offering expenses were approximately $9.2 million. During March 2022, the Jan 2022 Pre-Funded Warrant was exercised in full. The Jan 2022 Common Warrant is currently exercisable and will expire on February 10, 2027.

May 2022 Private Placement 2022 Private Placement – On May 27, 2022, we closed a private placement of 1,050,000 shares of common stock, pre-funded warrants to purchase an aggregate of 11,071,214 shares of common stock for a nominal exercise price per share (the “May 2022 Pre-Funded Warrants”), and preferred investment options to purchase up to an aggregate of 12,121,214 shares of common stock at an exercise price of $1.65 per share (the “May 2022 Preferred Investment Options”). Net proceeds after deducting placement agent commissions and other offering expenses were approximately $18.5 million.

The May 2022 Pre-Funded Warrants were exercised as to 1,980,304 shares concurrent with the closing and during June and July the remaining 9,090,910 were fully exercised. During August, the May 2022 Preferred Investment Options were exercised as to 4,621,214 shares, resulting in net proceeds to us of approximately $7,626,000.

Other Common Stock Transactions Common Stock Transactions – During May and July, we issued 68,500 and 75,000 shares, respectively, of our common stock pursuant to consulting agreements.

Stock Options Options – We have a stock-based incentive plan (the “2020 Plan”) pursuant to which our Board of Directors may grant stock options and other stock-based awards to our employees, directors and consultants. A total of 1,500,000 shares of our common stock are reserved for issuance pursuant to the 2020 Plan. During the nine months ended September 30, 2022, there were no stock option transactions related to the 2020 Plan. As of September 30, 2022, there are 962,300 stock options outstanding, with a weighted-average exercise price of $3.18 per share and a weighted-average remaining term of 8.6 years.

Stock Purchase Warrants – Purchase Warrants – The table below presents summary information about our warrants outstanding as of September 30, 2022.

Warrant Description	Number of Shares	Exercise Price	Expiration
2020 Warrants	120,000	$ 1.65	Jun 2025
2020 Unit Warrants	2,396,631	5.00	Sep 2025
2020 Representative Warrants	128,000	5.50	Mar 2024
2021 Representative Warrants	72,000	6.875	Aug 2024
2021 Warrants	100,000	13.00	Sep 2026
Jan 2022 Common Warrants	3,067,484	3.26	Feb 2027
May 2022 Preferred Investment Options	7,500,000	1.65	May 2028
Total Warrants Outstanding at September 30, 2022	13,384,115

########## 6. Stock-Based Compensation Expense

Stock-based compensation expense related to stock options is recognized on a straight-line basis over the requisite service period for the award and is allocated to research and development expense or general and administrative expense based upon the classification of the individual to whom the award is granted. As of September 30, 2022, there is $849,571 of unrecognized compensation expense that we expect to recognize over a weighted-average period of 1.7 years.

We also have issued shares of restricted common stock to consultants and recognize the related expense over the terms of the related agreements. As of September 30, 2022, there is $72,375 recorded as a prepaid expense for these arrangements, which will be recognized as expense over the terms of the related agreements.

The following table summarizes our total stock-based compensation expense for employees, directors and consultants:

Three Months Ended Sep. 30,	Nine Months Ended Sep. 30,
2022	2021	2022	2021
Stock options:
Research and development	$ 54,293	$ 21,468	$ 162,878	$ 64,404
General and administrative	135,898	34,722	407,695	104,166
Total stock option expense	190,191	56,190	570,573	168,570
Stock awards (consultants):
General and administrative	48,375	29,560	80,322	80,733
Total stock-based compensation expense	$ 238,566	$ 85,750	$ 650,895	$ 249,303