Effect of Coating Systems on the Dissolution and Mechanical Properties of Drug-Loaded Pellets (October 2012)
To evaluate dissolution and mechanical properties of extended-release (ER) coated drug loaded pellets, the drug loaded pellets were coated with different ER polymers using both aqueous and solvent coating systems. Sub-coating layer, top-coating layer and various polymers and their combinations were also evaluated.
Compared to aqueous coating systems, the solvent coating formulations can form dense and low permeable film, slow drug release and increase mechanical strength of ER pellets. The polymers added in the ethylcellulose solutions or aqueous dispersions may modify the drug release profiles and change mechanical strength of coated pellets. High mechanical strength can prevent the ER coated pellets from breaking during packaging and other applications.Read More
Characterization of the Mechanical Properties of High Drug Loading Pellets for Compressed Controlled Release Tablets (July 2012)
To characterize the mechanical properties of uncoated and coated pellets and study the drug release of coated pellets and compressed tablets
The mechanical strength of the uncoated pellets increases with increasing water and binder content of the granulation formulation for extrusion. The application of coating can also improve the mechanical strength of the uncoated pellets. To avoid the damage of coated pellets during tablet compression, a high mechanical strength of pellets is needed. The mechanical property characterization can accelerate the product development process.Read More
Minimize the Influence of Drug-Polymer Interaction on Drug Release from EntericCoated Extended Release Matrix Tablet (July 2011)
To develop formulation strategies to minimize the unexpected slow release due to drug-polymer interaction and to reduce pH dependent release behavior.
Unwanted retarded release in pH 6.0 phosphate buffer stage after an acid stage for 2 hours was observed for an Eudragit L100-55 coated ER tablet. The slow release was caused by a slowly soluble enteric film covering the tablet. Based on chemical reactivity of secondary amine group present in the drug, we proposed that drug-Eudragit L100-55 amide formed by neutralization and dehydration of amine group and carboxyl group in Eudragit carbon chain. The reaction was facilitated in acid medium and the complex was readily soluble in pH 6.8 or higher. The mechanisms of slow release can be regarded as a modification of Eudragit L100-55 function groups to increase pH trigger point to above 6.Our results showed the retarded release can be avoided either by a bilayer core tablet concept or by switching to other enteric polymers(such as HPMCP).Read More
Ionic Interaction to Achieve 24 Hour Zero Order Release for a Freely Soluble Drug
Design a 24 hour zero order release tablet containing a freely soluble basic drug (H131) Investigate the effect of anionic polymers and hydroxypropyl methylcellulose (HPMC) on drug release rate Evaluate the different manufacturing processes on drug dissolution profile
Neutral polymer and/or wax alone failed to control H131 release for up to 24 hours from matrix tablets due to API’s high water solubility and low dose. Anionic polymers, such as Eudragit® L100-55 and Carbopol® 971P, could interact with H131 at neutral and high pH environments. The combination of anionic polymers and HPMC can retard H131 release from matrix tablets. The approach applied drug-anionic polymer interaction to prolong drug release up to 24 hours with near zero order release was successfully demonstrated. The manufacturing processes have a significant effect on drug release.Read More