Application of Chitosan-Based Gels in Pharmaceuticals - Chitosan Based Hydrogels: Functions and Applications - page 312

TAble 7.1
Chitosan-Based Drug Delivery Systems Prepared Using Different Methods
for Various Ki nds of Drugs

Type of System Method of Preparation Drug

Tablets Matrix Diclofenac sodium, pentoxyphylline, salicylic acid,

theophylline

Coating Propranolol HCl

Capsules Capsule Shell insulin, 5-amino salicylic acid

Microspheres/
Microparticles

Emulsion cross-linking Theophylline, cisplatin, pentazocine, phenobarbitone,

theophylline, insulin, 5-fluorouracil, diclofenac
sodium, griseofulvin, aspirin, diphtheria toxoid,
pamidronate, suberoylbisphosphonate, mitoxantrone,
progesterone

Coacervation/precipitation Prednisolone, interleukin-2, propranolol-HCl

Spray-drying Cimetidine, famotidine, nizatidine, vitamin D-2,

diclofenac sodium, ketoprofen, metoclopramide-HCl,
bovine serum albumin, ampicillin, cetylpyridinium
chloride, oxytetracycline, betamethasone

Ionic gelation Felodipine

Sieving method Clozapine

Nanoparticles Emulsion-droplet coalescence Gadopentetic acid

Coacervation/precipitation DNA, doxorubicin

Ionic gelation Insulin, ricin, bovine serum albumin, CyA

Reverse micellar method Doxorubicin

Beads Coacervation/precipitation Adriamycin, nifedipine, bovine serum albumin,

salbutamol sulfate, lidocaine-HCl, riboflavin

Films Solution casting Isosorbide dinitrate, chlorhexidine gluconate, trypsin,

granulocyte-macrophage colony-stimulating factor,
acyclovir, riboflavine, testosterone, progesterone,
beta-estradiol

Gel Cross-linking Chlorpheniramine maleate, aspirin, theophylline,

caffeine, lidocaine-HCl, hydrocortisone acetate,
5-fluorouracil

Source: Adapted from Agnihotri, S. A., Mallikarjuna, N. N., and Aminabhavi, T. M. 2004. J Control Release 100:

5-28.

stirring during the formation of emulsion. This method is schematically represented in
Figure 7.1 [1]. The emulsion cross-linking method has a few drawbacks since it involves
tedious procedures as well as uses harsh cross-linking agents, which might induce
chemical reactions with the active agent. However, complete removal of the unreacted
cross-linking agent may be difficult in this process.

7.2.1.2 Coacervation/Precipitation

This method utilizes the physicochemical property of chitosan since it is insoluble in
an alkaline pH medium but precipitates/coacervates when it comes in contact with an
alkaline solution. Particles are produced by blowing a chitosan solution into an alkali
solution, such as sodium hydroxide, NaOH-methanol and ethanediamine, through a
compressed air nozzle to form coacervate droplets [4]. Separation and purification of