<unk>  is an enzyme derived from plasma of bovine origin or extracted from cultures of certain bacteria. It is used locally only and exclusively together with the enzyme desoxyribonuclease (extracted from bovine pancreas).<unk>  and desoxyribonuclease both act as lytic enzymes. The combination is available as ointment containing 1 BU (Biological Unit)<unk>  and 666 BUs desoxyribonuclease per gram.<unk>  attacks and inactivates fibrin molecules occurring in undesirable exudates on the surface of the human body and on human mucosa, e.g., in superficial wounds and burns, while desoxyribonuclease targets and destroys (human) DNA. The combination of the two enzymes has a synergistic effect on necrotic but not on living tissue. According to the manufacturer the ointment provides enhanced wound cleaning and accelerates the healing process.
Both enzymes are marginally resorbed into systemic circulation because of their very high molecular weight and their macromolecular structure.
The activity of both enzymes is almost completely exhausted after 24 hours. Usually, it is necessary to repeat the application (and renew the dressing) every 6 to 8 hours until healing becomes complete.
The ointment is marketed by Pfizer under the brand name Fibrolan® in a variety of countries (e.g. Switzerland). It is currently not approved in the USA.
Where approved, Fibrolan® has been licensed on the basis of claimed good therapeutical experience, but adequate and well controlled studies are still lacking.
In the past, combinations with the antibiotic chloramphenicol were available, but because chloramphenicol in any form of application has led to aplastic anemia and death, these  were banned. Additionally, combinations with the antifibrinolytic agent tranexamic acid have been withdrawn from pharma markets.
Fibrinolysin
Pneumolysin
Enterotoxin
Alpha-1 proteinase inhibitor
Chlorotoxin
Neurotoxin
Isozyme
Brinase