<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Effect of angiotensin II on liposome uptake by the rat brain <i>in vivo</i></span>

Abstract

Studies have been performed to assess the possibility of using small unilamellar liposomes as therapeutic carriers to the brain of hypertensive rats. Rats were made temporal hypertensive by the infusion of angiotensin II (AII; 15μg in 1 ml) through their right common carotid artery. Another control group was infused with physiological saline. Free ¹²⁵ iodine-BSA (¹²⁵I-BSA) and ¹²⁵I-BSA encapsulated liposomes (average diameter 100 nm) were injected in the tail vein 2 min after the infusion of AII or saline. Plasma radioactivity was monitored at different times up to 15 min when the cerebral uptake of ¹²⁵I -BSA was determined. While a little variation in plasma clearance pattern of liposomes in hypertensive and control group was noticed , the uptake by cerebral tissues was markedly higher in hypertensive group. Analysis of pharmacokinetic parameters in relation to cerebral uptake indicated AII induced a short term opening of the blood-brain barrier (BBB) resulting in an increased cerebral uptake. Positively charged liposomes was found to be most effective in hypertensive state.