Effect of Esketamine Nasal Spray on Olfactory Function and Nasal Tolerability in Patients with Treatment-Resistant Depression: Results from Four Multicenter, Randomized, Double-Blind, Placebo-Controlled, Phase III Studies.

BACKGROUND: Intranasal drug delivery offers a non-invasive and convenient dosing option for patients and physicians, especially for conditions requiring chronic/repeated-treatment administration. However, in some cases such delivery may be harmful to nasal and olfactory epithelia. OBJECTIVE: The aim of this study was to assess the potential impact of long-term intermittent treatment with esketamine nasal spray, taken in conjunction with an oral antidepressant (AD), on olfactory function and nasal tolerability in patients with treatment-resistant depression (TRD). METHODS: A total of 1142 patients with TRD participated from four multicenter, randomized, double-blind, phase III studies: three short-term studies (two in patients aged 18-64 years, one in patients ≥65 years), and one long-term maintenance study of esketamine nasal spray + AD versus placebo nasal spray + AD. Across the four studies, assessments were performed at 208 sites in 21 countries. Olfactory function was measured using the 40-item University of Pennsylvania Smell Identification Test (UPSIT®) and the single-staircase Snap & Sniff® Odor Detection Threshold Test (S&S-T). Nasal tolerability, including nasal examinations and a quantitative, self-administered nasal symptom questionnaire (NSQ), was also assessed. Data were analyzed using analyses of covariance. RESULTS: Of 1142 participants, 734 were women (64.3%). The mean age of all participants ranged from 45.7 to 70.0 years across the studies. Overall, 855 patients received esketamine nasal spray + AD and 432 received placebo nasal spray + AD. Objective evaluation of nasal function showed no evidence of an adverse impact following esketamine administration. Based on the UPSIT® and S&S-T results, intranasal administration of esketamine had no effect on the odor identification or threshold test scores compared with placebo nasal spray + oral AD. Similarly, repeated administration with esketamine nasal spray had no meaningful impact on assessments of nasal function. No dose-response relationship was observed between esketamine doses and the olfactory test scores. Esketamine nasal spray was well tolerated, as indicated by responses on the NSQ and negative nasal examination findings. CONCLUSION: Findings from this analysis indicate that there was no evidence of adverse effect on either olfactory or nasal health measures with repeated intermittent administration of esketamine nasal spray at any dose over the course of short-term (4 weeks) or long-term (16-100 weeks) studies. CLINICAL TRIAL REGISTRATION: TRANSFORM-1: NCT02417064, date of registration: 15/04/2015; TRANSFORM-2: NCT02418585, date of registration: 16/04/2015; TRANSFORM-3: NCT02422186, date of registration: 21/04/2015; SUSTAIN-1: NCT02493868, date of registration: 10/07/2015.

Nasal high flow higher than 60 L/min in patients with acute hypoxemic respiratory failure: a physiological study.

BACKGROUND: Nasal high flow delivered at flow rates higher than 60 L/min in patients with acute hypoxemic respiratory failure might be associated with improved physiological effects. However, poor comfort might limit feasibility of its clinical use. METHODS: We performed a prospective randomized cross-over physiological study on 12 ICU patients with acute hypoxemic respiratory failure. Patients underwent three steps at the following gas flow: 0.5 L/kg PBW/min, 1 L/kg PBW/min, and 1.5 L/kg PBW/min in random order for 20 min. Temperature and FiO2 remained unchanged. Toward the end of each phase, we collected arterial blood gases, lung volumes, and regional distribution of ventilation assessed by electrical impedance tomography (EIT), and comfort. RESULTS: In five patients, the etiology was pulmonary; infective disease characterized seven patients; median PaO2/FiO2 at enrollment was 213 [IQR 136-232]. The range of flow rate during NHF 1.5 was 75-120 L/min. PaO2/FiO2 increased with flow, albeit non significantly (p = 0.064), PaCO2 and arterial pH remained stable (p = 0.108 and p = 0.105). Respiratory rate decreased at higher flow rates (p = 0.014). Inhomogeneity of ventilation decreased significantly at higher flows (p = 0.004) and lung volume at end-expiration significantly increased (p = 0.007), but mostly in the non-dependent regions. Comfort was significantly poorer during the step performed at the highest flow (p < 0.001). CONCLUSIONS: NHF delivered at rates higher than 60 L/min in critically ill patients with acute hypoxemic respiratory failure is associated with reduced respiratory rate, increased lung homogeneity, and additional positive pressure effect, but also with worse comfort.

