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1, 2, 4, 6, and 24 h. Each compound concentration in the aspirates
Acknowledgment
was determined using the HPLC method described below.
This publication was supported in part by First Tech Interna-
tional Ltd (Hong Kong).
4.5.2. Stability studies
4.5.2.1. Stability in phosphate buffer. The stability of each of 1
and 9 was studied at 37 °C in phosphate buffer (pH 7.4). In amber
References and notes
vials, 500
and the solution was incubated at 37 °C. At interval times (0, 0.5,
1, 2, 4, 6, and 24 h), 50 L samples were collected and equal vol-
umes of methanol were added to each sample followed by HPLC
analysis.
lg/mL of each compound were dissolved in the buffer
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4.5.3. HPLC analysis of 1 and 9
A Shimadzu HPLC system (Columbia, MD) was used for quanti-
fication of 1 and 9. This system is composed of SIL 20-AHT auto-
sampler, SPD-20A UV/vis detector, and LC-20AB pump connected
to a Dgu-20A3 degasser. Data acquisition was achieved by LC Solu-
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l
C18 column (250 ꢁ 4.6 mm
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H2O–MeOH–N(Et)3 (10:90:0.05, v/v/v) for 5 min, followed by iso-
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4.6. Chemicals and reagents
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All reagents have been purchased from Sigma–Aldrich. (TRF)
50 g (Palm TRF 70%, low in tocopherol from First Tech International
Ltd, Hong Kong) was fractionated using Si gel 60 VLC using n-hex-
ane/EtOAc (gradient elution) as a mobile phase.
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