Nasal delivery efficiency

The nasal absorption of insulin after administration in chitosan powder was the most effective formulation for nasal delivery of insulin in sheep compared to chitosan nanoparticles and chitosan solution [11], Similarly, chitosan powder formulations have been shown to enable an efficient nasal absorption of goserelin in a sheep model where bioavailabilities of 20-40% were obtained depending on the nature of the formulation [9],... 

The nasal delivery of vaccines is a very attractive route of administration in terms of efficacy and consumer friendliness. A population-wide immunization against influenza has yet to be achieved. The pain of injections discourages many people from receiving a flu shot. The nasal route offers the advantage of a mucosal response followed by a seric response, and has proved to be a very efficient mode of administration. ... 

Nasal delivery is inefficient in terms of the amount of drug actually delivered to the body and to increase its efficiency, penetration enhancers must be added that may cause local irritation. 

Since the uptake of particles in nasal epithelial tissue is known to be mostly mediated by M cells, nasal administration has been investigated as a noninva-sive delivery of vaccines [37], However, since the uptake of naked DNA by endocytocis is limited, use of either nanoparticles as mucosal delivery systems [37] or hypotonic shock [38] is reported for the efficient transfection of gene and vaccine into the nasal epithelium. It was also reported that polypeptides and polypeptide-coated nanospheres (diameter about 500 nm) are transported through endocytic process in rat M cells [39],... 

The nasal application of drugs is an area of growing interest (21) and a number of publications has shown that simple molecules as well as more complex species (eg calcitonin, insulin etc) can be well absorbed by this route, either directly or in the presence of so-called absorption enhancers. One problem with such materials could be too rapid clearance of the delivery system from the nasal cavity through the efficient action of the mucociliary system. For this reason Ilium has considered the use of microsphere systems. 

In the treatment of nasal symptoms the patient adjusts the dose so that, perhaps, the theoretical bases of droplet and particle retention are less vital. Although formulation of the nasal drops, or sprays from plastic squeeze-bottles must obviously influence the efficiency of medication, little work has in the past been carried out relating formulation to the effect of intranasal medicines. Microsphere delivery systems have received some attention, however, with special interest being directed to bioadhesive microspheres. 

In addition to small molecules, a number of protein therapeutic agents, such as neurotrophic factors27 and insulin,28 have been successfully delivered to the CNS using IN delivery in a variety of species. The therapeutic benefit of IN delivery of proteins has been demonstrated by Liu et al. in rat stroke models.29 Their studies demonstrated that insulin-like growth factor I (IGF-I) could be delivered to the brain directly from the nasal cavity, even though IGF-I did not cross the BBB efficiently by itself. As a consequence, IN IGF-I markedly reduced infarct volume and improved neurological function following focal cerebral ischemia. Research in... 

Liquid scrubbing is also known as one of the most efficient methods for very fine-particle collection, but they are gathered in the form of a suspension that can be rather used for nasal, pulmonary, or parenteral delivery. The suspension stability is often a delicate issue because no chemical or biological degradation shall occur, nor particle decantation, which requires the use of complex mixtures, including a buffer (especially for biomolecules), preservatives (antimicrobial, antioxidant, etc.), and surfactants. Several systems have been described (37,86-88) ... 

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