A spraying applicator device is not required for efficacy of a live intranasal respiratory vaccine in young calves, which improves user convenience.

Almost all bovine intranasal respiratory vaccines require a spraying device, but there are no published reports which prove the necessity of this. The objective of this investigation was to compare the efficacy of the Bovilis® INtranasal RSP™ Live vaccine when applied with or without an (intra)nasal spraying device. This vaccine contains live, attenuated strains of bovine respiratory syncytial virus (BRSV) and bovine parainfluenza virus type 3 (BPI3V) and is licensed to protect young cattle against respiratory infections with wild-type field isolates of these viruses. Two efficacy studies, for BRSV and BPI3V respectively, were performed in which the vaccine was administered using a spraying device or directly from the tip of a syringe as a liquid stream. Both BRSV-vaccinated groups showed a reduction of nasal shedding, BRSV titres in lung washings and clinical symptoms. The BPI3V vaccinated groups showed a significant reduction of nasal shedding and a non-significant reduction of clinical symptoms. Overall, in both studies, the groups in which vaccine was administered without the spraying device performed better than the groups with the spraying device, although this difference was not statistically significant. In conclusion, a spraying device to administer Bovilis® INtranasal RSP™ Live was not required and both application methods induced a protective immune response. This makes application more convenient and flexible for future users and animals.

CFD Guided Optimization of Nose-to-Lung Aerosol Delivery in Adults: Effects of Inhalation Waveforms and Synchronized Aerosol Delivery.

PURPOSE: The objective of this study was to optimize nose-to-lung aerosol delivery in an adult upper airway model using computational fluid dynamics (CFD) simulations in order to guide subsequent human subject aerosol delivery experiments. METHODS: A CFD model was developed that included a new high-flow nasal cannula (HFNC) and pharmaceutical aerosol delivery unit, nasal cannula interface, and adult upper airway geometry. Aerosol deposition predictions in the system were validated with existing and new experimental results. The validated CFD model was then used to explore aerosol delivery parameters related to synchronizing aerosol generation with inhalation and inhalation flow rate. RESULTS: The low volume of the new HFNC unit minimized aerosol transit time (0.2 s) and aerosol bolus spread (0.1 s) enabling effective synchronization of aerosol generation with inhalation. For aerosol delivery correctly synchronized with inhalation, a small particle excipient-enhanced growth delivery strategy reduced nasal cannula and nasal depositional losses each by an order of magnitude and enabled ~80% of the nebulized dose to reach the lungs. Surprisingly, nasal deposition was not sensitive to inhalation flow rate due to use of a nasal cannula interface with co-flow inhaled air and the small initial particle size. CONCLUSIONS: The combination of correct aerosol synchronization and small particle size enabled high efficiency nose-to-lung aerosol delivery in adults, which was not sensitive to inhalation flow rate.

A narrative review on trans-nasal pulmonary aerosol delivery.

The use of trans-nasal pulmonary aerosol delivery via high-flow nasal cannula (HFNC) has expanded in recent years. However, various factors influencing aerosol delivery in this setting have not been precisely defined, and no consensus has emerged regarding the optimal techniques for aerosol delivery with HFNC. Based on a comprehensive literature search, we reviewed studies that assessed trans-nasal pulmonary aerosol delivery with HFNC by in vitro experiments, and in vivo, by radiolabeled, pharmacokinetic and pharmacodynamic studies. In these investigations, the type of nebulizer employed and its placement, carrier gas, the relationship between gas flow and patient's inspiratory flow, aerosol delivery strategies (intermittent unit dose vs continuous administration by infusion pump), and open vs closed mouth breathing influenced aerosol delivery. The objective of this review was to provide rational recommendations for optimizing aerosol delivery with HFNC in various clinical settings.

Pharmacokinetic study and brain tissue analysis of Zolmitriptan loaded chitosan nanoparticles in rats by LC-MS method.

