An abuse-deterrent pharmaceutical composition has been developed to reduce the likelihood of improper administration of drugs, especially drugs such as opiods. In the preferred embodiment, a
drug is modified to increase its
lipophilicity. In preferred embodiments the modified
drug is homogeneously dispersed within microparticles composed of a material that is either slowly soluble or not soluble in water. In some embodiments the
drug containing microparticles or drug particles are coated with one or more
coating layers, where at least one
coating is
water insoluble and preferably
organic solvent insoluble, but enzymatically degradable by enzymes present in the
human gastrointestinal tract. The abuse-deterrent composition retards the release of drug, even if the
physical integrity of the formulation is compromised (for example, by chopping with a blade or crushing) and the resulting material is placed in water, snorted, or swallowed. However, when administered
as directed, the drug is slowly released from the composition as the composition is broken down or dissolved gradually within the GI tract by a combination of
enzymatic degradation, surfactant action of bile acids, and mechanical
erosion.