Isradipine related to dihydropyridine (DHP) class of calcium channel blockers (CCBs). It is  used to treat hypertension, angina pectoris, as well as Parkinson disease. It goes under the BCS class II drug (low solubility-high permeability). The drug will experience extensive first-pass metabolism in liver, thus, oral bio-availability will be approximately15 to 24 %. 

       The aim of the study is preparing stable oral oil in water (o/w) nanoemulsion of isradipine to promote the colloidial dispersion of isradipine in the nano range, so that it may be absorded by intestinal lymphatic transport in order to avoid hepatic first-pass metabolism (israpidine undergoes 15-24% first pass metabolism) and increase drug bioavailability.

       The solubility study was carried out in various vehicles for selecting best solvent  for dissolving isradipine. Pseudo-ternary phase diagrams is formed at (1:1, 1:2, 1:3, 1:4 and 2:1) ratios related to Smix (co-surfactant and surfactant).  There are 11 nano-emulsion was  prepared through the use of many concentrations of ( Transcutol, Tween20, and Triacetin).

All formulations assessed for (in-vitro drug dissolution, pH measurement, viscosity, drug content, polydispersity index, particle size distribution, thermodynamic stability, dye test, and light transmittance). It is indicated that the extent as well as the rate of release regarding all the prepared formulations have considerably higher in comparison to that of crude drug powder. Results of characterization were explained that isradipine  nano emulsion (NE9) with S mix(1:4) : oil : deionized water (40: 5: 55) ratio was the optimized formula that has droplet size range (177.1nm), the lowest value of polydispersity index (0.12), the highest percent of drug content (99.7%) typical pH value for oral administration (5.21) , good percent of light transmittance (99.86 %), the range of viscosity (65.12 -25.2 m Pas. sec.) was suitable for oral administration, also the isradipine’s in vitro release has been considerably higher. It can be concluded that nano emulsion drug delivery system (DDS) can be considered as an encouraging method for improving the stability, dissolution and solubility of formulation.

Keywords: Nanoemulsion, Isradipine  , Peudoternary phase diagrams.