title: Recombinant Lucilia sericata chymotrypsin in a topical hydrogel formulation degrades human wound eschar ex vivo.
abstract: Larval biotherapy is a debridement tool used in wound management. The mechanism of action involves degradation of eschar by serine proteases including chymotrypsin within the alimentary fluids of first instar Lucilia sericata. With the rationale of obviating some limitations of biotherapy, including cost, complexity of use, and patient reticence, the present study describes a mobile hydrogel formulation containing freeze-dried recombinant L. sericata chymotrypsin designed for topical application. Neither freeze-drying nor formulation into the hydrogel significantly attenuated the measured activity of released enzyme compared to fresh-frozen enzyme in aqueous solution. Gel electrophoresis confirmed qualitatively that the chymotrypsin/hydrogel formulation both with and without supplementary urea at 10% (w) /(v) degraded human chronic wound eschar ex vivo. Mindful that the hallmark of intractability of chronic wounds is aberrant biochemistry, the pH activity profile for the enzyme/hydrogel formulation was compared with exudate pH in chronic wounds of mixed aetiology in a cohort of 48 hospital in-patients. Five patients' wounds were acidic, however, the remainder were predominantly alkaline and coincided with the pH optimum for the insect enzyme. Thus, a recombinant L. sericata chymotrypsin and hydrogel formulation could represent a pragmatic alternative to larval therapy for the management of chronic wounds.
authors.affiliation: School of Pharmacy and Centre for Skin Sciences, University of Bradford, Bradford BD7 1DP, UK. s.t.britland@brad.ac.uk
authors.forename: Stephen
authors.initials: S
authors.lastname: Britland
authors.forename: Annie
authors.initials: A
authors.lastname: Smith
authors.forename: Wayne
authors.initials: W
authors.lastname: Finter
authors.forename: Donald
authors.initials: D
authors.lastname: Eagland
authors.forename: Kath
authors.initials: K
authors.lastname: Vowden
authors.forename: Peter
authors.initials: P
authors.lastname: Vowden
authors.forename: Gary
authors.initials: G
authors.lastname: Telford
authors.forename: Alan
authors.initials: A
authors.lastname: Brown
authors.forename: David
authors.initials: D
authors.lastname: Pritchard
mesh_terms: D000287:Administration, Topical; D002918:Chymotrypsin / Q000008:administration & dosage / Q000627:therapeutic use*; D003646:Debridement / Q000379:methods*; D005612:Freeze Drying; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D019476:Insect Proteins; D011994:Recombinant Proteins; D014945:Wound Healing
chemical_list: D019476:Insect Proteins; D011994:Recombinant Proteins; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D002918:Chymotrypsin; C092875:Lucilia chymotrypsin b