An oral
delivery system for Class II drugs that have low oral
bioavailability due to their insolubility in water and slow
dissolution kinetics and method for making such a
drug delivery system are disclosed herein. The formulation may be a
controlled release or
immediate release formulation. The
immediate release formulation contains a Class II
drug, together with a
hydrophobic polymer, preferably a
bioadhesive polymer. In one embodiment, the
drug and
polymer are co-dissolved in a common
solvent. The solution is formed into small
solid particles by any convenient method, particularly by
spray drying. The resulting particles contain drug dispersed as
small particles in a
polymeric matrix. The particles are stable against aggregation, and can be put into capsules or tableted for administration. The
controlled release formulations contain a BCS Class II drug and a
bioadhesive polymer. The
controlled release formulations may be in the form of a tablet, capsules, mini-tab, microparticulate, or
osmotic pump. Enhancement of oral uptake of the drug from use of
bioadhesive polymers occurs through (1) increased
dissolution kinetics due to stable
micronization of the drug, (2) rapid release of the drug from the polymer in the GI tract; and (3) prolonged GI transit due to bioadhesive properties of the polymers. The combination of these effects allows the preparation of a compact, stable
dosage form suitable for
oral administration of many class II drugs.