Synovial fluid bupivacaine concentrations following single intra-articular injection in normal and osteoarthritic canine stifles.

Intra-articular bupivacaine helps alleviate pain in animals receiving joint surgery, but its use has become controversial as ex vivo studies have illuminated the potential for chondrotoxicity. Such studies typically involve cell cultures incubated in solutions containing high bupivacaine concentrations for long durations. The aim of this study was to measure the actual synovial fluid bupivacaine concentrations after intra-articular injection. Eight healthy beagles with normal stifles and 22 large and giant-breed dogs with stifle osteoarthritis (OA) were treated with a single intra-articular injection of bupivacaine (1 mg/kg) into a stifle. Joint fluid samples were taken from the treated stifle immediately after injection and 30 min after injection and analyzed for bupivacaine concentrations. Immediately after injection, the median bupivacaine concentrations in normal and OA stifles were 3.6 and 2.5 mg/mL, respectively. Thirty minutes after injection, bupivacaine concentrations in normal and OA stifles were 0.4 and 0.6 mg/mL, respectively. These results provide insight into the pharmacokinetics of bupivacaine after injection into a joint. Given its immediate dilution and rapid drop in synovial fluid concentration, bupivacaine is unlikely to damage chondrocytes when administered as a single intra-articular injection.

Effect of dehydration on raspberries: polyphenol and anthocyanin retention, antioxidant capacity, and antiadipogenic activity.

Fresh and dried raspberries prepared by freeze drying (FD), microwave-vacuum (MIVAC), hot-air drying (HAD), and a combination of hot-air drying and microwave-vacuum (HAD/MIVAC) drying methods were evaluated for polyphenol retention, total polyphenol and anthocyanin contents, total antioxidant capacity, and antiadipogenic activity (the inhibition of fat cell development). Ellagic acid and quercetin were present in the largest concentrations in fresh and dehydrated raspberries. Dehydration led to a loss of polyphenols and anthocyanins and antioxidant capacity. Polyphenols (aglycone form) were retained in the greatest amount: 20% (freeze dried) to 30% (HAD/MIVAC) (fresh = 100%). A total of 30% of polyphenols (glycoside form) were retained in raspberries dried by the HAD/MIVAC methods with 5% of retention observed for raspberries dried by FD, HAD, or MIVAC. FD and MIVAC resulted in higher retention of anthocyanins (aglycone form) than other drying methods. It was also observed that antioxidant activity was reduced by dehydration. Adipogenesis was inhibited by polyphenolic glycosides (30%) and aglycones (30% to 40%) in fresh and HAD/MIVAC raspberries. Extracts from dried raspberries by HAD/MIVAC methods were relatively more effective at inhibiting adipogenesis compared to HAD and FD dried raspberries.