10. For example, Fig. 6 shows PK profiles from infusions of moxifloxacin (MXF) designed to give a C max of ~4μg/mL and a
drug t 1/2 of ~10 h.
11. This will confirm the reproducibility of both the sampling
technique and subsequent sample analysis.
12. Our analyses of drug levels in PK samples taken simultaneously
from the CR and ECS compartments have given comparable
results in the case of smaller C2025D cartridges (ECS volume ¼ 3.2 mL). However, the same cannot be said for larger
C2011 HFCs (ECS volume ¼ 20 mL). In C2011 cartridges,
the C max for ECS samples was significantly lower than that
obtained for CR samples and the apparent drug half-life was
longer when measured in the ECS (see Fig. 6). Therefore, when
using a particular HFC size for the first time, we recommend
that PK samples are taken from both locations to confirm the
actual drug level(s) attained in the ECS. The reason for this
disparity remains unclear, but we speculate that the greatly
increased surface area presented by the larger HFCs may result
in increased binding and uneven distribution of the drug,
which is in turn influenced by its physico-chemical properties.
13. It is useful to leave an air bubble before the stopcock to help
visualize the precise moment at which drug enters the CR. We
typically make the infusion over 60 min at the same flow rate
being used to establish the apparent drug half-life.
14. For the C2025D cartridges that we use routinely, each cartridge is inoculated with bacterial numbers equivalent to a
3.2 mL volume at between 10e5 and 10e6 colony forming
units (cfu)/mL.
15. Discard the needle in a sharps container containing at least 10%
bleach as a supplementary biosafety precaution.
16. Plates may be supplemented with either 0.4% charcoal to minimize effects of drug carryover or specific drug concentrations
to select for resistant bacteria.
17. This not only distributes the culture evenly within the ECS,
avoiding excessive bacterial clumping and aggregation, but also
provides a visible appreciation of the culture density inside
the HFC.
18. The HFS operates under the relatively low pressure created by
the peristaltic pump. In the event of a malfunction that leads to
a pressure build-up, a weak tubing linkage in the system may be
forced apart. Similarly, a tubing connection might be broken,
for example, during transfer of the HFC between the incubator
and the BSC. In either case, such a failure compromises only
the sterility of the system, and the pathogenic bacteria remain
secured within the membrane-bound confines of the HFC.
730
A. Brett Mason and Ve ´ ronique Dartois
drug t 1/2 of ~10 h.
11. This will confirm the reproducibility of both the sampling
technique and subsequent sample analysis.
12. Our analyses of drug levels in PK samples taken simultaneously
from the CR and ECS compartments have given comparable
results in the case of smaller C2025D cartridges (ECS volume ¼ 3.2 mL). However, the same cannot be said for larger
C2011 HFCs (ECS volume ¼ 20 mL). In C2011 cartridges,
the C max for ECS samples was significantly lower than that
obtained for CR samples and the apparent drug half-life was
longer when measured in the ECS (see Fig. 6). Therefore, when
using a particular HFC size for the first time, we recommend
that PK samples are taken from both locations to confirm the
actual drug level(s) attained in the ECS. The reason for this
disparity remains unclear, but we speculate that the greatly
increased surface area presented by the larger HFCs may result
in increased binding and uneven distribution of the drug,
which is in turn influenced by its physico-chemical properties.
13. It is useful to leave an air bubble before the stopcock to help
visualize the precise moment at which drug enters the CR. We
typically make the infusion over 60 min at the same flow rate
being used to establish the apparent drug half-life.
14. For the C2025D cartridges that we use routinely, each cartridge is inoculated with bacterial numbers equivalent to a
3.2 mL volume at between 10e5 and 10e6 colony forming
units (cfu)/mL.
15. Discard the needle in a sharps container containing at least 10%
bleach as a supplementary biosafety precaution.
16. Plates may be supplemented with either 0.4% charcoal to minimize effects of drug carryover or specific drug concentrations
to select for resistant bacteria.
17. This not only distributes the culture evenly within the ECS,
avoiding excessive bacterial clumping and aggregation, but also
provides a visible appreciation of the culture density inside
the HFC.
18. The HFS operates under the relatively low pressure created by
the peristaltic pump. In the event of a malfunction that leads to
a pressure build-up, a weak tubing linkage in the system may be
forced apart. Similarly, a tubing connection might be broken,
for example, during transfer of the HFC between the incubator
and the BSC. In either case, such a failure compromises only
the sterility of the system, and the pathogenic bacteria remain
secured within the membrane-bound confines of the HFC.
730
A. Brett Mason and Ve ´ ronique Dartois