Vanessa is the first early stage researcher to come to High Pressure Processes Group in Valladolid within the framework of the WineSense project. She comes from Instituto De Biologia Experimental E Tecnológica (iBET, Portugal) and during her nine months of stay she will evaluate different carriers as suitable materials for the encapsulation of polyphenols with distinct polarities.
Vanessa Gonçalves (MSc Pharm Sciences, 2010) is also doing her PhD in Pharmaceutical Technology (IBET/ITQB-UNL – Portugal) under the supervision of Dr. Catarina Duarte and co-supervision of Dr. Ana Matias with the thesis “Overcoming Central Nervous System-barriers by the development of hybrid nanostructured systems for nose-to-brain drug delivery using precipitation clean technologies” (SFRH/BD/77350/2011).
The main aim of her thesis project is to develop multilayered and hybrid nanostructures, with mucoadhesive properties, through one- or multi-step supercritical precipitation techniques. These drug delivery systems could be further used for nose-to-brain drug delivery.
The blood-brain barrier
The brain is a crucial organ to our body, but also a fragile one. The blood-brain barrier (BBB) helps to maintain the homeostasis of the central nervous system. Due to the existence of efflux pumps and tight intercellular junctions, it has very low permeability that restricts the entry of potential neurotoxic substances. Nevertheless, it allows the entrance of essential nutrients.
Nowadays the neurological disorders contribute to around 6% of the world’s total diseases, however many drugs or drug delivery systems cannot cross the BBB, leading to the failure of their treatment. Since the nose and the brain are connect to each other through the olfactory and trigeminal route, and also by the peripheral circulation, the intranasal route for delivering drugs could be a non-invasive and effective approach to overcome the BBB.
Hybrid drug delivery systems
In recent years, drug delivery systems (DDS) composed by biocompatible carriers like polymers or lipids have been developed and studied, however they still exhibit numerous drawbacks and it’s necessary to develop an ideal biocompatible carrier. One way to achieve this is by producing hybrid particles, composed by 2 or more lipids, 2 or more polymers or a mixture of both, where by varying the types of lipids and polymers, or even their mass ratios, we could regulate, for instance, the drug load or release rate. For intranasal drug delivery, the ideal carrier should have a porous structure and mucoadhesive properties in order to be capable to deposit the drug in the nasal cavity, achieving prolonged residence time with high local drug concentration.
Supercritical Fluid Precipitation Technology
Nowadays there is an increasing attempt to reduce the use of organic solvents during the particle generation process and the supercritical fluid technology have been a clean alternative to those methods for the last 20 years. A supercritical fluid is a substance whose temperature and pressure are above their critical point, having some characteristics of the liquids, like the density and solvating power, and characteristics similar to those of gases, like diffusivity and viscosity. The sc-CO2 is the Supercritical Fluid (SCF) of election, mostly because its critical state can be achieve at mild pressure and temperature, which is an advantage while processing thermolabile substances. The SCF-based processes to produce particles are then a clean technology, where we can produce solvent-free products, have the possibility to process thermolabile molecules and also achieve porous structures of several compounds.