Jun.28,2007  25  US 2007/0148124 Al  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.  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 3  Example 1  EXAMPLES  Example 2 