Effects of Different N-Trimethyl Chitosans on In Vitro/In Vivo Ofloxacin Transcorneal Permeation

Oral absorption enhancement of salmon calcitonin by using bothN-trimethyl chitosan chloride and oligoarginines-modified liposomes as the carriers

“…The cytotoxicity in vitro of TMC It was reported that the permeation of TMC was increased in pace with increase of the DQ. The strongest absorption promotion for macromolecule was found when the DQ was between 40% with 60%; however, when the DQ was higher than 60% no significantly increase of permeation was found, but stronger cytotoxicity occurred (Di Colo et al, 2004). From Figure 3 the cytotoxicity of TMC was concentrationdependent.…”

“…It was reported that TMC acted on epithelial cell monolayers by opening the tight junctions between adjacent cells through an interaction of the polycationic polymers with the negatively charged sites on the cell membrane and/or in the tight junctions. Such an action would favor time dependent decrease in the TEER and paracellular drug transport (van der Merwe et al, 2004a, Di Colo et al, 2004. Moreover, TMC-Arg8-Lips showed sustained decrease effect on the TEER and only 70% of original TEER was found after 2 h incubation, which was 1.14-and 1.21-fold lower than that of FD4 þ TMC solution and TMCLips, respectively.…”

Biomaterials as novel penetration enhancers for transdermal and dermal drug delivery systems

“…To improve its solubility and effectiveness, N-trimethyl chitosan (TMC) has been developed and investigated, which exhibits considerably good permeation enhancement effect in basic environments when using Caco-2 cells as a model (Kotzé et al, 1997;Thanou et al, 2000). In addition, the molecular weight, deacetylation degree and the charge of TMC represented by the degree of quaternization, are considered as important factors determining its enhancing activity (Jonker et al, 2002;Di Colo et al, 2004;Giuseppina et al, 2005).…”

Polysaccharides as Excipients for Ocular Topical Formulations

“…These point out that Ch is biodegradable, has low toxicity and good ocular tolerability, exhibits bioadhesion and permeability-enhancing properties and also physico-chemical characteristics that make it suitable for the design of ocular drug delivery vehicles. The Ch repeating unit bears a primary amino group bestowing a reactivity on the polymer that allows its transformation into derivatives of interest as biocompatible and bioactive excipients for ophthalmic drug delivery systems (Di Colo et al, 2004a;Zambito et al, 2006a;Zambito et al, 2007). Over the last decade efforts have been made to put into evidence the ability of Ch to safely promote intraocular drug penetration by enhancing corneal permeability, and to synthesize Ch derivatives with improved such bioactivity.…”

“…Polycationic derivatives of Ch, soluble in tear fluid at the physiological pH of 7.4, can have an increased potential for enhancing the corneal permeability (Di Colo et al, 2004a). A similar derivative, i.e., N-trimethylchitosan (TMC), has been obtained by quaternizing the primary amino group of Ch with methyl iodide, thus bestowing fixed, pH-independent positive charges on the polymer (Fig.4).…”