Nifedipine gastrointestinal therapeutic system.

Area of Science:

• Pharmacology
• Drug Delivery Systems
• Cardiovascular Medicine

Background:

• Essential hypertension requires convenient, long-acting treatments.
• Nifedipine, a short-acting calcium channel blocker, poses formulation challenges for sustained release.
• Once-daily dosage regimens are highly desirable for patient compliance.

Purpose of the Study:

• To develop and characterize once-daily nifedipine dosage forms using the gastrointestinal therapeutic system (GITS).
• To evaluate the in vitro and in vivo performance of these novel nifedipine formulations.
• To confirm predictable drug absorption and plasma concentration profiles over a 24-hour period.

Main Methods:

• Formulation of nifedipine GITS dosage forms in three strengths (1.7/30, 3.4/60, 5.1/90 mg).
• In vitro drug release studies across a pH range (1.2-7.5) and at varying stirring rates.
• In vivo drug release and absorption studies in dogs and human subjects.

Main Results:

• Nifedipine GITS dosage forms demonstrated controlled drug delivery rates independent of pH and stirring rate.
• In vitro release rates accurately predicted in vivo drug delivery in dogs.
• Human studies showed cumulative drug absorption proportional to in vitro delivery, resulting in stable 24-hour plasma concentrations.

Conclusions:

• The GITS technology enables the development of effective once-daily nifedipine formulations for hypertension.
• These dosage forms offer predictable drug delivery and absorption, maintaining consistent plasma levels.
• This formulation approach overcomes nifedipine's short-acting nature for improved therapeutic management.