title: Evaluation of the enzymatic activity and stability of commercial bromelain incorporated in topical formulations.
abstract: BACKGROUND
  Bromelain is a mixture of proteolytic enzymes found in various tissues of the pineapple plant (Ananas comosus) and other species of Bromeliaceae. Owing to its proteolytic activity, bromelain has been used in the food, medical, pharmaceutical and cosmetic industries, for its cell renewal, anti-ageing, whitening and anti-cellulite properties.
  
  
  OBJECTIVE
  This study evaluated the stability of bromelain (commercial powder) incorporated in topical formulations.
  
  
  METHODS
  Bromelain was incorporated at three concentrations, 0.5%, 1.0% and 2.0%, in oil-in-water emulsion and gel, and stored for six months at varying stress conditions. Stability was accessed by measuring the changes in the protein content, enzymatic activity, viscosity, rheology, pH and colour of the selected formulations.
  
  
  RESULTS
  The colour of all the samples changed after 180 days of incubation, indicating the concentration-dependence and temperature-sensitive nature of these formulations. No relationship was observed between the changes in the pH, temperature and luminosity exposure in all the samples. Gels proved to be the least preferred base for incorporation of bromelain for use as a topical formulation, owing to its inability to maintain the integrity of bromelain, thereby affecting the formulation characteristics.
  
  
  CONCLUSIONS
  The emulsion-based formulations at all the concentrations of bromelain were more stable than the gel-based formulation over 180 days of evaluation, at a temperature of 5°C, protected from light.
authors.affiliation: Postgraduate Program in Biosciences and Technology of Bioactive Products, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: C B
authors.initials: CB
authors.lastname: Lourenço
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: J A
authors.initials: JA
authors.lastname: Ataide
authors.affiliation: Postgraduate Program in Biosciences and Technology of Bioactive Products, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: L C
authors.initials: LC
authors.lastname: Cefali
authors.affiliation: Posdoctorade Program in Medical Sciences, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: L C D L
authors.initials: LC
authors.lastname: Novaes
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: P
authors.initials: P
authors.lastname: Moriel
authors.affiliation: Posdoctorade Program in Medical Sciences, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil.|Genetics and Biochesmitry Institute, Uberlandia Federal University (UFU), Uberlandia, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Silveira
authors.affiliation: School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, Brazil.
authors.forename: E B
authors.initials: EB
authors.lastname: Tambourgi
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Campinas (UNICAMP), Campinas, Brazil. pmazzola@fcf.unicamp.br.
authors.forename: P G
authors.initials: PG
authors.lastname: Mazzola
mesh_terms: D000287:Administration, Topical; D001963:Bromelains / Q000737:chemistry* / Q000378:metabolism; D003116:Color; D003358:Cosmetics; D012212:Rheology; D013696:Temperature; D014783:Viscosity
chemical_list: D003358:Cosmetics; D001963:Bromelains
keywords: bromelain; cosmetics; emulsions; enzymatic activity; formulation; gels; stability