Τόμος 3 (1985) – Τεύχος 4 – Άρθρο 1 – Επιθεώρηση Κλινικής Φαρμακολογίας και Φαρμακοκινητικής-Ελληνική Έκδοση – Volume 3 (1985) – Issue 4 – Article 1 – Epitheorese Klinikes Farmakologias και Farmakokinetikes-Greek Edition

Transdermal Therapeutic Systems in Principle and Practice

CHARALAMBOS T. PLESSAS AND STAVROS T. PLESSAS

^{Τμήμα Επιστημονικής Πληροφόρησης}

3: 163-173 (1985)

PHARMAKON-Press: Epitheorese Klin. Farmakol. Farmakokinet.

3: 163-173 (1985)

Transdermal Therapeutic Systems

The last decade a variety of new therapeutic systems are available for rate-controlled drug dosing. These systems permit the isonaemic testing of drug effects, i.e. with plasma concentrations maintained at a con­stant levels and overcome the problems of undesirable peaks and troughs done with ordi­nary bolus dosage forms. Recently, rate-control is been incorporated into oral, transdermal and various locally acting pharmaceuticals for use, in routine outpatient therapy, and some syste­mically acting, rate-controlled products are now available for clinical use: a matrix form of oral theophylline, that has made that drug safer to use than previously; a trans-dermal glyceryl trinitrate product that avoids the intensive me­tabolism of the drug in the gut wall during absorption or in the liver (first-pass effect); and a transdermal scopolamine product that pre­vents motion sickness without its objectionable parasympatholytic actions. Other available pro­ducts for local use include an ocular insert that delivers pilocarpine at a low steady rate for 1 weak after each administration and an intrau­terine device which continually delivers proge­sterone. For the transdermal delivery systems presently available, the controlled-release rate may be achieved in 2 ways: (a) by use of a micrοpοrοus polymeric membrane acting as barrier to govern diffusion from the drug reser­voir to the skin or (b) by dissolving the drug in a silicone polymer matrix which limits the diffu­sion rate. The absorption rate from these sys­tems appears to be zero-order; it is similar to a slow intravenous infusion. The potential advan­tages of controlled transdermal delivery of gly­ceryl trinitrate over ointments and sublingual tablets are: (1) sustained therapeutic activity, (2) decreased side effects by the avoidance of high initial concentrations and (3) the ability to stop therapy rapidly by removal of the skin patch if intolerable side effects develop. The development of a controlled-release transder­mal preparation allows scopolamine to be absorbed slowly, avoiding high peak concentra­tions and minimising anticholinergic side ef­fects. The transdermal therapeutic systems ap­pear to improve the selectivity and duration of action of many drugs, including clonidine and oestradiol, enhancing their efficacy, safety and convenience.

1. Jaminet, Fr.: Pharmacie galénique moderne et formes pharmaceutiques nouvelles. J. Belg. 35: 200 (1980)
2. Ηeilmann Κ.: Therapeutic Systems. Pattern-Specific Drug Delivery: Concept and Development. Georg Thieme Publ., Stuttgart, 1978
3. Johnson, J.C.: Sustained Release Medications. Noyes Data Corporation. Park Ridge, New Jersey, USA, 1980
4. Kydonieus, Agis, F.: Controlled Release Technologies: Methods, Theory and Application. CRC Press Inc., Boca Raton, Florida, 1980
5. Puisieux, F., Poly, Ρ.A., Salir-Dronin, D.: Les liposomes, formes pharmaceutiques du futur. Labo-Pharma Probl. Techn. 30. 133 (1982)