A systematic review of inhaled intranasal therapy for central nervous system neoplasms: an emerging therapeutic option.

The intranasal route for drug delivery is rapidly evolving as a viable means for treating selected central nervous system (CNS) conditions. We aimed to identify studies pertaining to the application of intranasal drug administration for the treatment of primary CNS tumors. A systematic literature review was conducted to identify all studies published in the English language pertaining to intranasal therapy for CNS neoplasms, and/or general mechanisms and pharmacokinetics regarding targeted intranasal CNS drug delivery. A total of 194 abstracts were identified and screened. Thirty-seven studies met inclusion criteria. Of these, 21 focused on intranasal treatment of specific primary CNS tumors, including gliomas (11), meningiomas (1), and pituitary adenomas (4). An additional 16 studies focused on general mechanisms of intranasal therapy and drug delivery to the CNS using copolymer micelles, viral vectors, and nanoparticles. Inhaled compounds/substances investigated included perillyl alcohol, vesicular stomatitis virus, parvovirus, telomerase inhibitors, neural stem and progenitor cells, antimetabolites, somatostatin analogues, and dopamine agonists. Radiolabeling, CSF concentration measurement, imaging studies, and histological examination were utilized to clarify the mechanism and distribution by which drugs were delivered to the CNS. Successful drug delivery and tumor/symptom response was reported in all 21 tumor-specific studies. The intranasal route holds tremendous potential as a viable option for drug delivery for CNS neoplasms. A variety of antitumoral agents may be delivered via this route, thereby potentially offering a more direct delivery approach and ameliorating the adverse effects associated with systemic drug delivery.