# US 5,707,656 A · Pharmaceutical formulations containing a pharmacologically active ionizable substance as well as process for the preparation thereof

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- Number: US 5,707,656 A
- Document ID: US5707656A
- Status: Granted
- Kind: A
- Application number: 07/802,325
- Filed: 1991-12-04
- Granted: 1998-01-13
- Earliest claimed: 1990-12-07
- Assignees: Astra Aktiebolag
- Inventors: Bengt Magnus Lindstedt; Per Johan Gunnar Lundberg
- Web page: https://patentgrep.com/patent/US5707656A

## CPC

- A61K 9/2054: {Cellulose; Cellulose derivatives, e.g. hydroxypropyl methylcellulose}
- A61K 47/585: {Ion exchange resins, e.g. polystyrene sulfonic acid resin}
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)

## Abstract

A preparation of a pharmacologically active ionizable substance, wherein active substance is ionically complexed to an ion-exchanger resin, which is embedded in a hydrophilic eroding matrix as well as a process for the manufacture thereof.

## Claims

### Claim 1

An oral pharmaceutical composition for extended even release of an ionizable active substance comprising:
an ionizable acidic active substance having a water solubility of more than 10 mg/ml;
an ionizable acidic active substance;
an ionic exchange resin consisting of a cross-linked polymer ionically complexed with the acidic active substance so as to form an ionic complex, which is embedded in a hydrophilic eroding matrix consisting of derivatized cellulose.

### Claim 2

An oral pharmaceutical composition for extended even release of ionizable active substance comprising:
an ionizable basic active substance having a water solubility of more than 10 mg/ml, selected from the group consisting of metoprolol and terbutaline;
a cation-exchange resin which is a cross-linked polymer and which is ionically complexed with the basic active substance so as to form an ionic complex;
the ionic complex being embedded in a hydrophilic eroding matrix consisting of derivatized cellulose.

### Claim 3 (depends on 2)

An oral pharmaceutical composition according to claim 2, wherein the cation-exchange resin is a polystyrene sulfonate.

### Claim 4 (depends on 1, 2)

The pharmaceutical composition of claims 1 or 2 in tablet form.

### Claim 5 (depends on 1, 2)

The pharmaceutical composition of claims 1 or 2, wherein the ionic complex is embedded in a hydrophilic eroding matrix at weight ratio of about 1:3.

### Claim 6 (depends on 1, 2)

The pharmaceutical composition according to claim 1 or 2, wherein the ionic complex is formed in the presence of water and dried.