Differential pulse voltammetric determination of diclofenac in pharmaceutical preparations and human serum / Pulso diferencial determinação voltamétrica de diclofenaco em preparações farmacêuticas e em soro humano

This article describes a differential pulse voltammetric (DPV) method for the determination of diclofenac in pharmaceutical preparations and human serum. The proposed method was based on electro-oxidation of diclofenac at platinum electrode in 0.1 M TBAClO₄/acetonitrile solution. The well-defined two oxidation peaks were observed at 0.87 and 1.27 V, respectively. Calibration curves that obtained by using current values measured for second peak were linear over the concentration range of 1.5-17.5 μg mL^-1and 2-20 μg mL^-1 in supporting electrolyte and serum, respectively. Precision and accuracy were also checked in all media. Intra- and inter-day precision values for diclofenac were less than 3.87, and accuracy (relative error) was better than 4.12%. The method developed in this study is accurate, precise and can be easily applied to Diclomec, Dicloflam and Voltaren tablets as pharmaceutical preparation. In addition, the proposed technique was successfully applied to spiked human serum samples. No electro-active interferences from the endogenous substances were found in human serum...

Este artigo descreve um método de voltametria de pulso diferencial (VPD) para a determinação de diclofenaco em preparações farmacêuticas e em soro humano. O método proposto foi baseado em eletroxidação de diclofenaco no eléctrodo de platina em solução 0,1 M TBAClO₄/acetonitrila. Dois picos de oxidação bem definidos foram observados em 0,87 e 1,27 V, respectivamente. As curvas de calibração obtidas utilizando-se valores de corrente medidos por segundo pico foram lineares no intervalo de concentração de 1,5-17,5 μg mL^-1e 2-20 μg mL^-1em eletrólito suporte e soro, respectivamente. Precisão e exatidão também foram verificadas em todos os meios. Valores de precisão intra- e inter-dia para o diclofenaco foram inferiores a 3.87 e a precisão (erro relativo) foi melhor do que 4,12%. O método desenvolvido neste estudo é exato, preciso e pode ser facilmente aplicado a Diclomec, Dicloflam e comprimidos Voltaren, como preparação farmacêutica. Além disso, a técnica proposta foi aplicada com sucesso em amostras de soro humano. Não se observaram interferências das substâncias endógenas no soro humano...

Pharmacoknetic Study of Diclofenac and Its Interaction with Enrofloxacin in Buffalo Calves

A comparative pharmacokinetic study of diclofenac (1 mg/kg, i.v.) when given alone or in combination with enrofloxacin (4 mg/kg, i.v.) in five buffalo calves was carried out by using HPLC. The study revealed that the plasma concentrations of diclofenac were significantly lower (p<0.05) in combined administration of diclofenac with enrofloxacin (0.042 to 3 h), whereas significantly higher (p<0.05) levels of plasma drug concentrations were observed in later period (8 to 24 h). In urine, significantly lower (p<0.05) drug concentrations of diclofenac were observed from 0.167 to 1.5 h, whereas significantly higher (p<0.01) urine drug concentrations were observed in later period (4 to 48 h) when diclofenac was given in combination with enrofloxacin as compared to when diclofenac was given alone. Various kinetic parameters like A, Cpo and beta were significantly lower (p<0.05) whereas t1/2 beta, AUMC, MRT and various volume of distribution (VdC, VdB, Vdarea and VdSS) were significantly higher in combined administration of diclofenac with enrofloxacin as compared to when diclofenac was given alone (p<0.05).

Diclofenac vs nimesulida en artrosis: niveles plasmáticos y eficacia clínica / Diclofenac vs nimesulide in arthrosis: plasmatic levels and clinical efficacy

El diclofenac (liberación sostenida) y la nimesulida (fórmula convencional) son dos antiinflamatorios no esteroideos cuya dosificación es de un comprimido diario en nuestro país. Las escasas referencias en relación a la farmacocinética y duración de la acción de la nimesulida en pacientes añosos nos indujeron a diseñar el presente estudio controlado con diclofenac. Se selecionaron 20 pacientes con gonartrosis grado II-III asignándoles al azar el tratamiento A (diclofenac, liberación controlada 100mg) o B (nimesulida, presentación convencional 200mg). El estudio se desorrolló de acuerdo a un diseño doble ciego con grupos paralelos. Luego de un lavado de 7 días se comenzó con la medicación activa durante 84 días. Cada 14 días se evaluaron el dolor y otros parámetros clínicos. Se tomaron muestras de sangre los días 7, 49 y 91 a las 10 horas de la toma matutina para medir la concentración de los fármacos en plasma. Se realizaron exámenes de laboratório y al final del estudio. Ya a las dos semanas de comenzado el estudio se constataron mejorías estadísticamente significativas para los parámetros clínicos evaluados, que se mantuvieron durante todo el ensayo, en ambos tratamientos. El diclofenac y la nimesulida aumentaron su concentración plasmática durante los tres meses de estudio y se constató una aparente correlación lineal entre algunos parámetros clínicos y los niveles plasmáticos de los fármacos. La tolerancia, los exámenes de laboratório, y la apreciación clínica global del médico y del paciente para ambos grupos no mostraron diferencias estadísticamente significativas

Sustained release of diclofenac sodium form dry adsorbed emulsions

Sustained release W/O dry adsorbed emulsions containing diclofenac sodium were prepared. The effect of particle size, different emulsifying agents and various hydrophilic adsorbents on the sustained release characteristics of diclofenac sodium was studied. The drug release from dry adsorbed emulsions prepared with calcium stearate was slower than those prepared with Span 60. The effect of hydrophilic adsorbents on the drug release was found to be in the following order: Avical PH 101 > Aerosil 200 > Avicel RC-591. The release kinetics from the prepared particles showed that no one model was able adequately to describe the release situation. In vivo studies using human volunteers revealed a sustained release action up to 18 hours