The present invention provides a composition containing a particulate solid, an organic medium and/or water and a compound of Formula (1) and salts thereof: Formula (1) wherein R and R' are independently H or .sub.C1-30-optionally substituted hydrocarbyl; or R is H or .sub.C1-30-optionally substituted hydrocarbyl and R' is R''C.dbd.O (an acyl group where R'' is hydrogen, alkyl or an optionally substituted alkyl or aryl or an optionally substituted aryl); Y is C.sub.2-4-alkyleneoxy; T is C.sub.2-4 alkylene; A is the residue of a dibasic acid or anhydride thereof; Z is the residue of a polyamine and/or polyimine; W is the residue of an oxide, urea or dibasic acid or anhydride thereof, or mixtures thereof; x is from 2 to 90; and v represents the maximum available number of amino and/or imino groups in Z which does not carry the group RR'N-T-O--(Y)X-T-NH-A-. ##STR00001##