title: "From safe source to safe sink" development of colorimetric assay for gabapentin in bulk drug and capsules using naturally derived genipin.
abstract: A novel colorimetric assay for gabapentin in bulk drug and capsules has been developed via a safety-and-sustainability concerning concept. The method relied on the reaction of primary amino group of drug with non-toxic and eco-friendly genipin in totally aqueous medium to form the blue product which was subsequently measured by visible spectrophotometry at 590 nm. Under the optimized conditions, Beer's law was obeyed in the concentration range of 0.15-0.50 mM (r(2)=0.9998). It was accurate, precise and insensitive to the interferences from all related compounds specified in the United States Pharmacopeia as well as commonly used excipients. Furthermore, it gave the assay results in agreement with the pharmacopeial chromatographic method. Owing to the environmental concern and responsibility, a fast and facile method was also proposed for the treatment of waste generated from the assay based on the decoloration by using gypsum as a cheap and commonly available adsorbent. After the treatment, more than 95% of the initial blue product was removed from the waste solution and the treated waste was proven to be safe for aquatic organisms, as studied in brine shrimp and guppy fishes. Therefore, this work not only reports for the first time the application of naturally derived genipin to drug analysis, but also presents a new and contemporary paradigm that illustrates the fully benign-by-design development of the analytical methodologies in the era of Green Chemistry, starting from the safe source of reagents toward the safe sink when waste is released into the environment.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom 73000, Thailand.
authors.forename: Weerapath
authors.initials: W
authors.lastname: Winotapun
authors.forename: Khachen
authors.initials: K
authors.lastname: Kongpakwattana
authors.forename: Sirirat
authors.initials: S
authors.lastname: Dejpittayanunt
authors.forename: Suwaparp
authors.initials: S
authors.lastname: Pathomcharoensukchai
authors.forename: Udomluck
authors.initials: U
authors.lastname: Suksaran
authors.forename: Nopparat
authors.initials: N
authors.lastname: Nuntharatanapong
authors.forename: Theerasak
authors.initials: T
authors.lastname: Rojanarata
mesh_terms: D000588:Amines / Q000032:analysis* / Q000737:chemistry*; D001688:Biological Products / Q000737:chemistry*; D002214:Capsules; D003116:Color; D003124:Colorimetry / Q000379:methods* / Q000592:standards; D003509:Cyclohexanecarboxylic Acids / Q000032:analysis* / Q000737:chemistry*; D000077206:Gabapentin; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000737:chemistry; D039823:Iridoids / Q000737:chemistry*; D007753:Laboratories; D015203:Reproducibility of Results; D012449:Safety; D013997:Time Factors; D018505:Waste Management; D005680:gamma-Aminobutyric Acid / Q000032:analysis* / Q000737:chemistry*
chemical_list: D000588:Amines; D001688:Biological Products; D002214:Capsules; D003509:Cyclohexanecarboxylic Acids; D007202:Indicators and Reagents; D039823:Iridoids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; C007834:genipin