ABSTRACT
Stability and solubility concerns alone prevent the application of many drugs directly into a liquid formulation. Ion resin complexes can potentially be used for immediate-release formulations depending on drug affinity for the ion exchange resin; however, they are particularly useful for extended-release liquid formulations. To reduce free drug and competing ion content, the drug–resin complex slurry is typically filtered or centrifuged to remove the liquid portion, which contains the displaced counterions of both the drug and resin and remaining free, dissolved drug. Cyclodextrins provide a means to solubilize poorly soluble drugs and stabilize reactive drugs for successful incorporation into solution or suspension liquid dosage forms. An aqueous solution of a water-soluble drug can potentially be incorporated into an immediate-release liquid product. The bad taste of most drugs limits successful direct incorporation into a liquid dose form depending on the extent of bad taste and the dose/concentration requirement.
