NALIDIXIC ACID Acidum nalidixicum NALOXONE

Nalidixic acid

EUROPEAN PHARMACOPOEIA 5.0

01/2005:0701 Reference solution (b). Dilute 2 ml of test solution (b) to 10 ml with methylene chloride R. Reference solution (c). Dilute 1 ml of reference solution (b) NALIDIXIC ACID to 10 ml with methylene chloride R. Reference solution (d). Dilute 1 ml of reference solution (b) Acidum nalidixicum to 25 ml with methylene chloride R. Apply to the plate 10 µl of each solution. Develop over a path of 15 cm using a mixture of 10 volumes of dilute ammonia R1, 20 volumes of methylene chloride R and 70 volumes of alcohol R. Allow the plate to dry in air and examine in ultraviolet light at 254 nm. Any spot in the chromatogram obtained with the test solution (a), apart from the principal spot, is not more intense than the spot in the chromatogram obtained with reference solution (c) (0.1 per C12H12N2O3 Mr 232.2 cent) and not more than one such spot is more intense than the spot in the chromatogram obtained with reference DEFINITION solution (d). Nalidixic acid contains not less than 99.0 per cent and not Heavy metals (2.4.8). 1.0 g complies with limit test D for more than the equivalent of 101.0 per cent of 1-ethyl-7heavy metals (20 ppm). Prepare the standard using 2 ml of methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid, lead standard solution (10 ppm Pb) R. calculated with reference to the dried substance. Loss on drying (2.2.32). Not more than 0.5 per cent, determined on 1.000 g by drying in an oven at 100 °C to CHARACTERS 105 °C. An almost white or pale yellow, crystalline powder, practically insoluble in water, soluble in methylene chloride, Sulphated ash (2.4.14). Not more than 0.1 per cent, determined on 1.0 g. slightly soluble in acetone and in alcohol. It dissolves in dilute solutions of alkali hydroxides. ASSAY It melts at about 230 °C. Dissolve 0.150 g in 10 ml of methylene chloride R and add 30 ml of 2-propanol R and 10 ml of carbon dioxide-free IDENTIFICATION water R. Keep the titration vessel covered and pass First identification : B. nitrogen R through the solution throughout the titration. Second identification : A, C, D. Keep the temperature of the solution between 15 °C and A. Dissolve 12.5 mg in 0.1 M sodium hydroxide and dilute 20 °C. Titrate with 0.1 M ethanolic sodium hydroxide, to 50.0 ml with the same solvent. Dilute 2.0 ml of this determining the end-point potentiometrically (2.2.20) using solution to 100.0 ml with 0.1 M sodium hydroxide. a silver-silver chloride comparison electrode with a sleeve Examined between 230 nm and 350 nm (2.2.25), the diaphragm or a capillary tip, filled with a saturated solution solution shows two absorption maxima, at 258 nm and of lithium chloride R in ethanol R, and a glass electrode 334 nm. The ratio of the absorbance measured at 258 nm as indicator electrode. to that measured at 334 nm is 2.2 to 2.4. 1 ml of 0.1 M ethanolic sodium hydroxide is equivalent to 23.22 mg of C12H12N2O3. B. Examine by infrared absorption spectrophotometry (2.2.24), comparing with the spectrum obtained with STORAGE nalidixic acid CRS. Examine the substances prepared Store in an airtight container, protected from light. as discs. C. Examine the chromatograms obtained in the test 01/2005:0729 for related substances. The principal spot in the chromatogram obtained with the test solution (b) is NALOXONE HYDROCHLORIDE similar in position and size to the principal spot in the chromatogram obtained with reference solution (a). DIHYDRATE D. Dissolve 0.1 g in 2 ml of hydrochloric acid R. Add 0.5 ml of a 100 g/l solution of β-naphthol R in alcohol R. An Naloxoni hydrochloridum dihydricum orange-red colour develops. TESTS Absorbance. Dissolve 1.50 g in methylene chloride R and dilute to 50.0 ml with the same solvent. The absorbance (2.2.25) measured at 420 nm is not greater than 0.10. Related substances. Examine by thin-layer chromatography (2.2.27), using a TLC silica gel F254 plate R. Test solution (a). Dissolve 0.20 g of the substance to be examined in methylene chloride R and dilute to 10 ml with the same solvent. Test solution (b). Dilute 1 ml of test solution (a) to 20 ml with methylene chloride R. Reference solution (a). Dissolve 20 mg of nalidixic acid CRS in methylene chloride R and dilute to 20 ml with the same solvent. 2080

C19H22ClNO4,2H2O

Mr 399.9

DEFINITION Naloxone hydrochloride dihydrate contains not less than 98.0 per cent and not more than the equivalent of 102.0 per cent of 4,5α-epoxy-3,14-dihydroxy-17-(prop-2-enyl)morphinan6-one hydrochloride, calculated with reference to the anhydrous substance.

