Nanostructured lipid systems modified with waste material of propolis for wound healing: Design, in vitro and in vivo evaluation.

Propolis, a natural compound that can accelerate the wound healing process, is mainly used as ethanolic extract. The extractive solution may also be obtained from the propolis by-product (BP), transforming this waste material into a pharmaceutical active ingredient. Even if propolis does not show toxicity, when used as an extract over harmed skin or mucosa, the present ethanol content may be harmful to the tissue recovering, besides hindering the drug release. This study describes the development of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) as topical propolis delivery systems and the investigation of their in vitro and in vivo activities. The extracts were evaluated to guarantee their quality, and the lipid dispersions were characterized with respect to morphology (cryo-TEM), size and diffractometry (X-ray) properties. The occlusive capacity of formulations was also evaluated by an in vitro technique, which determines the occlusion factor. The drug entrapment efficiency (EE), as well as the in vitro drug release profile from the nanoparticulate systems was investigated as well. The size analysis performed through 90days was favorable to a topical administration and the polydispersity index, though not ideal in all cases due to the high content of resins and gums from the extracts, were relatively stable for the SLN. The propolis extract contributes to the occlusive potential of the formulations. The human immortalized keratinocytes presented good cell viability when tested with both extracts (propolis and BP) freely or entrapped in the systems. SLN modified with propolis material provided an acceleration of the in vivo wound healing process.

Pharmaceutical films made from the waste material from the preparation of propolis extracts: development and characterization

abstract This study investigated the development and characterized the physicochemical properties of films obtained from by-products (BP) from the preparation of propolis extracts. Films were produced in the presence and absence of a polymeric adjuvant (gelatin or ethylcellulose) and propylene glycol by a solvent casting method. Density, surface topography by scanning electron microscopy, mechanical properties (folding endurance, tensile strength and percentage elongation), water vapour permeability (WVP), moisture uptake capacity, thermogravimetry, differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR) were determined. The films were a transparent, light greenish-yellow colour, with a uniform surface, and were flexible and easy to handle. The thickness and density of the preparations indicated that the compounds were homogeneously dispersed throughout the film. Mechanical properties were influenced by the film composition; films containing gelatin were more resistant to stress, while those containing ethylcellulose were more flexible. Increasing the adjuvant concentration decreased the elasticity and the rupture resistance, but increased the moisture uptake capacity and WVP of the formulations. BP was thermally stable as were the films. FTIR tests suggested interactions between BP and the adjuvants. This work could contribute to the utilization of BP to prepare films for food and pharmaceutical uses.

resumo Este estudo investigou o desenvolvimento e as características físico-químicas de filmes obtidos com o resíduo (BP), normalmente descartado, advindo da preparação de extratos de própolis. Os filmes foram produzidos com e sem adjuvantes poliméricos (gelatina ou etilcelulose) e propilenoglicol, pelo método de evaporação de solvente. Foram determinadas a densidade, a topografia de superfície usando microscopia eletrônica de varredura, as propriedades mecânicas (resistência à dobra, tensão e elongação), transmissão de vapor de água (WVP), capacidade de absorção de umidade, termogravimetria, calorimetria exploratória diferencial e espectroscopia de infravermelho com transformada de Fourier (FTIR). Os filmes demonstraram coloração verde-amarelada, transparência, uniformidade de superfície, homogeneidade, flexibilidade e fácil manuseio. A espessura e a densidade das preparações indicaram que os compostos estavam dispersos de forma homogênea. As propriedades mecânicas foram influenciadas pela composição dos filmes e aqueles que continham gelatina apresentaram-se mais resistentes enquanto os compostos por etilcelulose demonstraram maior flexibilidade. Com o aumento da concentração polimérica, a resistência e a elasticidade diminuíam, porém aumentou a capacidade de absorção de água e a WVP das formulações. BP apresentou estabilidade térmica assim como os filmes. Os testes de FTIR sugeriram interações entre o BP e os adjuvantes utilizados. Este trabalho pôde contribuir com a utilização de BP na preparação de filmes para uso alimentício e farmacêutico.