EMAC 276 Brian Cheung, Connie Chien, Corinne Nelson, Michelle Song, Xiaoxin (Shawn) Zhu

First approved in day patch for motion sickness in astronauts Became popular in 1990s with nicotine patch Currently used for birth control, glucose monitoring, local anesthesia, etc

- only a couple hundred Daltons - heavily favor lipids and require doses of milligrams per day or less - hard for hydrophilic drugs to pass through

Matrix-formers Permeation enhancers Rate-controlling membrane Pressure-sensitive adhesives (PSAs) Backing laminate Release liner

1.Biocompatible 2.Highly dependent on the solubility of drug 3.Easy control of composition and thickness

Ethylene-Vinyl Acetate (EVA) Permeability can be altered by adjusting vinyl-acetate content VA group leads to better solubility and diffusivity of polar groups Cost of Material: $ per kilogram

Silicone Rubber: Good Biocompatibility, ease of fabrication Free rotation around silicone rubber backbone induce high permeability Cost of Material: $ per kilogram ticle.pdf ticle.pdf

Polyurethanes: Condensation of polyisocyanates and polyols PU is suitable for hydrophilic polar compounds Cost of Material: $ per kilogram

Natural polymers can potentially reduce the skin irritation or allergic reactions induced by synthetic polymers Formed by deacetylation of chitin Thacharodi, D., and K. P. Rao. "Development and in Vitro Evaluation of Chitosan-based Transdermal Drug Delivery Systems for the Controlled Delivery of Propranolol Hydrochloride." Biomaterials 16 (1995): Web. 8 Apr

1. Adhere easily 2. Permanently tacky 3. Does not cause instability of the a. drug b. enhancer, and c. adhesive 4. Does not leave residue when peeled off

Polyisobutylene: Mix of low and high molecular weights Fillers are used for reinforcement, reducing viscosity and cost Cost of Material: $1-100 per kilogram ticle.pdf ticle.pdf

Polyacrylates: Amorphous and water-clear color in solution Stability toward aging Great resistance to acidic and alkaline hydrolysis and UV degradation Cost of Material: $ per kilogram 600/article.pdf 600/article.pdf

Silicones: Stable adhesive in throughout a wide range of temperature (-73 to 250C) Outstanding combination of bicompatibility and ease of fabrication for hydrophilic drugs Poor solubility, permeability and releasing property Cost of Material: $ per kilogram rticle.pdf rticle.pdf

Layer of protective material Chemical Resistance is the most important factor It keeps the medication from seeping out of the patch Good chemical resistance: Low modulus High flexibility Good oxygen transmission High moisture vapor transmission rate

Relatively Inert Increase hydration of the skin Make sure that any polymers used do not irritate the skin

Polyethylene Vinyl Polyester

Protects the skin contacting adhesive It is removed immediately before being placed on the skin More a part of the packaging material than the actual patch itself Made of Polyethylene or PVC and Silicone or Teflon Cross linking may occur Increase force to remove liner from patch

Silicone Teflon PVC

Only small-sized molecules delivery (very thick stratum corneum) Difficult balancing the degree of damage and penetration

Electroporation Cavitational ultrasound Thermal ablation Microdermabrasion Biochemical enhancer Chemical enhancer combination Microneedles

SLS + phenyl piperazine +

S. H. Bariya, M. C. Gohel, T. A. Mehta, and O. P. Sharma, "Microneedles: An Emerging Transdermal Drug Delivery System," Journal of Pharmacy and Pharmacology, 64(1), (2012).

Questions?