Cj. Goodwin et al., EFFECT OF CO-MONOMER COMPOSITION ON THE INTEGRITY OF BIOACTIVE GROWTH-HORMONE RELEASED FROM NOVEL PEMA BASED POLYMERS, Journal of biomedical materials research, 32(4), 1996, pp. 635-643
The release of human growth hormone (hGH) from hormone loaded bone cem
ent was previously shown to enhance osteoid formation. hGH is a comple
x protein and its incorporation into such cements may compromise its b
ioactivity. We therefore characterized the release of hGH from a serie
s of methacrylate systems based upon poly(ethylmethacrylate) (PEMA). D
ifferent 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 e
nhanced cytotoxicity and also reduced release of the bioactive hormone
. Combinations of the monomers improved the recovery of bioactivity fr
om the polymers and reduced their cytotoxicity. hGH released from the
polymer with the lowest water uptake (100% n-BM, 0% HEMA) had an excep
tionally low bioactivity: immunoactivity ratio, suggesting that the bi
oactive site of the hormone is particularly susceptible to disruption
when it is incorporated into this matrix. (C) 1996 John Wiley & Sons,
Inc.