Development and evaluation of nitrendipine nanoemulsion for intranasal delivery

The clinical efficacy of Nitrendipine (NDP), a potent antihypertensive molecule, is limited due to its low oral bioavailability (10% to 20%) resulting from its extensive first-pass metabolism. The purpose of the present investigation was to enhance the bioavailability of NDP through formulating a nanoemulsion for its intranasal delivery. A Caproyl 90 based nanoemulsion sytem with Tween 80 as the surfactant, Transcutol P and Solutol HS-15 as solubiliser and cosurfactant respectively, was developed. A single isotropic region, which is considered as a bicontinuous nanoemulsion, was identified in the pseudo-ternary phase diagrams developed at various Tween 80: Transcutol P: Solutol HS-15 ratios. NDP was solubilized in a system consisting of Tween 80: Transcutol P: Solutol HS-15 at 1:2:1 weight ratio. The developed nanoemulsion was safe for nasal administration as confirmed by nasal histopathlogy studies with the mean globule size of 98.50 nm. The drug content per actuation was found to be 99.58 +/- 0.05%, with no significant changes over a period of one month. In vivo absorption studies revealed that NDP absorption from the nanoemulsion had a rapid onset of action and a relative bioavailability of 60.44%, significantly greater than the marketed oral tablets.