Note 2 – Intangible Assets

Intangible assets at June 30, 2022 and December 31, 2021 consisted of the following:

 Summary of Intangible Assets

Gross intangible assets consist primarily of costs we capitalized when we acquired the license rights to PCS499 in 2018. Amortization expense was $394,248 and $397,664 for the six months ended June 30, 2022 and 2021, respectively, and is included within research and development expense in the accompanying condensed consolidated statements of operations. As of June 30, 2022, our estimated amortization expense for the year ended December 31, 2022 and for annual periods thereafter until the asset is fully amortized is approximately $788,000.