Quantification of BNN27, a novel neuroprotective 17-spiroepoxy dehydroepiandrosterone derivative in the blood and retina of rodents, after single intraperitoneal administration.

BNN27 is a novel 17-spiroepoxy derivative of the neurosteroid Dehydroepiandrosterone with neuroprotective properties. The purpose of this study was the detection and quantification of BNN27 after single intraperitoneal administration, in the serum and retina of normal rodents. Forty-two C57BL/6 mice and 48 Sprague-Dawley rats were used for the quantification of BNN27 in the blood serum and retina, respectively. BNN27 was injected intraperitoneally (i.p.) at concentrations of 100 and 30 mg/kg of body weight (b.w.), respectively. The blood was collected with retro-orbital bleeding and the retina was isolated after enucleation at various time points. The molecule concentrations were measured with Liquid chromatography-mass spectrometry (LC-MS). Non-compartmental analysis was used to determine pharmacokinetic parameters. BNN27 was found to have an elimination constant k(el)  = 0.465 h(-1) and mean residence time (MRT) 2.154 h in the mouse serum. The maximum concentration (C(max) ) in the retina was detected at 2 h ( tCmax ) after intraperitoneal administration and was equal to 1100 ng/g. BNN27 is rapidly eliminated from both blood and retina. In the retina specifically, it is undetectable 6 h after injection. BNN27 shows a rapid systemic elimination as anticipated by its small size and lipophilicity. It is measurable in small peripheral tissues such as the rat retina, after one single i.p. injection, using a simple method such as LC-MS. Its detection in the retina corroborates the existing biological data that the molecule crosses the blood-retinal barrier, highlighting it as a potential neuroprotective agent for retinal disease.