Ketorolac tromethamine, KT ((k)-5-benzoyl-2,3-dihydro-1H pyrrolizine-l-carboxylic acid), is a member of the pyrrolopyrrole group of non-steroidal anti-inflammatory drugs 1 with cyclooxygenase inhibitory activity. 2 KT is a non-opioid analgesic which exists in three crystalline forms that are soluble in water. KT, when administered systemically, has demonstrated analgesic, anti-inflammatory, and anti-pyretic activity.3 KT is used for acute and short-term relief of pain. It increases the plasma levels of salicylates due to a decrease in plasma protein binding. The most frequent adverse events reported with the use of KT are transient stinging and burning on instillation. These events were reported for up to 40% of patients who were administered the drug in clinical trials. Other adverse events occurring approximately 1 to 10% of the time during treatment with KT included allergic reactions, corneal edema, iritis, ocular inflammation, ocular irritation, superficial keratitis and superficial ocular infections. Hence, a highly selective and accurate analytical method for measuring KT is desired, probably for optimizing its therapy and minimizing its side effects.For electrochemical detection and estimation, conducting polymers have recently been used as modifying substrates, because they can act as an electronic transducer for charged species binding to their surface. Biochemical units can also be covalently grafted to the polymer backbone, and subsequently used for detection. Polypyrrole (Ppy), modified onto platinum substrates was used to reduce the interference signal caused by ascorbic and uric acids on an ammonia amperometric sensor in aqueous solutions. 4 A platinum electrode modified by an electrogenerated overoxidized Ppy was used as a substrate for biosensor application.
5Miniaturized and disposable amperometric biosensors were developed for glucose determination in serum. A simple and label-free electrochemical sensor for the recognition of DNA hybridization was reported based on a functionalized conducting copolymer, poly [pyrrole-co-4-(3-pyrrolyl)butanoic acid]. 6 Several analytical techniques were developed for the determination of KT from the bulk drug, which included nonaqueous titration, thin-layer chromatography, UV spectrophotometry, 7,8 and high-performance liquid chromatography methods, 9 electrochromatography, 10 reversed-phase liquid chromatography-mass spectrometry 11 and flow-injection analysis.12 KT has been determined by gas chromatography-mass spectrometry using diazopropane.
13Studies in human serum have been performed. [14][15][16][17] However, these methods require tedious sample preparation and time-consuming experimental procedures. A simple and sensitive method is therefore needed for the fast, accurate detection and estimation of KT.In this work, an electro-analytical approach was developed for the detection and determination of KT by square-wave stripping voltammetry using a Ppy modified glassy carbon (GC/Ppy) electrode in an acetate buffer (pH 5.5). The method was also tested for t...
