5. Property and equipment

As at November 30, 2021, there was $Nil (November 30, 2020 - $514,502) of laboratory equipment that was not available for use and therefore, no depreciation has been recorded for such laboratory equipment. Also, during the year ended November 30, 2020, the Company returned equipment in the amount of $32,269, which was unpaid previously, and recorded loss on disposal of that equipment amounting to $11,294. The Company also sold equipment with a net book value of $59,500 for the amount of $29,191 and recognized a loss on sale of that equipment in the amount of $30,309.

As at November 30, 2021, there was $Nil (November 30, 2020 - $nil) unpaid balance for purchased equipment. During the year ended November 30, 2021, the Company recorded depreciation expense within cost of goods sold in the amount of $Nil (November 30, 2020 - $Nil; November 30, 2019 - $882).

Property and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Impairment is assessed by comparing the carrying amount of an asset with the sum of the undiscounted cash flows expected from its use and disposal, and as such requires the Company to make significant estimates on expected revenues from the commercialization of its products and services and the related expenses. The Company records a write-down for long-lived assets which have been abandoned and do not have any residual value. For the year ended November 30, 2021, the Company recorded a $514,502 write-down of long-lived assets (2020 - $Nil; 2019 - $Nil).