The solution and solid state stability and excipient compatibility of parthenolide in feverfew

The objectives of this research were to evaluate the stability of parthenolide in feverfew solution state and powdered feverfew (solid state), and explore the compatibility between commonly used excipients and parthenolide in feverfew. Feverfew extract solution was diluted with different pH buffers to study the solution stability of parthenolide in feverfew. Powdered feverfew extract was stored under 40°C/0%∼75% relative humidities (RH) or 31% RH/5∼50°C to study the influence of temperature and relative humidity on the stability of parthenolide in feverfew solid state. Binary mixtures of feverfew powered extract and different excipients were stored at 50°C/ 75% RH for excipient compatibility evaluation. The degradation of parthenolide in feverfew solution appears to fit a typical first-order reaction. Parthenolide is comparatively stable when the environmental pH is in the range of 5 to 7, becoming unstable when pH is less than 3 or more than 7. Parthenolide degradation in feverfew in the solid state does not fit any obvious reaction model. Moisture content and temperature both play important roles affecting the degradation rate. A fter 6 months of storage, parthenolide in feverfew remains constant at 5°C/31% RH. However, ∼40% parthenolide in feverfew can be degraded if stored at 50°C/31% RH. When the moisture changed from 0% to 75% RH, the degradation of parthenolide in feverfew increased from 18% to 32% after 6-month storage under 40°C. Parthenolide in feverfew exhibits good compatibility with commonly used excipients under stressed conditions in a 3-week screening study

No clinically relevant CYP3A induction after St. John’s wort with low hyperforin content in healthy volunteers

Objective Induction of CYP3A by St. John’s wort (SJW) products with high hyperforin content is well described. Since CYP3A induction is mediated by hyperforin in a concentration-dependent manner, and SJW preparations differ significantly in hyperforin content, the aim of the study was to evaluate the effect of an SJW powder with low hyperforin content on CYP3A function. Methods Twenty healthy male volunteers received an SJW powder with low hyperforin content for 2 weeks. Midazolam plasma concentration time profiles were characterized after a single oral dose of 7.5 mg midazolam on the day before and on the 14th day of SJW medication. Results Midazolam AUC0–∞ slightly decreased from 124.0 ± 62.5 ng/ml·h at baseline to 105.6 ± 53.2 ng/ml·h after SJW (P < 0.05), representing a mean 11.3% decrease (95% CI: −22.8 to 0.21). No significant change in midazolam Cmax, t1/2 and tmax was observed. For all pharmacokinetic parameters, the 90% CI for the geometric mean ratio of treatment over baseline were within the no-effect boundaries of 0.70–1.43. Conclusion Administration of an SJW product with low hyperforin content resulted in a mild induction of CYP3A not considered clinically relevant