Cost of Goods Sold
Cost of goods sold was $500,000 for both the year ended December 31, 2022 and 2021. Cost of goods sold relates to the minimum royalty due to the University under our license agreement.
Gross Profit (Loss)
Gross profit was $453,470 for the year ended December 31, 2022, compared with gross loss of $466,934 for the year ended December 31, 2021, an increase of $920,404, or 197.1%. The gross profit position for the year ended December 31, 2022 resulted from the recognition of the 2020 and 2022 minimum royalties due from Reprise. The gross loss position for the year ended December 31, 2021 resulted from the uncertainty of collecting the deferred minimum royalty from Reprise that made the contract not meet the requirements of ASC 606, therefore, we fully reserved against the minimum royalty.
Research and Development
Research and development expenses were $18,303,386 for the year ended December 31, 2022 and $10,755,959 for the year ended December 31, 2021, an increase of $7,547,427, or 70.2%. The increase was primarily due to lab supply increase of $3,398,536, headcount increase which resulted in an increase in payroll expense of $1,966,112, consulting expense increase of $1,251,262, contract pre-clinical cost increase of $636,316, depreciation expense increase of $365,251. The increase was partially offset by a decrease in office and other expense of $70,050.
Regulatory and Clinical
Regulatory and clinical expenses were $1,646,162 for the year ended December 31, 2022 and $551,494 for the year ended December 31, 2021, an increase of $1,094,668, or 198.5%. The increase was primarily due to headcount increase which resulted in an increase in payroll expense of $640,804 as well an increase in regulatory consulting and contracting expense of $370,365.
Quality Expenses
Quality expenses were $2,148,483 for the year ended December 31, 2022 and $547,129 for the year ended December 31, 2021, an increase of $1,601,354, or 292.7%. The increase was primarily due to lab supply increase of $753,732, headcount increase which resulted in an increase in payroll expense of $406,160 and consulting expense increase of $417,091.
General and Administrative
General and administrative expenses were $8,719,869 for the year ended December 31, 2022 and $4,643,473 for the year ended December 31, 2021, an increase of $4,076,396, or 87.8%. The increase was primarily due to headcount increase which resulted in an increase in payroll expense of $1,949,032, depreciation expense increase of $575,273, office expense increase of $567,371, insurance expense increase of $513,490, legal and accounting expense increase of $167,642 and public company expense increase of $133,978. These increases can primarily be attributed to the cost of being a public company.
Interest Income
Interest income was $333,469 for the year ended December 31, 2022 and $1,973 for the year ended December 31, 2021, an increase of $331,496. The increase was primarily due to U.S. Treasury securities purchased during the second quarter of 2022 with cash received from our IPO.
Interest Expense
Interest expense was $47,732 for the year ended December 31, 2022 and $613,882 for the year ended December 31, 2021, a decrease of $566,150, or 92.2%. The decrease was primarily due to the interest expense on the