In vitro availability profiles of oral methoxsalen commercial products.
The in vitro release rate of methoxsalen from three commercially available tablets and an experimental tablet were evaluated at pH 2 and 7, using the USP dissolution test. The experimental tablet and one commercial product showed that 74% of the labeled amount is released in 1 h and almost completely released after 3 h at pH 2 and 7. Two products showed that only 12 and 10% of the labeled amount was released in 1 h and a maximum of 25 and 23% after 3 h at pH 2. At pH 7, the percent released from these two products were slightly higher. These results correlate with the reported clinical effectiveness of one of the products showing fast methoxsalen release. Since exposure to long-wave UV radiation is carried out 1-3 h following methoxsalen oral administration, delayed release might explain the failure of some products to give satisfactory clinical results.
D006863:Hydrogen-Ion Concentration; D008730:Methoxsalen / Q000008:administration & dosage; D012995:Solubility; D013607:Tablets
D013607:Tablets; D008730:Methoxsalen