Therapeutics
The evolution of Transdermal Drug Delivery and treating migraine illustration
The Evolution of Transdermal Drug Delivery and Treating Migraine

The Evolution of Transdermal Drug Delivery and Treating Migraine

By Dr Mahmoud Ameri and Hayley Lewis
Winter 2018/19

Oral drug delivery is the most common and convenient route of drug administration due to a high rate of patient compliance, cost-effectiveness, portability, ease of production and pre-determined dosage.

However, there are limitations with oral drug delivery, such as incomplete delivery due to the unpredictability of gastrointestinal absorption. Parenteral route of administration, such as injection, is another common drug delivery method. Advantages of parenteral drug delivery include rapid onset of action and circumvention of gastrointestinal degradation of the drug, but this method is invasive and sometimes painful. It also has a lower rate of patient compliance and requires a trained administrator.

Transdermal Drug Delivery (TDD) is a promising method for drug application that has major advantages over some of the most common routes of drug administration. TDD involves the noninvasive delivery of medications through the skin surface and when applied can deliver the drug at a predetermined rate across the skin to achieve either a local or systemic effect.

History of transdermal delivery development

Transdermal delivery of medications is not a new concept. The use of transdermal delivery of homemade medicinal preparations dates to the early 20th century. Mustard plasters were used for severe chest congestion. The Belladonna Plaster, containing 0.25% of Belladonna alkaloid, had a place in the US pharmacopeia as a transdermal analgesic. Perhaps the most remarkable forerunner of modern transdermal medication was Stronger Mercurial Ointment, used as a treatment for syphilis when Salvarsan and other arsenicals were in use, before the discovery of penicillin. Even the composition of this ointment was remarkable; it contained 50% of elemental mercury!

First-generation TDD

TDD offers advantages over conventional parenteral or oral routes. They ensure controlled absorption and more uniform plasma drug concentrations. Bioavailability is improved by avoiding first-pass hepatic metabolism and enzymatic or pH-associated deactivation.

The first generation of TDD is responsible for most of the transdermal patches that have thus far been in clinical use. More than 30 years ago the nicotine patch revolutionised smoking cessation by continuously suppressing the smoker’s craving for a cigarette...

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