Design of a slow-release capsule using laser drilling

Area of Science:

• Pharmaceutical Sciences
• Materials Science

Background:

• Conventional hard gelatin capsules lack gastrointestinal (GI) tract resistance.
• Developing controlled-release drug delivery systems is crucial for therapeutic efficacy.

Purpose of the Study:

• To develop GI-tract resistant hard gelatin capsules using formalin vapor treatment.
• To investigate the controlled release of tetracycline hydrochloride from modified capsules.

Main Methods:

• Hard gelatin capsules were treated with formalin vapor to enhance GI resistance.
• In vitro GI resistance was tested using simulated gastric and intestinal fluids.
• In vivo X-ray studies in human volunteers confirmed capsule resistance.
• A carbon dioxide gas laser created micro-pores for controlled drug release.
• In vitro dissolution studies evaluated tetracycline hydrochloride release kinetics.

Main Results:

• Formalin treatment rendered capsules resistant to GI fluids.
• Residual formalin decreased over storage time.
• Laser-drilled pores facilitated slow tetracycline hydrochloride passage in acidic conditions.
• Drug release followed zero-order kinetics after a 30-minute lag phase.

Conclusions:

• Formalin vapor treatment is effective in creating GI-tract resistant gelatin capsules.
• Laser-drilled pores allow for predictable, zero-order drug release kinetics.
• These modified capsules show promise for controlled oral drug delivery systems.