1). The stability-indicating capability of the method was proven using stress conditions (acid and basic hydrolysis, oxidation, and photolysis). The proposed method was successfully applied for the determination of nitazoxanide in coated tablets and oral suspension powder.