Time-specific controlled release dosage formulations and method of preparing same

Patent 5891474 Issued on April 6, 1999. Estimated Expiration Date:

January 29, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

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Inventors

Application

No. 790530 filed on 01/29/1997

US Classes:

424/490, Coated (e.g., microcapsules)424/480, Cellulose or derivative424/489Particulate form (e.g., powders, granules, beads, microcapsules, and pellets)

Examiners

Primary: Page, Thurman K.
Assistant: Benston, William E. Jr.

Attorney, Agent or Firm

Townsend & Townsend & Crew, LLP, Dow; Karen B.

Foreign Patent References

0 305 918 A1 EP. 03/13/1989
0 366 621 A1 EP. 05/13/1990
0 453 001 A1 EP. 10/13/1991
0 572 942 A2 EP. 12/13/1993
0 629 398 A1 EP. 12/13/1994
WO 95/35100 WO 12/13/1995

International Classes

A61K 009/16
A61K 009/50

Abstract

The present invention provides a method of achieving the time-specific delivery of a pharmaceutically active agent to a patient in need of the therapeutic effects of the pharmaceutically active agent. The method includes administering a pharmaceutical formulation comprising (a) a core including the pharmaceutically active agent to be delivered, and (b) a swellable polymeric coating layer substantially surrounding the core. The swellable polymeric coating layer delays the release of the pharmaceutically active agent from the core for a predetermined period of time dependent upon the thickness of the swellable polymeric coating layer. The swellable polymeric coating layer surrounding the core is provided by a new method which includes alternately (i) wetting the core with a binder solution, and (ii) coating the core with powdered polymeric particles a sufficient number of times to produce a time-specific dosage formulation having the desired thickness of swellable polymeric coating layer.

Other References

K. Nishimura et al.; Dosage Form Design for Improvement of Bioavailability of Levodopa VI: Formulation of Effervescent Enteric-Coated Tablets, J. Pharm. Sci. 73(7):942-946 (1984)
A. Gazzaniga et al.; time-dependent oral delivery systems for colon targeting, S.T.P. Pharma Sciences, 5(1):83-88 (1995