R. Jeppsson
Mar 13, 2009
Citations
0
Influential Citations
5
Citations
Quality indicators
Journal
Acta pharmacologica et toxicologica
Abstract
: Emulsified soya bean oil has been used as a vehicle for dissolving the base form of four local anaesthetics, lidocaine, quatacaine, butacaine and benzocaine and these formulations have been injected subcutaneously and intravenously into mouse and cat. Pharmacological effects investigated were local anaesthesia, smooth muscle relaxation and anti-arythmic effect. The magnitude of these effects were quantitatively compared when using the emulsion formulation and a water solution of the corresponding hydrochloride. Both in vitro and in vivo the smooth muscle relaxation obtained when using the emulsion forms was smaller than with the water solutions, probably due to the fact that not all of the drug is immediately released from the oil phase. A moderate prolongation of the local anaesthetic effects in vivo of lidocaine and quatacaine when administered subcutaneously into the mouse tail supports the assumption of a prolonged release of drug from the oil particles. Lidocaine in lipid emulsion given intravenously to cat protected the heart from electrical induced arythmias during a longer period of time than did the water solution. This response prolongation was explained by a combination of trapping of lipid particles in the myocardium and a slow release of the drug from the particles.