It looks like the contaminated-heparin drug story won't go away. As many news sources, including The Wall Street Journal, reported today, a German drugmaker recalled batches of the commonly used anticoagulant. The decision came after the drugmaker cited patients who experienced the same allergic effects as those involved in the Baxter (NYSE: BAX) heparin recall that started almost three weeks ago and ended last week with a recall of the remaining product.

Heparin, like many other drugs, is produced using animal parts. It is developed from the intestines of pigs, and this raw material often comes from China. The German drugmaker Rotexmedica GmbH Arzneimittelwerk didn't find any problems with its heparin in testing, but did see more than the normal amount of adverse events in patients who used its Chinese-sourced heparin.

This heparin imbroglio reminds us that many non-synthetic drugs do have variability between different batches as a result of their manufacturing process. This variability can cause an adverse immune system response in some patients that can be severe enough to kill them.

Regardless of where the product comes from, drugmakers try to test their drugs to ensure quality and consistency, and have, at times, had to throw out millions of dollars worth of drugs in the manufacturing process. This has happened to multiple biopharmas in the past, including Genentech (NYSE: DNA) and Biogen IDEC (Nasdaq: BIIB). This problem will always be a bigger manufacturing issue for compounds that are biologic in nature -- protein-based biotech drugs -- than it is for synthetically produced ones, such as many oral pills or tablets.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has an A+ disclosure policy.