الفهرس 
Title : A pharmaceutical study on certain vesicular carriers for transdermal delivery of a certain anti-hypertensive drug
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Abstract
The first-pass effect (known as first-pass metabolism or presystemic metabolism) is a phenomenon in which the orally administered drug is metabolized in either the liver or the gastrointestinal tract before it reaches the systemic circulation resulting in a reduced bioavailability which in turn affects the drug therapeutic efficacy (George,C.1979). Felodipine is a dihydropyridines calcium channel blocker which is used in the treatment of hypertension and angina pectoris. It is almost completely absorbed from the gastrointestinal tract after oral administration but undergoes extensive first-pass metabolism, with a bioavailability of about 15% (range 10 to 25%); so, transdermal drug delivery could be suitable for felodipine as noninvasive pathway to enhance the bioavailability. Transdermal route for drug administration manifests definite advantages in the context of being user friendly and noninvasive, but its utilization has been hampered by naturally occurring protective barrier properties of the skin, especially the stratum corneum. Hence, the major emphasis of research related to transdermal delivery of felodipine has focused on overcoming the permeation difficulties utilizing different approaches