الفهرس 
ACKNOWLEDGEMENTOnly 14 pages are availabe for public view
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Abstract
The oral route of drug administration is the most common and preferred method of drug delivery, however
drug absorption from the gastrointestinal tract may be limited by poor dissolution rate. One of the
promising drug delivery technologies is Self Nano Emulsifying Drug Delivery System (SNEDDS) which is
novel lipid-based preparations believed to enhance the absorption of class II drugs by fastening the rate
limiting dissolution step through the formation of a nanoemulsion using gastrointestinal motility which is
capable of maintaining a poorly soluble drug in solution. The objective of this thesis was to formulate
valsartan SNEDDS using ternary phase diagram with the most suitable components according to the
solubility study, then the prepared formulation were evaluated for its performance. The optimized liquid
formulations were adsorbed onto a solid carriers yielding powder with suitable flowability properties ready
for encapsulation. The dissolution profiles of solid formulations filled into hard gelatin capsules were
established and compared with liquid formulations and commercial formulation to make sure that the selfemulsifying
properties did not change following conversion. These investigations along with the obtained
results can be summarized as follows:
1-The solubility study revealed that valsartan highest solubility was detected in capryol 90 as oil
(340.96±0.56mg/ml), tween-80 as a surfactant (114.71±0.45mg/ml) and PEG-400 as a co-surfactant
(45.06.±0.27 mg/ml) so they were selected for SNEDDS formulation.
2- The degree of self emulsification properties showed that the formulas containing more than 30% oil
content couldn`t produce nanoemulsion with the desired characteristics.
3-Viscosity measurements revealed that nanoemulsions have low values (< 30 cp) so it is oil in water type.
4-The results of the particle size measurements showed that only plain F8, F15, F21, F33, F34 and F36
showed a droplet size below 200 nm with poly dispersity index below 1 and when drug is added only F15,
F21, F33 and F34 remained with the same characteristics.
5- F15, F21 and F33 were robust to dilution and passed the three stages of thermodynamic stability study
while F34 was robust to dilution only as it failed to pass the second stage of thermodynamic stability study.
6- The solid SNEDDS did not show any peaks in the studied range which proved the presence of valsartan
in the amorphous state according to DSC study.
7-The lowest drug content was observed in S21 (96.35 ±0.07) while the highest drug content was observed
in F34 (99.64 ±0.05).
8-The rapid drug release was observed in F15 while F15 and F33 showed the highest extent (100%) .
9-According to t-test : Two-Sample Assuming Equal Variances at ( p>0.05), the release pattern of aerosil
based solid SNEDDS didn’t show a significant difference from corresponding liquid SNEDDS while silica
gel based solid SNEDDS showed a significant difference in the release patterns from corresponding liquid
SNEDDS.
10-The TEM showed homogenous well separated droplets with a bright background and the average
droplet size below 50 nm for all the studied samples
11-The kinetics of the in-vitro release of Valsartan predicted that Valsartan formulae obey Higuchi’s
diffusion model.
12-- The stability testing showed that the decomposition of Valsartan was slow and obeyed zero order
kinetic and may be described also as second order kinetics.
13- The relative bioavailability of F15 was increased 1.72 folds when compared with oral suspension.