| Abstrakt: |
The absorption and excretion of aminophylline, hydroxypropyltheophylline (Theon®) and choline theophyllinate (Choledyl®) after oral administration in capsules were studied by determining theophylline levels in plasma and urine. For comparison, a liquid formula containing choline theophyllinate, Brondaxin Syrup®, was also included in the investigation. — The current spectrophotometric method used by most investigators proved unreliable for measuring low concentrations of theophylline. Therefore, the compounds were labelled with tritium, and the theophylline concentrations in plasma determined by measuring the radioactivity of the samples. — Thirteen subjects were given on an average three of the compounds, each with a minimum interval of 3 days as designed. All doses were adjusted to the equivalent of 200 mg theophylline. — The plasma levels of theophylline showed no significant variations between the three different compounds administered as capsules. Detectable plasma levels of theophylline, with few exceptions, were not recorded until 30–60 min after taking the compounds. In contrast, Brondaxin Syrup® rapidly produced high plasma levels which remained higher than with any of the other compounds during the experiment (7 h). Maximum concentration in plasma was reached after about 4 h with the liquid as well as with the dry capsules. |
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