Bioavailability transdermal delivery

Andersson TL, Stehle B, Davidsson B, Hoglund P. Bioavailability of estradiol from two matrix transdermal delivery systems Menorest and Climara. Maturitas 2000 34(l) 57-64. 

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

Figure 8.6 Plasma concentration versus time profiles obtained following administration of different transdermal nitroglycerin systems for 24 hours (Modified from Transdermal Delivery Systems A Medical Rationale. Cleary, G.W. In Topical Drug Bioavailability, Bioequivalence, and Penetration. Shah, V.P. and Maibach, H.I. Eds. Plenum Press, New York, 1993, pp 17-68)...

Sarphie, D.F. Johnson, B. Cormier, M. Burkoth, T.L. Bellhouse, B.J. Bioavailability following transdermal powdered delivery (TPD) of radiolabeled insulin to hairless guinea pigs. J. Controlled Release 1997, 47, 61-69. Sarphie, D.F. Varadi, A. Bellhouse, B.J. Ashcroft, S. Transdermal delivery of powdered bovine insulin to diabetic and non-diabetic wistar rats. Diabetes 1995, 44 (Suppl. 1), 129a... 

When the transdermal penetration of a drug is inadequate to achieve and maintain a plasma concentration above the minimum therapeutic concentration required to produce the desired effect, a lipophilic prodrug that will be metabolized in the epidermis to the active drug could be used in the development of a controlled-release transdermal delivery system. This approach has been applied to estradiol esters (diacetate and valerate) which are rapidly converted by esterases in the skin tissue to estradiol (Chien et al, 1985). The prodrug serves to increase the transdermal bioavailability of the active drug to which it is converted by metabolism (generally ester hydrolysis) during the percutaneous absorption process. 

Cleary, G. W. 1993a. Transdermal delivery systems A medical rationale. In Topical drug bioavailability, bioequivalence, and penetration, edited by V. P. Shah, and H. I. Maibach. New York Plenum Press, pp. 17-68. 

Insulin to increase its iontophoretic mobility and bioavailability as part of a transdermal delivery system by acylation with succinic anhydride, or to improve its enzymatic stability by acylation with certain fatty acid anhydrides... 

Nicardipine, used in the treatment of hypertension, has proved to be an excellent candidate for transdermal delivery as its bioavailability is only 20-33% due the first pass effect in the liver and the short half life requires frequent dosing resulting in poor patient concordance. The effect of menthol on the transdermal delivery of nicardipine hydrochloride from a hydroxypropyl cellulose gel formidation was investigated. The ideal penetration enhancer should be pharmacologically inactive, non-irritant and non-damaging to the skin, potent and cosmetically acceptable. DSC results showed increased penetration of nicardipine hydrochloride due to the ability of mentiiol to partially extract the lipids firom the stratum comeum [19]. Extraction of lipids... 

Oil-in-water microemulsion has been widely studied and used for transdermal delivery of the drugs. Apart from its advantages as topical formulation, oil-in-water emulsion also offers numerous advantages such as bioavailability enhancement via transdermal, oral, ocular, and vaginal routes. 

Hathout RM and Elshafeey AH. (2012). Development and characterization of colloidal soft nanocarriers for transdermal delivery and bioavailability enhancement of an angiotensin II receptor blocker. European Journal of Pharmaceutical Science, 82, 230-240. 

A.S. Chauhan, S. Sridevi, K.B. Chalasani, Dendrimer-mediated transdermal delivery enhanced bioavailability of indomethacin, J. Control. Release 90 (2003) 335-343. 

Transdermal patch technology represents an important area of biomaterials, due to its non-invasive character, ease to use, and a relatively high bioavailability. Generally, these patches could deliver drugs from one to seven days. Currently, 11 drugs, or drugs combinations are delivery through body via this method [195],... 

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