3.3 Iron
Cross-Linked Beads by
Complex Coacervation
and Conventional
Ionotropic Gelation
1. Dissolve 4 g of CMC and gelatine separately in distilled water
(45
C). Adjust the gelatine solution to pH 7, add 6 g of
ibuprofen (see Note 11) and stir at 40
C for 30 min. Add
the CMC solution (see Note 12) [11].
2. Use the complex coacervation method to prepare the polymerdrug beads by dropping 10% (w/v) HCl into a polymer-drug
solution, cooling it to 5
C. Form microcapsules by dropping
the polymer-drug coacervate solution into 50 mL of 30%
(w/v) aqueous ferric chloride (see Note 13).
3. Drop the microcapsules into 15% (w/v) ferric chloride in a
hydro-alcoholic solvent using an 18-gauge needle attached to
a 3 mL syringe (see Note 14). Leave the microcapsules to crosslink for 1 h at 5
C.
4. Collect the beads using a nylon mesh and wash once using
100 mL distilled water and twice using 100 mL of
2-propanol. Dry at 40
C for 6 h.
3.4 Aluminium
Cross-Linked Beads by
Emulsification
and Vibration
Technology
of Ionotropic Gelation
1. Dissolve 6.25 g of CMSC in 50 mL degassed distilled water
and add 30% (w/v) glycine and polyethylene glycol as a plasticizer (see Note 15). Using emulsification, add the red palm oil
(see Note 16) gradually into the magnetically stirring CMSC
solution and homogenize the resulting solution using automated magnetic stirrer at 10,000 rpm for 5 min (see Note
17) [8].
2. Apply the external ionotropic gelation method using a syringe
pump. Set a Buchi encapsulator with a 2 mm nozzle positioned
10 cm above a 200 mL of a 5% (v/v) aluminum chloride
solution (see Note 18). Adjust the settings to a flow rate of
0.8 mL/min, electrode voltage of 900 mV, vibration frequency
of 1700 Hz, and 35
C (see Note 19).
3. Leave the beads to cross-link for 1 h. Collect the beads using a
plastic mesh and wash using distilled water. Freeze the oil
loaded beads at À80
C overnight and then freeze-dry for
24 h (see Note 20). Store the beads in a desiccator (see Note
21).
3.5 Calcium
Cross-Linked by
Vibration Technology
of Ionotropic Gelation
and Surface
Coated Beads
1. Dissolve 5 g of sodium alginate in 250 mL distilled water using
a magnetic stirrer. Stir 500 mg of ispaghula husk overnight in
100 mL of distilled water and remove debris using a muslin
cloth (see Note 22). Add the ispaghula filtrate into the alginate
solution [9].
2. Triturate 25–30 mL of the ispaghula-alginate solution onto
ground 5 g of ibuprofen (see Note 11). Stir the ibuprofenalginate solution and add the remaining alginate solution.
Hydrogel Beads of Natural Polymers for Colon-Targeted Drug Delivery
177
Cross-Linked Beads by
Complex Coacervation
and Conventional
Ionotropic Gelation
1. Dissolve 4 g of CMC and gelatine separately in distilled water
(45
C). Adjust the gelatine solution to pH 7, add 6 g of
ibuprofen (see Note 11) and stir at 40
C for 30 min. Add
the CMC solution (see Note 12) [11].
2. Use the complex coacervation method to prepare the polymerdrug beads by dropping 10% (w/v) HCl into a polymer-drug
solution, cooling it to 5
C. Form microcapsules by dropping
the polymer-drug coacervate solution into 50 mL of 30%
(w/v) aqueous ferric chloride (see Note 13).
3. Drop the microcapsules into 15% (w/v) ferric chloride in a
hydro-alcoholic solvent using an 18-gauge needle attached to
a 3 mL syringe (see Note 14). Leave the microcapsules to crosslink for 1 h at 5
C.
4. Collect the beads using a nylon mesh and wash once using
100 mL distilled water and twice using 100 mL of
2-propanol. Dry at 40
C for 6 h.
3.4 Aluminium
Cross-Linked Beads by
Emulsification
and Vibration
Technology
of Ionotropic Gelation
1. Dissolve 6.25 g of CMSC in 50 mL degassed distilled water
and add 30% (w/v) glycine and polyethylene glycol as a plasticizer (see Note 15). Using emulsification, add the red palm oil
(see Note 16) gradually into the magnetically stirring CMSC
solution and homogenize the resulting solution using automated magnetic stirrer at 10,000 rpm for 5 min (see Note
17) [8].
2. Apply the external ionotropic gelation method using a syringe
pump. Set a Buchi encapsulator with a 2 mm nozzle positioned
10 cm above a 200 mL of a 5% (v/v) aluminum chloride
solution (see Note 18). Adjust the settings to a flow rate of
0.8 mL/min, electrode voltage of 900 mV, vibration frequency
of 1700 Hz, and 35
C (see Note 19).
3. Leave the beads to cross-link for 1 h. Collect the beads using a
plastic mesh and wash using distilled water. Freeze the oil
loaded beads at À80
C overnight and then freeze-dry for
24 h (see Note 20). Store the beads in a desiccator (see Note
21).
3.5 Calcium
Cross-Linked by
Vibration Technology
of Ionotropic Gelation
and Surface
Coated Beads
1. Dissolve 5 g of sodium alginate in 250 mL distilled water using
a magnetic stirrer. Stir 500 mg of ispaghula husk overnight in
100 mL of distilled water and remove debris using a muslin
cloth (see Note 22). Add the ispaghula filtrate into the alginate
solution [9].
2. Triturate 25–30 mL of the ispaghula-alginate solution onto
ground 5 g of ibuprofen (see Note 11). Stir the ibuprofenalginate solution and add the remaining alginate solution.
Hydrogel Beads of Natural Polymers for Colon-Targeted Drug Delivery
177