A rheologically modified, osmotically balanced dispersion for an implant for the body. The dispersion includes an osmotic control agent of preferably polyvinylpyrrolidinone, a rheological agent of preferably guar gum, and an antimicrobial. Methods for filling an implant are also disclosed. The osmotic control agent or first polymeric osmotic control agent is present in the dispersion in an amount effective to substantially balance the osmotic pressure of the implant with the osmotic pressure of the portion of the body into which it is implanted. The rheological agent or second polymeric agent forms a three-dimensional network and is present in the dispersion in an amount effective such that the fill material is pseudoplastic. Both the first and second polymeric agents are biocompatible.