Phosphorylcholine Chloride

DescriptionPhosphorylcholine (abbreviated ChoP) is the hydrophilic polar head group of some phospholipids, which is composed of a negatively charged phosphate bonded to a small, positively charged choline group. It is a choline ester which forms a part of the phosphatide molecule, and as such occurs in nearly all organs. It probably often exists in the free state, being liberated from the phosphatides by enzymic hydrolysis.

UsesPhosphocholine is an intermediate in the synthesis of Uridine Diphosphate Choline Ammonium Salt (U829930), which is CDPcholine cholinephosphotransferase analog. Pipeline device with Phosphorylcholine surface treatment (Pipeline Shield) could mitigate device material related thromboembolic complications.

PreparationPhosphorylcholine was synthesised from choline chloride and phosphorus pentoxide, the solvent being 100 percent. phosphoric acid [phosphorylation method of Manaka, 1931]. 2.4 g choline chloride, dried over phosphorus pentoxide, were dissolved in 15 g. 100 per cent. phosphoric acid, the solution was heated at 70°C. in vacuo until evolution of HC1 ceased, and 5 g. phosphorus pentoxide were added. The mixture, which became homogeneous after a few minutes, was kept at 70°C. for 3 hours. The clear viscous solution was poured into 400c.c. of ice water, and a barium hydroxide solution, saturated at 50°C., was added until the solution showed a strongly alkaline reaction. At the end of the neutralisation a smell of trimethylamine appears. The barium phosphate was centrifuged, the excess of barium ions removed by carbon dioxide, the precipitate centrifuged, and the solution reduced in vacuo to a small volume. It still contained a certain amount of barium ions depending on the amount of negatively charged phosphorylcholine ions present. The latter is determined by the pH of the solution. The amount of barium ions present was determined in an aliquot part of the solution by precipitation with sulphuric acid, and the amount of n-sulphuric acid required for complete precipitation of the barium ions added.