	March 31, 2022		December 31, 2021
Raw materials	$	4,394	$	3,042
Work in process		1,231		1,642
Finished products		3,342		2,938
Inventory	$	8,967	$	7,622

We recorded inventory charges of $0.1 million and $0.5 million for the three months ended March 31, 2022 and 2021, respectively.

We rely on third parties to manufacture our finished products, and we have entered into long-term supply agreements for the manufacture of ANNOVERA, IMVEXXY, and BIJUVA. We do not have a long-term supply agreement for the manufacture of our prescription vitamins. Additionally, we do not have long-term contracts for the supply of all the active pharmaceutical ingredients (“API”) used in ANNOVERA and BIJUVA.

One of our third-party contract manufacturers that manufactures ANNOVERA has recently experienced an increase in difficulties with manufacturing of ANNOVERA, which has resulted in intermittent supply interruptions of ANNOVERA for commercial distribution. The challenges are multifactorial and include variability in raw material supply and normal manufacturing variation due to a semi-manual process. This has recently resulted in challenges to supply ANNOVERA at a rate that meets the projected demand for ANNOVERA. To mitigate the manufacturing challenges, in August 2021, we filed a supplemental New Drug Application (“NDA”) with the FDA to modify the testing specifications for ANNOVERA to allow increased consistency of supply of ANNOVERA. In December 2021, FDA determined that it could not approve the supplemental NDA without additional information. In its complete response letter (“CRL”), the FDA provided recommendations and requested additional information that could support approval of revisions to certain testing specifications. In January 2022, we responded to the CRL, and provided additional information to the FDA and modified the request to revise the manufacturing testing limits based on the FDA feedback. We expect a response from the FDA by the end of second quarter of 2022. We have continued to manufacture and supply ANNOVERA under the existing specifications as well as (i) ramping up manufacturing sufficient to better meet second quarter of 2022 demands notwithstanding existing challenges, (ii) added resources to increase production volumes, (iii) increasing yield per manufacturing batch, and (iv) increasing production capacity to better meet product demands to realize revenue potential, including reducing dependency on labor resources, increasing efficiency in manufacturing and testing, and automating some of the processes. In the meantime, our third-party contract manufacturer may not be able to supply us with sufficient ANNOVERA to adequately supply the market, which would have an adverse effect on our business,

results of operations and financial condition. Additionally, we may incur increased write-offs of ANNOVERA products manufactured in 2022 that do not meet existing specifications.

We have also experienced a greater than expected amount of raw materials for ANNOVERA being out of specification. If any of our third-party contract manufacturers or any suppliers of raw materials or API experience further difficulties, do not comply with the terms of an agreement between us, or do not devote sufficient time, energy, and care to providing our manufacturing needs, or if the manufacturing specification modifications that we have requested are not approved by the FDA, we could experience additional interruptions in the supply of our products, which may have a material adverse impact on our revenue, results of operations and financial position.