Extrusion-Spheronization of Talc using Microcrystalline Cellulose as a Pellet Aid: Part I

Fabrication and evaluation of fast disintegrating pellets of cilostazol

The present study was designed to formulate and develop fast disintegrating pellets of poorly soluble model drug (cilostazol) by reducing the proportion of micro-crystalline cellulose with pre-gelatinized starch (PGS), lactose and chitosan. The bioavailability enhancement of a model drug was achieved by preparing inclusion complex with Captisol® (Sulfobutyl Ether β cyclodextrin - SBE-β-CD). Extrusion-spheronization technique was used to formulate pellets. Placket-Burman design was used for the initial screening of most significant factors such as screen size (mm), ratio of micro crystalline cellulose: PGS + lactose + chitosan and % of HPMC which affects pellet properties. The inclusion complex of drug and Captisol^® (SBE-β-CD) was prepared by Solvent Evaporation method and were incorporated into pellets in a predefined proportion. Formulation was optimized by using 3² full factorial design, the optimized batch was selected on the basis of dependent variables such as % yield, pellet size, disintegration time and % Cumulative drug release (%CDR), the obtained results were 87.15%, 0.75 mm, 13 min and 91.024% respectively. Differential scanning calorimetry (DSC) and Fourier transform infrared spectrometry (FTIR) study revealed no significant interaction between drug and polymer. Scanning electron microscopy (SEM) confirmed uniform and spherical shaped pellets having pores on the surface which facilitates wicking action and fast disintegrating property of pellets. A design space was constructed to meet the desirable target and optimized batch. The scope of study can further extended to hydrophobic molecules which may useful due to rapid disintegration and enhanced dissolution rate.

Approaches to developing fast release pellets via wet extrusion-spheronization

Microcrystalline cellulose (MCC) is widely regarded as the excellent choice to manufacture pellets via wet extrusion-spheronisation (ES) process due to its excellent water uptake capability, water holding capacity, desirable rheological properties, cohesiveness and plasticity etc. Nevertheless, in spite of all these advantages, limitations associated with the application of MCC also have been reported. The most prevailing limitation is prolonged or incomplete drug release profile due to the lack of disintegration as pellet contracts significantly during the drying process, especially when in combination with poorly soluble drug at a high level. This characteristic limits the application of MCC in immediate release formulations. Over the years, many approaches have been tried to overcome this disadvantage, such as modifying MCC, incorporation of superdisintegrant, increasing the porosity of pellet, partial or complete substitution for MCC, enhancing the solubility of poorly soluble drug (e.g. solid dispersion, self-emulsifying drug-delivery system), etc. In this review, we will provide an updated and integrated discussion of current approaches to prepare fast release pellets via wet ES.