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. 2020 Sep 2;25(17):4002. doi: 10.3390/molecules25174002

Table 2.

In vitro activity of chitosan formulations against intracellular Leishmania amastigotes at two pH values.

Compound Properties Medium pH = 7.5 * Medium pH = 6.5 *
L. major ** L. mexicana ** L. major ** L. mexicana **
EC50 µg/mL EC90 µg/mL EC50 µg/mL EC90 µg/mL EC50 µg/mL EC90 µg/mL EC50 µg/mL EC90 µg/mL
Amphotericin B (AmB solution) Purity ≥ 95%, MW 924.1 0.09 ± 0.003 0.5 ± 0.04 0.3 ± 0.003 0.7 ± 0.02 0.09 ± 0.003 0.5 ± 0.02 0.5 ± 0.04 0.6 ± 0.04
AmBisome® Liposomal AmB, Size = 70–80 nm 1.2 ± 0.07 8 ± 0.3 1.8 ± 0.08 12 ± 1 1.3 ± 0.08 7 ± 0.1 1.8 ± 0.07 13 ± 1
HMW chitosan MW = 310–375 KDa 105 ± 7 1192 ± 58 123 ± 5 2206 ± 5 10 ± 0.3 127 ± 5 16 ± 0.7 165 ± 27
CH-TPP nanoparticles Size = 67 ± 7 nm, Zeta potential = 28.5 ± 1.9 mV 162 ± 10 828 ± 43 177 ± 7 4020 ± 352 13 ± 0.5 122 ± 19 21 ± 0.9 284 ± 10
AmB-CH-TPP nanoparticles Size = 69 ± 8 nm, Zeta potential = 25.5 ± 1 mV 0.14 ± 0.09 1 ± 0.09 0.5 ± 0.01 1.8 ± 0.1 0.06 ± 0.003 0.5 ± 0.08 0.3 ± 0.01 1.8 ± 0.02
CH-Dex nanoparticles Size = 170 ± 9 nm, Zeta potential = −12.9 ± 3 mV No activity up to 486
AmB-CH-DEX nanoparticles Size = 174 ± 8 nm, Zeta potential = −11 ± 1 mV 0.16 ± 0.008 1.4 ± 0.02 0.5 ± 0.01 1.8 ± 0.05 0.16 ± 0.007 0.9 ± 0.04 0.4 ± 0.01 1.8 ± 0.05
TPP MW = 367.864 g/mol No activity up to 486
dextran sulphate MW = 40 KDa No activity up to 486

Experiments were conducted in quadruplicate cultures, data expressed as mean +/− SD (experiment was reproduced further two times with confirmed similar data not shown). * Statistically significant differences were found for the EC50 values of chitosan or CH-TPP at pH = 6.5 and pH = 7.5 (p < 0.05 by using t-test). ** L. major amastigotes were significantly more susceptible to AmB solution and AmB-loaded chitosan nanoparticles than L. mexicana (p < 0.05 by using an extra sum-of-squares F test). AmB solution, AmB-CH-TPP and AmB-CH-Dex had a similar anti-leishmanial activity.