polyethylene glycol monomethyl ether

[NF] any of a series of addition polymers of ethylene oxide and methanol, represented by the general formula CH₃(OHC₂CH₂)_nOH, in which n is the average number of oxyethylene groups. Nominal molecular weights range from 350 to 10,000, the viscosity increasing and the solubility in water and in organic solvents decreasing as the molecular weight increases. Used as an excipient in pharmaceutical preparations.