"One of the primary effects of ketamine in the brain is to block the NMDA [N-methyl-d-aspartate] glutamate receptor," said James W. Murrough , MD, principal investigator of the study, and Assistant Professor of Psychiatry and Neuroscience , and Associate Director of the Mood and Anxiety Disorders Program at the Icahn School of Medicine at Mount Sinai. "There is an urgent clinical need for new treatments for depression with novel mechanisms of action. With further research and development, this could lay the groundwork for using NMDA targeted treatments for major depressive disorder."
The most common reason one would not choose an oral route and would instead elect to use nasal or buccal routes is due to delays in onset of oral medications and due to gastric acid destruction and first pass metabolism of drug resulting in very low levels available to the blood stream. Failure to utilize the nose brain path also occurs with oral (and buccal) medications - resulting in much slower drug delivery to the brain. Interestingly, oral medications are also commonly refused by 30% of pediatric patients making them completely ineffective in this situation. Buccal medications also require a cooperative patient who will retain the medication within their buccal and sublingual mucosal areas and not swallow or spit it out. In fact, even when buccal medications are administered to volunteers in research settings, only about 56% remains in the oral cavity for absorption. Even nasal drug delivery can have problems depending on the delivery method. Yuen et al report that in % of pediatric patients they were unable to dispense drops into the nose due to resistance to this delivery technique. While nasal delivery is possible the majority of the time, to overcome these delivery issues a number of device have been developed that enhance delivery - these are discussed in the delivery techniques section of this web site.