Preparation and in vitro evaluation of gliclazide sustained-release matrix pellets: formulation and storage stability

Abstract

Objective: Gliclazide-loaded matrix pellets consisting of ethylcellulose, microcrystalline cellulose (MCC), and sodium carboxymethyl starch were prepared by extrusion-spheronization. Method: To control the initial fast release of the matrix pellets, three coating methods were used: hot-melt coating, polymer aqueous dispersion film coating, and MCC powder coating. An orthogonal experiment (L₉(3)) was applied to optimize the key process variables of MCC-powder coating. The in vitro dissolution profiles of the coating pellets were compared with the commercial tablets Diamicron® by the similarity factor (f ₂). The storage stability was measured to choose the best coating method. Result: Initial fast release was overcome by using the three coating methods. Rotation speed of friction plate and time of coating (addition of binder/coating agents) were both found to have the more important influence to drug release. The f ₂ values between the three coated pellets and the commercial product were all greater than 50. The results of storage-stability tests suggest that the pellets prepared by MCC-powder-coating method are stable for at least 6 months under stress conditions (40°C/75%RH), whereas the others failed. Conclusion: The MCC-powder-coating method offered the advantage of a one-step procedure compared with film coating and hot-melt coating.

Keywords:

• Gliclazide
• matrix pellets
• MCC-powder coating
• storage ability
• initial burst release