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Naloxone hydrochloride dihydrate

EUROPEAN PHARMACOPOEIA 5.0

CHARACTERS

The chromatographic procedure may be carried out using :

A white or almost white, crystalline powder, hygroscopic, freely soluble in water, soluble in alcohol, practically insoluble in toluene.

— a stainless steel column 0.125 m long and 4.0 mm in internal diameter packed with end-capped octylsilyl silica gel for chromatography R (5 µm),

IDENTIFICATION

— as mobile phase at a flow rate of 1.5 ml/min a linear gradient programme using the following conditions :

First identification : A, C. Second identification : B, C. A. Examine by infrared absorption spectrophotometry (2.2.24) comparing with the spectrum obtained with naloxone hydrochloride dihydrate CRS. B. Examine by thin-layer chromatography (2.2.27), using a TLC silica gel G plate R. Test solution. Dissolve 8 mg of the substance to be examined in 0.5 ml of water R and dilute to 1 ml with methanol R. Reference solution. Dissolve 8 mg of naloxone hydrochloride dihydrate CRS in 0.5 ml of water R and dilute to 1 ml with methanol R. Apply to the plate 5 µl of each solution. Develop protected from light over a path of 10 cm using a mixture of 5 volumes of methanol R and 95 volumes of the upper layer from a mixture of 60 ml of dilute ammonia R2 and 100 ml of butanol R. Dry the plate in a current of air. Spray with a freshly prepared 5 g/l solution of potassium ferricyanide R in ferric chloride solution R1. Examine in daylight. The principal spot in the chromatogram obtained with the test solution is similar in position, colour and size to the principal spot in the chromatogram obtained with the reference solution. C. It gives reaction (a) of chlorides (2.3.1). TESTS Solution S. Dissolve 0.50 g in carbon dioxide-free water R and dilute to 25.0 ml with the same solvent. Appearance of solution. Solution S is clear (2.2.1) and colourless (2.2.2, Method II). Acidity or alkalinity. To 10.0 ml of solution S add 0.05 ml of methyl red solution R. Not more than 0.2 ml of 0.02 M sodium hydroxide or 0.02 M hydrochloric acid is required to change the colour of the indicator.

Mobile phase A. Mix 20 ml of acetonitrile R, 40 ml of tetrahydrofuran R and 940 ml of a solution prepared as follows : dissolve 1.17 g of sodium octanesulphonate R in 1000 ml of water R, adjust the pH to 2.0 with a 50 per cent V/V solution of phosphoric acid R and filter (octanesulphonic acid solution). Mobile phase B. Mix 170 ml of acetonitrile R, 40 ml of tetrahydrofuran R and 790 ml of the octanesulphonic acid solution. Time (min)

Mobile phase A (per cent V/V)

Mobile phase B (per cent V/V)

Comment

0 - 40

100 → 0

0 → 100

linear gradient

40 - 50

0

100

isocratic

— as detector a spectrophotometer set at 230 nm, maintaining the temperature of the column at 40 °C. Inject separately 20 µl of each solution. The test is not valid unless : the peak corresponding to naloxone in the chromatogram obtained with reference solution (a) has a signal-to-noise ratio of at least ten ; in the chromatogram obtained with reference solution (a), the resolution between the peaks corresponding to impurity A and naloxone is not less than four. If necessary, adjust the chromatographic conditions. When the chromatograms are recorded in the prescribed conditions, the retention time of naloxone is about 11 min and the relative retention time of impurity A is about 0.8 with respect to naloxone. In the chromatogram obtained with the test solution : the area of any peak, apart from the principal peak, is not greater than the area of the principal peak in the chromatogram obtained with reference solution (b) (0.5 per cent) ; the sum of the areas of all the peaks, apart from the principal peak, is not greater than twice the area of the principal peak in the chromatogram obtained with reference solution (b) (1 per cent). Disregard any peak with an area less than 0.1 times that of the principal peak in the chromatogram obtained with reference solution (b).

Specific optical rotation (2.2.7) : − 170 to − 181, determined Water (2.5.12) : 7.5 per cent to 11.0 per cent, determined on on solution S and calculated with reference to the anhydrous 0.200 g by the semi-micro determination of water. substance. Sulphated ash (2.4.14). Not more than 0.2 per cent, Related substances. Examine by liquid chromatography determined on 0.50 g. (2.2.29). Test solution. Dissolve 0.125 g of the substance to be examined in 0.1 M hydrochloric acid and dilute to 25.0 ml with the same acid. Reference solution (a). Dissolve 10.0 mg of naloxone hydrochloride dihydrate CRS and 10.0 mg of naloxone impurity A CRS in 0.1 M hydrochloric acid and dilute to 10.0 ml with the same acid. Dilute 1.0 ml to 100.0 ml with 0.1 M hydrochloric acid. Reference solution (b). Dilute 1.0 ml of the test solution to 20.0 ml with 0.1 M hydrochloric acid. Dilute 1.0 ml to 10.0 ml with 0.1 M hydrochloric acid. General Notices (1) apply to all monographs and other texts

