Cambrex did not provide any further details of the recall or the product and customer concerned, citing a confidentiality agreement.
It did note, however, that - based on the information available to date - " the recall decision is not linked in any way to Cambrex's performance as the manufacturer of the API ".
A report in the Associated Press inferred that the ingredient involved might be heparin.
This was based on recall notices issued as press releases on the US Food and Drug Administration's (FDA) website by two companies, American Health Packaging (AHP) and B. Braun Medical, on 20 March and 21 March respectively.
The Cambrex announcement was made on 21 March.
But heparin does not appear on the lists of proprietary and generic APIs published by Cambrex on its website.
Moreover, the aforementioned notices both relate to the wider recall of contaminated heparin made by Baxter and linked to hundreds of severe adverse events as well as 19 deaths.
The contaminant in question, identified by the FDA as oversulfated chondroitin sulphate, was found in the powdered form of raw heparin purchased by suppliers of Scientific Protein Laboratories (SPL) - which in turn supplies a refined form of the API to Baxter - in China.
In fact, B. Braun's notice specifically refers to finished heparin products based on SPL APIs, while the heparin vials recalled by AHP were manufactured by Baxter and then packaged by AHP into individually labelled bags for use in pharmacy automation equipment.
None of the ingredients mentioned among the more detailed account of drug recalls and field corrections in the FDA's most recent enforcement report (19 March) appear on the Cambrex lists.
The previous FDA report, issued on 12 March, does include the recall by drug delivery specialist Alza of the Duragesic (Fentanyl Transdermal System) patches that have been causing problems for Alza's parent, Johnson & Johnson, as well as generic manufacturers of fentanyl patches.
Cambrex supplies fentanyl, a highly potent narcotic analgesic, as an API, although whether Johnson & Johnson and affected generic companies such as Sandoz and Ranbaxy are among Cambrex's customers is a matter of speculation.
The fault in this case was not to do with the API itself but with leakage of fentanyl gel from the drug reservoir due to problems in cutting the patch.
For the moment, the financial implications of the product recall by one of Cambrex's API customers remains uncertain. "
While this event may materially affect Cambrex's 2008 performance, until the customer has resolved the issue, it is unknown what the impact will be ," the company stated.
" The Company will monitor the situation and update its 2008 guidance, if necessary, when it has enough information to do so ," Cambrex added.
The company's credibility has been under strain of late following a fire and explosion at its US plant in Charles City, Iowa last October.
Cambrex was fined a total of $15,375 over the incident after being found in breach of several safety regulations.
The company has been slimming down its operations over the last year and a half following a period in the financial doldrums, largely blamed on the Biopharma unit that was sold to Swiss contract manufacturer Lonza along with Cambrex's Bioproducts business at the beginning of 2007.
Cambrex reported an operating loss of $6.98m for 2007, compared with an operating profit of $11.8m in the previous year.
Net sales rose by 6.6 per cent to $251.2m last year.
The company, which recently completed construction of a new current Good Manufacturing Practice (cGMP) finishing facility for active pharmaceutical ingredients, offers around 70 generic APIs, with a number more under development, and several APIs for proprietary drugs.