Transdermal drug-delivery systems

Hydrophobic device for controlled transdermal release of diclofenac sodium was designed from in situ nanosilica/acrylic acid grafted guar gum membranes [64]. Nanocomposite/drug conjugates were formed by bringing down the medium pH from 9.0 to 7.0. The graft-copolymer nanocomposites provided excellent control 

Recently, Bhunia et al. prepared a transdermal device from 2-hydroxyethyl methacrylate grafted carnboxymethyl guar gum-functionalized multi-walled carbon nanotube (MWCNT) in situ composite membranes for sustained delivery of diclofenac sodium [65]. Pol5mier matrix-MWCNT interaction at 0.5 and 1 wt% MWCNT concentrations induces excellent copolymer-adsorbed fibrillar orientation of MWCNT compared to that at 2 and 3 wt%. 

It successively leads to efficient encapsulation and more sustained release of the drug molecules. Results showed that the releases are dominated by the viscoelastic relaxation behavior of the devices. Conversely, for the latter, the releases are comparatively less sustained and more swelling controlled. However, all devices have significantly increased the half life period of the drug molecules. 

Hritcu, I. M. Popa, Cell Chem. TechnoL, 45 (2011] 171-176. 

Goldstein, E. N. Alter, J. K. Seaman, Guar gum, in R. L. Whistler [ed.]. Industrial Gums, Polysaccharides and Their Derivatives, Academic Press, New York, 1973, pp. 303-321. 

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Solution SHS-GC-FID was used for the determination of dichloromethane (DCM) in PC [222] and solid SHS-GD for the analysis of residual solvents in transdermal drug-delivery systems [223] and rest... 

Transdermal Drug Delivery Systems. PHA 5110 Pharmaceutics II, University of Florida, College of Pharmacy, Department of Pharmaceutics, http //www.cop.ufl.edu/safezone/prokai/pha5110/tdds.htm... 

R. Lipp, H. Laurent, C. Gunther, J. Riedl, P. Esperling, U. Tauber, Prodrugs of Gesto-dene for Matrix-Type Transdermal Drug Delivery Systems , Pharm. Res. 1998,15, 1419 -1424. 

Murphy M, Carmichael AJ. Transdermal drug delivery systems and skin sensitivity reactions. Incidence and management. Am J Clin Dermatol. 2000 1 361-368. 

Good, W. Transdermal drug delivery systems. Medical Device Diagnostic Industry. 2 35-42, 1986. 

Transdermal Drug Delivery System with Enhanced Skin Permeability... 

This new type of transdermal drug delivery system is capable of releasing one or a combination of two or more skin permeation enhancers to the stratum corneum surface in order to modify the skin s barrier properties (10), prior to the controlled delivery... 

By delivering skin permeation enhancer from the adhesive polymer, which coats the drug-releasing surface of the transdermal drug delivery system, the skin permeability of drugs can be substantially enhanced. The extent of enhancement appears to be dependent upon the chemical structure of drug to be delivered transdermally and the type and concentration of enhancer used. 

Figure 8.5 Linear relationships between the steady-state plasma concentrations achieved and the active surface areas of the transdermal drug delivery systems applied (Modified from MacGregor et al Clin. Pharmacol. Ther. 38(1978) 278 Good W.R. etal., Drug Dev. Ind. Pharm. 9 (1983) 647-670 McLeskey, C, etal. American Society of Anesthesiology Annual Meeting, 1989)...

This section focuses on adhesives that are used for the assembly of medical devices. In medical device assembly, the primary substrates are plastics, elastomers, and metals. The total medical adhesive market is much larger since it encompasses a broader definition of products. For example, medical adhesives can be used for bonding human tissue, transdermal drug delivery systems, dental restoration, and wound care in addition to medical device assembly. 

Sugibayashi, K., and Morimoto, Y. (1994), Polymers for transdermal drug delivery systems, I. Controlled Release, 29,177-185. 

Scopolamine is available as a transdermal drug delivery system fisr prevention of motion sickness. When placed behind the ear the system delivers 0.5 mg of scopolamine for 3 days. Mydriasis and blurred vision can occur if scopolamine from the patch comes in contact with the eyes. 

Al-Qahtani [45] developed a simple and sensitive HPLC method of analysis of lornoxicam diffused from transdermal drug delivery system through rabbit skin [32], using Schimadzu HPLC system. The mobile phase consists of 60% of aqueous phosphate buffer and 40% methanol and the pH adjusted to 7.0 by addition of few drops of sodium hydroxide. 

Because of the large surface area of the skin and its bypass of the liver as a first pass step in metabolism, many drug delivery systems have been developed that control the rate of drug delivery to the skin for subsequent absorption. Effective transdermal drug delivery systems of this type deliver uniform quantities of drug to the skin over a period of time. Technically, transdermal drug delivery systems may be classified into monolithic and membrane-controlled systems (9). 

Hadgraft J, Lane ME. Passive transdermal drug delivery systems recent considerations and advances. Am. J. Drug DeUv. 2006 4 153-160. 

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