Date of Award

1988

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Pharmaceutical Sciences

First Advisor

Joan M. Lausier

Abstract

Nifedipine has been shown to be an effective and a well tolerated medication for the treatment of several cardiovascular diseases. Its low water solubility, however, leads to poor drug absorption from oral dosage forms while commercially available soft capsules lead to a short half - life. In this study a method was developed to prepare control led release nifedipine tablets which would release the drug quickly and sustain the release for a longer period of time. Solid dispersions of nifedipine with polyvinylpyrrolidone (40T) and polyethylene glycol 8000 were prepared to enhance dissolution and microporous polypropylene containing 75% void space was used to control the release to a desired level. Various ratios of the two polymers were used. The results indicate that the solid dispersion technique is a good approach to enhance the dissolution of nifedipine. However the polypropylene polymer used as a homogeneously dispersed matrix does not provide a zero - order release rate in low concentrations. A preliminary study was also carried out to measure the rate of photodegradation of nifedipine solution in a normally lighted lab devoid of sunlight. The results obtained show that the photodegradation of nifedipine follows first order kinetics with a t 90 of 19 minutes. The pH of the solution in the range of 4 .2 - 7 .4 did not alter this rate. The solubility of nifedipine in water was found to be about 5 mg/L at 25 degrees Celcius. There was no significant difference between the water solubility and the solubility in phosphate buffer (pH 7.4) or the solubility in 0.1 N HCl.

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