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The purpose of the experiment was to assess interactions of dopamine with propranolol as an infiltrative anesthetic.

Background: The purpose of the experiment was to assess interactions of dopamine with propranolol as an infiltrative anesthetic. Methods: After injecting the rats with four doses of drugs subcutaneously, the cutaneous analgesic effect of propranolol was compared with dopamine through the blockade of cutaneous trunci muscle reflex (CTMR) in response to local skin pinprick. Drug–drug interactions were examined viaan isobolographic analysis. Results: We demonstrated that the action of propranolol and dopamine was dose dependent to skin infiltrative analgesia. On the ED50(50% effective dose) basis, the rank of drug potency was propranolol (11.3 [10.6–12.2] µmol) > dopamine (195 [188–205] µmol) (p< 0.001). At the equi-anesthetic doses (ED25, ED50, ED75), the block duration caused by dopamine was equal to that caused by propranolol. Coadministration of dopamine and propranolol exhibited a synergistic effect on infiltrative cutaneous analgesia. Conclusions: The preclinical data showed that dopamine produced a lesser potency but a comparable duration of cutaneous analgesia compared to propranolol. Adding dopamine to propranolol potentiated and prolonged propranolol’s cutaneous analgesic effect.

This paper provides a novel route to prepare silica monoliths with hierarchical porous structure via freeze drying. In this method, macroporous silica monoliths were first produced by freeze-drying and calcination. By adjusting the concentration of cetyltrimethylammonium bromide in ethylsilicate, a layer of mesoporous thin film was attached on the macroporous silica monolith. The structural characterization of the hierarchical porous monoliths were studied by field emission scanning electron microscopy, mercury porosimeter and nitrogen adsorption-desorption techniques (BET). It turned out that the pore distribution of the obtained monoliths was ranged from 3.72 nm to 23.21nm and the maximum specific surface area calculated from BET was about 288 m2/g, which indicated the existence of hierarchical structure in the obtained material.