Synthesis of [14C]‐ and [35S]‐labelled PI‐88 for pharmacokinetic and tissue distribution studies

PI‐88, uniformly labelled with ¹⁴C] was prepared by incorporating D ‐¹⁴C]glucose into the fermentation of Pichia (Hansenula) holstii NRRL Y‐2448 under controlled conditions to produce ¹⁴C]‐labelled extracellular phosphomannan. Subsequent acid catalyzed hydrolysis gave the ¹⁴C]‐labelled oligosaccharide phosphate fraction which was sulfonated with excess sulfur trioxide pyridine complex to give ¹⁴C]PI‐88. ³⁵S]‐labelled PI‐88 was similarly prepared by the sulfonation of unlabelled oligosaccharide phosphate fraction with ³⁵S] sulfur trioxide pyridine complex. Copyright © 2002 John Wiley & Sons, Ltd.