pH-Controlled Drug Release by Diffusion through Silica Nanochannel Membranes

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Controlled drug release systems are crucial for effective therapeutic outcomes.
• Existing systems often face challenges with precise control over release kinetics and long-term stability.
• Nanotechnology offers novel platforms for developing advanced drug delivery vehicles.

Purpose of the Study:

• To fabricate a flow-through silica nanochannel membrane (SNM) for controlled drug release.
• To engineer pH-responsive properties into the SNM for tunable drug release kinetics.
• To evaluate the performance of the SNM using a model intestinal drug.

Main Methods:

• Fabrication of an ultrathin SNM with uniform nanochannels (∼2.3 nm diameter).
• Support of the SNM on a modified polyethylene terephthalate film for mechanical stability.
• Grafting of alkylamines onto the SNM surface to enable pH-responsive gating.
• Testing drug release kinetics of thiamphenicol glycinate hydrochloride (TPG) in simulated gastric and intestinal fluids.

Main Results:

• The SNM exhibited high permeability and size selectivity for small molecules.
• pH modulation of the SNM surface effectively controlled nanochannel gating.
• TPG release was 178 times faster in simulated intestinal fluid (pH 7.5) compared to gastric fluid (pH 1.2).
• Sustained, nearly zero-order release of TPG was achieved for up to 24 hours.

Conclusions:

• The developed pH-responsive SNM is a promising platform for controlled and sustained release of small-molecule drugs.
• The system demonstrates feasibility for long-term, continuous drug delivery applications.
• The tunable release mechanism offers potential for personalized medicine and improved therapeutic efficacy.