Nanocarriers for pulmonary drug delivery Sample Clauses

Nanocarriers for pulmonary drug delivery a) Liposomes Liposomes are colloidal vesicles formed of lipid bilayers that have been shown as suitable drug carrier systems. Liposomes can encapsulate both hydrophilic and hydrophobic drugs. As lipids are used to prepare liposomes they have a good compatibiliy with the lung tissue. A range of different drugs have been encapsulated in liposomes and released over a sustained period (Xxxx-Broichsitter et al., 2013; Xxxxx et al., 2008). For example, a liposome systems have been used to retard the rapid absorption of insulinin mouse alveoli and this reduced drug induced side-effects (Xxxxx and Xxxx, 2006). More recently, pulmonary delivery of liposomes in a rat model showed that the liposomes were effectively distributed in the respiratory tract and lungs, and that the release of salbutamol sulfate (SBS) from liposomes was sustained for at least 48 hours (Xxxx et al., 2012). Pharmacodynamic analysis in a guinea pig model showed that the anti-asthmatic effect of SBS liposomes persisted for up to 18 hours, whereas that of free SBS solution was less than 8 hours. Another inhaled liposomal ciprofloxacin formulation, known as Pulmaquintm is in phase 3 clinical studies for treatment of non-cystic fibrosis bronchiectasis (Serisier et al., 2013). It has been shown to provide a burst release followed by a sustained release over 24 h. However, a major challenge associated with conventional liposomal formulations, particularly for pulmonary delivery, is long-term instability (Xxxxx and Xxxxxx, 2013). Physicochemical property changes during the dehydration process that are used to store these formulations can create problems (He et al., 2010). Therefore the use of a colloidal system with similar material properties to liposomes, but greater structural stability could prove to be highly advantageous in the context of controlled pulmonary delivery.