Begell House Inc.
Critical Reviews™ in Therapeutic Drug Carrier Systems
CRT
0743-4863
17
6
2000
Site-Specific Drug Delivery in the Gastrointestinal Tract
64
10.1615/CritRevTherDrugCarrierSyst.v17.i6.10
Ian R.
Wilding
Pharmaceutical Profiles Ltd., Ruddington Fields, Ruddington, Nottingham, UK, NG11 6JS
In recent years there has been a significant increase in available strategies for site-specific delivery in the gastrointestinal tract both to maximize a therapeutic response and to reduce side effects. However, in only a few instances has there been close attention paid to how these products will perform in the heterogeneous environment of the human gut. Targeted oral delivery requires a multidisciplinary approach to research, involving contributions not only from polymer and pharmaceutical scientists but also from experts in gastroenterology and product evaluation. The objective of this article is, therefore, to examine our current understanding of human gastrointestinal physiology and to review the current "state of the art" of available targeting strategies. Emphasis will be placed on human data and, in particular, the interaction between the delivery system and the gastrointestinal tract, as assessed by product visualization studies.
Enhancement of Transdermal Drug Delivery: Chemical and Physical Approaches
38
10.1615/CritRevTherDrugCarrierSyst.v17.i6.20
Charles S.
Asbill
McWharter School of Pharmacy, 800 Lakeshore Dr., Birmingham AL 35229
Ayman F.
El-Kattan
University of South Carolina, Basic Pharmaceutical Sciences, 700 Sumter St., Columbia, SC 29208
Bozena
Michniak
Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey, Lab for Drug Delivery, Newark, New Jersey; University of South Carolina, Basic Pharmaceutical Sciences, 700 Sumter St., Columbia, SC 29208, USA
Transdermal drug delivery has been intensively studied over the last two decades because of the many advantages offered by this route of administration. However, the number of drugs used in transdermal drug delivery systems has been somewhat limited, in part resulting from the formidable barrier to drug permeation presented by the upper layer of the skin, the stratum corneum. In order to overcome this, different strategies have been implemented to render the skin more permeable to drugs. These strategies include both chemical and physical approaches. In this review, we outline the enhancing activities and mechanisms of action of some of the more extensively studied chemical penetration enhancers (oxazolidinones, propylene glycol, and epidermal enzymes). In addition, we discuss novel physical strategies, such as the use of microneedles or electroporation.