42
4 Notes
1. Aqueous host (e.g., cyclodextrin) solution can be a mixture of
host and other molecules that may not disturb the formation of
guest/host aggregates, for example ophthalmic vehicle consisting of host molecule and pharmaceutical excipients (e.g., polymer, preservative, antioxidant, buffer salts, and osmotic agent)
that may not participate in the aggregate formation [12–14].
2. Equilibration period should be sufficient to reach solubility
equilibrium and depends on, for example, the physicochemical
stability of the guest molecule.
3. For jacketed vertical Franz diffusion cells, temperature should
be controlled by a bath circulation which is connected to individual cell. The bath circulator flows through each cell to
maintain cell temperature at about 25 °C (or some other temperature). Prior to the test, allow for few minutes to obtain
stable temperature in Franz diffusion cells.
4. The stirring speed should not interfere with the unstirred layer
or create bubble underneath mounted membrane, for example, 300 rpm.
5. Confirm that soaked membrane has no visible damage before
mounting.
6. Verify the absence of leakage especially between donor and
receptor compartments. Mounted membrane should not be
pierced or torn off with a pipette tip.
7. Sampling time points and intervals are determined based on
the solubility of guest compound and sensitivity of the analysis
method. It is recommended to have at least five sampling
points and that the study duration does not exceed 6 h.
8. MWCOs of inserted membranes can be varied to suit the
experimental requirements. All Teflon bars must be assembled
prior to loading the Teflon block into the base.
9. Volume of each side can be varied from 25 to 150 μL.
10. The dialysis block can be incubated at desired temperature
and/or placed on an orbital or reciprocating shaker to facilitate equilibration. Equilibrium time depends on the solubility
of guest compound and sensitivity of the analytical method. It
is important to ensure that equilibrium conditions have been
achieved and study time should not exceed 6 h.
11. In case of miniature dialysis devices, calculate the steady-state
flux using
q
t
instead of
dq
dt
.
12. The fraction guest in aggregate ranges from 0 to 1, indicating
that all aggregates in tested solution are able or unable to permeate through the membrane, respectively.
Phennapha Saokham and Thorsteinn Loftsson
4 Notes
1. Aqueous host (e.g., cyclodextrin) solution can be a mixture of
host and other molecules that may not disturb the formation of
guest/host aggregates, for example ophthalmic vehicle consisting of host molecule and pharmaceutical excipients (e.g., polymer, preservative, antioxidant, buffer salts, and osmotic agent)
that may not participate in the aggregate formation [12–14].
2. Equilibration period should be sufficient to reach solubility
equilibrium and depends on, for example, the physicochemical
stability of the guest molecule.
3. For jacketed vertical Franz diffusion cells, temperature should
be controlled by a bath circulation which is connected to individual cell. The bath circulator flows through each cell to
maintain cell temperature at about 25 °C (or some other temperature). Prior to the test, allow for few minutes to obtain
stable temperature in Franz diffusion cells.
4. The stirring speed should not interfere with the unstirred layer
or create bubble underneath mounted membrane, for example, 300 rpm.
5. Confirm that soaked membrane has no visible damage before
mounting.
6. Verify the absence of leakage especially between donor and
receptor compartments. Mounted membrane should not be
pierced or torn off with a pipette tip.
7. Sampling time points and intervals are determined based on
the solubility of guest compound and sensitivity of the analysis
method. It is recommended to have at least five sampling
points and that the study duration does not exceed 6 h.
8. MWCOs of inserted membranes can be varied to suit the
experimental requirements. All Teflon bars must be assembled
prior to loading the Teflon block into the base.
9. Volume of each side can be varied from 25 to 150 μL.
10. The dialysis block can be incubated at desired temperature
and/or placed on an orbital or reciprocating shaker to facilitate equilibration. Equilibrium time depends on the solubility
of guest compound and sensitivity of the analytical method. It
is important to ensure that equilibrium conditions have been
achieved and study time should not exceed 6 h.
11. In case of miniature dialysis devices, calculate the steady-state
flux using
q
t
instead of
dq
dt
.
12. The fraction guest in aggregate ranges from 0 to 1, indicating
that all aggregates in tested solution are able or unable to permeate through the membrane, respectively.
Phennapha Saokham and Thorsteinn Loftsson