GLYCOLIC ACID COPOLYMER

A., and Hower, J. F., Sustained delivery of narcotic antagonists from lactic.glycolic acid copolymer implants, in Polymeric Delivery Systems (R. J. Kostelnik, ed.), Gordon and Breach, New York, 1978, Chap. 4. 

As pointed out by Heller (2), polymer erosion can be controlled by the following three types of mechanisms (1) water-soluble polymers insolubilized by hydrolytically unstable cross-links (2) water-insoluble polymers solubilized by hydrolysis, ionization, or protonation of pendant groups (3) hydrophobic polymers solubilized by backbone cleavage to small water soluble molecules. These mechanisms represent extreme cases the actual erosion may occur by a combination of mechanisms. In addition to poly (lactic acid), poly (glycolic acid), and lactic/glycolic acid copolymers, other commonly used bioerodible/biodegradable polymers include polyorthoesters, polycaprolactone, polyaminoacids, polyanhydrides, and half esters of methyl vinyl ether-maleic anhydride copolymers (3). 

Beer SJ, Mattlrews CB, Stem CS, Ross BD, HUfirrger JM, Davidsorr BL (1998) Poly (lacdc-glycolic) acid copolymer errcapsuladorr of recombirrarrt aderrovirus reduces immurrogerricity irr vivo. Gerre Ther 5 740-746. 

Lactic glycolic acid copolymers Lupron Depot (TAP)... 

D,L-Lactic and glycolic acid copolymer Zoladex (Zeneca)... 

Leuprolide acetate IM (microsphere suspension) After reconstitution 0.13% Gelatin 6.6% dl-Lactic and glycolic acid copolymer 13% Mannitol 0.2% Polysorbate 80 1% Carboxymethylcellulose in WFI... 

Photolithography and microfabrication are techniques used for the formation of scaffolds of specific shape and with distinct surface properties. Three-dimensional scaffolds are composed of hydrogels like biodegradable lactide/glycolic acid copolymers or nonbiodegradable polydimethylsiloxane. In the case of lactide/glycolic acid copolymers, the polymer is formed into a fibrous... 

Multiple uses of poly(lactic add), poly(glycolic acid) homopolymers, and poly(lactic-co-glycolic acid) copolymers have been described including sutures, vascular grafts, drug carriers, and scaffolds for tissue engineering (discussed below). This is due in part to the FDA approval of these polymers for use as implantable materials. 

Y. Yang, J. Cai, X. Zhuang, Z. Guo, X. Jing, X. Chen, pH-dependent self-assembly of amphiphilic poly (l-glutamic acid)-block-poly (lactic-co-glycolic acid) copolymers. Polymer 51 (2010) 2676-2682. 

Chandrashekar, G. and Udupa, N., 1996. Biodegradable injectable implant systems for long term drug delivery using poly(lactic-co-glycolic) acid copolymers. J. Pharm. Pharmacol, 48(7), 669-674. 

Figure 2.8 Chemical structures of a block copolymer poly(alMcyanoacrylate)-block-poly (ethylene glycol) (a), and of a random poly(lactic acid-co-glycolic acid) copolymer (b).

The most successful scaffolds have been lactic acid—glycolic acid copolymers. Formation of the copolymer via a condensation reaction is shown in Equation 12.5 ... 

A small hydrophilic prodrug (PROLI/NO) to be delivered to the alveolar region of the lungs was encapsulated with microparticles of a biodegradable, hydrophilic lactic acid-glycolic acid copolymer and an ethylene oxide-lactic acid copolymer and the kinetics of release of nitric oxide characterised using three parameters. These parameters were maximum concentration of nitric oxide per unit weight of microparticles, window of time over which the concentration exceeded 50% of the maximum concentration and the initial rate of release. 18 refs. 

Details are given of the use of various stabilisers in the preparation of polymer microparticles and the outcome in terms of particle size and encapsulation efficiency. Data are presented for polylactic acid, polyglycolic acid, lactic acid-glycolic acid copolymer and polyphosphazene microparticles loaded with drugs and prepared by emulsification/solvent evaporation. 18 refs. 

The molecular dynamics of the degradation process of lactic acid-glycolic acid copolymer nanospheres were investigated. The MWD of the copolymers was determined as a function of time as degradation progressed. The degradation of nanospheres containing epirubicin was also analysed. 18 refs. 

Details are given of the targeted delivery of antiinflammatory drugs to inflammatory sites using biodegradable lactic acid-glycolic acid copolymer microspheres. A carbohydrate that serves as a ligand to selectins was attached to the surface of the microspheres to mimic the adhesive behaviour of leukocytes on selectins. 47 refs. 

Details are given of the development of lactic acid-glycolic acid copolymer microspheres for continuous delivery of dexamethasone. The microspheres were prepared using an oil-in-water emulsion technique. Drug loading and release rates were determined by HPLC-UV analysis. 42 refs. 

An attempt is made to prepare and characterise injectable carboplatin-loaded poly(D,L-lactic-co-glycolic) acid copolymer (PLGA) microspheres for the intracerebral... 

Tai, H. Y., Upton, C. E., White, L. J., Pint, R., Storti, G., Mazzotti, M., Shakesheff, K M. Howdle, S. M. (2010). Studies on the interactions of C02 with biodegradable poly(DL-lactic acid) and poly(lactic acid-co-glycolic acid) copolymers using high pressure ATR-IR and high pressure rheology. Polymer 51(6) 1425-1431. 

PLGA Poly(D,L-lactic-co-glycolic acid) copolymer... 

Poly(lactic-glycolic acid) copolymer A soil micro-organism isolation [99]... 

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