Chromatographic methods for simultaneous determination of diiodohydroxyquinoline and metronidazole in their binary mixture.

Two chromatographic methods were developed for analysis ofdiiodohydroxyquinoline (DIHQ) and metronidazole (MTN). In the first method, diiodohydroxyquinoline and metronidazole were separated on TLC silica gel 60F254 plate using chloroform: acetone: glacial acetic acid (7.5: 2.5: 0.1, by volume) as mobile phase. The obtained bands were then scanned at 254 nm. The second method is a RP-HPLC method in which diiodohydroxyquinoline and metronidazole were separated on a reversed-phase C18 column using water : methanol (60 :40, V/V, PH=3.6 )as mobile phase at a flow rate of 0.7 mL.min-1 and UV detection at 220 nm. The mentioned methods were successfully used for determination of diiodohydroxyquinoline and metronidazole in pure form and in their pharmaceutical formulation.

LC of pharmaceutically important halogenated 8-hydroxyquinolines after precolumn derivatization with Pd (II).

An accurate, sensitive, and selective reversed phase high performance liquid chromatographic (HPLC) method was developed for the analysis of two halogenated 8-hydroxyquinoline derivatives; clioquinol (CQN) and iodoquinol (IQN). The proposed method depends on the complexation ability of the studied compounds with Pd(II) ions. Reversed phase chromatography was conducted using a 300 x 3.9 mm i.d. stainless steel column packed with 10 microm Bondclone phenyl at ambient temperature. A solution containing 0.005% w/v of Pd(II)-chloride in a mixture of acetonitrile-methanol-water (3:3:4 v/v/v) of pH 3.7 as a mobile phase pumped at a flow rate of 0.75 ml min(-1). UV-detection was performed at 282 and 285 nm for CQN and IQN, respectively. The method showed excellent linearity in the range 0.05-1.8 and 0.1-3.0 microg ml(-1) with limit of detection (S/N=2) 4.8 ng ml(-1) (1.57 x 10(-8) M) and 6.4 ng ml(-1) (1.61 x 10(-8) M) for CQN and IQN, respectively. The suggested method was successfully applied for the analysis of the studied drugs in bulk with average% recoveries of 99.68+/-0.44 for CQN and 99.65+/-0.53 for IQN. The proposed method was successfully applied for the analysis of the studied drugs in single or combined dosage forms with average% recoveries of 99.41+/-0.51-100.02+/-0.63. The proposed method could be used successfully for the determination of the studied compounds in the presence of their degradation product as they could be eluted with different retention times. The presence of metronidazole (MNZ) or tolnaftate (TFT) with the studied drugs does not affect their accurate determination. The results obtained were favorably compared with those obtained by the reference method. The results were satisfactorily, accurate, and precise.

Application of the bivariate spectrophotometric method for the determination of metronidazole, furazolidone and di-iodohydroxyquinoline in pharmaceutical formulations.

The bivariate calibration algorithm was applied to the spectrophotometric determination of metronidazole, furazolidone and di-iodohydroxyquinoline in pharmaceutical dosage forms. The results obtained were compared with the results of derivative spectrophotometry. The statistical evaluation of method bias was carried out, and it was shown that the proposed procedure may be competitive with commonly used first-derivative spectrophotometry. The advantage of the bivariate calibration is its simplicity, and the fact that there is no need to use the derivatization procedures.

Reverse-phase high-performance liquid chromatographic determination of halogenated 8-hydroxyquinoline compounds in pharmaceuticals and bulk drugs.

A reverse-phase high-performance liquid chromatographic (HPLC) method was developed for determining iodochlorhydroxyquin, 5,7-dichloro-8-hydroxyquinoline, and 5,7-diiodo-8-hydroxyquinoline in creams, ointments, shampoos, tablets, and bulk drugs. A column packed with 10-micron phenyl-silica and a mobile phase of 0.001 M NiCl2 in acetonitrile-methanol-water (30:20:50) was used to separate the nickel complexes of the three drugs, with detection at 273 nm. Analysis of creams, ointments, shampoos, and tablets gave results close to the label declarations. Recovery of standard material added to samples was greater than or equal to 98%. Linearity of response was shown over a range of 30-150% of label claim for standards of the three drug substances. Multiple analyses of iodochlorhydroxyquin and diiodohydroxyquinoline bulk drugs showed purities of 99.96 and 98.77% with CV of 1.17 and 0.73%, respectively. The HPLC method offers an alternative to current USP procedures, which lack stability-indicating and specificity characteristics.