Development and in-vitro evaluation of diclofenac sodium spray-dried with polyacrylate and sodium carboxymethylcellulose

Abstract

Diclofenac sodium microspheres were prepared by spray drying technique. Two combinations of a polyacrylate and sodium carboxymethylcellulose (Eudragit® RD 100, Eudragit® RL30D with sodium carboxymethylcellulose) were used as polymeric matrices. Collodal silica (Aerosil®200) of 15 and 30 percent weight by weight of drug and polymer content was added as an antiadherent. The physicochemical properties of spray dried powders and the release of drug from microspheres were evaluated. The influence of processing variables such as inlet temperature and feed rate on the physicochemical properties and release patterns of spray dried powders were also studied. The scanning electron photomicrographs showed different shape and size of powders when prepared with different types and amount of polymer including amount of Aerosil®200 and different inlet temperature and feed rate. The powders tended to be smoother and more spherical when increasing the inlet temperature and amount of Aerosil®200 whereas the size seemed to be smaller when decreasing the feed rate. The flow rate from various spray dried powders showed similar results but improved when adding Aerosil.200 in the formulation. The IR spectra revealed no interaction between drug and polymers. The higher baseline of X-ray diffractograms and the shift of exothermic and endothermic peaks in DSC thermograms of the microspheres seemingly showed an appearance of amorphous form. The release of drug in pH change system increased with the decrease in the amount of polymer and the increase in the amount of Aerosil®200. The release patterns from various polymers seemed to be similar. Microspheres which prepared by Eudragit®RD 100 at the polymer to drug ratio of 1:1.5 and sprayed at 130℃, feed rate of 20 ml/min with Aerosil 30 percent weight by weight of drug and polymer content showed the release of drug similar to the commercial products.