unicampChalcones, encapsulated in liposomes, as seen through a microscopeunicamp
An unusual pharmaceutical formulation developed by a group of researchers from São Paulo and Rio de Janeiro may facilitate and make the treatment of leishmaniasis more efficient. This parasite-caused disease afflicts millions of people around the world. The referred formulation is a compound containing a synthetic by-product of chalcone, extracted from the matico plant (Piper aduncum) and encapsulated in liposomes, nanometric-sized vesicles formed by phospholipids, a type of fat. This substance is able to penetrate the skin and kill the protozoa that causes the disease. The drug is at the laboratory development stage and has already been successfully tested in vitro and on animals. The innovation has resulted in the filing of a patent with the Instituto Nacional de Propriedade Industrial/INPI National Institute of Industrial Property, with validity abroad via the Patent Cooperation Treaty/ PCT. The next step, according to Maria Helena Andrade Santana, a professor at the School of Chemical Engineering/FEQ of the State University of Campinas/ Unicamp, will be a new battery of pre-clinical trials, which will precede tests on human beings to prove the drug’s efficiency in treating this disease.
Leishmaniasis is a disease caused by several species of protozoan parasites that belong to the Leishmania genus. It afflicts 12 million people around the world. Data provided by the World Health Organization/WHO estimates that 2 to 2.5 million new cases appear each year. The disease is endemic in Brazil, where 34 thousand new cases are reported every year. Considered as a neglected disease, because it gets little or no attention from the big pharmaceutical companies, it is prevalent in low income populations in countries in Asia, Africa and Latin America. It is classified in two broad groups: tegumentary, subdivided into cutaneous and mucocutaneous; this form is characterized by skin and mucosa sores, and visceral, which affects vital organs such as the liver and the spleen and can lead to death. Treatment is difficult because of the parasite’s location in the macrophages, a cell in the immune system which makes access difficult, thus reducing the efficacy of the pharmaceutical remedies. Conventional therapy is quite painful, as it consists of the application of daily injections for a prolonged period of time. These injections cause serious side effects, such as muscle and abdominal pain and nausea; in addition, they are not always efficacious. The main advantage of this new formulation containing chalcones encapsulated in liposomes – for use only in the treatment of cutaneous leishmaniasis – is the fact that it is applied topically. ” The drug can be formulated in the form of creams or lotions containing the pharmaceutical compound encapsulated in liposomes. The cream or lotion penetrates deeply into the lesion, resulting in simpler and painless treatment. Because it is non-invasive, as needles do not have to be used, it makes treatment of children easier and increases patient compliance with the treatment,” says Maria Helena.
unicampChalcones, encapsulated in liposomes, as seen through a microscopeunicamp
Chalcone has proven anti-inflammatory and has healing properties. Several studies have attested to its efficacy in the treatment of cutaneous leishmaniasis. It destroys the parasite’s cell membrane and kills the parasite. However, chalcone also has a residual toxic effect on the patient’s cells. To mitigate this effect, researchers have developed new classes of chalcones, of which nitrogen chalcone, developed at the Federal University of Rio de Janeiro/UFRJ, was found to be the most selective and active for the treatment of the disease. The challenge for Brazilian researchers was to create a means for the delivery of the active principle – in this case, nitrogenated chalcone – to reach the deepest layers of the skin, with the objective of achieving better penetration into the lesion. “The problem is that free chalcone, in simple cream composition, is a big molecule, unable to penetrate the skin’s superficial layer,” explains the researcher from Unicamp. So the researchers came up with the idea of encapsulating the chalcone in liposomes. “Encapsulating the chalcone made it easier to deliver it to the site, thus increasing the drug’s efficiency. We achieved deeper penetration of the skin in in vitro tests; in animals, the effect was the same as that of injecting chalcone directly into the lesion,” the researcher explains.
Slow and gradual
The liposomes have nanometric dimensions – their diameter measures approximately 100 nanometers. They are considered as an excellent system for the slow and controlled release of drugs. In addition to being directed to specific action sites, they interact efficiently with the body’s cells, because they mimic the cells’ physical, chemical and biological properties. A category of liposomes, called elastic liposomes because of their structural flexibility, can penetrate the skin’s pores, the diameter of which is only 30 nanometers. These elastic vesicles can undergo deformation, changing from their characteristic spherical shape to the shape of a needle-like cylinder and thus enter the pores, which are smaller than these liposomes. “Their elasticity allows them to become deformed without harming their integrity. After going through the pore, the liposomes start to interact with the epidermis (the upper layers of the skin), releasing the drug gradually through diffusion and their own disintegration,” Maria Helena explains.
“The liposome are the nanometric particles for therapeutic use that attract the scientific community the most,” says the researcher. Pharmaceutical drugs encapsulated in liposomes are already available on the market. One of these drugs is doxorubicin, used in chemotherapy for cancer patients; another is amphotherecin B, prescribed for fungal infections. Research groups in Germany and Holland have already been able to develop elastic forms for medical applications, but no group has used chalcone nor the elastic liposomes for the treatment of cutaneous leishmaniasis. “When we did the bibliographical revision for patent filing purposes, there was nothing similar to chalcones, or elastic liposomes, in relation to leishmaniasis.”
unicampChalcones, encapsulated in liposomes, as seen through a microscopeunicamp
The encapsulated chalcone was produced and chemically formulated at the Laboratório de Desenvolvimento de Processos Biotecnológicos, Biotechnological Development Lab, at Unicamp’s FEQ. The research group included Beatriz Zanchetta, who is enrolled in the master’s program. The nitrogenated chalcone was supplied by biologist Bartira Bergmann, from the Laboratório de Imunofarmacologia Immunopharmacology Lab, at the UFRJ’s Biophysics Institute. The biological and in vivo tests on mice were performed by pharmacist Camila Falcão, enrolled in the doctorate program at the UFRJ’s Biophysics Institute. The researchers intend to continue the pre-clinical trials and, in the future, pass this technology on to a pharmaceutical lab interested in producing the drug commercially. “This development relies on an inter-disciplinary team, comprised of biologists, pharmacists and chemical engineers and is a promising technology which may be commercially developed,” Maria Helena points out.
The project
Project, assembly and operation of the facility for the scalable production of liposomes with the objective of producing pharmaceutical applications (nº 02/03168-5); Modality Regular Funding of Research Project; Coordinator Maria Helena Andrade Santana – Unicamp; Investment R$ 46.112,50 (FAPESP)
