Microcrystalline cellulose (MCC) is a widely used pharmaceutical excipient in direct compression as a direct compression aid and disintegrant. It is available in many grades that can differ in terms of their bulk density, particle size, moisture content and method of production. These differences can impact on blend compressibility, and hence the disintegration and dissolution behaviour of drugs.
To study impact of MCC grade on the disintegration and dissolution behaviour of Ibuprofen/MCC tablets prepared by direct compression with increasing drug concentration.
Binary blends of ibuprofen (1-30% w/w loading) and MCC were compressed. Two different MCC grades: Vivapur®102, air stream dried quality, and Emcocel®90, spray dried quality, were compared. Dissolution studies were performed on tablets of similar tensile strength with an Erweka® flow-through type IV apparatus; dissolution medium of phosphate buffer pH 7.2 recirculated in closed loop model. Dissolution data was fitted to the Korsmeyer-Peppas model of dissolution to determine differences in the mechanism of drug release. Tablet disintegration was studied using a Broadband Acoustic Resonance Spectroscopy method.
Figure 1 shows dissolution profiles for blends studied. At lower Ibuprofen loading concentrations, both Emcocel and Vivapur blends show a comparable drug release rate and data fitted to a model indicating non-Fickian anomalous transport with a cylinder geometry. Increasing the drug concentration in Emcocel blends results in the data fitting to a model indicating Non-Fickian Super Case II transport model with a cylinder geometry, and hence improved solvent penetration while maintaining the drug release rate. In contrast, increasing the drug loading in the Vivapur blend, significantly decreased the release rate of Ibuprofen while maintaining non-Fickian anomalous transport.
The disintegration and dissolution behaviour of Ibuprofen/MCC tablets was influenced by both the Ibuprofen concentration and the grade of MCC.