Drug Delivery
Triptans for migraine relief. Triptans are a class of
medications that are selective serotonin receptor agonists, meaning they work by
stimulating serotonin (5-HT), a neurotransmitter (NT) found
in the brain. Triptans are often used in treating migraine because they reduce
inflammation, constrict blood vessels and block pain pathways in the brain
non-injectable sustained-release opioid pain-man- agement solution that lasts three days per applica- tion. The Exelon® patch, a rivastigmine patch introduced in 2007, embodies an innovative treat- ment route for dementia patients and their care givers. It affords a visible reminder to both patients and their caregivers that they have taken the medicine. The Exelon patch has a superior safety profile. eg less nausea and vomiting and a convenient once-a-day dosing interval, compared with the capsule and oral solution. Its precipitous success exemplifies how development of a trans- dermal patch can be a sound approach for product lifecycle management.
Second-generation TDD The second generation of TDD recognises that skin permeability enhancement is required to expand the scope of transdermal drugs. All of the products that have been commercialised have been devoted to iontophoresis, which is a method of transferring substances across the skin by applying an electrical potential difference. The LidoSite™ Topical System, an iontophoretic patch with a portable electronic controller and energy source, delivers lidocaine and epinephrine simultaneously
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to attain dermal analgesia on intact skin. Imparting dermal analgesia prior to venipunctures takes 10 minutes, much faster than a topical anaesthetic such as EMLA (eutectic mixture of lidocaine and prilocaine) topical cream, which may take up to one hour. In spite of its medical benefit, eg faster onset of action, the treatment cost compared with a conventional topical cream limited its commercial success. Vyteris decided to remove Lidosite from the market in 2008 after only two years on the market. SYNERA®, a topi- cal anaesthetic patch with a controlled heating pod, delivers lidocaine and tetracaine to numb intact skin in 20 minutes, prior to minor needle procedures for pediatric patients. Although both of these products illustrate how technological advances in TDDs could foster therapeutic advan- tages, they also make the case that TDDs need to proactively address the total value proposition to the patients and payers while providing a strong, compelling medical benefit. IONSYS™, an iontophoretic transdermal patch
for on-demand, self-activating delivery of fen- tanyl, permits patients to have control of their own pain management. In 2006, both the US FDA and the European Medicines Agency approved
Drug Discovery World Winter 2018/19
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