Novel multifunctional pharmaceutical excipients derived from microcrystalline cellulose-starch microparticulate composites prepared by compatibilized reactive polymer blending.

The choice of excipients remains a critical factor in pharmaceutical formulations. Microcrystalline cellulose-maize starch composites (MCC-Mst) have been prepared by mixing colloidal dispersions of microcrystalline cellulose (MCC) with 10% (w/w) of chemically gelatinized maize starch (Mst) at controlled temperature conditions for use as multifunctional excipients with direct compression and enhanced disintegration abilities. The novel excipient was evaluated for its direct compression and enhanced disintegrant properties and the result compared with the properties of the individual components. Some of its physicochemical and thermal properties were also determined together with effects of freeze-thaw cycles of processing on the functional and physicochemical properties. The scanning electron micrograph (SEM) shows that the particles of the MCC-Mst were irregular in shape and multiparticulate with a marked degree of asperity. The indirect assessment of the powder flow properties as determined by Carr's compressibility index and angle of repose showed that the MCC-Mst possesses better flow compared with MCC and Mst. MCC-Mst is moderately hygroscopic and shows a Type III moisture sorption isotherm. The FT-IR spectra and DSC thermograms of the composite were different from those of MCC and Mst. The hardness of aspirin tablets was enhanced by incorporating MCC-Mst and MCC, but was reduced by Mst. While the tablets prepared with MCC-Mst and Mst disintegrated within 7min, aspirin compacts devoid of any excipient and those prepared with MCC did not disintegrate even after 2h. Acetaminophen compacts prepared with MCC and MCC-Mst showed similar compact hardness characteristics and loading properties. The loading capacity of the different samples of the composite decreased with increase in the freeze-thaw cycles. The loading capacity of the different materials as assessed by their compact hardness efficiency can be represented as follows (MCC>T0>T1>T4>T3>T2>Mst). Generally, the different samples of MCC-Mst are characterized by physicochemical and functional properties that are similar at different degrees to MCC and Mst.

Preparation and characterization of mucinated cellulose microparticles for therapeutic and drug delivery purposes.

Mucinated cellulose microparticles were generated by mixing equal concentrations of colloidal dispersions of porcine mucin (Mc) and microcrystalline cellulose (MCC). The hybrid polymer was recovered by precipitating at controlled temperature and pH conditions using acetone. Some physicochemical, functional and thermal properties of the hybrid polymer were determined and compared with those of Mc and MCC. The new polymer Mc-MCC had swelling and moisture sorption profiles that were different from those of Mc and MCC in buffer solutions with different pH values and relative humidity, respectively. The mucoadhesive property of the new polymer was similar to that of Mc. The scanning electron micrographs (SEMs) showed that the microparticles generated from the hybridization were similar to those of MCC, but with larger and denser particles. The Fourier Transform Infrared (FT-IR) spectrum and Differential Scanning Calorimeter (DSC) thermogram of the hybrid polymer were characteristically different from those of Mc and MCC. The presence of new peaks in the FT-IR spectrum and distinct cold crystallization exotherm, which were absent in both Mc and MCC, confirms the formation of a new polymer type with synergistic physicochemical and functional properties.