Universiteit Utrecht Faculteit Farmacie

Farmaceutische Analyse

ToetsGrondstoffenonderzoek 17 september 1999.

Geef bij elke vraag zonodig een berekening en verklaar altijd het antwoord, ook al wordt dit niet expliciet aangegeven !
Succes !

Raadpleeg bij de beantwoording van deze vragen de bijlagen.

Raadpleeg ook de uitwerking van dit tentamen.

Bestudeer zorgvuldig bijgaande monografie 1997:1010 van droperidol (bijlage I) en beantwoord de volgende vragen. Licht het antwoord altijd duidelijk toe.

Elke vraag telt voor 10 punten

IDENTIFICATION

A.

Vraag 1.

Met welke in de monografie genoemde eigenschap van droperidol houdt de laatste zin (If the spectra �.) van identiteitstest A verband?

D.

Vraag 2.

In de blanco van identiteitstest D is een rood complex aanwezig. Wat is de aard van dit complex? Wat is de reden dat dit complex in de testoplossing niet ontstaat?

NB. De alizarine-oplossing is geel.

Appearance of solution

Vraag 3.

Geef zo zorgvuldig mogelijk aan hoe je de beide tests m.b.t. het uiterlijk van de oplossing in de praktijk zou uitvoeren.

Related substances

Vraag 4.

In de verstrekte copie van de monografie zijn aan het einde van de beschrijving van de test op verwante verbindingen bij de eisen twee percentages vervangen door # resp $. Geef aan welke percentages daar in de originele monografie moeten hebben gestaan.

Vraag 5.

Praktijkgeval (1).

We hebben de test op verwante verbindingen uitgevoerd aan droperidol-monster Y. We hebben de apparatuur volgens voorschrift geëquilibreerd en ingesteld en geconstateerd dat ook aan de resolutie-eis wordt voldaan. In onderstaande tabel zijn de oppervlakken van de pieken in de chromatogrammen van de testoplossing (T) en de referentieoplossing (b) (Rb) weergegeven. De pieken van de dimethylformamide-blanco zijn reeds weggelaten.

Bereken de percentages van de verontreinigingen. Voldoet de grondstof aan de eisen m.b.t. de related substances? Beredeneer het antwoord.

testoplossing

  

ref. opl. (b)

  

tijd (s)

opp (counts)

tijd (s)

opp (counts)

338

329

    

380

1437

    

409

1468823

412

3672

433

3475

    

441

675

    

448

1012

    
   

498

101

513

86

    

600

790

    

Vraag 6.

Geef aan waar (vóór, na) ten opzichte van de hoofdpiek de onzuiverheid A (zie IMPURITIES) in het chromatogram van de testoplossing verwacht mag worden.

Beantwoord dezelfde vraag voor onzuiverheid B en voor onzuiverheid E.

Zie voor nadere informatie over de structuren bijlage II

Heavy metals

Vraag 7.

Waarom zou men hier niet de zware metalen grensreactie A of B hebben voorgeschreven?

Wat is het essentiele verschil tussen C en D. (Geef voordelen en nadelen van deze methodes t.o.v. elkaar.)

Zie ook bijlage III: 2.4.8. Heavy metals A-D.

ASSAY

Vraag 8.

Welke is/zijn de basische functie(s) die bij deze assay getitreerd wordt/worden?

Praktijkgeval (2).

Van een monster Z hebben we met behulp van IR geconstateerd dat het droperidol is. Bij het zuiverheidsonderzoek van de stof hebben we vastgesteld dat aan de eisen m.b.t. het uiterlijk van de oplossing wordt voldaan. Het monster voldoet ook aan de tests op verwante verbindingen en zware zware metalen.

Bij het bepalen van het droogverlies gingen we uit van 0,946 g grondstof. Na de vereiste bewerkingen volgens de regels te hebben uitgevoerd hielden we 0,941 g gedroogde stof over.

De sulfaatas, bepaald voor 1,05 g grondstof, woog 0,7 mg. Ga er vanuit dat de procedures hier, net als bij het droogverlies, correct zijn uitgevoerd.

Voor het bepalen van het gehalte hebben we twee monsters afgewogen van 297,5 resp. 325,2 mg. Het verbruik aan 0,0987 M perchloorzuur bedroeg 7,85 resp. 8,67 ml. We bepaalden het blanco-verbruik op 0,02 ml.

