A process for making water-soluble phosphonooxymethyl ethers of hindered alcohol and phenol containing phar-maceuticals, such as camptothecin, propofol, etoposide, Vitamin E and Cyclosporin A. In particular, the process for preparing wa- ter-soluble phosphonooxymethyl derivatives comprises the steps of Formula (i) and Formula (ii) R-OH represents an alcohol- or phenol-containing drug, n represents an integer of 1 or 2, R1 is hydrogen, an alkali metal ion, or a pharmaceutically acceptable cation, and R2 is hydrogen, an alkali metal ion, or a pharmaceuticaUy acceptable cation.
