Comparative Biodistribution and Pharmacokinetic Analysis of Cyclosporine-A in the Brain upon Intranasal or Intravenous Administration in an Oil-in-Water Nanoemulsion Formulation

The main objective of this study was to evaluate comparative biodistribution and pharmacokinetics of cyclosporine-A (CsA) following intranasal (IN) administration versus intravenous (IV) administration in Sprague–Dawley rats using an oil-in-water nanoemulsion delivery system. CsA, a hydrophobic peptide that is also a substrate for P-glycoprotein, is a well-known immunosuppressive agent. In the brain, CsA has been shown to be a potent anti-inflammatory and neuroprotective agent. CsA nanoemulsions (CsA-NE) and solution formulations (CsA-S) were prepared using an ultrasonication method and were characterized for drug content, encapsulation efficiency, globule size, and zeta potential. We compared the uptake of CsA-NE and CsA-S in brain regions and peripheral organs following IN and IV administration using LC-MS/MS based bioanalytical method. CsA-NE IN resulted in the highest accumulation compared to that with any other treatment and route of administration; this was consistent for all three regions of brain ...