De titer van het perchloorzuur was bepaald bij 20,7°. De temperatuur in het vertrek waar onze buretten staan was 20,5°.

Vraag 9. Reken het droperidol-gehalte van de grondstof uit

Vraag 10. Geef aan of monster Z aan de eisen van de monografie voldoet.

Bijlagen

Bijlage I

DROPERIDOL

Droperidolum

C22H22FN3O2
Mr 379.4

DEFINITION

Droperidol contains not less than 99.0 per cent and not more than the equivalent of 101.0 per cent of 1-[1-[4-(4-fluorophenyl)-4-oxobutyl]-1,2,3,6-tetrahydropyridin-4-yl]-2,3-dihydro-1H-benzimidazol-2-one, calculated with reference to the dried substance.

CHARACTERS

A white or almost white powder, practically insoluble in water, freely soluble in dimethylformamide and in methylene chloride, sparingly soluble in alcohol.

It shows polymorphism.

IDENTIFICATION

First identification: A.

Second identification: B, C, D.

  1. Examine by infrared absorption spectrophotometry (2.2.24), comparing with the spectrum obtained with droperidol CRS. Examine the substances prepared as discs. If the spectra obtained show differences, dissolve the substance to be examined and the reference substance separately in the minimum volume of acetone R, evaporate to dryness on a water-bath and record new spectra using the residues.

  2. Examine by thin-layer chromatography (2.2.27), using silica gel GF254 R as the coating substance.

    Test solution. Dissolve 30 mg of the substance to be examined in a mixture of 1 volume of acetone R and 9 volumes of methanol R and dilute to 10 ml with the same mixture of solvents.

    Reference solution (a). Dissolve 30 mg of droperidol CRS in a mixture of 1 volume of acetone R and 9 volumes of methanol R and dilute to 10 ml with the same mixture of solvents.

    Reference solution (b). Dissolve 30 mg of droperidol CRS and 30 mg of benperidol CRS in a mixture of 1 volume of acetone R and 9 volumes of methanol R and dilute to 10 ml with the same mixture of solvents.

    Apply separately to the plate 10 ml of each solution. Develop over a path of 15 cm using a mixture of 1 volume of acetone R and 9 volumes of methanol R. Allow the plate to dry in air and examine in ultraviolet light at 254 nm. The principal spot in the chromatogram obtained with the test solution is similar in position and size to the principal spot in the chromatogram obtained with reference solution (a). The test is not valid unless the chromatogram obtained with reference solution (b) shows two clearly separated spots.

  3. Dissolve about 10 mg in 5 ml of ethanol R. Add 0.5 ml of dinitrobenzene solution R and 0.5 ml of 2 M alcoholic potassium hydroxide R. A violet colour is produced and becomes brownish-red after 20 min.

  4. Mix about 5 mg with 45 mg of heavy magnesium oxide R and ignite in a crucible until an almost white residue is obtained (usually less than 5 min). Allow to cool, add 1 ml of water R, 0.05 ml of phenolphthalein solution R1 and about 1 ml of dilute hydrochloric acid R to render the solution colourless. Filter. To a freshly prepared mixture of 0.1 ml of alizarin S solution R and 0.1 ml of zirconyl nitrate solution R, add 1.0 ml of the filtrate. Mix, allow to stand for 5 min and compare the colour of the solution with that of a blank prepared in the same manner. The test solution is yellow and the blank is red.

TESTS

Appearance of solution. Dissolve 0.20 g in methylene chloride R and dilute to 20.0 ml with the same solvent. The solution is clear (2.2.1) and not more intensely coloured than reference solution BY5 (Method II, 2.2.2).

Related substances. Examine by liquid chromatography (2.2.29). Prepare the solutions immediately before use.

Test solution. Dissolve 0.10 g of the substance to be examined in dimethylformamide R and dilute to 10.0 ml with the same solvent.

Reference solution (a). Dissolve 2.5 mg of droperidol CRS and 2.5 mg of benperidol CRS in dimethylformamide R and dilute to 100.0 ml with the same solvent.

Reference solution (b). Dilute 1.0 ml of the test solution to 100.0 ml with dimethylformamide R. Dilute 5.0 ml of this solution to 20.0 ml with dimethylformamide R.

The chromatographic procedure may be carried out using:

Equilibrate the column for at least 30 min with acetonitrile R and then equilibrate at the initial mobile phase composition for at least 5 min.