INTRODUCTION: Migraine has recently become a major interest to the neuroscientists. Zolmitriptan is an effective medicine used in the treatment of migraine. The nasal spray was prepared from Zolmitriptan loaded chitosan nanoparticles and evaluated for pharmacokinetic properties. METHODS: In this study male Wistar albino rats weighing between 200 and 250 g were taken and divided into 4 groups with 6 rats in each group. Nasal spray containing Zolmitriptan loaded Chitosan nanoparticles were administered nasally (using specific inhalation mask) at a dose of 0.5 mg/kg as a test formulation and compared with the control groups which received either water for injection or marketed standard drug (Zolmist) or standard drug solution at a same dose. The pharmacokinetic parameters such as Cmax, Tmax, and brain tissue analyses for accumulation of drug were performed for Zolmitriptan by LC-MS method. RESULTS: Amount of drug in the plasma from the test formulation, standard marketed drug (Zolmist) and standard drug solution was found to be 41.37 ±â€¯2.31, 34.76 ±â€¯4.22 and 23.74 ±â€¯2.42 ng/ml at 10 min respectively, which indicated significantly (p < 0.05) greater amount of drug being delivered from the test formulation compared to the both standard groups. The amount of the drug (Zolmitriptan) present in brain tissue (Olfactory lobe) was found to be 15 ±â€¯0.08, 13 ±â€¯0.14 and 8 ±â€¯0.13 ng/g at 60 min for test formulation, marketed standard and standard drug solution respectively which indicates significantly (p < 0.05) higher amount of drug absorption in brain tissue from the test formulation compared to both the standard groups. CONCLUSION: Pharmacokinetics studies of nasal spray containing Zolmitriptan loaded chitosan nanoparticles proved rapid onset of action in animals and is promising in treatment of migraine.

Deposition of drugs in the nose and sinuses with an exhalation delivery system vs conventional nasal spray or high-volume irrigation in Draf II/III post-surgical anatomy.

BACKGROUND: Endoscopic sinus surgery is often performed to improve delivery of topical medication into sinus cavities. Intranasal steroids are guideline recommended in post-surgical patients, and experiments with cadavers suggest that surgery improves delivery of drug into sinuses. Exhalation delivery systems (EDS) use a new mechanism for intranasal delivery and have been shown to reach superior/posterior regions of the nasal cavity better than nasal sprays in unoperated patients. METHODS: Silicone casts of the nasal cavity and sinuses from a patient after Draf II, and then Draf III, were made from high-resolution computed tomography (CT) data using 3D printing. Internal surfaces were coated with liquid-sensitive, color-changing gel. Color changes were evaluated following conventional nasal spray delivery (0.1 mL x 2) (Nasonex), EDS delivery (0.1 mL x 2) (XHANCE), and high-volume, low-flow (HVLF) delivery (80 mL) with head tilted either 45° or 90°. RESULTS: Conventional nasal spray deposited liquid only in anterior nasal segments. EDS deposited liquid throughout the nasal cavity, in surgically opened ethmoid and maxillary spaces, at entrances of the frontal sinuses in Draf II geometry, and into frontal sinuses in Draf III. Tilted 45° HVLF delivery enters the maxillary sinuses but not the frontal sinuses or the ethmoid region. At full 90° inclination, HVLF delivery reaches most of the frontal and maxillary sinuses but not the roof and posterior wall of the ethmoid region. CONCLUSIONS: HVLF and EDS produced a deep intranasal/intrasinal deposition in the silicone cast compared with conventional nasal spray delivery; both deposited liquid inside the surgically opened sinuses. HVLF offers the benefit of lavage, whereas EDS may be more efficient and convenient.

Comparison of short nozzle and long nozzle spray in sinonasal drug delivery: a cadaveric study.

The aim of this study is to compare the delivery site of topical drugs using the short nozzle and the long nozzle. Fourteen fresh frozen cadaver heads were obtained. All cadaver specimens underwent bilateral endoscopic wide maxillary antrostomy, frontal sinusotomy, and complete sphenoethmoidectomy. The right nasal cavity of each cadaver was sprayed with radiolabeled saline using the short nozzle (short nozzle group), while the left nasal cavity was sprayed using the long nozzle (long nozzle group). The distribution of radioactive saline within the sinus cavities was determined using single-photon emission computed tomography/computed tomography. The distribution of the radiolabeled saline in reference with the maxillary line, vestibule, maxillary, ethmoid, sphenoid, and frontal sinus was compared between the 2 groups using Fisher exact test. The number of specimens that demonstrated radioactivity above the maxillary line is higher in the long nozzle group (14 cadavers, 100%) compared to short nozzle group (9 cadavers, 64.3%; p = .02). There are fewer specimens that demonstrated deposition of radioactive saline in the vestibule in the long nozzle group (6 cadavers, 42.86%) compared to short nozzle group (13 cadavers, 92.86%; P = .006). Compared to short nozzle group, there are more specimens demonstrating radioactivity in the maxillary, ethmoid, sphenoid, and frontal sinus in the long nozzle group, but the differences were not statistically significant (p = 0.241, 0.347, 0.126, 0.5). Compared to short nozzle, long nozzle more frequently delivers intranasal drugs beyond the maxillary line and less frequently in the vestibule. These findings support the hypothesis that the use of long and narrow nozzle, instead of the conventional short nozzle, can improve sinonasal drug delivery in post-endoscopic sinus surgery nose.

