used in combination with a second therapeutic agent active against the same or different virus, the same or different strain of bacteria, or the same or different type of fungal infection, the dose of each compound may either be the same as or differ from that when the compound is used alone. Appropriate doses will be readily determined by those skilled in the art, or by the attending physician. 

[0254] Further, compounds of Formula I and Formula II and the pharmaceutically acceptable formulations thereof can be vehicles or adjuvants for use in therapeutic and cosmetic applications, a thickener for topical administration or as an anti-infective agent. 

[0255] The following examples are provided to illustrate various embodiments of the present invention and shall not be considered as limiting the scope of the present invention in any way. Furthermore, they illustrate different synthetic means for preparing compounds of the present invention. These synthetic procedures are representative and illustra› tive of the procedures for preparing the compounds of the present invention. 

[0256] Cellulose acetate phthalate (CAP), cellulose acetate trimellitate (CAT), and hydroxypropyl methyl cel› lulose phthalate (HPMCP) and commercially available. They were purchased from Sigma/ Aldrich, and these three polymers had carboxylic acid moiety substitution patterns between 32 and 35 weight percent, and average molecular weight distributions in the range of 50 kD. The Dextran sulfate (DS) used had an average molecular weight of about 500 KD. All polyanions used in these studies were sus› pended in 50 nM sodium citrate buffer pH 7.0 at concen› trations ranging from 2% to 5% and were stored at 4 ° C. until use. 

Synthesis of Acrylic Based Polymers, Copolymers or Oli› gomers. 

[0257] Acrylic based polymers and copolymers are obtained using a variety of techniques that are apparent to one skilled in the art. For example, a synthetic scheme to synthesize MVE/MA involves the addition of 404.4 parts cyclohexane, and 269.6 parts ethyl acetate into a 1 liter pressure reactor. Next 0.3 parts of t-butylperoxypivilate are added at 58° C. in three installments of0.1 part each at times 0, 60 and 120 minutes from the first addition. Seventy-five parts of molten maleic anhydride and 49.0 parts of methyl vinyl ether are mixed together and gradually added to the reaction vessel at 58° C. and 65 psi over a 2 hour period of time. The reaction mixture is then held at 58° C. for two hours after the last addition of initiator. (The presence of maleic anhydride is determined by testing with triphenyl phosphene to ascertain the extent of the completion of the reaction; the resulting complex precipitates out of solution). After the reaction is complete, the product is cooled to room temperature, filtered and dried in a vacuum oven. If cross› linked copolymer is desired, then 6 parts of 1,7 octadiene is added to the reaction vessel before the addition of the t-butylperoxypivilate. 

## EXAMPLES 

## Example 1 

Derivatization of Acrylic-Based Polymers, Copolymers or Oligomers to Achieve Enhanced Solubility at Low pH. 

[0258] One skilled in the art could imagine several differ› ent mechanisms for creating diversity within the acrylic polymer or copolymer motif that will allow for variation in charge density or hydrophobicity. One mechanism is to interchange maleic anhydride in Example 1 above with any anhydride derivative of moieties containing one or more carboxylic acid group as shown in, but not limited to, Table 1. Alternatively a mixture of two or more anhydride con› taining moieties, derived from examples shown in Table 1, can be used to generate a polymer with alternating charged moieties. These moieties could be aliphatic or aromatic. 

[0259] A second mechanism to modify the hydrophobicity or electrostatic charge of an acrylic based polymer is to replace methyl vinyl ether described in Example 1 above with styrene, methyl methacrylate phthalic acid, trimellitic acid, vinyl acetate, or N-butyl acrylate. In addition, poly› mers or copolymers that incorporate coumarone, indene and carbazole can also be prepared. These aromatic structures, linked as copolymers to moieties bearing carboxylic acid, sulfonates or sulfates add variation to the hydrophobicity and electrostatic profile of the polymer or copolymer and are readily synthesized using standard technology (See. e.g. Brydson, J. A. Plastics Materials, second edition, Van Nos› trand Reinhold Company, New York (1970)). 

[0260] A third mechanism one could employ to alter the hydrophobic or electrostatic nature of a copolymer as depicted in Formula II, and Scheme 1 is to modify the anhydride intermediate of the copolymer to form a half ester. To do this, the anhydride ring is opened up in the presence of the alcohol intermediate of the desired moiety to be added as shown in Scheme 1. Some examples of compounds with desirable functional groups for addition to the polymer backbone are shown in Table 1. 

Synthesis of Cellulose-Based Polymers and Copolymers or Oligomers. 

[0261] For the synthesis of hydroxypropyl methylcellu› lose trimellitate (HPMCT), 700 grams of HMPC is dis› solved in 2100 grams of acetic acid (reagent grade) in a 5 liter kneader at 70° C. Trimellitic anhydride (Waka Pure Chemical Industries) and 275 grams of sodium acetate (reagent grade) as a catalyst are added and the reaction is allowed to proceed at 85 to 90° C. for 5 hours. After the reactions, 1200 grams of purified water is poured into the reaction mixture, and the resultant mixture is poured into an excess amount of purified water to precipitate the polymer. The crude polymer is washed well with water and then dried to yield HPMCT. Hydroxypropyl methylcellulose acetate maleate (HPMC-AM) is synthesized similarly using a mix› ture of acetic and maleic anhydride in place of trimellitic anhydride. Other methods can be employed to generate the carboxylic acids substituted polymers of the present inven› tion. 

[0262] The degree of carboxylic acid substitution is dependent upon the conditions used and the purity of the reactants. For example, Kokubo et al. ("Development of cellulose derivatives as novel enteric coating agents soluble at pH 3.5-4.5 and higher."Chem. Pharm. Bull. 45:1350-1353 (1997)) demonstrate how the degree of substitution per unit of glucose of methoxyl, hydroxypropoxyl, and trimellityl can have large differences in the pH solubility of the 

## Example 2 

## Example 3 

