Single-dose glass ampules have been developed for ease of administration, accuracy of measurement of dosage, sterility, and use in prepackaged procedure kits. Glass particle fragmentation and ampule contamination upon opening has been previously described in the literature (1-9). In a recent editorial, Waller and George discuss particulate contamination in intravenous solutions and in glass ampules after they have been opened (9). They note the reduction of phlebitis with in-line filtration of intravenous solutions. They suggest, as do others, that filtration will reduce the risk of contamination and is a "sensible precaution" after opening of glass ampules. To date, however, a randomized, blinded, controlled study of the efficacy of filtration of glass ampules is lacking. The purpose of this study was twofold. The first phase was designed to examine glass particle contamination as a function of ampule size and the second phase to be a randomized, blinded, controlled study of glass particle contamination after aspiration of the contents of the ampule using needles of different sizes with and without a filter attached to the needle.
MethodsPhase I Three sizes (1, 5, and 20 ml) of single-dose glass ampules were examined. For each size, ten ampules from the same manufacturer lot number were opened by hand without use of special devices. From each ampule, the entire contents were withdrawn into a 3 mm internal diameter tubing attached to a prewashed 10-ml plastic syringe. The ampules were then rinsed in triplicate with sterile water with one-third the ampule's volume each time. Both the original contents and the rinsing solutions were then filtered through a Durapore Filter 0.22 micron 47 mm in a Buchner
The gamma and Erlang density functions describe a large class of lagged, right-skewed distributions. The Erlang distribution has been shown to be the analytic solution for a chain of compartments with identical rate constants. This relationship makes it useful for the analysis of first-pass pulmonary drug uptake data following intravenous bolus administration and the incorporation of this analysis into an overall systemic drug disposition model. However, others have shown that one Erlang density function characterizes the residence time distribution of solutes in single tissues with significant systematic error. We propose a model of two Erlang density functions in parallel that does characterize well the arterial appearance of indocyanine green, antipyrine, and alfentanil administered simultaneously by right atrial bolus injection. We derive the equations that permit calculation of the higher order moments of a system consisting of two parallel Erlang density functions and use the results of these calculations from the data for all three indicators to estimate pulmonary capillary blood volume and mean transit time in the dog.
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