Adjust the sensitivity of the system so that the height of the principal peak in the chromatogram obtained with 10 ml of reference solution (b) is at least 50 per cent of the full scale of the recorder.

Inject 10 ml of reference solution (a). When the chromatogram is recorded in the prescribed conditions, the retention times are: benperidol, about 6.5 min and droperidol, about 7 min. The test is not valid unless the resolution between the peaks due to droperidol and benperidol is at least 2.0. If necessary, adjust the final concentration of acetonitrile in the mobile phase or adjust the time programme for the linear gradient.

Inject 10 ml of dimethylformamide R as a blank, 10 ml of the test solution and 10 ml of reference solution (b). 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) (0.25 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) (0.5 per cent). Disregard any peak obtained with the blank and any peak with an area less than 0.2 times the area of the principal peak in the chromatogram obtained with reference solution (b).

Heavy metals (2.4.8). 1.0 g complies with limit test D for heavy metals (20 ppm). Prepare the standard using 2 ml of lead standard solution (10 ppm Pb) R.

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 105 �C.

Sulphated ash (2.4.14). Not more than 0.1 per cent, determined on 1.0 g.

ASSAY

Dissolve 0.300 g in 50 ml of a mixture of 1 volume of glacial acetic acid R and 7 volumes of methyl ethyl ketone R. Using 0.2 ml of naphtholbenzein solution R, titrate with 0.1 M perchloric acid until the colour changes from orange-yellow to green.

1 ml of 0.1 M perchloric acid is equivalent to 37.94 mg of C22H22FN3O2.

STORAGE

Store in a well-closed container, protected from light.

IMPURITIES

  1. 2,3-dihydro-1-(1,2,3,6-tetrahydropyridin-4-yl)-1H-benzimidazol-2-one,

  2. 1-[1-[4-(2-fluorophenyl)-4-oxobutyl]-1,2,3,6-tetrahydropyridin-4-yl]-2,3-dihydro-1H-benzimidazol-2-one,

  3. 4-(2,3-dihydro-2-oxo-1H-benzimidazol-1-yl)-1-[4-(4-fluorophenyl)-4-oxobutyl]pyridinium chloride

  4. 1-[1-[4-(4-fluorophenyl)-4-oxobutyl]-1,2,3,6-tetrahydropyridin-4-yl]-2,3-dihydro-1H-benzimidazol-2-one N-oxide,
  5. 2,3-dihydro-1-[1-[4-[4-[4-(2,3-dihydro-2-oxo-1H-benzimidazol-1-yl)-1,2,3,6-tetrahydropyridin-1-yl]-1-oxobutyl]phenyl]-1,2,3,6-tetrahydropyridin-4-yl]-1H-benzimidazol-2-one.

Bijlage II

.

Omschrijving van de structuren van benperidol en van de IMPURITIES van droperidol.

We kennen aan structuurgedeelten van droperidol de letters P en Q toe als volgt:

Verontreiniging A is het splitsingsproduct H-P-Q.

Verontreiniging B is de ortho-fluor isomeer van droperidol.

Verontreiniging E is het product waarin de benzimidazol-groep -Q nog een tweede keer voorkomt, namelijk ook in plaats van het F-atoom.

Benperidol is zeer verwant aan droperidol: het structuurgedeelte P is geheel verzadigd (piperidine-ring).

Bijlage III

2.4.8. HEAVY METALS

METHOD A

To 12 ml of the prescribed aqueous solution add 2 ml of buffer solution pH 3.5 R. Mix and add to 1.2 ml of thioacetamide reagent R. Mix immediately. Prepare a stan-dard in the same manner using a mixture of 10 ml of lead standard solution (1 ppm or 2 ppm Pb) R, as prescribed, and 2 ml of the solution to be examined. Prepare a blank, using a mixture of 10 ml of water R and 2 ml of the solution to be examined. Compared to the blank, the standard shows a slight brown colour.

After 2 min, any brown colour in the test solution is not more intense than that in the standard.

METHOD B

The substance to be examined is dissolved in an organic solvent containing a minimum percentage of water (for example, dioxan containing 15 per cent of water or acetone containing 15 per cent of water).

