14. 18-gauge needle size was used to prevent clogging of the
coacervate complex extrusion.
15. Plasticizer addition affects the oil loading of the bead but
improves its fragile characteristics to a smoother surface and
shape. Adding PEG-400 improves the thermal stability of the
beads.
16. The beads size should not change regardless of the oil loading
concentration. The loading efficiency is independent of the oil
loading when it exceeds 40% since oil can leak through the
polymer matrix into the cross-linking solution due to phase
separation.
17. Emulsification allows a temporarily stable mixture of immiscible polymer and oil. Elevated shear flow allows a homogenizer
to disperse the immiscible oil into small droplets, which cannot
be done by stirring.
18. A 5% AlCl 3 cross-linker solution is used since elevated concentrations (e.g., 10%) would cause too rapid cross-linking that
compacts the beads matrix excessively, leading to the oil
leakage.
19. Using vibration technology-based ionotropic gelation allows
the liquid jet to be prilled into small droplets by using vibrational frequencies. This enables the reproducible production of
mono-dispersed and homogeneous particles.
20. Conventional oven drying flattens out the shape of the bead.
Freeze drying is advantageous as it minimizes oxidation of oil
by not exposing the beads to heat.
21. The percentage of oil lost during the storage phase should be
investigated due to the porous nature of the polymer matrix
allowing the oil to seep out.
22. Ispaghula concentrations varies every time undissolved husk
material was removed using muslin (cheese) cloth. There is no
control over the ratio of dissolved and undissolved husk. The
filtration is time consuming due to the viscous, non-flowing
nature of ispaghula.
23. Using a conventional spray bottle to coat the beads with zein
has minimal control over the thickness and even distribution of
the coating material. It would be advised to use a pharmaceutical coating pan.
24. Drug entrapment efficiency is considered low with less than
40% compared to [7, 10, 11] despite increasing drug concentration to 20%. This is because tragacanth gum has a less rigid
matrix, allowing the drug to diffuse through the matrix easily
during cross-linking. The number of carboxymethylation of
the tragacanth gum backbone chain is low and therefore is
expected to yield a less rigid hydrogel matrix.
Hydrogel Beads of Natural Polymers for Colon-Targeted Drug Delivery
181
coacervate complex extrusion.
15. Plasticizer addition affects the oil loading of the bead but
improves its fragile characteristics to a smoother surface and
shape. Adding PEG-400 improves the thermal stability of the
beads.
16. The beads size should not change regardless of the oil loading
concentration. The loading efficiency is independent of the oil
loading when it exceeds 40% since oil can leak through the
polymer matrix into the cross-linking solution due to phase
separation.
17. Emulsification allows a temporarily stable mixture of immiscible polymer and oil. Elevated shear flow allows a homogenizer
to disperse the immiscible oil into small droplets, which cannot
be done by stirring.
18. A 5% AlCl 3 cross-linker solution is used since elevated concentrations (e.g., 10%) would cause too rapid cross-linking that
compacts the beads matrix excessively, leading to the oil
leakage.
19. Using vibration technology-based ionotropic gelation allows
the liquid jet to be prilled into small droplets by using vibrational frequencies. This enables the reproducible production of
mono-dispersed and homogeneous particles.
20. Conventional oven drying flattens out the shape of the bead.
Freeze drying is advantageous as it minimizes oxidation of oil
by not exposing the beads to heat.
21. The percentage of oil lost during the storage phase should be
investigated due to the porous nature of the polymer matrix
allowing the oil to seep out.
22. Ispaghula concentrations varies every time undissolved husk
material was removed using muslin (cheese) cloth. There is no
control over the ratio of dissolved and undissolved husk. The
filtration is time consuming due to the viscous, non-flowing
nature of ispaghula.
23. Using a conventional spray bottle to coat the beads with zein
has minimal control over the thickness and even distribution of
the coating material. It would be advised to use a pharmaceutical coating pan.
24. Drug entrapment efficiency is considered low with less than
40% compared to [7, 10, 11] despite increasing drug concentration to 20%. This is because tragacanth gum has a less rigid
matrix, allowing the drug to diffuse through the matrix easily
during cross-linking. The number of carboxymethylation of
the tragacanth gum backbone chain is low and therefore is
expected to yield a less rigid hydrogel matrix.
Hydrogel Beads of Natural Polymers for Colon-Targeted Drug Delivery
181