3. Immediately use the external ionotropic gelation method via a
Buchi encapsulator with a 750 μm nozzle positioned above a
5% (w/v) calcium chloride solution. Adjust the settings to an
air pressure of 500–700 mbar, electrode voltage of 1000 mV,
and vibration frequency of 600 Hz (see Note 19). Leave the
beads to cure for 30 min. Remove the beads using a nylon mesh
and wash using distilled water repeatedly. Dry the beads at
40
C until constant weight and store them in glass vials at
room temperature.
4. To coat the beads with zein, a manual atomizer spray bottle is
used to spray 5 mL of 10% zein solution onto 1 g of uniform
layered polymer-drug beads (see Note 23). Dry the beads using
a conventional hair dryer at 40–50
C. Repeat the same spraying process after turning the beads to ensure an even coating.
3.6 Aluminium
Cross-Linked Beads by
Conventional
Ionotropic Gelation
1. Prepare the CM-TG diclofenac beads by dissolving 100 mL
10/20% (w/v) of CM-TG (DS 1.2) and adding 10/20% (w/v)
of sodium diclofenac (see Note 24), respectively. Stir using
automated magnetic stirrer at 600 rpm and subject the solution
to sonication for 1 min using Hielscher UIP500hd ultrasonic
homogenizer at 60% amplitude [12].
2. Use the conventional ionotropic method by dropping the
CM-TG diclofenac solution into a magnetically stirred 5%
(w/v) aluminum chloride solution using a 10 mL syringe
with 21-gauge needle positioned at a 6 cm distance from the
cross-linking solution. Leave the beads to cross-link for 15 min
(see Note 25).
4 Notes
1. 10% (w/v) CMSP solution was chosen as any concentration
range below 10% (w/v) (2.5–7.5%) would not provide sufficient viscosity to yield stable beads. A CMSP concentration
above 10% (w/v) would cause excessive viscosity resulting in
extruding difficulties of the CMSP solution using the conventional method. This yields the formation of teardrop-shaped
beads. Due to elevated viscosity, the formation of air bubbles
could be induced (in reference to Fig. 2).
2. The CMSC solution is adjusted to pH 4.3 to allow 5-ASA to be
predominantly present as insoluble dipolar zwitterionic species
by approaching its isoelectric point. This leads to a higher drug
loading efficiency as the degree of solubility promotes the loss
of the drug of the polymer matrix into the gelation medium
during the ionotropic gelation process. The stability of the
5-ASA was tested in different pH media and found that it is
stable up to pH 7 (in reference to Fig. 3).
178
Janarthanan Pushpamalar et al.
Buchi encapsulator with a 750 μm nozzle positioned above a
5% (w/v) calcium chloride solution. Adjust the settings to an
air pressure of 500–700 mbar, electrode voltage of 1000 mV,
and vibration frequency of 600 Hz (see Note 19). Leave the
beads to cure for 30 min. Remove the beads using a nylon mesh
and wash using distilled water repeatedly. Dry the beads at
40
C until constant weight and store them in glass vials at
room temperature.
4. To coat the beads with zein, a manual atomizer spray bottle is
used to spray 5 mL of 10% zein solution onto 1 g of uniform
layered polymer-drug beads (see Note 23). Dry the beads using
a conventional hair dryer at 40–50
C. Repeat the same spraying process after turning the beads to ensure an even coating.
3.6 Aluminium
Cross-Linked Beads by
Conventional
Ionotropic Gelation
1. Prepare the CM-TG diclofenac beads by dissolving 100 mL
10/20% (w/v) of CM-TG (DS 1.2) and adding 10/20% (w/v)
of sodium diclofenac (see Note 24), respectively. Stir using
automated magnetic stirrer at 600 rpm and subject the solution
to sonication for 1 min using Hielscher UIP500hd ultrasonic
homogenizer at 60% amplitude [12].
2. Use the conventional ionotropic method by dropping the
CM-TG diclofenac solution into a magnetically stirred 5%
(w/v) aluminum chloride solution using a 10 mL syringe
with 21-gauge needle positioned at a 6 cm distance from the
cross-linking solution. Leave the beads to cross-link for 15 min
(see Note 25).
4 Notes
1. 10% (w/v) CMSP solution was chosen as any concentration
range below 10% (w/v) (2.5–7.5%) would not provide sufficient viscosity to yield stable beads. A CMSP concentration
above 10% (w/v) would cause excessive viscosity resulting in
extruding difficulties of the CMSP solution using the conventional method. This yields the formation of teardrop-shaped
beads. Due to elevated viscosity, the formation of air bubbles
could be induced (in reference to Fig. 2).
2. The CMSC solution is adjusted to pH 4.3 to allow 5-ASA to be
predominantly present as insoluble dipolar zwitterionic species
by approaching its isoelectric point. This leads to a higher drug
loading efficiency as the degree of solubility promotes the loss
of the drug of the polymer matrix into the gelation medium
during the ionotropic gelation process. The stability of the
5-ASA was tested in different pH media and found that it is
stable up to pH 7 (in reference to Fig. 3).
178
Janarthanan Pushpamalar et al.