Controlled drug delivery membrane

Strabing S, Metz H, Mader K. Mechanistic analysis of drug release from tablets with membrane controlled drug delivery. Eur J Pharm Biopharm 2007 66(1) 113-119. 

A membrane-controlled drug delivery device was developed to release tetracycline at zero-order rates. The tetracycline delivery vehicle Is a trllamlnate disk consisting of core and coating membranes fabricated from a series of 2-hydroxyethyl-methacrylate and methylmethacrylate copolymers. Appropriate adjustment of the monomer composition ratio Imparts a hydrophobic nature to the copolymer outer coating membrane (relative to the... 

In membrane diffusion systems the polymer membrane with a given pore size or pore size distribution controls the diffusion of the active substance from the drug reservoir. Dosage forms with membrane-controlled drug delivery can be coated tablets, coated granules or pellets, or so-called multiparticulate systems on which various coats are applied. One possibility for transdermal drug administration is the transdermal patch controlled with a membrane [4-7,34-39]. 

Figure 18.6 Schematic drawing illustrating drug release from membrane controlled drug delivery systems (membrane diffusion systems and osmeotic systems).

One of these types is the membrane-controlled transdermal therapeutic system, which is outlined in Figure 18.12. These systems consist of the following parts i) covering membrane, ii) drug reservoir, iii) micropore membrane controlling drug delivery, and iv) adhesive contact surface. (Further types of transdermal systems are going to be described in Chapter 16.2.4.3.3). The most commonly used membranes are polyethylene vinyl acetate and polyethylene [60-62]. 

K Tojo, Y Sun, M Ghannam, Y Chien. Characterization of a membrane permeation system for controlled drug delivery studies. AIChE J 31 741, 1985. 

Controlled drug delivery, membrane technology in, 15 847-848 Controlled drug release formulations (CDRFs), 9 51, 55 polymers in, 9 71-73 Controlled drug release systems, 9 50-51 design, 9 51-52 development, 9 55-57 intelligent, 9 56-57 in market, 9 83—85... 

Membrane separators, 23 795-796 Membrane/sonication/wet oxidation (MEMSONIWO) systems in wastewater treatment, 25 911-912 Membrane systems, as advanced wastewater treatment, 25 909 Membrane technology, 25 796-852 applications for, 25 824-848 in controlled drug delivery,... 

Diacyllipid-polyethyleneoxide conjugates have been introduced into the controlled drug delivery area as polymeric surface modiLers for liposomes (Klibanov et al., 1990). Being incorporated into the liposome membrane by insertion of their lipidic anchor into the bilayer, such molecules can ster-ically stabilize the liposome against interaction with certain plasma proteins in the blood that results in signiLcant prolongation of the vesicle circulation time. The diacyllipid-PEO molecule itself represents a characteristic amphiphilic polymer with a bulky hydrophilic (PEO) portion and a very short but extremely hydrophobic diacyllipid part. Typically, for other PEO-containing amphiphilic block... 

The use of synthetic polymers in medicine and biotechnology is a subject of wide interest. Polymers are used in replacement blood vessels, heart valves, blood pumps, dialysis membranes, intraocular lenses, tissue regeneration platforms, surgical sutures, and in a variety of targeted, controlled drug delivery devices. Poly(organosiloxanes) have been used for many years as inert prostheses and heart valves. Biomedical materials based on polyphosphazenes are being considered for nearly all the uses mentioned above. 

Six developed and a number of developing and yet-to-be-developed industrial membrane technologies are discussed in this book. In addition, sections are included describing the use of membranes in medical applications such as the artificial kidney, blood oxygenation, and controlled drug delivery devices. The status of all of these processes is summarized in Table 1.1. 

Medical applications of membranes Artificial kidneys Artificial lungs Controlled drug delivery Well-established processes. Still the focus of research to improve performance, for example, improving biocompatibility... 

Isotropic microporous membranes have much higher fluxes than isotropic dense membranes and are widely used as microfiltration membranes. Further significant uses are as inert spacers in battery and fuel cell applications and as the ratecontrolling element in controlled drug delivery devices. 

The majority of controlled drug delivery systems now being marketed or under development are based on diffusion of the drug through a semipermeable membrane to achieve the requisite release rate. Diffusion control is particularly important to transdermal delivery, where biodegradation and dissolution are not viable mechanisms of controlling the release rate. Provided the process is Fickian, the rate of diffusion through the semipermeable polymer is determined by... 

Giannos, S., Dinh, S., and Berner, B., Temporally controlled drug delivery systems Coupling of pH oscillators with membrane diffusion, Journal of Pharmaceutical Sciences, Vol. 84, No. 5, 1995, pp. 539-543. 

Those anaiytioai systems where liposomes are used as artificial cell membranes to study body distribution mechanisms as efficient drug-delivery systems, controlled drug delivery, the synthesis of new biomaterial for tissue engineering and gene therapy are worthy of special mention. 

Polymer membrane permeation-controlled drug delivery systems. 

Polymer Membrane Permeation-Controlled Drug Delivery Systems... 

Fig. 3 Release of drug from various shapes of pol5mer membrane permeation-controlled drug-delivery systems (A) sphere-type, (B) cylinder-type, and (C) sheet-type. In (D), the drug concentration gradients across the rate-controlling polymeric membrane and hydrodynamic diffusion layer exist in series. Both the polymer membrane, which is either porous or non-porous, and the diffusion layer have a controlled thickness and h, respectively).

Major polymer applications sizing agents, binders, protective colloids, photographic papers, toners, fihn, water-soluble laundry bags, seed tapes, sanitary pads, belts, printing rolls, controlled drug delivery, membranes... 

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