Inventories are valued at the lower of cost or net realizable value. The cost is determined using the first-in, first-out (FIFO) method. Inventories are also written down for management’s estimates of product which will not sell prior to its expiration date. Write-downs of inventories establish a new cost basis which is not increased for future increases in the net realizable value of inventories or changes in estimated obsolescence.

Inventories consisted of the following at March 31, 2024 and September 30, 2023:


	March 31,		September 30,
	2024		2023

Raw material	$	842,691	$	1,854,810
Work in process		49,995		112,799
Finished goods		4,856,635		4,913,295
Inventories, gross		5,749,321		6,880,904
Less: inventory reserves		(944,656)		(183,787)
Inventories, net	$	4,804,665	$	6,697,117

We record equipment, furniture and fixtures, and leasehold improvements at historical cost. Expenditures for maintenance and repairs are recorded to expense. Depreciation and amortization are primarily computed using the straight-line method. Depreciation and amortization are computed over the estimated useful lives of the respective assets. Leasehold improvements are depreciated on a straight-line basis over the lesser of the remaining lease term or the estimated useful lives of the improvements.

Plant and equipment consisted of the following at March 31, 2024 and September 30, 2023:


	Estimated	March 31,		September 30,
	Useful Life	2024		2023
Plant and equipment:
Manufacturing equipment	5 - 8 years	$	3,020,613	$	3,008,122
Office equipment, furniture and fixtures	3 - 10 years		1,472,328		1,471,870
Leasehold improvements	3 - 8 years		960,694		960,694
Total plant and equipment			5,453,635		5,440,686
Less: accumulated depreciation and amortization			(3,919,439)		(3,787,954)
Plant and equipment, net		$	1,534,196	$	1,652,732

Depreciation expense was approximately $66,000 and $45,000 for the three months ended March 31, 2024 and 2023, respectively and approximately $132,000 and $93,000 for the six months ended March 31, 2024 and 2023, respectively. Plant and equipment included $226,000 and $214,000 at March 31, 2024 and September 30, 2023, respectively, for deposits on equipment, furniture, and leasehold improvements, which have not been placed into service; therefore, the Company has not started to record depreciation expense.