Scopolamine, transdermal delivery

Nachum Z, Shahal B, Shupak A, et al. Scopolamine bioavailability in combined oral and transdermal delivery J Pharmacol Exp Ther. 2001 296 121-123. 

Such design criteria have been successfully utilized in commercially available membrane-reservoir type of transdermal delivery systems for scopolamine, nitroglycerin, and more recently, estradiol (40,41). 

Scopolamine was the first drug to be marketed as a transdermal delivery system (Transderm-Scop) to alleviate the discomfort of motion sickness. After oral administration, scopolamine has a short duration of action because of a high first-pass effect. In addition, several side-effects are associated with the peak plasma levels obtained. Transderm-Scop is a reservoir system that incorporates two types of release mechanims a rapid, short-term release of drag from the adhesive layer, superimposed on an essentially zero-order input profile metered by the microporous membrane separating the reservoir from the skin surface. The scopolamine patch is able to maintain plasma levels in the therapeutic window for extended periods of time, delivering 0.5 mg over 3 days with few of the side-effects associated with (for example) oral administration. 

Advances in transdermal delivery systems (TDSs) and the technology involved have been rapid because of the sophistication of polymer science, which now allows incorporation of polymeric additives in TDSs in adequate quantity. Drugs with which transdermal therapy was pioneered include scopolamine, nitroglycerine, iso-sorbide dinitrite, clonidine, estradiol, nicotine, and testosterone [74],... 

Scopolamine, a semisynthetic derivative of atropine, is marketed as a transdermal delivery system (Transderm Sc5p) to prevent motion sickness. The device, which is... 

Since the introduction of transdermal scopolamine,f" many transdermal delivery systems have been developed for systemic activity. Major advantages claimed for this drug delivery route include continuous release of drug over a specified period, low presystemic clearance, facile drug withdrawal by simply removing the device, and good patient convenience and compliance. 

As shown in Table 4, sophisticated adhesive patches for transdermal delivery of scopolamine (motion sickness), nitroglycerine (anginal symptoms), clonidine (regulation... 

The skin is biologically intended to be a barrier. Evading this barrier is not easy, because drugs must traverse dead epithelium and live dermis the former is hydrophobic, while lipophilic drugs tends to form a reservoir in the latter. As in oral transmucosal administration, potent drugs, with modest requirements for mass absorbed and reasonable lipophilicity, are the best candidates for transdermal delivery. Fentanyl, nicotine, and scopolamine are good examples. 

In contrast to hyoscyamine/atropine which shows central depressant as well as central excitatory properties, its congener scopolamine is only characterized by the former property. Thus, it is suitable as a prophylactic antiemetic applied by a certain patch before a surgery or a travel in order to avoid nausea. An advantage of such a so-called transdermal delivery system (TDS) is given in so far as a steady blood level for three days is produced which is high enough to act as an antiemetic but low enough to be free from severe side effects (Tolksdorf et al. 1985). 

Fig. 15 Schematic diagram of a transdermal device for the delivery of scopolamine.

Applied to the skin in a transdermal patch (transdermal therapeutic delivery system), this drug is used to prevent or reduce the occurrence of nausea and vomiting that are associated "with motion sickness. Diphenhydramine Chlorpromazine Ondansetron Dimenhydrinate Scopolamine... 

Scopolamine is available as a transdermal drug delivery system fisr prevention of motion sickness. When placed behind the ear the system delivers 0.5 mg of scopolamine for 3 days. Mydriasis and blurred vision can occur if scopolamine from the patch comes in contact with the eyes. 

Membrane permeation-controlled transdermal drug delivery (Fig. 5.2) has been successfully applied in therapeutic systems for scopolamine (prevention of motion sickness for a 3-day period), nitroglycerin (prophylaxis against attack of angina pectoris over a 24-h period), clonidine (control of hypertension for a 7-day period), and fentanyl (control of constant pain for 72 h). 

Transdermal drug delivery can be used in pediatric patients (1) to avoid problems of drug absorption from the oral route and complications from the intravenous route and (2) to maximize duration of effect and minimize adverse effects of drugs. Unfortunately, the commercially available transdermal dosage forms (e.g., clonidine and scopolamine) are not intended for pediatric patients these would deliver doses much higher than those needed for infants and children. 

Transdermal scopolamine is a muscarinic receptor antagonist used for the prevention of post-operative nausea and vomiting. It is supplied as a circular adhesive patch (0.2 mm thick and 2.5 cm ) applied to the post-auricular skin. Each patch contains 1.5 mg of the belladonna alkaloid programmed to continuously release in vivo approximately 1.0 mg over 72 hours. The patch consists of four distinctive layers. Going from visible surface to the surface adherent to the skin, these layers are (1) backing layer (2) drug reservoir of scopolamine (3) microporous polypropylene membrane that controls the rate of scopolamine delivery (4) adhesive contact surface with the skin. 

Transdermal scopolamine has current FDA indication only for the prevention of nausea and vomiting associated with motion sickness and recovery from anesthesia and surgery in adults. There is currently no FDA approval for use in the pediatric setting. A single 1.5 mg transdermal scopolamine patch should only be applied to the hairless area of the skin over-lying the mastoid process. Only one patch should be worn at any time. The patch should not be cut or altered in any way as this will disrupt the delivery process. 

Absolute transdermal scopolamine is absolutely contraindicated in patients with documented hypersensitivity to scopolamine or belladonna alkaloids. Hypersensitivity to the inactive components within the delivery system, which includes mineral oil and polyisobutylene, is also contraindicated. Patients with angle-closure (narrow-angle) glaucoma, myasthenia gravis, and intestinal bowel obstruction should not receive scopolamine. Patients scheduled for MRls should have the patch removed as the aluminized backing may cause burn injury. 

General transdermal scopolamine is only available as a 1.5 mg patch designed to deliver approximately 1.0 mg of scopolamine over a 72 hour period. The patch must not be ingested, cut, divided, or altered in any way as this will disrupt the delivery system. 

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