BACKGROUND The persistence of dermal fillers containing crosslinked hyaluronic acid (XLHA) correlates linearly to the concentration of polymer in solution. For dermal fillers composed of XLHA, a polymer concentration above approximately 25 mg/mL is not practical because it cannot be easily injected through a small-bore needle.

OBJECTIVE Formulating dermal fillers from mixtures of carboxymethylcellulose (CMC) and polyethylene oxide (PEO) has several advantages over XLHA. We hypothesize that increasing the concentration of CMC/PEO will increase the persistence in the dermis. These polymers of CMC and PEO can be formulated at higher concentrations than XLHA to produce smooth, particulate-free gels resulting in easier, more controllable injection. Second, these gels are not required to be covalently crosslinked; CMC/PEO forms a stable gel-like structure in solution without crosslinking.

MATERIALS AND METHODS Here we have prepared dermal fillers from CMC/PEO polymer blends at concentrations of 20 mg/mL (dermal filler 1), 29 mg/mL (dermal filler 2), 37 mg/mL (dermal filler 3), and 45 mg/mL (dermal filler 4) and measured their rheologic properties compared to commercial XLHA dermal fillers.

RESULTS AND CONCLUSIONS The data here demonstrate that it is possible to duplicate the rheologic properties of commercial XLHA fillers using CMC/PEO at different polymer concentrations to formulate improved dermal fillers. All of the dermal filler formulations prepared can be easily injected through 30-gauge needles.