Enhanced design for microscale distribution of drug heads for transdermal patches. (April 2020)

• Record Type: Journal Article
• Authors: Joseph, Ajith; Narasimhan, Arunn
• Is Part Of: International journal of heat and mass transfer. Volume 151(2020)
• Publication Date: 2020-04
• Subjects: Transdermal drug delivery -- Numerical modeling -- Porous medium -- Drug delivery device design -- Mass transfer -- Diffusion; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2020.119397
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Human skin layers and capillaries are considered as composite porous medium involving convection and diffusion of fluids. Dynamic boundary conditions are employed to model skin layer growth. New design with optimally spaced multiple drug heads is proposed to enhance transdermal drug diffusion. This arrangement reduce skin irritation associated with conventional patches. An enhancement of 100% in diffusive flux from patch heads and a reduction of upto 50% in steady state approach time over the conventional patch were achieved by varying the effective area ratio. Depending upon the effective area ratio chosen, two superior drug head configurations suggested were found to increase the average flux of the design further by 5% to 40%. Abstract: In this study, we propose an enhanced design of transdermal drug patch that offers better pharmacological efficacy and patient compliance than conventional designs that necessitate the entire skin under the patch to be in direct contact with the drug. This new design involves several periodically repeating portions of patched and unpatched areas, which creates a series of high local flux regions around the boundary between these patched and unpatched areas because of increased lateral spread of drug. Using numerical simulations of governing mass transfer equations for blood flow through trans-dermal regions modelled as a porous medium, the proposed design was found to be 100% more effective than the conventional one in terms of average flux from the drug head. A reduction of up to 50%, in the time required to reach steady state was also observed with the new design. Depending upon the effective area ratio chosen, the two superior drug head configurations suggested were found to be able to increase the average flux of the design further by 5% to 40%. The findings of the study provide a new approach by which one can design and fabricate transdermal patches that can accurately deliver any required dose without the use of a rate limiting membrane.