## STP FOR RAMIPRIL AND HYDROCHLOROTHIAZIDE TABLETS

1.0) Description: Visual

2.0) Average Weight: Check weight of 20 tablets at randomly. And calculate the average weight by formula :  wt of 20 tablets (gm) x 1000 / 20. found avg. wt in mg

3.0)                  Uniformity of weight:

Weigh 20 tablets selected at random and calculate the average weight. Not more than two of the individual weights deviate from the average weight by more than the percentage shown in table.

Weigh the tablets individually and calculate the percentage of deviation for each tablet. By using formula = (experimental weight – theoretical weight)    x 100%

Theoretical weight

 Average weight of tablets Percentage deviation More than 80mg but Less than 250mg 7.5% 25mg or More 5%

4.0)      Identification Test:

In the assay the principal peak in the chromatogram obtained with the test solution corresponds to the peak in the chromatogram obtained with the reference solution.

5.0)      Disintegration Time:

Unless otherwise stated in the individual monograph, introduce one tablet into each tube and add a disc to each tube. The assembly is suspended in the liquid medium in a suitable vessel, preferably a 1-litre beaker. The volume of liquid is such that the wire mesh at its highest point is at least 15mm below the surface of the liquid, and at its lower point is at least 25mm above the bottom of the beaker. At no time should the top of the basket-rack assembly become submerged. There is a thermostatic arrangement for heating the liquid and maintaining the temperature at 37±2°.

If 1 or 2 tablets fail to disintegrate, repeat the test on 12 additional tablets; not less than 16 of the total of 18 tablets tested disintegrate.

If the tablets adhere to the disc and the preparation under examination fails to comply, repeat the test omitting the disc. The preparation complies with the test if all the tablets in the repeat test disintegrate.

6.0)      Hardness:

The standard method used for tablet hardness testing is compression testing. The tablet is placed between two jaws that crush the tablet. The machine measures the force applied to the tablet and detects when it fractures. Although compressive force is applied to the tablet, along the diameter of the tablet at right angles to the applied force.

7.0)      Dimension of Tablet:

Length, breadth and thickness are determined by vernier in mm.

8.0)      Friability:

The test is applicable to compressed tablets and is intended to determine the physical strength of tablets. Tablets with a unit weight equal to or less than 650 mg, take a sample of whole tablets corresponding as near as possible to 6.5g. For tablets with a unit weight of more than 650mg, take a sample of 10 whole tablets. The tablets should be carefully dedusted prior to testing. Accurately weigh the tablet sample, and place the tablets in the drum. Rotate the drum 100 times and remove the tablets. Remove any loose dust from the tablets as before, and accurately weigh.

The test is run only once unless the results are difficult to interpret or if the weight loss is greater than the target value, in which case, the test is repeated twice and the mean of the three tests is determined.

Formula: initial wt. – after friability wt. x100 / initial wt.

A maximum loss of weight (From a single test or from the mean of three tests) not greater than 1.0 percent is acceptable for most tablets.

9.0)      Dissolution:

Medium: 750ml of 0.1 M HCl

Speed: 45 minutes

Time: 100rpm

Limit: NLT 80percent of the stated amount of ramipril and hydrochlorothiazide.

Withdraw a suitable volume of the medium and filter

Determine by liquid chromatography

Test solution: Dilute the filtrate, if necessary, with the dissolution medium

Reference solution (a): Dissolve a quantity of Ramipril reference standard in the mobile phase and dilute with dissolution medium to obtain a solution having known concentration similar to the test solution.

Reference solution (b): Dissolve a quantity of hydrochlorothiazide reference standard in mobile phase and dilute with dissolution medium to obtain a solution having a known concentration similar to the test solution.

Chromatographic system:

• A stainless steel column 25cm X4.6mm, packed with octadecylsilane bonded to porous silica (5µm) (such as thermo quest hypersil),
• Mobile phase: a mixture of 55 volumes of water, 45 volumes of acetonitrile, and 0.1 volume of triethylamine, adjust to pH 3.0 with orthophosphoric acid,
• Flow rate: 0.7ml per minute,
• Spectrophotometer set at 210nm,
• Injection volume: 20µl

Inject reference solution (a) and (b). The relative standard deviation for replicate injections for each peak is not more than 2.0 per cent.

Inject reference solutions (a), (b) and test solution.

Calculate the content of ramipril and hydrochlorohiazide in the medium.

10.0)    Related substances: Determine by liquid chromatography.

Test solution: Disperse a quantity of powdered tablets containing about 10mg of ramipril in mobile phase, sonicate for 15 minutes and dilute to 10.0ml with the same solvent.

Reference solution (a): A solution containing 0.2 percent w/v of ramipril reference standard and 0.1 percent w/v of hydrochlorothiazide reference standard in mobile phase.

Reference solution (b): Dilute 5.0ml of reference solution (a) to 50ml with mobile phase. Dilute 5.0ml of this solution to 100ml with the same solvent.

