Drug Information for ISOFLURANE, USP (HOSPIRA, INC.): DESCRIPTION

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  • Isoflurane, USP, a nonflammable liquid administered by vaporizing, is a general inhalation anesthetic drug. It is 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether, and its structural formula is:

    Some physical constants are:

    Molecular weight

    184.5

    Boiling point at 760 mm Hg

    48.5°C (uncorr.)

    Refractive index nD20

    1.2990-1.3005

    Specific gravity 25°/25°C

    1.496

    Vapor pressure in mm Hg**

    20°C

    238

    25°C

    295

    30°C

    367

    35°C

    450

    **Equation for vapor pressure calculation:

    log10Pvap =

    A + B/T

    where:

    A = 8.056

    B = -1664.58

    T = °C + 273.16 (Kelvin)

    Partition coefficients at 37°C

    Water/gas

    0.61

    Blood/gas

    1.43

    Oil/gas

    90.8

    Partition coefficients at 25°C - rubber and plastic
    Conductive rubber/gas 62.0
    Butyl rubber/gas 75.0
    Polyvinyl chloride/gas 110.0
    Polyethylene/gas ~2.0
    Polyurethane/gas ~1.4
    Polyolefin/gas ~1.1
    Butyl acetate/gas ~2.5
    Purity by gas chromatography >99.9%

    Lower limit of flammability in oxygen or nitrous oxide at 9 joules/sec. and 23°C

    None

    Lower limit of flammability in oxygen or nitrous oxide at 900 joules/sec. and 23°C

    Greater than useful concentration in anesthesia.

    Isoflurane is a clear, colorless, stable liquid containing no additives or chemical stabilizers. Isoflurane has a mildly pungent, musty, ethereal odor. Samples stored in stability chambers in amber glass for five years, as well as samples directly exposed for 7 days to accelerated light conditions were unchanged in composition as determined by gas chromatography. Isoflurane in one normal sodium methoxide-methanol solution, a strong base, for over six months consumed essentially no alkali, indicative of strong base stability. Isoflurane does not decompose in the presence of soda lime, (at normal operating temperatures), and does not attack aluminum, tin, brass, iron or copper.

  • Drug Information Provided by National Library of Medicine (NLM).
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