Methods and compositions for self-regulated release of active pharmaceutical ingredient

1. An abuse deterrent pharmaceutical composition comprising:

a. a pharmaceutically active ingredient;

b. an acid soluble ingredient; and

c. a buffering ingredient;

wherein the buffering ingredient is in an amount sufficient to increase the gastric pH to greater than about 4 such that the acid soluble ingredient retards release of the pharmaceutically active ingredient when the composition is ingested in excess of a dosage appropriate to provide a therapeutic effect.

2. The composition of claim 1 , wherein the pharmaceutically active ingredient comprises a drug susceptible to abuse.

3. The composition of claim 1 , wherein the pharmaceutically active ingredient comprises a drug with narrow therapeutic index.

4. The composition of claim 1 , wherein the acid soluble ingredient comprises calcium carbonate, cationic copolymer, or combinations thereof.

5. The composition of claim 1 , wherein the acid soluble ingredient comprises a cationic copolymer based on dimethylaminoethyl methacrylate, butyl methacrylate, and methyl methacrylate.

6. The composition of claim 1 , wherein the pharmaceutically active ingredient is contained within a matrix of the acid soluble ingredient.

7. The composition of claim 1 , wherein the acid soluble ingredient is present in an amount of about 1 wt % to about 40 wt % of the pharmaceutical composition.

8. The composition of claim 1 , wherein the buffering ingredient comprises calcium carbonate, sodium bicarbonate, magnesium oxide, tribasic sodium phosphate, or combinations thereof.

9. The composition of claim 1 , wherein the buffering ingredient is present in an amount of about 45 wt % to about 95 wt %.