Elimination of exogenously injected sodium‐hyaluronate from rabbit flexor tendon sheaths

Abstract

To obtain information about the elimination of Na hyaluronate (NaHe) deposited in flexor tendon sheaths in rabbits, two flexor tendon sheaths from each hind limb were operatively exposed in 15 animals and each filled with one of four different NaHe preparations, namely: 10 mg/ml, MW 2.6 × 10⁶; 10 mg/ml, MW 6.3 × 10⁶; 19 mg/ml, MW 3.0 × 10⁶; and 19 mg/ml, MW 6.5 × 10⁶. One, 3, and 7 days after surgery, the NaHe concentration was measured in frozen specimens from the tendon sheaths. One day after surgery, NaHe concentration in the tendon sheath fluid was close to 10 mg/ml in all groups. Three and 7 days after surgery it was higher in tendon sheaths in which NaHe preparations with a high (19 mg/ml) rather than with a low concentration (10 mg/ml) had been deposited. At 3 days, NaHe concentration was also higher in sheaths that had received a preparation with a high MW (6.5 × 10⁶) than those with a lower MW (2.6 or 3.0 × 10⁶). The findings suggest that within the first 24 h, a dilution of concentrated NaHe preparations takes place, probably as a result of their hyperoncotic properties. After 24 h, there was a slower decline in NaHe concentration when more concentrated solutions (19 mg/ml) and solutions with high MWs (6.5 × 10⁶) were administered. Development of pharmaceutical NaHe preparations with slow elimination from tendon sheaths should reasonably be focused on a solution with a high MW and high concentration.