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:

Carry out the following procedure in subdued light.

  1. When examined in the range 230nm to 400nm, the final solution obtained in the assay shows absorption maxima at about 266nm and 367nm.

5.0)      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.

6.0)      Dimension of Tablet:

Length, breadth and thickness are determined by vernier in mm

7.0)      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.

8.0)      Dissolution:

            Apparatus: paddle

Medium: 900ml phosphate buffer pH 6.8

Speed: 100rpm

            Time: 1st, 4th, 8th, 12th

Acceptance Limit: 1st Hour: NMT 25%

                                            4th Hour: 25%-50%

                                            8th Hour: 45%-75%

                                            12th Hour: NLT 80%

Standard solution: Weigh 25mg of Nitrofurantoin reference standard in 50ml volumetric flask & dissolve with n-dimethylformamide buffer. And make up to mark with dissolution medium. And then 1ml of above solution in 50ml volumetric flask make up to mark with dissolution medium.

Test Solution: Withdraw the sample from dissolution & filter the solution. Add medium into dissolution how much u are withdrawing. Take 1ml of filtered solution add to 50ml of volumetric flak and makeup with the medium used in dissolution.

Check the absorbance of the test as well as sample by UV spectrophotometer at 367nm.

            Calculate the content of Nitrofurantoin.

9.0)      Leak test:

The apparatus is used to test for the integrity of packed strips, blisters and Alu-Alu Blister pack containing tablets. Ensure apparatus bath is filled with purified water upto mark indicated and add 0.5% crystal violet solution in water. Samples are placed into the desiccators and the lid is placed in position. The pump starts to produce a vacuum 15inHg inside the desiccators and the vacuum is held for 1 minute. The sample remains at the required vacuum level for given time interval buzzer will sound after time is over and will cut off the vacuum pump. As the package is immersed in a colored dye solution the venting of the desiccators will allow any holes to be penetrated by the dye and the contents of the flexible packaging will also be stained with the same coloring material.

Examine all the strips for any leakage by opening the pockets manually. If anyone pocket shows evidence of leakage, reject the sample, stop the Blister / Strip machine and immediately take corrective action.

10.0)    Assay: Determined by UV spectrophotometer

Carry out the following procedure in subdued light.

Weigh and powder 20 tablets. Weigh a quantity of the powder containing about 0.15g of Nitrofurantoin, add 50ml of dimethylformamide, shake for 5 minutes, add sufficient water to produce 1000ml and mix. Dilute 5ml to 100ml with a solution containing 1.8 per cent w/v solution of sodium acetate and 0.14 per cent v/v glacial acetic acid. Measure the absorbance of the resulting solution at the maximum at about 367nm, using as the blank the sodium acetate acetic acid solution. Calculate the content of Nitrofurantoin, taking 765 as the specific absorbance at 367nm.

           Formula for calculation:

Absorbance of TEST       1000             1000                   100

—————————-X————-X—————–X———-X Avg. Wt.

765                          100            Test wt (mg)         5


Wt.: Weight

mg: Miligram

ml: Milileter

Avg.: Average

NLT: Not less than

NMT: Not more than