Abstract
A simple, rapid and sensitive spectrophotometric procedure for the assay of some drugs has been developed. The method is based on the reaction of the studied drugs with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The latter is employed to abstract a hydrogen atom from the drugs thereby promoting a process of radical coupling. This results in a reduction of the violet color of DPPH with the formation of the yellow colored 2,2-diphenyl-1-picrylhydrazine (DPPH2). The decrease in the intensity of the violet color is used to measure the concentration of the drugs. All measurements are made at λ= 520 nm on methanolic solutions of the reagent and drugs. Beer's law is obeyed in the ranges of 5-30 µg/ml (for aceclofenac, diclofenac sodium and thiaprofenic acid), 2-15 µg/ml (for tenoxicam, furosemide and lansoprazole) and 2-12 µg/ml (for benoxinate hydrochloride and ritodrine). The validity of the method was tested by carrying out standard addition procedure analyzing the studied drugs in pure form as well as in their pharmaceutical preparations without interference from common additives. Results of the proposed methods are in good agreement with those of the official or reported methods.
Highlights
DPPH 2,2- Diphenyl-I-Picrylhydrazyl (DPPH) is an intense, violetcolored, stable, free radical which reacts as a chromogenicH
A simple, rapid and sensitive spectrophotometric method is adopted for the determination of aceclofenac, thiaprofenic acid, tenoxicam, lansoprazole, furosemide, ritodrine, diclofenac sodium and benoxinate hydrochloride in the pure forms and in pharmaceutical preparations with 2,2-diphenyl-1-picrylhydrazyl (DPPH)
The reaction is assumed to proceed via abstraction of hydrogen atoms from the drugs by D P P H ~T~h.is is accompanied by the change of violet color of DPPH to give the yellow colored DPPH, and the corresponding free radical of the drug ( Scheme 1 )
Summary
DPPH 2,2- Diphenyl-I-Picrylhydrazyl (DPPH) is an intense, violetcolored, stable, free radical which reacts as a chromogenic. Salem : reagentqvb2y abstracting a hydrogen atom from the analyt to form yellow colored N,N-diphenylpicrylhydrazine (DPPH,) This decrease in the intensity of the violet color is used as a measure of the quantity of the tested drugs. A simple, rapid and sensitive spectrophotometric method is adopted for the determination of aceclofenac, thiaprofenic acid, tenoxicam, lansoprazole, furosemide, ritodrine, diclofenac sodium and benoxinate hydrochloride in the pure forms and in pharmaceutical preparations with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The pharmaceutical grade pure drugs; aceclofenac was obtained from Bristol-Myers Squibb (Squibb, Egypt), furosemide, lansoprazole and thiaprofenic acid were obtained from Hoechst (Hoechst, Egypt), diclofenac sodium and ritodrine were obtained from Pharco (Pharco, Egypt) and benoxinate hydrochloride and tenoxicam were obtained from Eipico (E.I.P.I.Co, Egypt). A stock solution of 1.5 mgl ml was prepared by dissolving 0.15 g of DPPH in methanol and diluted to 100 ml with the same solvent.
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