title: Validation of a high performance liquid chromatography method for the stabilization of epigallocatechin gallate.
abstract: Epigallocatechin gallate (EGCG) is a green tea catechin with potential health benefits, such as anti-oxidant, anti-carcinogenic and anti-inflammatory effects. In general, EGCG is highly susceptible to degradation, therefore presenting stability problems. The present paper was focused on the study of EGCG stability in HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) medium regarding the pH dependency, storage temperature and in the presence of ascorbic acid a reducing agent. The evaluation of EGCG in HEPES buffer has demonstrated that this molecule is not able of maintaining its physicochemical properties and potential beneficial effects, since it is partially or completely degraded, depending on the EGCG concentration. The storage temperature of EGCG most suitable to maintain its structure was shown to be the lower values (4 or -20 °C). The pH 3.5 was able to provide greater stability than pH 7.4. However, the presence of a reducing agent (i.e., ascorbic acid) was shown to provide greater protection against degradation of EGCG. A validation method based on RP-HPLC with UV-vis detection was carried out for two media: water and a biocompatible physiological medium composed of Transcutol®P, ethanol and ascorbic acid. The quantification of EGCG for purposes, using pure EGCG, requires a validated HPLC method which could be possible to apply in pharmacokinetic and pharmacodynamics studies.
authors.affiliation: CEBIMED, Investigation Centre of Biomedicine, Faculty of Health Sciences, Fernando Pessoa University (UFP-FCS), Rua Carlos da Maia 296, 4200-150 Porto, Portugal; Faculty of Health Sciences, Fernando Pessoa University (UFP-FCS), Rua Carlos da Maia 296, 4200-150 Porto, Portugal.
authors.forename: Joana F
authors.initials: JF
authors.lastname: Fangueiro
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Alexander
authors.initials: A
authors.lastname: Parra
authors.affiliation: Department of Biology and Environment, University of Trás-os Montes e Alto Douro (UTAD), Quinta de Prados, 5001-801 Vila Real, Portugal; Centre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB-UTAD), Quinta de Prados, 5001-801 Vila Real, Portugal.
authors.forename: Amélia M
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Department of Physical Chemistry, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain; Institute of Nanoscience and Nanotechnology, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Egea
authors.affiliation: CEBIMED, Investigation Centre of Biomedicine, Faculty of Health Sciences, Fernando Pessoa University (UFP-FCS), Rua Carlos da Maia 296, 4200-150 Porto, Portugal; Faculty of Health Sciences, Fernando Pessoa University (UFP-FCS), Rua Carlos da Maia 296, 4200-150 Porto, Portugal; Institute of Biotechnology and Bioengineering, Centre of Genomics and Biotechnology, University of Trás-os-Montes e Alto Douro (UTAD), Quinta de Prados, 5000-801 Vila Real, Portugal. Electronic address: eliana@ufp.edu.pt.
authors.forename: Eliana B
authors.initials: EB
authors.lastname: Souto
authors.affiliation: Department of Physical Chemistry, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain; Institute of Nanoscience and Nanotechnology, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Garcia
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain; Institute of Nanoscience and Nanotechnology, University of Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Calpena
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis* / Q000737:chemistry; D016588:Anticarcinogenic Agents / Q000032:analysis* / Q000737:chemistry; D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry; D002021:Buffers; D002392:Catechin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D004355:Drug Stability; D004356:Drug Storage; D005026:Ethylene Glycols / Q000737:chemistry; D005079:Excipients / Q000737:chemistry*; D006531:HEPES / Q000737:chemistry; D006358:Hot Temperature / Q000009:adverse effects; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D019163:Reducing Agents / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013053:Spectrophotometry
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016588:Anticarcinogenic Agents; D000975:Antioxidants; D002021:Buffers; D005026:Ethylene Glycols; D005079:Excipients; D019163:Reducing Agents; D012997:Solvents; D002392:Catechin; C010111:carbitol; C045651:epigallocatechin gallate; D001205:Ascorbic Acid; D006531:HEPES
keywords: Catechins; Epigallocatechin gallate (EGCG); Reverse phase high performance liquid chromatography (RP-HPLC); Validation