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*R - the moiety, that when covalently attached to the polymer, copolymer, or oligomer backbone, results in a molecule that is able to remain molecu› larly dispersed, and mostly dissociated, in solution over a wide range of pH. Ras defined, refers to any one of R 1 , R 2 , R 3 , R 4 , or R 5 , as defined herein. **pKa values given at room temperature and taken from a variety of 

sources including (Hall, H.K., J. Am Chem. Soc. 79:5439-5441, 1957; Handbook of Chemistry and Physics (Hodgman, C.D., editor on Chief, Chemical Rubber Publishing Company, Cleveland, OH p. 1636-1637, 1951). 

[0266] In the examples of Table 1, except for maleic and succinic acid, the linkage to the oxygen atom by R1, R 2 , R 3 , R 4 and Rs is via an ester through an acyl group of the carboxylic acid or anhydride. However, with respect to the acrylic polymers, the linkage of the maleic acid and succinic acid by Rs is obtained by replacing a hydrogen atom of the CH$_{2 }$ in succinic acid or a hydrogen atom of CH=CH in maleic acid with a bond to the oxygen atom in the polymer. However, the linkage of the maleic and succinic acid of R 1 , R 2 , R 3 and R 4 in the cellulose based polymer to the oxygen atom is through the acyl group. 

[0267] It is understood to one skilled in synthetic organic chemistry that Table 1 represents only a partial list of suitable substituents, and that many more examples are possible provided that no other reactive functionalities are present which would compete with the primary desired reaction of forming substituted cellulose- or acrylic-based polymers or oligomers. One skilled in the art can prepare one or more active compounds in this class by performing the above synthesis or similar methods using combinatorial synthesis or equivalent schemes by altering the monocar› boxylic acid moiety, or the di- or tri-carboxylic acid moiety, or a mixed moiety containing both carboxylic acid groups and sulfate or sulfonate groups, or a moiety containing a sulfate or sulfonate group. Furthermore, additional hydro› phobicity can be added using techniques known in the art on those resulting molecules. This can be accomplished in a number of ways including the addition of a naphthalene group such as those shown in Table 1 (naphthalene tetra› carboxylic dianhydride or naphthalimide) to the cellulose backbone. 

[0268] Other substituents for R1, R 2 , R 3 , R 4 of Formula I or Rs of Formula II are obtained by using a mixture of the moieties identified or suggested herein or in Table 1. Hydroxypropyl methylcellulose acetate maleate (HPMC› AM) is just such a compound in which a mixture of acetic and maleic anhydride is used to derivatize the hydroxypro› pyl methyl cellulose backbone, and is illustrative of the compounds of the present invention. 

