الفهرس 
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Abstract
The objective of the present work is applying emulsion solvent evaporation technique for
controlling the release of Ranitidine hydrochloride (RH) using two polymers, ethyl
cellulose (EC) , Eudragit E100 (E E-100) and mixture of EC/E -E100. These investigations
together with the obtained results and the attained conclusions can be summarized as
follows:
1-The maximum wavelength of absorbance of RH was 312.6 nm in 0.1 N HCl and 224.6 in rabbit
blood plasma.
2-The calibration curves of RH in 0.1 N HCl and in rabbit blood plasma obey Beer’s Lambert law in
the concentration range used.
3-The formulae RH-E E100 (1:2.5) 400 rpm had the best value for the production yield
(98.68%) while formula RH-EC (1:4) 400 rpm had the best value for Entrapment efficiency
(79.3%) and formulae RH-E E100 (1:1) 400 rpm was the best one for in vitro buoyancy test
(92%).Particle size of RH microspheres ranged from 66.77 to 10.41 μm. Optical microscope
confirmed their spherical structure.
4-The micromeritic properties of the prepared RH microspheres indicated that emulsion
solvent evaporation technique produces spherical microspheres with good flowability.
5-The amount of drug released decreased as the coat to core ratio increased.
6-The in-vitro release of RH from the RH/EC formulae followed Higuchi’s diffusion model
While, RH-E E100 formulae followed First order models and RH-EC/E E100 formulae
followed Zero o order kinetics.
7- Assessment of the AUC showed that the bioavailability is lesser for the pure drug
(normal oral bioavailabili ty being only 50%) and increased to nearly 2.4-times with
formulation. The elimination was less rapid with the microparticulate formulation when
compared to the free drug and marketed product.
8-Both IR and DSC showed that there was no chemical interaction between the drug (RH)
and the polymers (EC, E E100and EC/E E100).
9-The best formula in this study was RH-E E100 (1:2.5) 300 rpm which showed the best
micromeritic properties, in vitro buoyancy and in-vitro release.