cellulose, carbopol and citric acid) on drug release from chitosan matrix tablets was
investigated using diltiazem hydrochloride. Upadrastha and coworkers investigated
the potential applications of chitosan as a binder. Chitosan, when used at a concentration of 2% of the tablet weight, led to only 30% of the drug being dissolved in the
same time period.
6.1.2 Chitosan for Dental Disease
Local delivery of drugs and other bioactive agents directly into the periodontal
pocket has received a lot of attention lately. The adherence of oral bacteria on the
tooth surface leads to plaque formation. It is believed that the adhesion between the
bacteria and tooth surface is due to electrostatic and hydrophobic interactions.
These interactions are disrupted by chitosan because of competition by the positively charged amine groups. A cross-over experiment was performed to evaluate
the effect of phosphorylated chitosan on plaque formation. The test group of human
subjects rinsed with a mouthwash containing 0.5% (w/v) phosphorylated chitosan
three times a day. After 3 days of wash out, the same subjects rinsed with a
mouthwash without chitosan (placebo group). Following a 4-day rinsing period,
the newly formed plaque on the upper front teeth was distinguished from the old
plaque by the use of a two-tone disclosing agent (Dis-plaque). In comparison to
placebo, the test solution significantly reduced both the newly formed and old
plaque on the upper front teeth. The test solution reduced the newly formed plaque
by 26% as compared to the placebo, whereas the old plaque was reduced by 61% as
compared to placebo [49].
A very intriguing development concerns a drug delivery system for the
treatment of periodontitis. It consists of two components. The first is a clay
product loaded with tetracycline. The clay product is coated with chitosan to
retard drug release. The second component is a thermo-responsive polymer
mixed with polyethylene glycol that is syringable at room temperature but
solidifies upon warming up to body temperature. The solidified polymer remains
60 min in situ. After that time, it still inhibits the formation of bacterial colonies,
and still contains much more of the antibiotic than the control containing no
chitosan.
6.2 Chitosan for Buccal Delivery Systems
An ideal buccal delivery system should stay in the oral cavity for at least few hours
and release the active ingredients in a unidirectional way towards the mucosa in a
controlled or sustained-release fashion. Muco- and bioadhesive polymers are supposed to prolong the residence time of the device in the oral cavity. One of the
experiments developed a direct staining method to visualize the polymer adhesion
to human buccal cells after exposure to an aqueous dispersion of chitosan. An
in vivo study was performed on a test group of human subjects, who rinsed with
Biopolymeric Micro- and Nanoparticles: Preparation, Characterization and. . .
287
investigated using diltiazem hydrochloride. Upadrastha and coworkers investigated
the potential applications of chitosan as a binder. Chitosan, when used at a concentration of 2% of the tablet weight, led to only 30% of the drug being dissolved in the
same time period.
6.1.2 Chitosan for Dental Disease
Local delivery of drugs and other bioactive agents directly into the periodontal
pocket has received a lot of attention lately. The adherence of oral bacteria on the
tooth surface leads to plaque formation. It is believed that the adhesion between the
bacteria and tooth surface is due to electrostatic and hydrophobic interactions.
These interactions are disrupted by chitosan because of competition by the positively charged amine groups. A cross-over experiment was performed to evaluate
the effect of phosphorylated chitosan on plaque formation. The test group of human
subjects rinsed with a mouthwash containing 0.5% (w/v) phosphorylated chitosan
three times a day. After 3 days of wash out, the same subjects rinsed with a
mouthwash without chitosan (placebo group). Following a 4-day rinsing period,
the newly formed plaque on the upper front teeth was distinguished from the old
plaque by the use of a two-tone disclosing agent (Dis-plaque). In comparison to
placebo, the test solution significantly reduced both the newly formed and old
plaque on the upper front teeth. The test solution reduced the newly formed plaque
by 26% as compared to the placebo, whereas the old plaque was reduced by 61% as
compared to placebo [49].
A very intriguing development concerns a drug delivery system for the
treatment of periodontitis. It consists of two components. The first is a clay
product loaded with tetracycline. The clay product is coated with chitosan to
retard drug release. The second component is a thermo-responsive polymer
mixed with polyethylene glycol that is syringable at room temperature but
solidifies upon warming up to body temperature. The solidified polymer remains
60 min in situ. After that time, it still inhibits the formation of bacterial colonies,
and still contains much more of the antibiotic than the control containing no
chitosan.
6.2 Chitosan for Buccal Delivery Systems
An ideal buccal delivery system should stay in the oral cavity for at least few hours
and release the active ingredients in a unidirectional way towards the mucosa in a
controlled or sustained-release fashion. Muco- and bioadhesive polymers are supposed to prolong the residence time of the device in the oral cavity. One of the
experiments developed a direct staining method to visualize the polymer adhesion
to human buccal cells after exposure to an aqueous dispersion of chitosan. An
in vivo study was performed on a test group of human subjects, who rinsed with
Biopolymeric Micro- and Nanoparticles: Preparation, Characterization and. . .
287