title: Effect of co-monomer composition on the integrity of bioactive growth hormone released from novel PEMA based polymers.
abstract: The release of human growth hormone (hGH) from hormone loaded bone cement was previously shown to enhance osteoid formation. hGH is a complex protein and its incorporation into such cements may compromise its bioactivity. We therefore characterized the release of hGH from a series of methacrylate systems based upon poly(ethylmethacrylate) (PEMA). Different mixtures of two monomers, hydroxyethylmethacrylate (HEMA) and n-butylmethacrylate (n-BM) were used to provide polymers with graded water uptakes. Exclusive use of only one of the monomers resulted in enhanced cytotoxicity and also reduced release of the bioactive hormone. Combinations of the monomers improved the recovery of bioactivity from the polymers and reduced their cytotoxicity. hGH released from the polymer with the lowest water uptake (100% n-BM, 0% HEMA) had an exceptionally low bioactivity: immunoactivity ratio, suggesting that the bioactive site of the hormone is particularly susceptible to disruption when it is incorporated into this matrix.
authors.affiliation: Department of Molecular Pathology, University College London, United Kingdom.
authors.forename: C J
authors.initials: CJ
authors.lastname: Goodwin
authors.forename: K W
authors.initials: KW
authors.lastname: Davy
authors.forename: M
authors.initials: M
authors.lastname: Braden
authors.forename: S
authors.initials: S
authors.lastname: Downes
authors.forename: N J
authors.initials: NJ
authors.lastname: Marshall
mesh_terms: D000818:Animals; D001665:Binding Sites; D001682:Biological Availability; D001834:Body Water / Q000378:metabolism; D003692:Delayed-Action Preparations; D004343:Drug Implants; D019382:Human Growth Hormone / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D006801:Humans; D008223:Lymphoma / Q000473:pathology; D008689:Methacrylates / Q000737:chemistry / Q000633:toxicity; D008768:Methylmethacrylates / Q000737:chemistry* / Q000633:toxicity; D051381:Rats; D014407:Tumor Cells, Cultured
chemical_list: D003692:Delayed-Action Preparations; D004343:Drug Implants; D008689:Methacrylates; D008768:Methylmethacrylates; D019382:Human Growth Hormone; C005044:hydroxyethyl methacrylate; C009931:poly(ethylmethacrylate); C016284:butyl methacrylate