Avaliação da estabilidade de géis após incorporação de lipossomas desenvolvidos à base de lecitina e colesterol.

Abstract

The objective of this study was to evaluate the stability of different gels after incorporation of liposomes. Gels are semisolid systems consisting of dispersions of molecules in an aqueous liquid vehicle that acquires the gel like consistency by the addition of a gelling agent. Liposomes may be defined as dispersed lipid systems often consist of phospholipids in aqueous media which are organized spontaneously form bilayered spherical vesicles. Due to its composition, the liposomes are highly unstable. The storage in the form of an aqueous suspension is often incompatible with the stability required for pharmaceutical products. Studies show that the incorporation of liposome gels can make them remain stable for up to 2 years. Given this, starch gels (corn and jackfruit seeds) and natrosol® gel, incorporated by liposomal formulations composed of lecithin and cholesterol were assessed. The extraction of starch from jackfruit seeds, which showed a yield of 10.51 % w/w, and the extraction of lecithin from egg to chicken, which resulted in obtaining a liquid, viscous yellow product was performed, used to production of the liposomes. The MLVs lecithin liposomes formed only showed values lower than liposomes comprised of lecithin and cholesterol absorbance. Preliminary studies and accelerated stability, which evaluated the macroscopic characteristics, pH and viscosity were performed. After the preliminary stability study it was observed that the samples suffered not incorporated in gels creaming phenomenon. The formulations incorporated in starch gels proved to be unstable due to have occurred the phenomenon of syneresis (water loss); natrosol® gel was stable not to submit changes. All showed varying pH. As for the accelerated stability, study after 48 h was observed in the occurrence of creaming liposome samples were not incorporated in gels. Within 7 days we observed that the gels formed by starch were unstable by the occurrence of syneresis and deformation of the gel. The gel natrosol® only were unstable in 15 days, when its viscosity decreased and the gel is disrupted. In all embedded in gel formulations was not observed the phenomenon of creaming or coalescence of lipid vesicles, indicating that although unstable after 15 days, prevented all these phenomena occur. The gel Natrosol ® was the most stable among the studied gels.