Transdermal delivery devices

Other pressure-sensitive adhesives used in transdermal delivery device include those shown in Table 8.f f. 

A two-chamber diffusion cell has fluid on both sides of the skin and is used to apply a large (infinite) dose of test compound to one side of skin that will eventually result in a maximum, steady-state rate of absorption through skin. This information can be useful when infinite doses are applied to skin, such as in a transdermal delivery device. 

In 1992 the 3 M disclosed blends that comprised 100 parts VLDPE [Flexomer or Attane 80-95 mol% ethylene and 5 mol% C4 g comonomer(s)] and 15-600 parts m-LLDPE [DOWLEX ethylene copolymer with 2-8 mol% Cg]. The blends showed excellent processability. Formed into 10-300 pm thick films, they were used for transdermal drug delivery devices as single-layer backings. The films were clear, colorless, transparent to visible light, and sealable at relatively low temperature. They were permeable to O2, stable to various common components of transdermal delivery devices, strong, and comfortable and did not absorb significant amounts of common elements of transdermal carriers (Godbey and Martin 1993, 1994). 

Methods and devices for transdermal delivery of lithium (US6,375,990 Bl) Methods to estimate serotonin and norepinephrine transporter occupancy after drug treatment using patient or animal serum (provisional filing April 2001)... 

Govil SK. Transdermal drug delivery devices. In Tyle P, ed. Drug Delivery Devices. Fundamentals and Applications. New York Marcel Dekker, 1988 386 19. 

U. S. Patent 5,698,217 Wilking, S. L. Transdermal Drug Delivery Device Containing a Dessicant. December 16,1997. 

Approved packaging is normally selected after completing package performance qualification testing as well as product compatibility and stability studies. Since in most cases (exceptions transdermal delivery systems, diagnostic tests, and medical devices) packaging is not intimately involved in the manufacturing process of the product itself, it differs from other factors, such as raw materials. 

Barry, B.W. 2001. Novel mechanisms and devices to enable successful transdermal delivery. Eur J Pharm Sci 14 101. 

Banga, A.K., and Y.W. Chien. 1993. Hydrogel-based iontotherapeutic delivery devices for transdermal delivery of peptides/protein drugs. Pharm Res 10 697. 

Transdermal delivery is a noninvasive intravenous infusion of drug to maintain efficacious drug levels in the body for predictable and extended duration of activity. Diffusion-controlled transdermal systems are designed to deliver the therapeutic agent at a controlled rate from the device to and through the skin into the systemic circulation. This route of administration avoids unwanted presystemic metabolism (first-pass effect) in the GI tract and the liver. Patient satisfaction has been realized through decreased... 

Membrane-reservoir systems based on solution-diffusion mechanism have been utilized in different forms for the controlled delivery of therapeutic agents. These systems including membrane devices, microcapsules, liposomes, and hollow fibres have been applied to a number of areas ranging from birth control, transdermal delivery, to cancer therapy. Various polymeric materials including silicone rubber, ethylene vinylacetate copolymers, polyurethanes, and hydrogels have been employed in the fabrication of such membrane-reservoir systems (13). 

Figure 3 Transdermal delivery rate (mean S.D.) of PG across hairless mouse skin In vitro from device (a) (PG alone).

Chien, Y. W., Lelawongs, P., Siddiqui, O., and Shi, W. M. Facilitated transdermal delivery of therapeutic peptides and proteins by iontophoretic delivery devices. J. Contr. Release 13 263, 1990. 

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. 

There are several variants to this apparatus, which is based on a sample holder that oscillates up and down in the medium vessel. The sample holder may take the form of a disk, cylinder, or a spring on the end of a stainless steel or acrylic rod, or it may simply be the rod alone. The sample is attached to the outside of the sample holder either by virtue of being self-adhesive (e.g., transdermal delivery system) or is glued in place using a suitable adhesive. This apparatus may be used for transdermal products, coated drug delivery systems, or other suitable products (e.g., osmotic pump devices). It is prescribed for the drug-release testing of Psuedoephedrine hydrochloride extended-release tablets USP where the tablets are enclosed in a 5x5 cm of nylon, which is then attached to the rod. 

The skin offers an even less naturally permeable boundary to macromolecules than the gastrointestinal tract. Thus, passive transdermal delivery of proteins and peptides using patch technology has not succeeded. Peptides and proteins can be shot through the skin into the body using high-pressure needle-less injection devices. The devices, which inject proteins like insulin, have been available for years, however they have failed to impress doctors or patients due to the associated discomfort and the potential for splash back to transmit blood-borne diseases such as AIDS or hepatitis. 

---