To 12 ml of the prescribed solution add 2 ml of buffer solution pH 3.5 R. Mix and add to 1.2 ml of thioacetamide reagent R. Mix immediately. Prepare a standard in the same manner using a mixture of 10 ml of lead standard solution (1 ppm or 2 ppm Pb) as prescribed and 2 ml of the solution to be examined. Prepare the lead standard solution (1 ppm or 2 ppm Pb) by diluting lead standard solution (100 ppm Pb) R with the solvent used for the substance to be examined. Prepare a blank, using a mixture of 10 ml of the solvent used for the substance to be examined and 2 ml of the solution to be examined. Compared to the blank, the standard shows a slight brown colour.

After 2 min, any brown colour in the test solution is not more intense than that in the standard.

METHOD C

Place the prescribed quantity (not more than 2 g) of the substance to be examined in a silica crucible with 4 ml of a 250 g/l solution of magnesium sulphate R in dilute sulphuric acid R. Mix using a fine glass rod. Heat cautiously. If the mixture is liquid, evaporate gently to dryness on a water-bath. Progressively heat to ignition and continue heating until an almost white or at most greyish residue is obtained. Carry out the ignition at a temperature not exceeding 800 �C. Allow to cool. Moisten the residue with a few drops of dilute sulphuric acid R. Evaporate, ignite again and allow to cool. The total period of ignition must not exceed 2 h. Take up the residue in two quantities, each of 5 ml, of dilute hydrochloric acid R. Add 0.1 ml of phenolphthalein solution R, then concentrated ammonia R until a pink colour is obtained. Cool, add glacial acetic acid R until the solution is decolorised and add 0.5 ml in excess. Filter if necessary and wash the filter. Dilute to 20 ml with water R. To 12 ml of the solution thus obtained add 2 ml of buffer solution pH 3.5 R. Mix and add to 1.2 ml of thioacetamide reagent R. Mix immediately. Prepare a standard using 4 ml of a 250 g/l solution of magnesium sulphate R in dilute sulphuric acid R and the prescribed volume of lead standard solution (10 ppm Pb) R. In the same conditions as prescribed for the test, ignite, take up with hydrochloric acid, add ammonia and then acetic acid. Dilute to 20 ml with water R. To 10 ml of the solution add 2 ml of the solution obtained with the substance to be examined and 2 ml of buffer solution pH 3.5 R. Mix and add to 1.2 ml of thioacetamide reagent R. Mix immediately. Prepare a blank, using a mixture of 10 ml of water R and 2 ml of the solution obtained with the substance to be examined. Compared to the blank, the standard shows a slight brown colour.

After 2 min, any brown colour in the solution obtained with the substance to be examined is not more intense than that in the standard.

METHOD D

In a silica crucible, mix thoroughly the prescribed quantity of the substance to be examined with 0.5 g of magnesium oxide R1. Ignite to dull redness until a homogeneous white or greyish white mass is obtained. If after 30 min of ignition the mixture remains coloured, allow to cool, mix using a fine glass rod and repeat the ignition. If necessary repeat the operation. Heat at 800 �C for about 1 h. Take up the residue in two quantities, each of 5 ml, of a mixture of equal volumes of hydrochloric acid R1 and water R. Add 0.1 ml of phenolphthalein solution R and then concentrated ammonia R until a pink colour is obtained. Cool, add glacial acetic acid R until the solution is decolorised and add 0.5 ml in excess. Filter if necessary and wash the filter. Dilute to 20 ml with water R. To 12 ml of the solution thus obtained, add 2 ml of buffer solution pH 3.5 R. Mix and add to 1.2 ml of thioacetamide reagent R. Mix immediately. Prepare a standard as follows. To 0.5 g of magnesium oxide R1 add the prescribed quantity of lead standard solution (10 ppm Pb) R. Dry in an oven at 100 �C to 105 �C. In the same conditions as prescribed for the test, ignite, take up with hydrochloric acid, add ammonia and then acetic acid. Dilute to 20 ml with water R. To 10 ml of the solution add 2 ml of the solution obtained with the substance to be examined and 2 ml of buffer solution pH 3.5 R. Mix and add to 1.2 ml of thioacetamide reagent R. Mix immediately. Prepare a blank, using a mixture of 10 ml of water R and 2 ml of the solution obtained with the substance to be examined. Compared to the blank, the standard shows a slight brown colour.

After 2 min, any brown colour in the solution obtained with the substance to be examined is not more intense than that in the standard.

Farmaceutische Analyse 5e-jaar |

17 september 1999
Staf Farmaceutische Analyse 5e-jaar