Synthesis, Characterization, and In Vivo Evaluation of Desmethyl Anethole Trithione Phosphate Prodrug for Ameliorating Cerebral Ischemia-Reperfusion Injury in Rats

Anethol trithione (ATT) has a wide range of physiological activities, but its use is limited due to its poor water solubility. To improve the solubility of ATT, we synthesized and characterized a novel phosphate prodrug (ATXP) relying on the availability of the hydroxy group in 5-(4-hydroxyphenyl)-3H-1,2-dithiole3-thione (ATX), which was transformed from ATT rapidly and extensively in vivo. Our results showed that ATXP significantly improved drug solubility. ATXP was rapidly converted to ATX and reached a maximum plasma concentration with a T_max of approximately 5 min after intravenous (iv) administration. Furthermore, after the oral administration of ATXP, the C_max was 3326.30 ± 566.50 ng/mL, which was approximately 5-fold greater than that of the parent drug form, indicating that ATXP has greater absorption than that of ATT. Additionally, the oral phosphate prodrug ATXP increased the ATX in the area under the plasma concentration vs time curves (AUC_0–t = 3927.40 ± 321.50 and AUC_0–∞ = 4579.0 ± 756.30), making its use in practical applications more meaningful. Finally, compared to the vehicle, ATXP was confirmed to maintain the bioactivity of the parent drug for a significant reduction in infarct volume 24 h after reperfusion. Based on these findings, the phosphate prodrug ATXP is a potentially useful water-soluble prodrug with improved pharmacokinetic properties.