How to characterize a nasal product. The state of the art of in vitro and ex vivo specific methods.

Nasal delivery offers many benefits over other conventional routes of delivery (e.g. oral or intravenous administration). Benefits include, among others, a fast onset of action, non-invasiveness and direct access to the central nervous system. The nasal cavity is not only limited to local application (e.g. rhinosinusitis) but can also provide direct access to other sites in the body (e.g. the central nervous system or systemic circulation). However, both the anatomy and the physiology of the nose impose their own limitations, such as a small volume for delivery or rapid mucociliary clearance. To meet nasal-specific criteria, the formulator has to complete a plethora of tests, in vitro and ex vivo, to assess the efficacy and tolerance of a new drug-delivery system. Moreover, depending on the desired therapeutic effect, the delivery of the drug should target a specific pathway that could potentially be achieved through a modified release of this drug. Therefore, this review focuses on specific techniques that should be performed when a nasal formulation is developed. The review covers both the tests recommended by regulatory agencies (e.g. the Food and Drug Administration) and other complementary experiments frequently performed in the field.

Subunit-based mucosal vaccine delivery systems for pulmonary delivery - Are they feasible?

Pulmonary infections are the most common cause of death globally. However, the development of mucosal vaccines that provide protective immunity against respiratory pathogens are limited. In contrast to needle-based vaccines, efficient vaccines that are delivered via noninvasive mucosal routes (such as via the lungs and nasal passage) produce both antigen-specific local mucosal IgA and systemic IgG protective antibodies. One major challenge in the development of pulmonary vaccines using subunit antigens however, is the production of optimal immune responses. Subunit vaccines therefore rely upon use of adjuvants to potentiate immune responses. While the lack of suitable mucosal adjuvants has hindered progress in the development of efficient pulmonary vaccines, particle-based systems can provide an alternative approach for the safe and efficient delivery of subunit vaccines. In particular, the rational engineering of particulate vaccines with optimal physicochemical characteristics can produce long-term protective immunity. These protect antigens against enzymatic degradation, target antigen presenting cells and initiate optimal humoral and cellular immunity. This review will discuss our current understanding of pulmonary immunology and developments in fabricating particle characteristics that may evoke potent and durable pulmonary immunity.

Nasal high-flow preoxygenation for endotracheal intubation in the critically ill patient: a randomized clinical trial.

PURPOSE: Preoxygenation with high-flow therapy by nasal cannulae (HFNC) is now widespread in the intensive care unit (ICU). However, no large randomized study has assessed its relevance in non-severely hypoxemic patients. In a randomized controlled trial (PROTRACH study), we aimed to evaluate preoxygenation with HFNC vs. standard bag-valve mask oxygenation (SMO) in non-severely hypoxemic patients during rapid sequence intubation (RSI) in the ICU. METHODS: Randomized controlled trial including non-severely hypoxemic patients requiring intubation in the ICU. Patients received preoxygenation by HFNC or SMO during RSI. HFNC was maintained throughout the intubation procedure whereas SMO was removed to perform laryngoscopy. The primary outcome was the lowest pulse oximetry (SpO2) throughout the intubation procedure. Secondary outcomes included drop in SpO2, adverse events related to intubation, and outcome in the ICU. RESULTS: A total of 192 patients were randomized. In the intent-to-treat analysis, 184 patients (HFNC n = 95; SMO n = 89), the median [IQR] lowest SpO2 was 100% [97; 100] for HFNC and 99% [95; 100] for the SMO group (P = 0.30). Mild desaturation below 95% was more frequent with SMO (23%) than with HFNC (12%) (RR 0.51, 95% CI 0.26-0.99, P = 0.045). There were fewer adverse events in the HFNC group (6%) than in the SMO group (19%) (RR 0.31, 95% CI 0.13-0.76, P = 0.007), including fewer severe adverse events, respectively 6 (6%) and 14 (16%) with HFNC and SMO (RR 0.38, 95% CI 0.15-0.95, P = 0.03). CONCLUSIONS: Compared with SMO, preoxygenation with HFNC in the ICU did not improve the lowest SpO2 during intubation in the non-severely hypoxemic patients but led to a reduction in intubation-related adverse events. TRIAL REGISTRATION: Clinical trial Submission: 7 March 2016. Registry name: Benefits of high-flow nasal cannulae oxygen for preoxygenation during intubation in non-severely hypoxemic patients: the PROTRACH study. Clinicaltrials.gov identifier: NCT02700321. Eudra CT: 2015-A00145-44. CPP: 15/13-975 (Comité de protection des personnes de Rennes). URL registry: https://clinicaltrials.gov/ct2/show/record/NCT02700321 .