ASSAY Dissolve 0.300 g in 50 ml of alcohol R and add 5.0 ml of 0.01 M hydrochloric acid. Carry out a potentiometric titration (2.2.20), using 0.1 M ethanolic sodium hydroxide. Read the volume added between the two points of inflexion. 1 ml of 0.1 M ethanolic sodium hydroxide is equivalent to 36.38 mg of C19H22ClNO4. STORAGE Store in an airtight container, protected from light. 2081

Naphazoline hydrochloride

EUROPEAN PHARMACOPOEIA 5.0

IMPURITIES

A. R1 = R2 = R3 = H : 4,5α-epoxy-3,14-dihydroxymorphinan6-one (noroxymorphone), B. R1 = R3 = CH2-CH=CH2, R2 = H : 4,5α-epoxy-14-hydroxy17-(prop-2-enyl)-3-(prop-2-enyloxy)morphinan-6-one (3-O-allylnaloxone), C. R1 = H, R2 = OH, R3 = CH2-CH=CH2 : 4,5α-epoxy-3, 10α,14-trihydroxy-17-(prop-2-enyl)morphinan-6-one (10α-hydroxynaloxone),

Second identification : A, C. A. Dissolve 50.0 mg in 0.01 M hydrochloric acid and dilute to 250.0 ml with the same acid. Dilute 25.0 ml of the solution to 100.0 ml with 0.01 M hydrochloric acid. Examined between 230 nm and 350 nm (2.2.25), the solution shows 4 absorption maxima, at 270 nm, 280 nm, 287 nm and 291 nm. The ratios of the absorbances measured at the maxima at 270 nm, 287 nm and 291 nm to that measured at the maximum at 280 nm are 0.82 to 0.86, 0.67 to 0.70 and 0.65 to 0.69, respectively. B. Infrared absorption spectrophotometry (2.2.24). Comparison : Ph. Eur. reference spectrum of naphazoline hydrochloride. C. It gives reaction (a) of chlorides (2.3.1).

TESTS Solution S. Dissolve 0.5 g in carbon dioxide-free water R and dilute to 50 ml with the same solvent. Appearance of solution. Solution S is clear (2.2.1) and colourless (2.2.2, Method II). Acidity or alkalinity. To 20 ml of solution S add 0.2 ml of 0.01 M sodium hydroxide and 0.1 ml of methyl red solution R. The solution is yellow. Not more than 0.6 ml of 0.01 M hydrochloric acid is required to change the colour of the solution to red. D. 7,8-didehydro-4,5α-epoxy-3,14-dihydroxy-17-(prop-2Related substances. Liquid chromatography (2.2.29). enyl)morphinan-6-one (7,8-didehydronaloxone), Test solution. Dissolve 50.0 mg of the substance to be examined in the mobile phase and dilute to 100.0 ml with the mobile phase. Reference solution (a). Dissolve 5 mg of 1-naphthylacetic acid R in the mobile phase, add 5 ml of the test solution and dilute to 100 ml with the mobile phase. Reference solution (b). Dissolve 5.0 mg of naphazoline impurity A CRS in the mobile phase and dilute to 100.0 ml with the mobile phase. Dilute 1.0 ml to 100.0 ml with the E. 4,5α:4′,5′α-diepoxy-3,3′,14,14′-tetrahydroxy-17, mobile phase. 17′-bis(prop-2-enyl)-2,2′-bimorphinanyl-6,6′-dione Reference solution (c). Dilute 1.0 ml of the test solution to (2,2′-bisnaloxone). 10.0 ml with the mobile phase. Dilute 1.0 ml of this solution to 100.0 ml with the mobile phase. 01/2005:0730 Column : — size : l = 0.25 m, Ø = 4.0 mm, NAPHAZOLINE HYDROCHLORIDE — stationary phase : base-deactivated end-capped octylsilyl silica gel for chromatography R (4 µm) with a pore size Naphazolini hydrochloridum of 6 nm. Mobile phase : dissolve 1.1 g of sodium octanesulphonate R in a mixture of 5 ml of glacial acetic acid R, 300 ml of acetonitrile R and 700 ml of water R. Flow rate : 1 ml/min. Detection : spectrophotometer at 280 nm. Injection : 20 µl. C14H15ClN2 Mr 246.7 Run time : 3 times the retention time of naphazoline. DEFINITION Retention time : naphazoline = about 14 min. 2-(Naphthalen-1-ylmethyl)-4,5-dihydro-1H-imidazole System suitability : reference solution (a) : hydrochloride. — resolution : minimum 5.0 between the peaks due to Content : 99.0 per cent to 101.0 per cent (dried substance). naphazoline and to impurity B. Limits : CHARACTERS — impurity A : not more than the area of the principal peak Appearance : white or almost white, crystalline powder. in the chromatogram obtained with reference solution (b) Solubility : freely soluble in water, soluble in alcohol. (0.1 per cent), mp : about 259 °C, with decomposition. — any other impurity : not more than the area of the IDENTIFICATION principal peak in the chromatogram obtained with reference solution (c) (0.1 per cent), First identification : B. 2082

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