title: Degradation of parabens by Pseudomonas beteli and Burkholderia latens.
abstract: p-Hydroxybenzoic acid esters (parabens) are commonly used antimicrobial preservatives in pharmaceutical formulations. Two microorganisms, isolated from non-sterile methyl paraben (MP) and propyl paraben (PP) solutions, were found to degrade the respective parabens. Identification by 16S rRNA partial gene sequencing revealed them to be Pseudomonas beteli and Burkholderia latens, respectively. The present work describes a previously unreported interaction of the parabens with P. beteli and B. latens. Degradation of MP at various concentrations by P. beteli, followed a logarithmic pattern, while that of PP by B. latens was found to be linear. It was subsequently observed that P. beteli could degrade only MP, while B. latens could degrade both the parabens. Absence of HPLC chromatogram peaks of expected degradation products indicated that the parabens were used up as a carbon source. The behaviour of pathogens (Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus niger) of the pharmacopoeial preservative effectiveness test (PET), towards MP, showed that none had the ability to degrade the paraben. It was concluded that, for a paraben-preserved multi-dose ophthalmic formulation, the sole use of the four pathogens that are recommended by the pharmacopoeia for PET can falsely indicate the formulation to be effective against 'in-use' contamination.
authors.affiliation: National Institute of Pharmaceutical Education and Research (NIPER), Punjab, India.
authors.forename: Aeshna
authors.initials: A
authors.lastname: Amin
authors.forename: Sateesh
authors.initials: S
authors.lastname: Chauhan
authors.forename: Manish
authors.initials: M
authors.lastname: Dare
authors.forename: Arvind Kumar
authors.initials: AK
authors.lastname: Bansal
mesh_terms: D019117:Burkholderia / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004340:Drug Contamination; D004355:Drug Stability; D009883:Ophthalmic Solutions; D010226:Parabens / Q000378:metabolism* / Q000592:standards; D010602:Pharmacopoeias as Topic; D011310:Preservatives, Pharmaceutical / Q000378:metabolism* / Q000592:standards; D011549:Pseudomonas / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S
chemical_list: D009883:Ophthalmic Solutions; D010226:Parabens; D011310:Preservatives, Pharmaceutical; D012336:RNA, Ribosomal, 16S; C015358:methylparaben; C006068:propylparaben