In the present study, an attempt was made to prepare immediate-release enteric-coated pellets of
aceclofenac, a poorly soluble nonsteroidal anti-inflammatory
drug that has a gastrointestinal intolerance as its serious side effect. Formulation of enteric-coated pellets with improved solubility of
aceclofenac could address both of these problems. To achieve these goals, pellets were prepared by extrusion-spheronization method using pelletizing agents that can contribute to the faster disintegration and thereby improve the solubility of the
drug. Different disintegrants like
beta-cyclodextrin,
kollidon CL, Ac-Di-
Sol, and
sodium starch glycolate were tried in order to further improve disintegration time. The pellets were characterized for
drug content, particle size distribution, flow properties, infrared spectroscopy, surface morphology, disintegration rate, and dissolution profile. The formulations, which showed best disintegration and dissolution profiles, were coated with
Eudragit L100-55, an enteric-coated
polymer which does not dissolve at gastric pH but dissolves at intestinal pH, releasing the
drug immediately in the dissolution medium. The optimized enteric-coated formulation containing 20%
kappa-carrageenan,
lactose, and
sodium starch glycolate as a disintegrant did inhibit the release of the
drug for 2 h in 0.1 N HCl, whereas 87% of the
drug was released within 45 min. The improvement was substantial when it was compared with solubility of pure
drug under the same conditions. Thus, dissolution profiles suggested that combination of
kappa-carrageenan and
sodium starch glycolate resulted into fast-disintegrating, immediate-release pellets, overcoming the bioavailability problem of the poorly soluble
drug,
aceclofenac, and enteric coating of these pellets avoids the exposure of
aceclofenac to
ulcer-prone areas of the gastrointestinal tract.