Multilayered polymer coating modulates mucoadhesive and biological properties of camptothecin-loaded lipid nanocapsules.

Lipid core nanocapsules (NCs) coated with multiple polymer layers were rationally designed as a potential approach for the colonic delivery of camptothecin (CPT). Chitosan (CS), hyaluronic acid (HA) and hypromellose phthalate (HP) were selected as coating materials, to modulate the mucoadhesive and permeability properties of CPT regarding the improvement of local and targeted action in the colon cancer cells. NCs were prepared by emulsification/solvent evaporation method and coated with multiple polymer layers by polyelectrolyte complexation technique. NCs exhibited spherical shape, negative zeta potential, and size ranged from 184 to 252 nm. The high efficiency of CPT incorporation (>94%) was evidenced. The ex vivo permeation assay showed that nanoencapsulation reduced the permeation rate of CPT through the intestinal mucosa by up to 3.5 times, and coating with HA and HP reduced the permeation percentage by 2 times when compared to NCs coated only with CS. The mucoadhesive capacity of NCs was demonstrated in gastric and enteric pH. Nanoencapsulation did not reduce the antiangiogenic activity of CPT and, additionally, it was observed that nanoencapsulation resulted in localized antiangiogenic action of CPT.

Polymeric-based drug delivery systems for veterinary use: State of the art.

One of the challenges to the success of veterinary pharmacotherapy is the limited number of drugs and dosage forms available exclusively to this market, due to the interspecies variability of animals, such as anatomy, physiology, pharmacokinetics, and pharmacodynamics. For this reason, studies in this area have become a highlight, since they are still scarce in comparison with those on human drug use. To overcome many limitations related to the bioavailability, efficacy, and safety of pharmacotherapy in animals, especially livestock and domestic animals, polymers-based drug delivery systems are promising tools if they guarantee greater selectivity and less toxicity in dosage forms. In addition, these tools may be developed according to the great interspecies variability. To contribute to these discussions, this paper provides an updated review of the major polymer-based drug delivery systems projected for veterinary use. Traditional and innovative drug delivery systems based on polymers are presented, with an emphasis on films, microparticles, micelles, nanogels, nanoparticles, tablets, implants and hydrogel-based drug delivery systems. We discuss important concepts for the veterinarian about the mechanisms of drug release and, for the pharmacist, the advantages in the development of pharmaceutical forms for the animal population. Finally, challenges and opportunities are presented in the field of pharmaceutical dosage forms for veterinary use in response to the interests of the pharmaceutical industry.