Summary
Vaccination is undoubtedly one of the most successful inventions in medical history. But today the number of people refusing vaccines is increasing mainly in developed countries. Avoiding syringe and needle by using alternative administration routes is one opportunity to tackle this issue. For this purpose nasal administration of powder vaccine formulations offers some great advantages. Nasal drug delivery is non-invasive, well accepted and with respect to vaccines it leads to a better immunisation especially in younger patients. In this work a nano-in-microparticle (NiM) vaccine formulation was prepared and analysed with respect to its deposition profile in a child’s and an adult’s nose by using two nasal cast models (from Boehringer Ingelheim) with and without mimicked inspiration. Nanoparticles were achieved via ionic coacervation of chitosan and sodium deoxycholate. Bovine serum albumin was used as model antigen and was encapsulated in the nanoparticles. To obtain a dry powder NiM formulation the nanosuspension was spray dried using mannitol as matrix. Physical and chemical stability of the nanoparticles is unaffected by the spray drying process. The final formulation was administered with a device for nasal powder application (Powder UDS, Aptar Pharma). The studies show that the amount of vaccine formulation which is deposited in the desired regions (entire nasal cavity without nostrils) as well as the distribution within the nasal cavity differs between adult and child. Nasal deposition averaged 83.5% (of the delivered dose) without air flow and 72.4% with air flow for the adult’s model; for the child’s nose, it averaged 79.5% and 74.2%, respectively. For both models the amount of vaccine that has been deposited in the desired regions was higher without simulated inspiration. Application without inspiration was probably also easier to perform for patients and healthcare staff.