High flow nasal therapy in perioperative medicine: from operating room to general ward.

BACKGROUND: High flow nasal therapy (HFNT) is a technique in which humidified and heated gas is delivered to the airways through the nose via small nasal prongs at flows that are higher than the rates generally applied during conventional oxygen therapy. The delivered high flow rates combine mixtures of air and oxygen and enable different inspired oxygen fractions ranging from 0.21 to 1. HFNT is increasingly used in critically ill adult patients, especially hypoxemic patients in different clinical settings. MAIN BODY: Noninvasive ventilation delivers positive pressure (end-expiratory and inspiratory pressures or continuous positive airway pressure) via different external interfaces. In contrast, HFNT produces different physiological effects that are only partially linked to the generation of expiratory positive airway pressure. HFNT and noninvasive ventilation (NIV) are interesting non-invasive supports in perioperative medicine. HFNT exhibits some advantages compared to NIV because HFNT is easier to apply and requires a lower nursing workload. Tolerance of HFNT remains a matter of intense debate, and it may be related to selected parameters. Patients receiving HFNT and their respiratory patterns should be closely monitored to avoid delays in intubation despite correct oxygenation parameters. CONCLUSION: HFNT seems to be an interesting noninvasive support in perioperative medicine. The present review provides anesthesiologists with an overview of current evidence and practical advice on the application of HFNT in perioperative medicine in adult patients.

Opportunities and challenges for intranasal oxytocin treatment studies in nonhuman primates.

Nonhuman primates provide a human-relevant experimental model system to explore the mechanisms by which oxytocin (OT) regulates social processing and inform its clinical applications. Here, we highlight contributions of the nonhuman primate model to our understanding of OT treatment and address unique challenges in administering OT to awake behaving primates. Prior preclinical research utilizing macaque monkeys has demonstrated that OT can modulate perception of other individuals and their expressions, attention to others, imitation, vigilance to social threats, and prosocial decisions. We further describe ongoing efforts to develop an OT delivery system for use in experimentally naïve juvenile macaque monkeys compatible with naturalistic social behavior outcomes. Finally, we discuss future directions to further develop the rhesus monkey as a preclinical test bed to evaluate the effects of OT exposure and advance efforts to translate basic science OT research into safe and effective OT therapies.

Recent advances in carrier mediated nose-to-brain delivery of pharmaceutics.

Central nervous system (CNS) disorders (e.g., multiple sclerosis, Alzheimer's disease, etc.) represent a growing public health issue, primarily due to the increased life expectancy and the aging population. The treatment of such disorders is notably elaborate and requires the delivery of therapeutics to the brain in appropriate amounts to elicit a pharmacological response. However, despite the major advances both in neuroscience and drug delivery research, the administration of drugs to the CNS still remains elusive. It is commonly accepted that effectiveness-related issues arise due to the inability of parenterally administered macromolecules to cross the Blood-Brain Barrier (BBB) in order to access the CNS, thus impeding their successful delivery to brain tissues. As a result, the direct Nose-to-Brain delivery has emerged as a powerful strategy to circumvent the BBB and deliver drugs to the brain. The present review article attempts to highlight the different experimental and computational approaches pursued so far to attain and enhance the direct delivery of therapeutic agents to the brain and shed some light on the underlying mechanisms involved in the pathogenesis and treatment of neurological disorders.

Development of coated liposomes loaded with ghrelin for nose-to-brain delivery for the treatment of cachexia.

