Transdennal patches

Apparatus. The nature of die dosage fonn will detennine die type of dissolution apparatus that will be used for mediod development and validation. The following questions must be asked when selecting die dissolution apparatus. Is it a capsule Will a sinker be required How stable is die drug substance after dissolution in the medium Is die formulation an immediate release or an extended release formulation Is diis a transdennal patch ... 

Apply transdennal patches to clean, dry, nonhairy areas of intact skin. 

Rotate sites for transdennal patches to prevent skin irritation. The chest, flank, and upper ann are die most commonly used sites. Do not shave die area to apply die patch sliaving may cause skin irritation. 

Observe for at least 4-6 hours to mle out delayed toxicity, especially after skin exposure. For Ingestion of intact gum tablets or transdennal patches, observe for a longer period (up to 12-24 hours). 

Dru may be applied to the skin and mucous membranes using several routes topically (on die outer layers of skin), transdennally tiirough a patch on which die drug has been implanted, or inhaled tiirough the membranes of the upper respiratory tract. 

Fentanyl transdennal is a transdermal system tliat is effective in the management of the severe pain associated witli cancer. The transdermal system allows for a timed-release patch containing the drug fentanyl to be activated over a 72-hour period. A small number of patients may require systems a )plied every 48 hours. The nurse monitors for adverse effects in tlie same manner as for other narcotic analgesics (, tlie nurse notifies the primary health care provider if tlie respiratory rate is 10/min or less). 

FIGURE 7.14 Kinetics of drug transfer through the skin using a patch (transdennal system) for various values of the diffusivity in the polymeric device. 1 D = 4.4 10- 2 D =... 

If it is true that, more often, it is desirable to have rubber with a great resistance to liquids, sometimes it is preferable to have rubber able to control the transport of the diffusing substance. This is the case with a transdennal system (patch) for drug delivery. 

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