Desenvolvimento, caracterização e avaliação de nanocarreadores contendo acetil hexapeptídeo-3 e toxina botulínica tipo A

Abstract

Cutaneous aging is a complex biological phenomenon that depends on a number of intrinsic, responsible for chronological aging and the extrinsic factors, which is responsible for cutaneous photo aging. Another important factor that must be taken into account is the appearance of wrinkles caused by repeated movements of the facial muscles. Currently there is a huge demand for anti-aging products and one of the strategies that is most commonly employed for this end, is the application of botulinum toxin Type A which is regarded as the principal treatment for the mitigation of wrinkles. Another active substance which functions in the same way as botulinum toxin A, is acetyl hexapeptide-3, which is marketed under the name of Argireline. This anti-aging agent acts in a similar way to botulinum toxin by smoothing out the expressive lines and wrinkles caused by repeated movements. Both the active agents are responsible for the release of acetylcholine at the neuromuscular junction. One of the main differences between these active agents is in their form of application since, whereas botulinum toxin A is administered by injection, acetyl hexapeptide-3 is used in the form of a cream for topical application. Given the fact that the two active agents are hydrophilic neuropeptides of high molecular mass, their ability to penetrate the skin is improbable. Thus, the purpose of this study was to develop, characterize and evaluate systems comprising nanocarriers that are able to allow or improve the permeation of these active agents through the skin. Acetyl hexapeptide-3 was encapsulated in liposomes and botulinum toxin was encapsulated through two systems, liposomes and polymeric nanoparticles. The evaluation of the acetyl-hexapeptide-3 showed an encapsulation efficiency of 95%. The vesicles showed a zeta potential of -31 mV. The results demonstrated that the active agent had a good cutaneous permeation and its encapsulation did not affect the permeation through the skin. The botulinum toxin Type A were successfully encapsulated into nanoparticles by multiple emulsion method and solvent evaporation. The nanoparticles had an average size of approximately 570 nm and a zeta potential of -7,40 mV, which is characteristic of the polyester used. The multilamellar liposomes were obtained through a method that involved hydrating the lipid film and showed an average size of approximately 1370 nm and a zeta potential of -37 mV. It was possible to demonstrate by means of infrared fourier transform spectroscopy, the presence of botulinum toxin Type A in the polymeric nanoparticles and the liposomes. The in vitro assays that were carried out suggested that the liposomes that contained the botulinum toxin Type A had an effect on the neurotransmitters in the assays that were conducted, whereas it was not possible to identify the same effect in the nanoparticles that contained the botulinum toxin.These results showed that the encapsulation of botulinum toxin A can be an alternative for the topical application of botulinum toxin Type A in a non-invasive way and with a good deal of comfort to the patient. With regard to acetyl hexapeptide-3, it can be claimed that this active agent when released shows the same degree of penetration through the skin as the encapsulated active agent. This suggests that the penetration of acetyl hexapeptide-3 does not undergo any alteration when encapsulated in liposomes. Thus, the active agent can be applied topically in this way.