Cationic Vectors in Ocular Drug Delivery

Abstract

Despite extensive research in the field, the major problem in the ocular drug delivery domain still is rapid precorneal drug loss and poor corneal permeability. One of the approaches recently developed is the drug incorporation into cationic submicronic vectors which exploit the negative charges present at the corneal surface for increased residence time and penetration. This review will focus on the formulation of three main representative cationic colloids developed for ophthalmic delivery: liposomes, emulsions and nanoparticles (NP). Parameters such as choice of the vector type and size, nature of the cationic molecule, pH and ionic strength of the external phase and characteristics of the encapsulated drug will be discussed with accent on the relevance of the positive charge.

Targeted lung cancer therapy: preparation and optimization of transferrin-decorated nanostructured lipid carriers as novel nanomedicine for co-delivery of anticancer drugs and DNA

“…44 Cationic vectors could exploit the negative charges present at the cell surface for increased residence time and penetration. 45 Nanocarriers with a higher surface charge may bind strongly to the cell membrane, and may show increased cellular uptake due to electrostatic interactions between the anionic membrane and cationic carries. 46 The results of the zeta potential analysis showed the decoration of Tf-PEG-PE ligands covered some of the surface charge of the NLC, resulting in a decrease in the positive charge.…”

Bioadhesive hyaluronan–chitosan nanoparticles can transport genes across the ocular mucosa and transfect ocular tissue

“…Namely, (1) they are able to associate great amounts of DNA, thus allowing the amount of polymer used for in vivo transfection purposes to be minimized, (2) they have a very small size, a feature which is known to be critical for the adequate interaction with the ocular mucosa 28 and (3) their surface charge can be modulated depending on the HA-CS ratio. This modulation is important since a positive charge is supposed to facilitate the interaction of the nanoparticles with the ocular surface, 23,29 whereas the disposition of HA onto the surface of the nanoparticles may also play a role in their interaction with epithelial cells. 20,21 In order to evaluate the efficacy of the nanoparticles as ocular gene carriers, a cell culture model derived from HCE cells was used prior to the in vivo studies.…”

Biomateriais para formulações de base nanotecnológica visando terapia gênica ocular

“…Atualmente, é fato que a captação de nanoestruturas na superfície ocular é geralmente governada pela sua carga superficial seguindo a seguinte relação: positivos > negativos > neutros. 62 Nanoemulsões compostas por DOTAP e lecitina de ovo contendo oligonucleotídeos antissentido específicos para VEGF (fator de crescimento vascular endotelial) foram testados em células humanas do endotélio venoso de cordão umbilical 63 e in vivo em ratos e camundongos 64 e demonstraram boa transfecção e baixa toxicidade. Lipossomas com DOTMA/ colesterol demonstraram alta eficiência de transfecção e expressão gênica no tecido ocular de coelhos em testes realizados in vivo.…”