Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065, USA.
J Am Soc Mass Spectrom. 2013 Mar;24(3):399-409. doi: 10.1007/s13361-012-0542-4. Epub 2013 Jan 24.
Steroid hormones and their metabolites are currently undergoing clinical trials as potential therapeutics for traumatic brain injury (TBI). To support this work, it is necessary to develop improved procedures for differentiating isobaric species in this compound class. Equilin sulfate (E-S), estrone sulfate (E1-S), 17α-dihydroequilin sulfate (ADHE-S), and 17β-dihydroequilin sulfate (BDHE-S) are primary constituents in hormone replacement therapies, such as Premarin, which are among pharmaceuticals being investigated for TBI treatment. The latter three compounds are isomers and can be difficult to differentiate in trace analytical determinations. In this work, a systematic study of the fragmentation of ADHE-S, BDHE-S, E1-S, and E-S under different stages of higher order tandem mass spectrometry (MS(n)) and variation of collision energy, allowed optimization of conditions for distinguishing the isomeric structures. For epimeric variants (e.g., ADHE-S versus BDHE-S; α- versus β-stereoisomerization in the C-17 position), differentiation was achieved at MS(4) and fragmentation was demonstrated through MS(5). Computational analysis was performed to further explore differences in the fragmentation pathways due to changes in stereochemistry.
甾体激素及其代谢物目前正在作为创伤性脑损伤 (TBI) 的潜在治疗方法进行临床试验。为了支持这项工作，有必要开发改进的程序来区分该化合物类别的等排异构体。硫酸雌酮 (E-S)、硫酸雌二醇 (E1-S)、17α-去氢硫酸雌酮 (ADHE-S) 和 17β-去氢硫酸雌酮 (BDHE-S) 是激素替代疗法（如 Premarin）中的主要成分，这些药物正在被研究用于 TBI 治疗。后三种化合物是异构体，在痕量分析测定中很难区分。在这项工作中，对 ADHE-S、BDHE-S、E1-S 和 E-S 在不同阶串联质谱 (MS(n)) 阶段和碰撞能变化下的碎裂进行了系统研究，优化了区分异构体结构的条件。对于差向异构体（例如，ADHE-S 与 BDHE-S；C-17 位置的 α-与 β-立体异构化），在 MS(4) 中实现了区分，通过 MS(5) 进行了碎裂证明。进行了计算分析以进一步探索由于立体化学变化而导致的碎裂途径的差异。
