Evaluation of acrylamide grafted moth bean starch as controlled release excipient

Mechanical properties of starch esters at particle and compact level - Comparisons and exploration of the applicability of Hiestand's equation to predict tablet strength

Hydrophobic starch esters have potential as tablet matrix formers in controlled drug delivery. The mechanical properties of native starch (SN), starch acetate (SA) and starch propionate (SP) were studied at particle and compact level. Particle microhardness and modulus of elasticity were evaluated by nanoindentation. Force-displacement data of compressed powder were analyzed using Heckel in conjunction with piecewise regression, Kuentz-Leuenberger, Kawakita and Adams models, and yield pressure parameters were derived. Starches were characterized for chemical structure by Raman spectroscopy, crystallinity from powder x-ray diffraction (PXRD) patterns and surface energy from apparent contact angle measurements. A-type starch reflections were absent in the PXRDs of esters indicating greater amorphicity. Consequently, the particle microhardness of starch esters decreased leading to greater deformation during compaction and lower values of yield pressure parameters. These parameters increased with microhardness and ranked the starches in the order: SP < SA < SN. Fitting the experimental data into Hiestand's bonding index equation, a linear correlation (R² = 0.902) was established between experimental and calculated tablet strength describing results of all starches, when Adams (τ_ο') yield pressure was used as the 'effective compression pressure' in the above equation.

Microwave grafted, composite and coprocessed materials: drug delivery applications

Novel modified pharmaceutical materials with desired functionalities are required for the development of drug delivery systems. Excipients are no more inert ingredients but these are playing crucial roles in modifying physicochemical properties of drugs and for imparting desired functionalities in the delivery system. In this review article, modified materials such as grafted, composite and coprocessed have been discussed along with the updated reported literature on the same. Applications of grafted materials as drug release retardant, mucoadhesive polymer and tablet superdisintegrant have been elaborated. Use of composite materials in the development of transdermal films, hydrogels, microspheres, beads and nanoparticles have been discussed. Methods for the preparation of coprocessed materials along with commercial products of different coprocessed excipients have also been enlisted.

Preparation and characterization of pullulanase debranched starches and their properties for drug controlled-release

Linear short amylose and glucan tend to align and aggregate to form hydrogels that hold less water. The drug release properties of debranched starch based tablets can be controlled by the pullulanase modification conditions.