Challenge of transdermal patches

Mailen Agüero – Business Development Analyst
Francisco Stefano – Director


The skin is an accessible and convenient way to administer medications But it has certain limitations.

The administration of drugs through transdermal patches has advantages such as the controlled and constant administration of the active principle, it is a non-invasive method, easy to apply, and facilitates better patient compliance.

However, only a limited number of principles or combination is administered by this route and only half of them are currently on the market, (Scopolamine Nitroglycerin Estradiol, Norelgestromin/ethinylestradiol, Fentanyl Rivastigmine, Diclofenac Oxybutynin, Buprenorphine Rotigotine, Ropinirole Tulobuterol Donepecil Capsaicin Ibuprofen Asenapine Acetylestradiol and Pregnanedione)


The characteristics of the skin can initially explain the reduced amount of substances incorporated into the transdermal arsenal.


The intrinsic protective function of the skin imposes physicochemical limitations on the type of permeant that can cross the barrier. For a drug to be passively administered through the skin, it must have adequate lipophilicity, also a molecular weight less than 500Da(Daltons) is essential to ensure ease of diffusion through the stratum corneum since the diffusivity of the solute is inversely related to its size.


One way to predict individual skin penetration fluxes for candidate drugs to be used in patches is to define physicochemical limits within which all candidates in patch systems must fall. A candidate drug for transdermal patches should normally be moderately lipophilic (log P range 1 to 5), have a low molecular weight (MW < 500 Da) and a low melting point (MP < 250°C).

  However, most of the commercialized patches are above the lower limit of the Berner-Cooper variables of MW() = 500 (molecular weight), log P(Octanol-water partition coefficient) = 5 and MP (melting point of the highest peak) < 250 °C indication that dedicated pharmacotechnical work can increase permeation without producing undesirable effects.


Recent advances involve the use of other types of technology developed such as Nanoparticles (NP) and Microneedles that show great potential to improve the penetration of drugs through the skin.


Subscribe to

Partner with us!

We offer expertise and experience, together with flexibility and the ability to adapt to your needs.