Treatment resistant depression (TRD) affects 1 in 3 sufferers of depression creating an urgent need for therapeutics that differ in action to conventional anti-depressants. This case study describes a collaborative project to develop an esketamine nasal spray to meet this demand. The developed product utilizes Aptar Pharma’s patented Bidose nasal spray pump to deliver two subsequent drug doses, providing patients with a non-invasive, self-administered option for treatment. Use is heavily regulated due to the addictive nature of esketamine but the product has delivered promising results when used in combination with oral anti-depressants. Formulation as a nasal spray exploits recognized potential for ‘nose to brain’ drug delivery and has proven effective in minimizing side effects. The product is a first-in-class solution for TRD and was recognized as one of the top new drugs of 2019 with respect to sales potential.