Intranasal drug use is a known and widely used route of administration for a number of drugs for a long time. It is used for vaccine prophylaxis, treatment of migraine, osteoporosis, sexual dysfunction and even for insulin replacement therapy. The most obvious advantages of this route of administration when using drugs which are not intended for oral administration and are generally injected. The advantages of intranasal administration are the ease of implementation, the convenience for the patient and the relatively low cost.

At the same time, intranasal drug administration poses certain problems. Among them, the differences in physiological processes in the nasal cavity in various people, the presence of pronounced protective mechanisms, the development of local complications and the low bioavailability of drugs, which requires the use of special "absorption stimulators" , which in turn can damage the mucous membranes of the nasal cavity.

Therefore, when developing the intranasal method of administering a particular drug, it is extremely important to study in detail its mechanisms of action, as well as the physicochemical characteristics of the drug itself. For example, the safety of intranasal use of local anti-inflammatory drugs has been confirmed by studies and experience of their clinical use, at the same time, too little data is available on the local effects of systemic drugs administered by intranasal route.

The low bioavailability of drugs administered intranasally is associated with the functioning of a special family of proteins that make up the mucous membrane of the nasal cavity and control the transport of all molecular and cellular objects that enter the mucosa.

To increase the intranasal absorption of drugs, Nastech proposed the use of recently discovered non-toxic substances which bind to mucous proteins according to the principle of the interaction of receptors and open transport channels. At the same time, the bioavailability of drugs increases by 30 to 50%, which is 3 to 6 times higher than the effectiveness of using traditional "absorption enhancers". The second way to solve the problem of low bioavailability is to develop new formulations of drugs and technical means for intranasal administration.

The most important feature of intranasal administration of drugs is the possibility of their penetration directly into the central nervous system. Scientists believe that the transport of drugs from the nasal cavity to the central nervous system is carried out without the involvement of the mucosa, extracellular along the trigeminal and olfactory nerves. After 10 to 15 minutes, chemicals administered intranasally are detected in the brain. This fact attracts universal attention because it offers revolutionary new opportunities in the treatment of diseases of the central nervous system. Theoretically, drugs enter the brain only from the olfactory region, where there is a possibility of extracellular and intracellular penetration of drugs through the epithelial barrier and their entry not into the bloodstream, but directly into the brain shells.

In previous animal experiments, encouraging results have been obtained, however, the extrapolation of these data to the intranasal use of drugs in humans should be made with great caution, as there are pronounced differences in the distribution of mucous secretion carrying the drug inside the nasal cavity in humans and animals. In particular, a person receives too small a quantity of a drug substance directly in the olfactory region and his desired concentration is not reached. In addition, the possibility of direct transport of drugs to the central nervous system can only be evaluated in an experiment using drugs that do not enter the bloodstream and, with it, brain structures. However, even with the proven possibility of a direct effect on the central nervous system with the intranasal administration of drugs in humans, special endoscopic equipment should be used for their administration in the olfactory region, since conventional sprays do not allow not a sufficiently high concentration of the drug substance in this area.

Thus, intranasal administration of drugs has great potential. Already, twice as many dosage forms for intranasal use are being developed than for intravenous administration.