Drugresins

Drugresins are a class of pharmaceutical materials consisting of drug-binding resins, typically polymeric resins, used to form drug-resin complexes that can modulate release and mask taste. They can be natural, semi-synthetic, or synthetic polymers bearing charged groups that allow binding of drug molecules.

The binding usually occurs through ionic interactions on ion-exchange resins or other interactions on hydrophobic or covalent cross-links, depending on the resin chemistry. Commonly used are cross-linked polystyrene-based resins with sulfonic or carboxylic groups. The resulting complex can be formulated into tablets, capsules, or beads. Release is triggered by exchange with counterions present in gastric or intestinal fluids or by diffusion through the resin matrix, and can be influenced by pH, ionic strength, and temperature.

Preparation involves mixing the drug with resin under controlled pH to maximize binding and then filtering, drying, and formulating into dosage forms (pellets, beads, coated granules). Some formulations incorporate the resin-drug complex into taste-masked syrups or oral suspensions.

Applications include oral sustained or targeted release formulations and taste masking, particularly for bitter or unpalatable drugs. Advantages include improved stability, reduced dosing frequency, and patient compliance; limitations include variability in release, potential incomplete drug release, and the need for compatibility screening and quality control.