Enhanced Bioavailability in the Oxalate Salt of the Anti-Tuberculosis Drug Ethionamide
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- 作者：M. K. Chaitanya Mannava ; Kuthuru Suresh ; Ashwini Nangia
- 刊名：Crystal Growth & Design
- 出版年：2016
- 出版时间：March 2, 2016
- 年：2016
- 卷：16
- 期：3
- 页码：1591-1598
- 全文大小：511K
- ISSN：1528-7505
文摘
Ethionamide (ETH) is an anti-tuberculosis (TB) Biopharmaceutics Classification System class II drug of poor aqueous solubility. The objective of the present study was to evaluate the solubility and bioavailability parameters of ETH cocrystals/salts with Generally Regarded as Safe (GRAS) coformers. Five cocrystals, namely, ETH–GLA (glutaric acid), ETH–ADP (adipic acid), ETH–SBA (suberic acid), ETH–SEBA (sebacic acid), ETH–FA (fumaric acid), and one salt ETH–OA (oxalic acid) were prepared by liquid-assisted grinding, and their structural characterization was carried out using spectroscopic, thermal, and powder X-ray diffraction techniques. The crystal structures of ETH–ADP, ETH–SBA, ETH–FA, and ETH–OA were confirmed by X-ray diffraction. The three cocrystal structures are sustained by the robust acid···pyridine synthon, while the ETH–OA salt has an ionic N–H···O hydrogen bond between carboxylate and pyridinium ions. The ETH–OA salt exhibited the highest dissolution compared to ETH (25 times), and its cocrystals (10 to 2 times higher). The intrinsic dissolution rates are ETH–OA > ETH–GLA > ETH–FA > ETH–SBA > ETH–ADP > ETH–SEBA > ETH. The best crystal form of ETH–OA was administered orally and exhibited 2.5 times enhanced plasma concentration in rats with Cmax of 4.08 ± 0.2 μg mL–1 at Tmax of 30 min, and AUC(0–8h) increased 1.9 fold to 6.49 ± 0.19 μg mL–1 h–1 compared to ETH. The oxalate salt exhibits the highest bioavailability enhancement for BCS class II drug ethionamide.