Abstract
Abstract: :
Purpose: Our research is focused in drug delivery through the ocular mucosa to treat ocular surface diseases by using colloidal systems as drug carriers. The purpose of this study is to evaluate the toxicity and the capacity of entering the cells of a new class of colloidal systems, liposome–chitosan nanoparticles (LCNp). Methods: Three different kind of LCNp were prepared by combining chitosan nanoparticles and phospholipid vesicle suspensions followed by freeze drying in the presence of 5.0 % trehalose. The IOBA–NHC cell line, derived from human conjunctival epithelium, was exposed to 1, 0.5 and 0.25 mg/ml of each FITC– LCNp formulation for 15, 30, and 60 min at 37oC. The XTT–based toxicity test was assayed to evaluate in vitro citotoxicity. Uptake of LCNp by IOBA–NHC cells and mucus–like producing primary cultures from human conjunctival epithelium was examined by confocal microscopy. TRITC–Phalloidin was used to identify cytoskeleton. Results: LCNp formulations had a low toxic effect, being the 0.5 and 0.25 mg/ml concentrations the least toxic. Uptake of LCNp formulations was different in IOBA–NHC cells and in primary cultures. In the first case, the LCNp were identified inside cells after 15 min. Regarding primary cultures, LCNp seemed to be retained in the mucus layer and started to be seen inside cells after 30 min, showing a different pattern depending on the particular formulation. Conclusions: Tested LCNp had a low toxic effect on conjunctival epithelial cells. Also, LCNp were capable of entering cells after short incubation times. Therefore, they are potentially useful as drug carriers for the ocular surface.
Keywords: conjunctiva • drug toxicity/drug effects • microscopy: confocal/tunneling