Previous patents filed by Pfizer (*word disallowed by google – 1999 - Expired)...

Previous patents filed by Pfizer (*word disallowed by google – 1999 - Expired) and Bayer (Vardenafil – 2002 Expired) resulted in no commercialisation from either company. The challenge is making the drug stable in liquid form (shelf life, and not crystallizing), and not causing adverse effects in the nose. If it was easy to solve, then many more drugs would be taken intranasally (less drug, faster effect). If Bayer and Pfizer were cracked it, they both would have an intranasal formulation in market to fend off the impact of rolling to generic in 2017.Solving these problems took SDS (LTP's research group with lodged patents) around 8 years in total, first trying *word disallowed by google and then moving on to Vardenafil. The pilot trial for Spontan showed no adverse events as defined by the FDA. Some patients experienced sneezing, nasal discomfort, a running nose (these were described as very transient ie less than 15 minutes and described as “tolerable”). When these patients took a second dose, these non-serious effects fell by 50%.