We studied the first-order degradation kinetics of Bisphenol F diglycidyl ether (BFDGE) in three water-based food simulants [3% (w/v) acetic acid, distilled water, and 15% (v/v) ethanol] at various temperatures. BFDGE and its first and second hydrolysis products were determined by reversed phase high-performance liquid chromatography with fluorescence detection. Nonlinear regression was used to fit the experimental data at 40, 50, and 60 degrees C with the proposed kinetic equations; the Arrhenius equation was then fitted to the rate constants obtained, and the kinetic models were tested by comparing experimental data obtained at 70 degrees C with the kinetic curves calculated using the rate constants predicted for this temperature. The half-life of BFDGE was longest in ethanol and shortest in acetic acid. The difference between the hydrolysis rates of BFDGE and Bisphenol A diglycidyl ether may be due to 10% of the BFDGE used being in n = 1 monomer form. The results imply that resins which comply with existing legislation on the migration of unreacted monomer may still contaminate foodstuffs.

Locomotor activity and food and water consumption are potentially indices of post-operative pain in laboratory rodents, but it is important to establish whether these variables are directly affected by opioid analgesics or by halothane anaesthesia in normal rats. The effects of three opioids, buprenorphine, nalbuphine and butorphanol administered alone or following halothane anaesthesia, were studied in groups of normal non-operated adult Wistar rats. All 3 analgesics affected food intake and activity levels, but had little or no effect on water intake. Buprenorphine caused a significant elevation of activity levels and a reduction in food intake at clinical doses (0·01 and 0·05 mg/kg s/c). Nalbuphine (0·5, 1 and 2 mg/kg s/c) caused a reduction in food intake but had a smaller stimulatory effect on locomotion. Butorphanol (0·4 mg/kg s/c) caused a reduction in food intake and elevation in activity. These results suggest that water consumption is likely to be a more reliable variable to use when assessing post-operative pain and the efficacy of analgesics in rats.

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