Development and evaluation of nefopam transdermal matrix patch system in human volunteers

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Materials Science

Background:

• Nefopam hydrochloride is an effective analgesic for acute and chronic pain, but requires frequent administration.
• Existing administration routes can lead to fluctuating plasma levels and potential dependence issues.
• A need exists for sustained drug delivery to improve patient compliance and therapeutic outcomes.

Purpose of the Study:

• To develop and characterize a novel transdermal drug delivery system (TDDS) for nefopam hydrochloride.
• To investigate the influence of hydrophilic (polyvinyl pyrrolidone - PVP) and lipophilic (ethyl cellulose - EC) polymers on drug release and skin permeation.
• To evaluate the in vivo performance of the optimized transdermal patch in human volunteers.

Main Methods:

• Fabrication of transdermal patches using various combinations of PVP and EC.
• Physical characterization including weight variation, moisture content, and morphology (SEM).
• In vitro drug release and skin permeation studies using cadaver skin and Keshary-Chein diffusion cells.
• Fourier transform infrared spectroscopy (FTIR) for drug-excipient interaction analysis.
• In vivo pharmacokinetic evaluation in human volunteers.

Main Results:

• Drug-excipient interactions, particularly between nefopam and PVP, suggested a controlled release mechanism.
• Scanning electron microscopy confirmed uniform drug dispersion within the polymeric matrix.
• Increased PVP concentration enhanced in vitro drug release.
• The PVP:EC (1:3) formulation exhibited the slowest release and highest sustained skin permeation in vitro.
• In vivo application of PVP:EC (1:3) patches resulted in systemic drug availability for up to 48 hours.

Conclusions:

• A novel transdermal system for nefopam hydrochloride was successfully developed using PVP and EC.
• The PVP:EC (1:3) formulation demonstrated optimal characteristics for sustained release and prolonged systemic availability.
• This transdermal approach offers a promising alternative for managing severe pain and potentially reducing dependence issues associated with traditional nefopam administration.