Related Experiment Videos
Bioavailability of propylthiouracil in humans
Journal of Pharmaceutical Sciences
|December 1, 1983
Summary
Propyl-thiouracil (PTU) formulations showed significant in vivo differences despite meeting USP standards. In vitro dissolution varied greatly, but these did not correlate with in vivo blood levels in healthy volunteers.
Area of Science:
- Pharmacokinetics
- Pharmaceutical Sciences
- Drug Formulation
Background:
- Propyl-thiouracil (PTU) is a critical medication for managing hyperthyroidism.
- Ensuring consistent therapeutic efficacy across different PTU formulations is essential for patient care.
- Variability in drug product performance can impact clinical outcomes.
Purpose of the Study:
- To evaluate the in vitro and in vivo performance of commercially available 50-mg propyl-thiouracil (PTU) formulations.
- To identify potential differences in drug release and absorption among various PTU products.
- To assess the correlation between in vitro dissolution and in vivo bioavailability of PTU.
Main Methods:
- In vitro testing of five PTU formulations for drug content, content uniformity, and disintegration time according to USP XIX.
- Dissolution rate and extent were measured for each formulation.
- In vivo crossover blood level studies were conducted in 12 healthy male volunteers to assess plasma concentrations over time.
Main Results:
- All tested PTU formulations met USP specifications for content, uniformity, and disintegration.
- Significant differences in the rate and extent of in vitro dissolution were observed among the products.
- In vivo studies revealed statistically significant differences in plasma drug levels between formulations at most sampling times.
- No statistically significant differences were found in the overall area under the plasma level-time curves (AUCs).
- No significant correlations were established between in vitro dissolution parameters and in vivo pharmacokinetic data.
Conclusions:
- Commercially available PTU formulations exhibit significant in vivo performance variability despite meeting compendial standards.
- In vitro dissolution testing alone may not adequately predict the in vivo behavior of PTU formulations.
- Further investigation is warranted to understand the factors contributing to the observed in vivo differences and to ensure consistent therapeutic efficacy of PTU products.