ANYL 155 |
| Calcium phosphate pastes (CPPs), frequently used in bone repair, often exhibit poor injectability characteristics. To improve clinical performance of CPPs, the impact of liquid-to-powder ratio (L/P) and needle length on viscosity and injection force was examined. The injection force of CPP through a 3 ml syringe with a 16-gauge needle was measured at a constant rate of injection using needle lengths from zero to 4.5 inches. The viscosities of two CPPs with a L/P of 0.64 and 0.80 were measured as a function of shear rate. Pressure differentials across the needles were used to calculate the theoretical viscosities of the pastes using the Hagen-Poiseuille relationship and compared to measured values. Results showed the injection forces linearly increased as viscosity and needle length increased. The calculated viscosities of the CPPs were higher than the measured viscosities and indicated non-Newtonian behavior. |
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General Papers
7:00 PM-9:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Division of Analytical Chemistry |