Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Capsules
Reexamination Certificate
1997-12-16
2001-02-20
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Capsules
C424S490000, C424S489000, C424S480000
Reexamination Certificate
active
06190692
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to controlled release dosage formulations. More particularly, the present invention relates to a method of preparing a time-specific controlled release dosage formulations.
BACKGROUND OF THE INVENTION
Pharmaceutical formulations for oral administration have employed various coatings for the purpose of preserving the integrity of the formulation while passing through the gastric tract. The high acidity, and presence of proteolytic and other enzymes generates a highly digestive environment which readily disintegrates pharmaceutical formulations which do not possess some type of gastro-resistance protection.
In recent years, a need has arisen for formulations which are capable of passing over the entire tract of the small intestine, including the duodenum, jejunum, and ileum, so that the active ingredients are released directly in the colon. For example, European Patent Application No. 366 621 provides a formulation for delivery in the colon which includes a core containing the active ingredient and three protective layers having differing solubilities around the core. As another example, our European Application No. 572 942, disclosure of which is hereby incorporated by reference in its entirety, provides an oral pharmaceutical composition including a core containing the active ingredient, an intermediate coating layer which delays the release of the active ingredient contained in the core for a programmed time period, and an outer layer, the dissolution of which activates the process of swelling/dissolution/erosion of the intermediate layer. In the composition described in European Application No. 572 942, the coating layers are applied sequentially by watery or organic film coating or by press coating techniques, such as double press coating. A primary disadvantage of these coating methods is that these methods employ solutions of the coating polymers, which coating polymers have very high viscosities in water-based environments.
Double press coating techniques have some disadvantages in that the core of the formulation may not be properly centered within the coating, and a relatively large amount of polymer is required for proper coating.
There also remains a need in the art for pharmaceutical formulations which release active ingredient after a predetermined latency or lag time period in the body, i.e., time-specific release formulations.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method of preparing a time-specific release pharmaceutical formulation which is faster than conventional coating techniques. It is also an object of the present invention to provide a time-specific pharmaceutical formulation, the disintegration of which is triggered by time lapse, independently of the pH of the environment to which it is subjected.
As a first aspect, 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.
As a second aspect, the present invention provides a method of providing the swellable polymeric coating layer surrounding the core. The method 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.
As a third aspect, the present invention provides another method for time-specific delivery of a pharmaceutically active agent to a patient in need of the therapeutic effects of the pharmaceutically active agent. The method comprises administering a pharmaceutical formulation comprising (a) a core including the pharmaceutically active agent, and (b) a swellable polymeric coating layer substantially surrounding the core, that 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 is formed from powdered polymeric particles.
As a fourth aspect, the present invention provides a method for producing a time-specific dosage formulation for the time-specific delivery of a pharmaceutically active agent. The method comprises coating a core containing the pharmaceutically active agent with a swellable polymeric coating layer that 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 step of coating the core with the swellable polymeric coating layer comprises 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.
As a fifth aspect, the present invention provides another method for time-specific delivery of a pharmaceutically active agent to a patient in need of the therapeutic effects of the pharmaceutically active agent. The method comprises administering to the patient, a pharmaceutical formulation comprising: (a) a core which comprises a capsule containing a liquid form of the pharmaceutically active agent, 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 is provided by 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.
As a sixth aspect, the present invention provides yet another method for time-specific delivery of a pharmaceutically active agent to a patient in need of the therapeutic effects of the pharmaceutically active agent. The method comprises administering a pharmaceutical formulation comprising: (a) a core which comprises a capsule containing a liquid form of the pharmaceutically active agent, and (b) a swellable polymeric coating layer substantially surrounding the core. The swellable polymeric coating 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 is formed from powdered polymeric particles.
As a seventh aspect, the present invention provides another method for producing a time-specific dosage formulation for time-specific delivery of a pharmaceutically active agent. The method comprises coating a core comprising a capsule containing a liquid form of the pharmaceutically active agent, with a swellable polymeric coating layer that 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 step of coating the core with the swellable polymeric coating layer comprises 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. The core can be provided by the steps
Busetti Cesare
Crimella Tiziano
Ghali Isis
Page Thurman K.
Townsend & Townsend & Crew
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