الفهرس 
GENERAL INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Pulsatile drug delivery systems are systems in which the drug is released suddenly after a well-defined lag time according to the circadian rhythm of the disease. They are advantageous if the drug exhibits tolerance if delivered at a constant rate. Diseases with established circadian rhythm include: hypertension, osteoarthritis, nocturnal asthma and peptic ulcer.
Valsartan, a long-acting angiotensin II receptor blocker is an antihypertensive drug, chosen to prepare different pulsatile formulations.
This thesis focuses on the formulation and evaluation of oral pulsatile different dosage forms. It is divided into three chapters:
•Chapter One: Formulation and Evaluation of Valsartan Core-in-cup Pulsatile Tablet Formulations
•Chapter Two: Formulation and Evaluation of Valsartan Time-Clock Pulsatile Tablet Formulations
•Chapter Three: Formulation and Evaluation of Valsartan Sandwich Capsule Pulsatile Formulations
Chapter One: Formulation and Evaluation of Valsartan Core-in-cup Pulsatile Tablet Formulations
This chapter aimed at designing and evaluating single pulse and floating double pulse core-in-cup tablets, to release valsartan after certain lag time, as to maximize its absorption thus improving its bioavailability.
Core-in-cup tablets consisted of a core tablet, an impermeable ethylcellulose (EC) cup and a top plug layer of a soluble polymer. Core blends were prepared by mixing valsartan with Aerosil, magnesium stearate, Avicel PH-101 and croscarmellose sodium (CCNa) as a superdisintegrant. Five core formulations (C0, C1, C2, C5 and C6) were prepared containing (0, 1, 2, 5 and 6 mg) CCNa, respectively