Improvement of Nifedipine Bioavailability in Oral Drug Delivery Systems / Rania Mohamed BadrEldeen ; Supervised Ahmed Abd El Bary , Laila Hasanen Emara

Thesis (Ph.D.) - Cairo University - Faculty Of Pharmacy - Department Of Pharmaceutics

Nifedipine is a calcium channel antagonist known to be an effective and relatively well tolerated treatment for stable , variant and unstable angina , mild to severe hypertensionConventional formulations of nifedipine are associated with rapid drug absorption and this , coupled with short elimination half - life , can result in significant fluctuations in plasma concentrationsBy controlling the drug input with a modified release dosage form , plasma drug concentrations may be maintained at the desired level with minimal fluctuationsIt is therefore , important to develop a controlled - release form of nifedipine to prove the therapeutic efficacy , and reduce the incidence of side effectsNifedipine is a poorly water soluble drug , this poor solubility results in a decrease in the dissolution rate and thus reduced bioavailability when administered orally in crystalline or powdered formsA number of attempts have been made to modify the dissolution characteristics and thereby improve the absorption rate ofSeveral techniques such as decreasing the particle size , the use of wetting agents , coprecipitation and solid dispersions have been reported to increase the dissolution rateThe aim of this thesis is to improve the bioavailability of nifedipine by investigating the different methods of improving the solubility of the drug (egvia incorporation in solid dispersions) using fusion , hot - melt extrusion , and spray drying techniquesControlled - release oral dosage forms , using the most promising nifedipine solid dispersions were preparedIn - vitro and In - vivo evaluation of these formulations were considered

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