In vivo rat pharmacokinetic study

Rats were cared for in accordance with the Guide for the Care and Use of Laboratory Animals, 8^th Edition. All research protocols were approved by the Amgen, Inc. Institutional Animal Care and Use Committee (protocol number: 2008–00092). Rats were individually housed at an AAALAC, International accredited facility in static caging on corn cob bedding. Rats had ad libitum access to pelleted feed (2020X, Harlan, IN, USA) and reverse osmosis-purified water via water bottles. Rats were maintained on a 12:12 hour light:dark cycle in rooms at 64–79°F and humidity range of 30–70%, respectively, and had access to enrichment opportunities (nestlets, Nylabones, and igloos).

The PK profiles of the human IgG1 and IgG2 antibodies were determined in male adult Sprague-Dawley (SD) rats (n = 3 per group, 8 to 12 weeks of age, 300–350 g) by injecting 5 mg/kg subcutaneously (bolus) in the midscapular region of the dorsal back or intravenously and collecting 250 μl samples of blood in conscious animals from the jugular vein catheter or lateral tail vein at 0, 0.25, 1, 4, 24, 48, 72, 168, 336, 504, 672, 840 and 1008 hours post-dose. Each blood sample was maintained at room temperature after collection, and following a 30–40 minute clotting period, samples were centrifuged at 2–8°C at 11,500 rpm for about 10 minutes using a calibrated Eppendorf 5417R Centrifuge System (Brinkmann Instruments, Inc., Westbury, NY). The collected serum was then transferred into a pre-labeled (for each rat), cryogenic storage tube and stored at -60°C to -80°C for future bioanalysis.