Evaluation of microwave assisted grafted sago starch as controlled release polymeric carrier

Synthesis, characterization and fabrication of sodium carboxymethyl-okra-gum-grafted-polymethacrylamide into sustained release tablet matrix

The objective of the present study was to modify okra gum (Abelmoschus esculentus) by carboxymethylation and subsequent graft-copolymerization, characterize and fabricate into sustained-release tablet matrix. Firstly, okra gum was carboxymethylated using sodium hydroxide and monochloroacetic acid followed by grafting with polymethacrylamide employing synergistic combination of free-radical-initiator and microwave-irradiation. The FTIR, NMR, elemental analysis and viscosity study corroborate the formation of sodium-carboxymethyl-okra gum-grafted-polymethacrylamide copolymer (SCMOG-g-PMA). The maximum degree of carboxymethyl-substitution (DCS) and % grafting (%G) were found to be 0.604 ± 0.011 and 644.1, respectively. Water-uptake-capacity was found to increase by 3.5 fold. The tablet formulation of diclofenac sodium with SCMOG-g-PMA (DCS 0.604 and 423.4% G) showed to exhibit excellent sustained-release capacity with 90% drug-release at 11.7 h and similarity-factor of 72.0. The toxicity and biodegradability study also exhibited the bio-compatible and biodegradable nature of the copolymer, which might make the copolymer suitable for sustained-release drug delivery systems as smart semi-synthetic biopolymer.

Mung bean (Vigna radiata) porous starch for solubility and dissolution enhancement of poorly soluble drug by solid dispersion

In this study, a novel Vigna radiata based porous starch (PS) is prepared by solvent exchange technique and explored as a solubilizer for model drug albendazole (ABZ). PS carrier was investigated for different chemical, functional, and micromeritic properties. Solubilizing potential of PS is evaluated by formulating ABZ-PS solid dispersion (1:0.5-1:2) based tablets (SDT). ABZ-PS solid dispersions were evaluated for micromeritic properties, dissolution studies, and anthelmintic activity. Direct compression suitability and susceptibility of mung bean starch were studied by SeDem diagram, Heckel, and Kawakita analysis respectively. PS had an A-type crystallinity pattern and evinced functional properties similar to other legume starches. PS was determined to be suitable for direct compression (good compressibility index = 5.50). SD (1:2) manifested 36.18 fold and 1.6-3.04 fold improvement in the % dissolution and anthelmintic activity of ABZ respectively. All SD batches (R² = 0.949-0.996) and ABZ (R² = 0.168) followed the Higuchi-matrix release kinetic model. DSC and P-XRD analysis corroborated the amorphous form of ABZ. SDT showed ≈ a 1.90 fold improvement in dissolution rate than the marketed formulation. Conclusively, Vigna radiata PS could be explored as an alternative to reduce the large burden on the established starches.

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.