Inorganic matrices: an answer to low drug solubility problem

Many active pharmaceutical ingredients (APIs), in development and already on the market, show a limited and variable bioavailability mainly associated to inadequate biopharmaceutical properties such as aqueous solubility and dissolution rate. The latter is the main factor responsible for the limited, and sometimes inadequate, efficacy of many orally administered drugs, belonging to class II and IV of the Biopharmaceutics Classification System (BCS). Moreover, because of their low solubility, such drugs require high doses to be administered in order to obtain their pharmacological effect, increasing the side effect incidence.

The present review reports the most common technological approaches intended to improve solubility and dissolution rate of BCS class II and IV drugs such as nanocrystals, solid dispersions, cyclodextrins and solid lipid nanoparticles. Particular attention will be focused on the use of inorganic matrices (lamellar anionic clays and mesoporous materials) as host for the delivery of poor soluble APIs (guest).

The employment of inorganic matrices for the realization of host-guest composites is a suitable strategy for the biopharmaceutical properties enhancement. This objective can be achieved without any modification of API chemical structure.