Controlled antibody release from a matrix of poly(ethylene‐co‐vinyl acetate) fractionated with a supercritical fluid

Abstract

SYNOPSISA new method is presented for controlling the rate of antibody ( Ab) release from a n inert matrix composed of poly (ethylene-co-vinyl acetate) ( EVAc) , a biocompatible polymer that is frequently used to achieve controlled release. Using supercritical propane, a parent EVAc sample ( M , = 70 kDa, M , / M , = 2.4) was separated into narrow fractions with a range of molecular weights (8.7 < M , < 165 kDa, 1.4 < M,,,/M, < 1.7). Solid particles of Ab were dispersed in matrices composed of different polymer fractions and the rate of Ab release into buffered saline was measured. The rate of Ab release from the EVAc matrix depended on molecular weight: > 90% of the incorporated Ab was released from low molecular weight fractions ( M , < 40 kDa) during the first 5 days of release, while < 10% was released from the high molecular weight fraction ( M , > 160 kDa) during 14 days of release. No significant differences in polymer composition, glass-transition temperature, or crystallinity were identified in the different molecular weight fractions of EVAc. Mechanical properties of the polymer did depend on the molecular weight distribution, and correlated directly with Ab release rates. Because it permits rapid and reproducible fractionation of polymers, supercritical fluid extraction can be used to modify the performance of polymeric biomaterials. 0 1993 John Wiley & Sons, Inc.

Supercritical fluid fractionation of copolymers based on chemical composition and molecular weight

“…Also, notice that the molecular weight of the first fraction obtained with propylene is lower than that of the final fraction obtained with propane, indicating that propane can only remove fractions that are lean in acrylate even if the molecular weight is greater than available oligomers that have a higher acrylate content. EMABO/(O was also fractionated with F22 to confirm that chlorodifluoromethane is too "good" a solvent for this copolymer; the results are given in Table V. Using very small pressure increments, 14 fractions were obtained with modest polydispersities. No discernible trend was detected with the backbone composition of the fractions, indicating that F22 was only able to discriminate on the basis of molecular weight and not on the basis of composition.…”

Sustained release and stabilization of therapeutic antibodies using amphiphilic polyanhydride nanoparticles

“…Therefore, the development of sustained delivery vehicles would significantly benefit drug bioavailability and patient compliance (Nelson et al, 2010;Scweizer et al, 2013). The development of formulations for parenteral administration and controlled delivery of protein drugs is particularly challenging, resulting in a lack of commercially available sustained delivery systems for antibodies and a limited number of studies on this topic (Grainger, 2004;Guziewicz et al, 2011;Saltzman, 1993;Salzman et al, 1993;Scweizer et al, 2013).…”

Efeito da incorporação de agentes antimicrobianos sobre propriedades físicas de materiais resilientes temporários para base de prótese

“…A remoção do contato do biofilme das bases acrílicas com os tecidos de suporte das próteses por meio de reembasamento tem sido relatada como eficaz para romper o ciclo de reinfecção por Candida e reduzir o trauma causado por essa superfície contaminada, auxiliando o tratamento da estomatite protética (HOLMBERG, 1980;MARIN ZULUAGA;GOMEZ VELANDIA;RUEDA CLAUIJO, 2011;MEDEIROS;PACHECO, 2000). Se realizado com materiais resilientes, o reembasamento ainda favorece a recuperação dos tecidos injuriados e promove conforto ao paciente (BROWN, 1988;FARRELL, 1975 WATKINSON, 1988;LEITE et al, 2010;PAVAN et al, 2007;PISANI et al, 2010;POLYZOIS et al, 2013 SAHIN, 1999;HAYAKAWA et al, 1997;KAWANO et al, 1994;MANCUSO et al, 2009;PARKER;BRADEN, 1989;PISANI et al, 2010 VAN NOORT, 1985;MARK SALTZMAN et al, 1993). Todos esses mecanismos possivelmente contribuíram para o aumento da solubilidade com a adição de cetoconazol ao Trusoft e Softone.…”