polymers of the present invention are tailored with a smaller number of strong hydrophobic groups like naphthyl or a larger number of less hydrophobic groups like phenyl. One skilled in the art possesses the ability to strike the above balance between hydrophobicity, solubility and dissociation properties by manipulating the parameters of the modifica› tion and degree of substitution to arrive at the desired performance. 

[0192] The modifications, according to the present inven› tion, are not limited to reactions with anhydrides but include any substitution of R at any of the hydroxyl groups in the cellulosic backbone. It is thus highly desirable to have modified polymers bearing one or more hydrophobic groups such as phenyl and the like. It has been demonstrated by the present invention that such balance could be made in the case ofHPMCT at a range of trimellityl substitution of about 0.25 to about 0.7 per glucose unit. This balance and subse› quent biological activity can be duplicated with other modi› fiers by changing conditions and level of substitution. There› fore, it is understood to one skilled in the art that the scope of the invention is not limited to the discrete formulae or examples in the specification. 

[0193] For acrylic-based polymers, a similar balance between hydrophobicity, solubility and dissociation is effected to affect the biological function needed to suppress infectivity or STD transmission. For example, in MVE/MA› like polymers, desired functional groups may be incorpo› rated into the polymer either by selectively substituting the R $^{5 }$group of the viny 1 co-monomer used, or by mixing under the proper conditions the resulting anhydride with the appro› priate R---0 H-bearing intermediates as shown in Scheme 1. It is thus feasible using a variety of strategies to incorporate moieties such as those shown in Table 1 into the acrylic› based polymer. For the purpose of the present invention, it is preferable to have a molecularly dispersed polymer that remains dissociated in the pH range from about 3 to about 14, and possesses a level of hydrophobicity that would be optimal for blocking infectivity with STD causing agents. Further, introduction of sulfate or sulfonate groups, or other groups with low pKa values brings favorable solubility and dissociation parameters to very low pH levels ( e.g. ~ 1.0). One skilled in the art can readily ascertain the suitable reaction conditions to achieve the latter result. 

[0194] It is yet another embodiment of the present inven› tion to include both strong and weak acid groups in the polymer or copolymer, either cellulosic- or acrylic-based such as those described in the instant specification. Weak acid groups include carboxylic groups having low pKa values as given in Table 1. Strong acid groups include sulfate, sulfonate, or others with low pKa values in the range of 1.0 or below. Resulting molecules possessing the prop› erties given in polymers such as HPMCT or acrylic equiva› lents and including strong acid groups such as sulfate and sulfonates will operate by more than one mechanism to prevent infectivity and transmission of STDs. For example, the presence of sulfate groups in a polymeric molecule is known to strongly bind to the V3 loop of HIV-1 gp 120 (Este, J. A., Schols, D., De Vreese, K., Cherepanov, P., Witvrouw, M., Pannecouque, C., Debyser, Z., Desmyter, J., Rando, R. F., and De Clercq, E., "Human immunodeficiency virus glycoprotein gp120 as the primary target for the antiviral action of ARI 77 (Zintevir)."Mol. Pharm. 53:340- 345 (1998)), and thus the addition of sulfate or sulfonate 

groups to the cellulose molecules of Formula I or acrylic molecules of Formula II, such as in a molecule like HPMCT, will expand the spectrum of activity by conferring to the new molecule the ability to act via multiple distinct mechanisms. An example of a sulfate or sulfonated moiety in the cellulose backbone is illustrated by the substitution of, but not limited to, the anhydride of 2-sulfobenzoic acid, as shown in Table 1. The incorporation a sulfate or sulfonated moiety into a cellulose backbone along with carboxylic acid groups is readily apparent to one skilled in the art, e.g., the polymer backbone is substituted by, but not limited to the anhydride of 4-sulfo-1,8-naphthalic acid, as shown in Table 1. Further› more, the position of the sulfate or sulfonate groups on the ring structures can be varied to adjust performance of the resulting polymer. 

[0195] In one aspect, of the present invention, R1, R 2 , R 3 , and R 4 in Formula I or R 5 in Formula II is an aliphatic or aromatic moiety containing more than one carboxylic acid groups such that once covalently attached to the polymer, copolymer, or oligomer backbone the resultant compound remains molecularly dispersed and mostly dissociated in solution at a range of pH from about 3 to about 14, and more preferably from about pH 3 to about pH 5; 

[0196] In another aspect, the oligomer or polymer in Formula I is hydroxylpropyl methyl cellulose (HPMC)› based. 

[0197] In another aspect, the oligomer or polymer in Formula I is cellulose acetate based. 

[0198] In another aspect, one of R1, R 2 , R 3 , and R 4 in Formula I is derived from the reaction with trimellitic anhydride, and the resultant molecule is hydroxypropyl methylcellulose trimellitate, abbreviated HPMCT, which can remain molecularly dispersed and mostly dissociated in solution at pH ranging from about 3 to about 14. 

[0199] In another aspect, R1, R 2 , R 3 , and R 4 in Formula I is derived from the reaction with a mixture of maleic anhydride and acetic acid, and the resultant molecule is hydroxypropyl methylcellulose acetate maleate, abbreviated HPMC-AM, which can remain molecularly dispersed and mostly dissociated in solution at pH ranging from about 3 to about 14. 

[0200] In another aspect R1, R 2 , R 3 , and R 4 in Formula I is derived from the reaction with a mixture of2-sulfobenzoic acid cyclic anhydride and acetic acid, and the resultant molecule is hydroxypropyl methylcellulose acetate sul› fobenzoate, and can remain molecularly dispersed and mostly dissociated in solution at pH ranging from about 3 to about 14. 

[0201] In another aspect R1, R 2 , R 3 , and R 4 in Formula I is derived from the reaction with a mixture of trimellitic anhydride and acetic acid, and the resultant molecule is cellulose acetate trimellitate, abbreviated CAT, which is molecularly dispersed and mostly dissociated in solution at pH ranging from about 3 to about 14. 

[0202] In another aspect R1, R2, R 3 , and R 4 in Formula I is derived from reaction with a mixture of 2-sulfobenzoic acid cyclic anhydride and acetic acid, and the resultant molecule is cellulose acetate sulfobenzoate, which is molecularly dispersed and mostly dissociated in solution at pH ranging from about 3 to about 14. 

