Macromolecule controlled delivery

Machluf M, Regev O, Peled Y, et al. Characterization of microencapsulated liposome systems for the controlled delivery of liposome-associated macromolecules. / Control Release 1997 43 35 5. 

S. Jana, B. Laha, S. Maiti, Boswellia gum resin/chitosan polymer composites controlled delivery vehicles for aceclofenac. International Journal of Biological Macromolecules 77 (2015) 303-306. 

M. Thanou, S. Henderson, A. Kydonieus, and C. Elson, N-sulfonato-N, O-carboxy-methylchitosan A novel polymeric absorption enhancer for the oral delivery of macromolecules,/. Control. Release, 117 (2), 171-178,2007. 

Core-shell bicomponent nanofibers, where a core nanofiber of one polymer is sheathed by the shell of a different polymer, can have interesting applications in several areas. For instance these might be used in die controlled delivery of pharmaceuticals or biological macromolecules (as already... 

Lactide/glycoUde polymers have been investigated for delivery of several other macromolecules. Synthetic double-stranded RNA, poly-isosinic acid/polycytidylic acid, a potent inducer of interferon, was formulated in a 53 47 copolymer of DL-lactide-co-glycoUde. The microspheres were evaluated in mice challenged with Right Valley fever virus. More than 16 days protection was afforded versus only 3 days for controls (137). 

Noteable are recent studies on the generation of polymer particles as carriers for controlled drug release [333] and of cationic solid lipid micro-particles as synthetic carriers for the targeted delivery of macromolecules to phagocytic antigen-presenting cells [334]. The industrial interest, although rarely disclosed, is evident from the patents filed in the field (see, e.g., [335, 336]). 

Ethylene vinyl acetate has also found major applications in drug delivery. These copolymers used in drug release normally contain 30-50 wt% of vinyl acetate. They have been commercialized by the Alza Corporation for the delivery of pilocarpine over a one-week period (Ocusert) and the delivery of progesterone for over one year in the form of an intrauterine device (Progestasert). Ethylene vinyl acetate has also been evaluated for the release of macromolecules such as proteins. The release of proteins form these polymers is by a porous diffusion and the pore structure can be used to control the rate of release (3). Similar nonbiodegradable polymers such as the polyurethanes, polyethylenes, polytetrafluoroethylene and poly(methyl methacrylate) have also been used to deliver a variety of different pharmaceutical agents usually as implants or removal devices. 

J. Kopecek and R. Duncan, Poly(/V-(2-hydro-xypropyl)methacrylamide) macromolecules as drug carrier systems, in Polymers in Controlled Drug Delivery (L. Ilium and S. S. Davis, eds.), Wright, Bristol, 1987, p. 152. 

Polymers are macromolecules composed of specific repeating units. The properties of the polymer, such as viscosity of a solution, elasticity, and solid strength, are determined by the number of repeating units, or monomers, and ultimately the radius of the polymer. The properties of a polymer can be predicted based upon theoretical calculations (Flory 1953). The diversity and predictability of properties are the reason that polymers are so useful in controlled drug delivery. Careful choice of the polymer leads to dosage forms that can deliver an active agent with reproducibility and... 

Bernkop-Schnurch, A., C.E. Kast, and D. Guggi. 2003. Permeation enhancing polymers in oral delivery of hydrophilic macromolecules Thiomer/GSH systems. J Control Release 93 95. 

Conventional systems do not offer sufficient flexibility in controlling drug-release rate and sustaining the release over time periods extending from days to months. Therefore specific modified release vaginal delivery systems are continuously under development and are based on mucoadhesive systems. Penetration enhancement may represent a necessary feature for certain delivery systems, particularly when the absorption regards a macromolecule (such as a peptide or a protein). 

Bernkop-Schnurch A, Gockel NC (1997) Development and analysis of a polymer protecting from luminal enzymatic degradation caused by a-chymotrypsin. Drug Dev Ind Pharm 23 733-740 Bernkop-Schnurch A, Kast CE, Guggi D (2003) Permeation enhancing polymers in oral delivery of hydrophilic macromolecules thiomer / GSH systems. J Control Release. 2003 Dec 5 93(2) 95-103. 

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