Controlled delivery of oestradiol-17-b from silastic implants: in vitro and in vivo evaluation.
Oestradiol-17-b release from silastic implants of different length was determined in vitro over periods of up to 511 days. Sink conditions were provided by either Sodium lauryl sulphate (1%) or polyethylene glycol 400 (50%) in aqueous based media. Drug release profiles were fitted to the kinetic expression for matrix controlled release from a cylindrical delivery system, thus allowing prediction of both the rate and extent of release with time. A linear relationship was found between the cumulative amount of drug released in vitro and that released in vivo; the latter being measured from implants recovered from animals slaughtered in the period 96-515 days post implantation. A linear relationship was also obtained between serum oestradiol concentrations in the period 14 to 84 days post implantation and the in vitro release rate.
O'Sullivan
M
M
School of Pharmacy, Trinity College Dublin, Ireland.
Clancy
J M
JM
Roche
J F
JF
Corrigan
O I
OI
D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004343:Drug Implants; D004958:Estradiol / Q000008:administration & dosage* / Q000493:pharmacokinetics; D008297:Male; D009919:Orchiectomy; D012044:Regression Analysis; D012826:Silicone Elastomers; D012995:Solubility
D004343:Drug Implants; D012826:Silicone Elastomers; D004958:Estradiol