Using chitosan gels as a toluidine blue O delivery system for photodynamic therapy of buccal cancer: In vitro and in vivo studies  Thierllen Barroso Graciano, Tatielle Soares Coutinho, Camila Beatriz Cressoni, Cristhiane de Paula Freitas, Maria Bernadete Riemma Pierre, Sanívia Aparecida de Lima Pereira, Marcos Massao Shimano, Renata Cristina da Cunha Frange, Maria Teresa Junqueira Garcia, PhD  Photodiagnosis and Photodynamic Therapy  Volume 12, Issue 1, Pages 98-107 (March 2015) DOI: 10.1016/j.pdpdt.2014.11.003 Copyright © 2014 Elsevier B.V. Terms and Conditions

Fig. 1 Apparent viscosity values as function of shear rate of 3%, 4% and 5% CH gels containing 1% TBO. Each value is the mean of three different experiments±SD. Photodiagnosis and Photodynamic Therapy 2015 12, 98-107DOI: (10.1016/j.pdpdt.2014.11.003) Copyright © 2014 Elsevier B.V. Terms and Conditions

Fig. 2 Tensile strength values required to break the adhesive bonds between the mucous membrane and CH gels at different concentrations containing 1% TBO. Each value is the mean of five different experiments±SD. Statistical test: one-way ANOVA test (Tukey's multiple comparisons). Values considered significant between groups: (a) 3% CH and 4% CH, p<0.05; (b) 4% CH and 5% CH, p<0.01; (c) 3% CH and 5% CH, p<0.001. Photodiagnosis and Photodynamic Therapy 2015 12, 98-107DOI: (10.1016/j.pdpdt.2014.11.003) Copyright © 2014 Elsevier B.V. Terms and Conditions

Fig. 3 In vitro release profile of 1% TBO from the control formulation (1.0% TBO in distilled water) and from the CH gels at 3%, 4% and 5%. Each value is the mean of six different experiments±SD. J=TBO flux through a cellulose acetate membrane, as obtained from the slope of the linear portion of the curve. Jcontrol=38.62μg/cm2h; J3%CH=94.91μg/cm2h**; J4%CH=190.22μg/cm2h***; J5%CH=193.02μg/cm2h***. Statistical test: one-way ANOVA test (Tukey's multiple comparisons). **Significantly different from the control (p<0.01); ***significantly different from the control (p<0.001). Photodiagnosis and Photodynamic Therapy 2015 12, 98-107DOI: (10.1016/j.pdpdt.2014.11.003) Copyright © 2014 Elsevier B.V. Terms and Conditions

Fig. 4 Amount of TBO retained in the pig cheek vs. time of exposure to the formulation (control or CH gel at different concentrations) (n=5). Statistical test: one-way ANOVA test (Tukey's multiple comparisons). Control=1% TBO in distilled water. * Significantly different (p<0.05) from the control, at the respective times. ** Significantly different (p<0.01) from the control, at the respective times. Photodiagnosis and Photodynamic Therapy 2015 12, 98-107DOI: (10.1016/j.pdpdt.2014.11.003) Copyright © 2014 Elsevier B.V. Terms and Conditions

Fig. 5 In vivo TBO retention after 1h of tongue mucosa exposition to the formulations (Control (1% TBO in distilled water) or 4% CH gel containing 1% TBO) (n=5). Statistical test: Unpaired t test (Welch correction). *** Significantly different (p<0.001) from the control (1% TBO in distilled water). Photodiagnosis and Photodynamic Therapy 2015 12, 98-107DOI: (10.1016/j.pdpdt.2014.11.003) Copyright © 2014 Elsevier B.V. Terms and Conditions