Preparation of benzylpenicilloyl-polylysine: a preliminary study.

The manufacturing of PrePen (benzylpenicilloyl-polylysine) was suspended from September 2000 through November 2001 because of Food and Drug Administration intervention. PrePen is penicilloyl bound to polylysine and is considered to be the major determinant of penicillin metabolism; it is used as a skin-testing reagent to detect immunoglobulin E antibodies in people with a history of penicillin allergy. Because of the uncertainty of whether PrePen would be made available in the future, we attempted to make benzylpenicilloyl-polylysine in our laboratory using a modification of a previously described method. Subsequently, we compared our preparation with PrePen by enzyme-linked immunosorbent assay and skin testing. Using a patient previously documented to have a positive reaction to PrePen by history and intradermal skin testing, a puncture test to PrePen as well as dilutions of benzylpenicilloyl-polylysine was negative. Positive intradermal tests were performed on PrePen and benzylpenicilloyl-polylysine at 5 mg/mL. The enzyme-linked immunosorbent assay was performed to compare the antigenicity of PrePen and benzylpenicilloyl-polylysine and revealed similar binding to both. Subsequently, cutaneous testing on 10 additional penicillin-allergic people was performed, with corroborative results. Our benzylpenicilloyl-polylysine production methodology could prove useful to those who do not have access to PrePen or another similar reagent.