The quantitative determination of morphine in paregoric by reversed-phase high-pressure liquid chromatography is described. The method is simple, accurate, and fast compared to the USP method. Benzoic acid in paregoric also can be determined quantitatively with the same column. The method was applied to two commercial samples with excellent results.
Keyphrases Morphine-high-pressure liquid chromatographic analysis in commercial samples of paregoric High-pressure liquid chromatography-analysis, morphine in commercial samples of paregoric 0 Paregoric-high-pressure liquid chromatographic analysis of morphine and benzoic acid, commercial samples 0 Analgesic agents-morphine, high-pressure liquid chromatographic analysis in commercial samples of paregoric
The USP method (1) for the quantitative determination of morphine in paregoric is tedious and time consuming. No other easy method is available for determining morphine in paregoric USP. The purpose of these investigations was to develop a simple, accurate, and fast method for the analysis of morphine using high-pressure liquid chromatography (HPLC). A method for the quantitative determination of benzoic acid in paregoric using the same column also is described.
EXPERIMENTAL Apparatus-A high-pressure liquid chromatograph' capable of operating a t an inlet pressure up to 6000 psig was used.
Column-The column' (30 cm long and 4 mm i.d.) was purchased and used as received. It consisted of a monomolecular layer of octadecyltrichlorosilane permanently bonded to silica uia silicon-carbon bonds.
Recorder-The recorder3 was equipped with an integrator. Chromatographic Conditions-The chromatographic solvents were: ( a ) 0.1 M KHZP04 buffer solution in 7% (v/v) methanol in water for morphine and ( b ) 0.1 M KHzPOd buffer solution in 10% (v/v) ' Waters ALC 202 equipped with U6K Universal liquid chromatograph injector and UV detector (254 nm), Waters Associates, Milford, Mass.
-pRondapak/Cl!.+ Waters Associates, Milford, Mass.
:' Ornniscrihe model 5213-12, Houston Instruments, Austin, Tex.