| Abstrakt: |
The in vitrodissolution and in vivoabsorption characteristics of various nitrofurantoin and nitrofurantoin-deoxycholic acid preparations were studied. In vitropariculate dissolution studies compared the dissolution of a 1:5 molar ratio nitrofurantoin-deoxycholic acid coprecipitate to that of a 1:5 physical mixture of nitrofurantoin and deoxycholic acid, precipitated nitrofurantoin, and pure nitrofurantoin. In pH 7.4 buffer, the dissolution rate of the coprecipitate system was approximately six times greater than the dissolution rate of the 1:5 physical mixture. However, no statistical differences could be shown among the dissolution rates of the 1:5 physical mixture, the pure nitrofurantoin, and the precipitated form of nitrofurantoin. In pH 1.2 buffer solution, the 1:5 coprecipitate showed a faster initial dissolution rate than the pure nitrofurantoin but became slower than the pure compound after 35min. The in vivoabsorption of the 1:5 coprecipitate, the 1:5 physical mixture, and pure nitrofurantoin, as determined by urinary excretion of unchanged nitrofurantoin, was carried out in four subjects in a crossover study. The 1:5 nitrofurantoin-deoxy-cholic acid coprecipitate showed significant increases in both the initial urinary excretion and the total cumulative amount of unchanged nitrofurantoin excreted when compared to either the 1:5 physical mixture or the pure nitrofurantoin. The study demonstrated the potential usefulness of drug-bile acid coprecipitate systems in increasing the in vivoabsorption of dissolution rate-limited drugs. |
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