Bioactivities of Chitosan and Its Derivatives - Chitosan Based Hydrogels: Functions and Applications - page 155

was collected by centrifugation and redissolved in water. The solution was then loaded
onto the Sephadex G25 column and deionized water was used as the eluent. The eluate
was monitored for protein by measuring the absorbance at 280 nm. The first active fraction
was collected as the purified hemicellulase solution.
Chitosan (200 g) was completely dissolved in 4000 mL of 2% acetic acid. After 3 h, the
solution was neutralized to pH 5.5 and left overnight. The solution in the reaction vessel
was placed in a water bath at 50°C, and 20 mL of enzyme solution (9.8 wt%) was added in
order to initiate reaction. When 0.2 mL of the mixture was taken out and mixed with 5 mL
of 4% NaOH solution and no precipitate was produced, the reaction mixture was cooled.
After centrifugation, the supernatant was processed according to the following methods,
to gain HCOS-B, MCOS-B, and LCOS-B samples ( cf . Table 3.4).
Assays of antitumor activities : Antitumor effects on Sarcoma-180 (S-180) were observed in
normal Kunming mice or adult BALB/c mice. The test was performed at a dose of 0.2 mL
(~1.0 × 10 7 mL −1 ) implanted subcutaneously at the right groin, and then observing the
effect on the growth of the tumor in ascite form. After 24 h of tumor implantation, the test
samples dissolved in physiological saline were provided once a day by intraperitoneal (i.p.)
injection or by oral administration (p.o.) for 10 days, whereas 0.9% saline was provided for
t The cont rol g roup. T The a n i mals were sacr iiced, a nd t The t u mors were dissected a nd weighed.
The tumor growth inhibition ratio was calculated by using the formula

100 × ( CT

C

− )

Inhibition rate (%) =

where C is the average tumor weight of the control group and T is the tumor weight of the
treated sample group. The spleen index was calculated by using the formula

Spleen weight
Finalbodyweight

Spleen index = × 100

The maximum inhibition rate of UCOS-B reaches 64%. However, BCOS-B shows a lower
activity than UCOS-B, indicating that boiling to remove enzyme modified the structure of
COSs caused by side reactions such as the Maillard reaction. UCOS-B with free amine has
a higher inhibitory rate than the acetate of the separated three fractions HCOS-A, MCOS-A,
and LCOS-A, suggesting that the free amine group might be an important factor for the
antitumor activity of chitosan.

TAble 3.4
Plasma Pharmacokinetic Variables Following Administration of DTX (i.v.) and
LMWC-DTX (p.o.) in Normal Mice

LMWC-DTX (p.o) DTX (i.v.)

Variable 5 mg/kg 10 mg/kg 5 mg/kg 10 mg/kg

C max (μg/mL) 0.82 2.08 65.57 125.58

T max (min) 240.00 240.00 1.00 1.00

Half-life (min) 202.20 489.60 35.40 33.00

29.02 43.20 4.69 11.34

AU C 0→∞ (μg h/mL)