Use of a partially neutralized, anionic (meth) acrylate copolymer as a coating for the production of a medicament pharmaceutical form releasing active substance at reduced pH values

1. A pharmaceutical form consisting essentially of an active substance-containing core which is coated with a partially neutralized, anionic (meth)acrylate copolymer consisting of free radical-polymerized units of 25 to 95% by weight of C 1 - to C 4 -alkyl esters of acrylic or methacrylic acid and 5 to 75% by weight of (meth)acrylate monomers having an anionic group, more than 10% of said anionic groups being neutralized by means of a base;

wherein said pharmaceutical form releases at least 30% of the contained active substance in 30 minutes at a pH between 2 and 6 at which the active substance is soluble and stable and at which pH a corresponding pharmaceutical form which is coated with the un-neutralized anionic (meth)acrylate copolymer would release less than 10% of the contained active substance in 30 minutes.

2. The pharmaceutical form as claimed in claim 1 , wherein the base which is employed for the partial neutralization has a molecular weight of at most 150.

3. The pharmaceutical form as claimed in claim 1 , wherein NaOH, KOH or ammonia is employed for the partial neutralization.

4. The pharmaceutical form as claimed in claim 1 , wherein the degree of partial neutralization is more than 10 to 20%.

5. The pharmaceutical form as claimed in claim 4 , wherein the pH between 2 and 6 at which at least 30% of the active substance contained is released in 30 minutes and at which the active substance is soluble and stable and at which a corresponding pharmaceutical form which is coated with the un-neutralized anionic (meth)acrylate copolymer would release less than 10% of the active substance contained in 30 minutes lies around 1.5 to 2.5 pH units below the pH of the start of the specific active substance release in intestinal juice or artificial intestinal juice of a not partially neutralized, anionic (meth)acrylate copolymer.

6. The pharmaceutical form as claimed in claim 1 , wherein the degree of partial neutralization is more than 20 to 40%.

7. The pharmaceutical form as claimed in claim 6 , wherein the pH between 2 and 6 at which at least 30% of the active substance contained is released in 30 minutes and at which the active substance is soluble and stable and at which a corresponding pharmaceutical form which is coated with the un-neutralized anionic (meth)acrylate copolymer would release less than 10% of the active substance contained in 30 minutes lies around 2.5 to 3.5 pH units below the pH of the start of the specific active substance release in intestinal juice or artificial intestinal juice of a not partially neutralized, anionic (meth)acrylate copolymer.

8. The pharmaceutical form as claimed in claim 1 , wherein the anionic (meth)acrylate copolymer consists of free radical-polymerized units of 40 to 60% by weight of methacrylic acid and 60 to 40% by weight of methyl methacrylate or 60 to 40% by weight of ethyl acrylate.

9. The pharmaceutical form as claimed in claim 1 , wherein the anionic (meth)acrylate copolymer is employed in the form of an aqueous dispersion having a 10 to 50% solids content.

10. The pharmaceutical form as claimed in claim 1 , wherein the coating contains up to 50% by weight of an additional film-forming polymer which contains no or only insignificant amounts of ionic side groups.

11. The pharmaceutical form as claimed in claim 10 , wherein said additional film-forming polymer which contains no or only insignificant amounts of ionic side groups is selected from the group consisting of a copolymer of methyl methacrylate and ethyl acrylate, a polyvinyl alcohol-polyethylene glycol graft copolymer, polyvinyl acetate, hydroxyethylcellulose, hydroxy-propylcellulose, hydroxypropylmethyl-cellulose, hydroxy-methylethylcellulose, ethylcellulose, methylcellulose, cellulose esters and mixtures thereof.

12. The pharmaceutical form as claimed in claim 1 , wherein the active substance is selected from the group consisting of omeprazole, lanzoprazole, pantoprazole, rabe-prazole, perprazole, esomprazole, tenatoprazole, anastrozole, aripiprazole, dapriprazole, hydroxy-omeprazole, leminoprazole, and paroxetine, pindolol, reboxetine, 5-aminosalicylic acid, sulfasalazine budenoside, natamycin, preglumetacin, sulfasalacine, nitro-furantion, didanosine, acetylsalicylic acid, acemetacin, ibuprofen, diclofenac, naproxen, ketoprofen, dexketoprofen, indometacin, tiaprofenic acid, pravastatin, valproic acid, and ramipril, and salts thereof.

13. The pharmaceutical form as claimed in claim 1 , wherein the active substance is a proton pump blocker and the coating is a partially neutralized, anionic (meth)acrylate copolymer of free radical-polymerized units of 40 to 60% by weight of methacrylic acid and 60 to 40% by weight of ethyl acrylate.

14. The pharmaceutical form as claimed in claim 1 , wherein the active substance is acetyl salicylic acid and the coating is an anionic (meth)acrylate copolymer, which is partially neutralized to more than 20 to 40%, of free radical-polymerized units of 40 to 60% by weight of methacrylic acid and 60 to 40% by weight of ethyl acrylate.

15. A pharmaceutical form consisting essentially of:

(1) an active substance-containing core, and

(2) a partially neutralized, anionic (meth)acrylate copolymer coating which covers said core and consists of free radical polymerized units of 25 to 95% by weight of C 1 - to C 4 -alkyl esters of acrylic or methacrylic acid and 5 to 75% by weight of (meth)acrylate monomers having an anionic group, more than 10% of said anionic groups being neutralized by means of a base;

wherein said pharmaceutical form releases at least 30% of the contained active substance in 30 minutes at a pH between 2 and 6 at which the active substance is adequately soluble and stable and at which pH a corresponding pharmaceutical form which is coated with the un-neutralized anionic (meth)acrylate copolymer would release less than 10% of the contained active substance in 30 minutes.

16. A pharmaceutical form consisting essentially of:

(1) an active substance-containing core, and

(2) a partially neutralized, anionic (meth)acrylate copolymer coating which covers said core and consists of free radical polymerized units of 25 to 95% by weight of C 1 - to C 4 -alkyl esters of acrylic or methacrylic acid and 5 to 75% by weight of (meth)acrylate monomers having an anionic group, more than 10% of said anionic groups being neutralized by means of a base;

wherein said pharmaceutical form releases at least 30% of the contained active substance in 30 minutes at a pH between 2 and 6 at which the active substance is soluble and stable and at which pH a corresponding pharmaceutical form which is coated with the un-neutralized anionic (meth)acrylate copolymer would release less than 10% of the contained active substance in 30 minutes.