Abstract
Diclofenac sodium (DS) is a very common non-steroidal anti-inflammatory drug used in the treatment of rheumatoid disorders and others inflammatory diseases. The required repeated daily dosages can cause damages to gastrointestinal, hepatic, cardiac systems, and others. Besides, DS is unstable in acid condition, what can decrease the therapeutic effect due the degradation of the drug. Sodium alginate is a natural polysaccharide extracted from brown seaweed that has an abundant use in drug delivery systems. The bioconjugation of sericin, a hydrophilic protein present in silkworm cocoons (Bombyx mori), with polymers has provided new drug delivery methods with reduced immunogenicity and increased drug stability. In this work particles of sericin-alginate blend with sodium diclofenac incorporated were produced by ionic gelation technique (dripping the blend in calcium solution). The release kinetic study was investigated at pH 1.2 and 6.8, simulating the pH of gastric and enteric systems and the obtained data were evaluated by different release mechanisms models. The zero order, first order, second order, Weibull, Higuchi, Hixson-Crowell, Korsmeyer-Peppas, Baker- Londale, quadratic, logistic and Gompertz mathematical models were evaluated. The kinetic study showed that the amount of DS release versus time in gastric pH was almost negligible when compared with the enteric system. The drug release mechanism that best fit the enteric system was Gompertz model and to gastric system,the Logistic model fit the data with high value of R2, both values close to 1. It was concluded that the particlesproduced with sericin/alginate with DS incorporated can protect the DS in acid condition and improve the DS release in enteric simulated condition.
