Preparation of an extended-release matrix tablet using chitosan/Carbopol interpolymer complex

Area of Science:

• Polymer Science
• Materials Science
• Pharmaceutical Science

Background:

• Chitosan and Carbopol are biocompatible polymers with potential in drug delivery.
• Developing stable interpolymer complexes can enhance drug formulation properties.
• Controlled drug release is crucial for therapeutic efficacy and patient compliance.

Purpose of the Study:

• To synthesize and characterize a chitosan-Carbopol interpolymer complex (IPC).
• To investigate the complexation mechanism and ratio between chitosan and Carbopol.
• To evaluate the drug release profile of theophylline from an IPC-based tablet.

Main Methods:

• Precipitation method in acidic solution for IPC formation.
• Characterization using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and turbidity measurements.
• Preparation and in vitro drug release testing of theophylline tablets.

Main Results:

• FT-IR confirmed electrostatic interaction between chitosan's amine and Carbopol's carboxylate groups.
• DSC showed distinct thermal properties for the IPC compared to individual polymers.
• Turbidity measurements indicated a chitosan/Carbopol complexation ratio of 1/4.
• Theophylline tablets exhibited pH-independent release, comparable to HPMC tablets.
• Drug release mechanisms varied with pH: diffusional at pH 6.8 and relaxational at pH 1.2.

Conclusions:

• A chitosan-Carbopol interpolymer complex was successfully formed via electrostatic interactions.
• The IPC demonstrates suitable characteristics for use as a matrix in drug delivery systems.
• The pH-independent drug release profile suggests potential for consistent therapeutic outcomes.