ABSTRACT
The stability of propofol emulsion following the addition of various amounts of lignocaine solution was investigated. The investigations used were macroscopic and microscopic observations and electroacoustic determination of both droplet size and zeta potential. Evidence of emulsion instability was present following the addition of even small amounts of lignocaine. Resultant changes are unlikely to be clinically important following the addition of less than 20 mg of lignocaine to 200 mg of propofol (20 ml of propofol emulsion). It is recommended, however, that anaesthetists consider the possibility of destabilisation of propofol emulsion when adding larger doses of lignocaine, or when there is a delay between formulation and administration of the propofol-lignocaine mixtures.
Subject(s)
Anesthetics, Intravenous/chemistry , Anesthetics, Local/chemistry , Lidocaine/chemistry , Propofol/chemistry , Anesthetics, Local/administration & dosage , Chemical Phenomena , Chemistry, Physical , Dose-Response Relationship, Drug , Drug Incompatibility , Drug Stability , Emulsions , Lidocaine/administration & dosageABSTRACT
The compressibilities of three lunar samples were studied at room temperature from 0 to 40 kilobars. The samples were a fine-grained vesicular crystalline rock (type A), a microbreccia (type C), and fines (type D). All samples were porous. The microbreccia and fines were quite compressible at all pressures; the compressibility of the crystalline rock was somewhat less, being 8.4 megabar(-1) at 1 atmosphere and 1.5 megabar(-1) at 35 kilobars. Some porosity appeared to remain in the samples at all pressures. Thus the pressure-volume data derived from these samples may be representative of porous surface and near-surface material in the vicinity of the Apollo 11 landing site but may not be representative of lunar material at depth.
