1. Evaluation of electrospun ﬁbers as solid phase extraction sorbents for sample preparation in HPLC-MS/MS conﬁrmatory doping control analysis of dexamethasone and betamethasone
Tania Possi-Pezzali, Samuel Chigome, Alejandra Rodr´ ıguez-Haralambides*, Nelson Torto. Anal. Methods, 2013, 5, 4230–4237
Polystyrene fibers were fabricated by electrospinning and evaluated their capacity to interact with twomodel drugs for sample preparation. The packing in microcolumn devices showed high recoveries for dexamethasone and betamethasone in water and urine samples, and breakthrough volumes measured for both analytes indicated that the system could be applicable not only for a clean-up but also as a pre-concentration step. This sample preparation approach was successfully applied to urine samples to detect the presence of dexamethasone and betamethasone by HPLC-MS/MS for qualitative confirmatory analyses. The method requires only 200 mL of methanol per sample, and the extraction is performed in less than 15 min.
2. The conversion of allenes to strained three-membered heterocycles
C. S. Adams, C. D. Weatherly, E. G. Burke and J. M. Schomaker*. Chem. Soc. Rev., 2014, 43, 3136—3163
In 1996, chemists at Schering-Plough reported an alternative approach to the corticoid betamethasone that proceeded through an SDE intermediate. Treatment of the steroidal allene with in situ-generated DMDO provided the requisite SDE in 2 : 1 dr; however, ring-opening with Bu4NOAc provided a single ketone product, indicating that the source of diastereoselectivity was at C20. The disubstituted ketone was obtained in 85% over two steps, and was readily carried on to a known betamethasone precursor.
3. Quantitative determination of betamethasone sodium phosphate and betamethasone dipropionate in human plasma by UPLC-MS/MS and a bioequivalence study
Man-Yun Chen, Yong-Jun Tang, Zhi-Rong Tan,* Wei-Hua Huang*. Anal. Methods,2016, 8, 3550–3563
BSP and BDP could be hydrolyzed by phosphatase as fast-release phosphate prodrugs and esterase enzymes as sustained-release dipropionate prodrugs into active pharmaceutical ingredients betamethasone (BOH), betamethasone 17-monodipropionate (B17P) and betamethasone 21-monodipropionate (B21P), respectively. Because the activating enzymes such as phosphate and esterase were highly eﬃcient and ubiquitous in human blood, BSP that was highly ionized and hydrophilic could be rapidly absorbed into blood from the administration place and then be metabolized quickly into active betamethasone (BOH) without a rate-limiting step.