Chromatographic system:

• A stainless steel column 25cm X4.6mm, packed with octadecylsilane bonded to porous silica (5µm)
• Mobile Phase: A. a mixture of 60 volumes of buffer solution prepared by dissolving 4gm of sodiumperchlorate in 600ml of water, add 1.0ml of triethylamine, adjusted to pH 2.6 with O.P.A. and 40 volumes of acetonitrile.
1. a mixture of 85 volumes of buffer solution and 15 volumes of acetonitrile,
• A gradient programme using the conditions given below
• Spectrophotometer set at 210nm
• Injection volume: 20µl
• Column temperature: 35°
• Flow rate: 1ml per minute

 Time (in min.) Mobile phase A (per cent v/v) Mobile phase B (per cent v/v) 0 0 100 13 0 100 17 50 50 20 100 0 80 100 0 82 0 100 87 0 100

The relative retention time with reference to ramipril for ramipril impurity A is about 0.9, for ramipril impurity B is about 1.2, for ramipril impurity C is about 1.5 and forramipril impurity D is about 1.7.

Inject reference solution (b). The test is not valid unless the relative standard deviation for replicate injections for replicate injections for each peak is not more than 5.0 percent.

Inject reference solution (b) and the test solution. The retention time of ramipril is about 30 minutes and of hydrochlorothiazide is about 10 minutes. In the chromatogram obtained with test solution the area of each peak due to ramipril impurity A, B and C is not be more than the area of the principal peak due to ramipril in the chromatogram obtained with reference solution (b); the area of the peak due to ramipril impurity D is not more than 7 times the area of the principal peak due to ramipril in the chromatogram obtained with reference solution (b) (7.0 percent); the area of any other peak secondary peak is not more than area of the principal peak due to ramipril in the chromatogram obtained with reference solution (b) (1.0 percent). Ignore the peak due to hydrochlorothiazide.

11.0)    Uniformity of content:

Test solution: Disperse 1 intact tablet water and dilute to 25 ml with the mobile phase. Dilute 3.0ml of this solution to 25.0ml with the mobile phase and mix.

Reference solution (a):  A 0.024 per cent w/v solution of ramipril reference standard in the mobile phase.

Reference solution (b): A 0.06 per cent w/v solution of hydrochlorothiazide reference standard in the mobile phase.

Reference solution (c): Dilute reference solution (a) and (b) with the mobile phase to obtain a solution having a known concentration similar to the test solution.

Chromatographic system:

• A stainless steel column 25cm X4.6mm, packed with octadecylsilane bonded to porous silica (5µm) (such as thermo quest hypersil),
• Mobile Phase: a mixture of 55 volumes of water, 45 volumes of acetonitrile and 0.1 volume of triethylamine, adjusted to pH 3.0 with O.P.A.
• Flow rate: 1ml per minute,
• Spectrophotometer set at 210nm,
• Injection volume: 20µl

12.0)    Assay: Determined by liquid chromatography.

Test solution: Weigh and powder 20 tablets. Weigh a quantity of powder containing about 25mg ramipril, disperse in water and dilute to 250.0ml with the mobile phase, filter. Dilute 3.0ml of this solution to 25.0ml with the mobile phase and mix.

Reference solution (a):  A 0.024 per cent w/v solution of ramipril reference standard in the mobile phase.

Reference solution (b): A 0.06 per cent w/v solution of hydrochlorothiazide reference standard in the mobile phase.

Reference solution (c): Dilute reference solution (a) and (b) with the mobile phase to obtain a solution having a known concentration similar to the test solution.

Chromatographic system:

• A stainless steel column 25cm X4.6mm, packed with octadecylsilane bonded to porous silica (5µm) (such as thermo quest hypersil),
• Mobile Phase: a mixture of 55 volumes of water, 45 volumes of acetonitrile and 0.1 volume of triethylamine, adjusted to pH 3.0 with O.P.A.
• Flow rate: 1ml per minute,
• Spectrophotometer set at 210nm,
• Injection volume: 20µl

Inject reference solution (c). The test is not valid unless the relative standard deviation for replicate injections for each peak is not more than 2.0 percent.

Inject reference solution (c) and the test solution.

Calculate the content of Ramipril and Hydrochlorothiazide in the tablet.

Acceptance criteria: 90.0%-110.0%

13.0)    MICROBIOLOGICAL PURITY

Perform the test according to requirements of IP,

Total aerobic Microbial count (TAMC): NMT 103 CFU/g

Total combined yeasts/Moulds count (TYMC): NMT 102 CFU/g

Pathogens: in 1gm drug.

Escherichia Coli – Should be absent

Pseudomonas aeroginosa – Should be absent

Salmonella – Should be absent

Staphylococcus aureus– Should be absent

Abbreviations:

Wt.: Weight

mg: Miligram

ml: Milileter

STD: Standard

inHg: Inch of Mercury

rpm: Rounds per minute

CFU: Colony forming unit

HCl: Hydrochloric acid

O.P.A.: Orthophosphoric acid

w/v: Weight/Volume