The aim of the present study was to develop a ghrelin-containing formulation based on liposomes coated with chitosan intended for nose-brain delivery for the treatment of cachexia. Among the three types of liposomes developed, anionic liposomes provided the best results in terms of encapsulation efficiency (56%) and enzymatic protection against trypsin (20.6% vs 0% for ghrelin alone) and carboxylesterase (81.6% vs 17.2% for ghrelin alone). Ghrelin presented both electrostatic and hydrophobic interactions with the anionic lipid bilayer, as demonstrated by isothermal titration calorimetry. Then, anionic liposomes were coated with N-(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride. The coating involved a size increment from 146.9±2.7 to 194±6.1 nm, for uncoated and coated liposomes, respectively. The ζ-potential was similarly increased from -0.3±1.2 mV to 6±0.4 mV before and after coating, respectively. Chitosan provided mucoadhesion, with an increase in mucin adsorption of 22.9%. Enhancement of permeation through the Calu3 epithelial monolayer was also observed with 10.8% of ghrelin recovered in the basal compartment in comparison to 0% for ghrelin alone. Finally, aerosols generated from two nasal devices (VP3 and SP270) intended for aqueous dispersion were characterized with either coated or uncoated liposomes. Contrarily to the SP270 device, VP3 device showed minor changes between coated and uncoated liposome aerosols, as shown by their median volume diameters of 38.4±5.76 and 37.6±5.74 µm, respectively. Overall, the results obtained in this study show that the developed formulation delivered by the VP3 device can be considered as a potential candidate for nose-brain delivery of ghrelin.

A Method to Administer Agents to the Larynx in an Awake Large Animal.

Purpose: This research note describes an adapted experimental methodology to administer an exogenous agent to the larynx and upper airway of awake animals. The exogenous agent could be a perturbation. In the current study, the agent was isotonic saline. Isotonic saline was selected because it is safe, of similar composition to extracellular fluid, and used in voice studies. The described approach allowed large animals such as pigs to be comfortably restrained without chemical sedation or anesthesia for extended periods while receiving the agent. Method: Six Sinclair pigs were successfully trained with positive reinforcement to voluntarily enter and then be restrained in a Panepinto Sling. Once restrained, the pigs accepted a nose cone that delivered nebulized isotonic saline. This procedure was repeated 3 times per day for 20 days. At the end of the study, the larynx and airway tissues were excised and examined using histology and transmission electron microscopy. Results: Pathology related to the procedure (i.e., nebulized inhaled isotonic saline or stress) was not identified in any examined tissues. Conclusions: This methodology allowed for repeated application of exogenous agents to awake, unstressed animals. This method can be used repeatedly in the laboratory to test various therapeutics for safety, toxicity, and dosage. Future studies will specifically manipulate the type of agent to further our understanding of laryngeal pathobiology.

Dose-dependent social-cognitive effects of intranasal oxytocin delivered with novel Breath Powered device in adults with autism spectrum disorder: a randomized placebo-controlled double-blind crossover trial.

The neuropeptide oxytocin has shown promise as a treatment for symptoms of autism spectrum disorders (ASD). However, clinical research progress has been hampered by a poor understanding of oxytocin's dose-response and sub-optimal intranasal delivery methods. We examined two doses of oxytocin delivered using a novel Breath Powered intranasal delivery device designed to improve direct nose-to-brain activity in a double-blind, crossover, randomized, placebo-controlled trial. In a randomized sequence of single-dose sessions, 17 male adults with ASD received 8 international units (IU) oxytocin, 24IU oxytocin or placebo followed by four social-cognitive tasks. We observed an omnibus main effect of treatment on the primary outcome measure of overt emotion salience as measured by emotional ratings of faces (η2=0.18). Compared to placebo, 8IU treatment increased overt emotion salience (P=0.02, d=0.63). There was no statistically significant increase after 24IU treatment (P=0.12, d=0.4). The effects after 8IU oxytocin were observed despite no significant increase in peripheral blood plasma oxytocin concentrations. We found no significant effects for reading the mind in the eyes task performance or secondary outcome social-cognitive tasks (emotional dot probe and face-morphing). To our knowledge, this is the first trial to assess the dose-dependent effects of a single oxytocin administration in autism, with results indicating that a low dose of oxytocin can significantly modulate overt emotion salience despite minimal systemic exposure.