Targeting the insulin receptor: nanoparticles for drug delivery across the blood-brain barrier (BBB).

Human serum albumin (HSA) nanoparticles (NP) were prepared by desolvation. Insulin or an anti-insulin receptor monoclonal antibody (29B4) were covalently coupled to the HSA NP, using the NHS-PEG-MAL-5000 crosslinker. Loperamide-loaded HSA NP with covalently bound insulin or the 29B4 antibodies induced significant antinociceptive effects in the tail-flick test in ICR (CD-1) mice after intravenous injection, demonstrating that insulin or these antibodies covalently coupled to HSA NP are able to transport loperamide across the blood-brain barrier (BBB) which it normally is unable to cross. Control loperamide-loaded HSA NP with immunoglobulin G antibodies yielded only marginal effects. The loperamide transport across the BBB using the NP with covalently attached insulin could be totally inhibited by the pretreatment with the antibody 29B4.