muramidase and apaflurane

To overcome the disadvantages of microemulsion and nanoprecipitation methods to produce protein-containing nanoparticles, a novel bottom-up process was developed to produce nanoparticles containing the model protein lysozyme. The nanoparticles were generated by freeze-drying a solution of lysozyme, lecithin and lactose in tert-butyl alcohol (TBA)/water co-solvent system and washing off excess lecithin in lyophilizate by centrifugation. Formulation parameters such as lecithin concentration in organic phase, water content in TBA/water co-solvent, and lactose concentration in water were optimized so as to obtain desired nanoparticles with retention of the bioactivity of lysozyme. Based on the results, 24.0% (w/v) of lecithin, 37.5% (v/v) of water content, and 0.56% (w/v) of lactose concentration were selected to generate spherical nanoparticles with approximately 200 nm in mean size, 0.1 in polydispersity index (PI), and 99% retained bioactivity of lysozyme. These nanoparticles rinsed with ethanol containing dipalmitoylphosphatidylcholine (DPPC), Span 85 or oleic acid (3%, w/v) could readily be dispersed in HFA 134a to form a stable suspension with good redispersibility and 98% retained bioactivity of lysozyme. The study indicates there is a potential to produce pressed metered dose inhaler (pMDI) formulations containing therapeutic protein and peptide nanoparticles.

Topics: Administration, Inhalation; Aerosol Propellants; Anti-Infective Agents; Drug Carriers; Drug Compounding; Drug Delivery Systems; Freeze Drying; Hydrocarbons, Fluorinated; Lactose; Lecithins; Metered Dose Inhalers; Muramidase; Nanoparticles; Particle Size; Peptides; Proteins; tert-Butyl Alcohol; Water

The objective of the present study was to investigate the physical stability of spray-dried proteins within surfactant-free hydrofluoroalkane (HFA) pressurised metered dose inhalers (pMDIs) during prolonged storage. Two model proteins (lysozyme and catalase) were spray-dried and stabilised in the presence of excipients, and subsequently suspended within HFA 134a. The pMDIs were stored valve-up for 6 months at room temperature (ca. 25 degrees C). Activities of the proteins were determined using biological assays and the fine particle fraction of the pMDIs was measured using a twin-stage impinger. The biological activities of catalase and lysozyme were found to be preserved in the presence of sugars and/or 80% hydrolysed polyvinyl alcohol (PVA) during spray drying. In addition, suspending the stabilised proteins within HFA for up to 6 months had little effect on their activity. The aerosolisation performance of lysozyme or catalase formulations containing either sucrose or trehalose as stabilisers appeared to deteriorate as a function of storage time. However, those formulations containing PVA were found to generate the greatest fine particle fraction, which in some cases was up to 50%, and to possess excellent physical stability during storage. The results indicated that the presence of PVA in the spray-dried stabilised protein particles could enhance the physical stability of particles, when suspended in the surfactant-free HFA MDI formulations, without affecting the protein stability upon prolonged storage.

Topics: Aerosol Propellants; Catalase; Drug Stability; Drug Storage; Excipients; Hydrocarbons, Fluorinated; Metered Dose Inhalers; Microscopy, Electron, Scanning; Muramidase; Particle Size; Polyvinyl Alcohol; Proteins; Surface Properties