Assay Method (N)

Assay Method of
 Nalbuphine Hydrochloride Injection

Standard

Take 40 mg Working Standard of Nalbuphine Hydrochloride in to a 25 ml volumetric flask. Then add 15 ml of distilled water and shake for 10 minutes. Then volume it up to 25 ml with the same solvent (distilled water). Filter the solution by Whatman filter paper. Then take 10 ml of the filtrate solution in to a 100 ml volumetric flask and volume it up to 100 ml with the same solvent (distilled water).  Then Measure the absorbance at 284 nm taking distilled water as a blank. (Conc.=0.016 %)

Sample

Take 4 ml of the sample [Equivalent to 40 mg of Nalbuphine Hydrochloride] in to a 25 ml volumetric flask. Then add 15 ml of distilled water and shake for 10 minutes. Then volume it up to 25 ml with the same solvent (distilled water). Filter the solution by Whatman filter paper. Then take 10 ml of the filtrate solution in to a 100 ml volumetric flask and volume it up to 100 ml with the same solvent (distilled water).  Then Measure the absorbance at 284 nm taking distilled water as a blank. (Conc.=0.016 %)

Assay Method of 
 Nalidixic Acid  Tablet

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Sample	To a quantity of the powdered sample containing 100 mg of Nalidixic Acid add 150 ml of 1M sodium  hydroxide, shake for 3 minutes, dilute to 200 ml with 1M sodium hydroxide, mix and allow to stand  for 15 minutes. Dilute 2 ml to 200 ml with water.Measure the absorbance of the solution at 334  nm using 0.01M sodium hydroxide as blank.
Calculation	% of Nalidixic Acid =  Absorbance of Sample ´ 100 / Conc. Of spl. ´ 494

Assay Method of
 Naproxen Tablet

Standard	Dissolve about 50 mg of Naproxen WS in 70 ml of methanol and dilute to 100 ml with same solvent. Dilute 10 ml of the filtrate to 50 ml with methanol.
Sample	Shake a quantity of powder containing 50 mg of Naproxen with 70 ml of methanol for 30 minutes, add sufficient methanol  to produce 100 ml and filter. Dilute 10 ml of the filtrate to 50 ml with methanol. Measure the absorbance of sample and standard solution at 331 nm using methanol as blank.

Assay Method of 
 Nateglinide Tablet

Standard	Weigh accurately and transfer about 50 mg Nateglinide of working standard in a 50-ml volumetric flask. Add 30 ml of methanol and shake for 10 minutes and then make the volume up to mark with methanol. Measure the absorbance of the standard at λ max 258.5 nm taking methanol as a blank.
Sample	Weigh and powder the 20 tablets. Take powder equivalent to 50 mg of Nateglinide in a 50-ml volumetric flask.  Add 30 ml of methanol and shake for 20 minutes and then make the volume up to mark with methanol. Filter this solution with Whatman filter paper. Measure the absorbance of the standard at λ max 258.5 nm taking methanol as a blank.

                                     

     Assay Method of
    Nitrazepam Tablet

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Sample

Weigh  and powder 20 tablets. To a quantity of  powder containing 5 mg of Nitrazepam add  5 ml of  water, mix , allow to stand for 15 minutes. Add 70 ml of  a 0.5 % v/v solution of Hydrochloric acid in  Methanol, shake for 15 minutes, add sufficient of the Hydrochloric acid solution to  produce 100 ml .  Mix and Filter. Dilute 10 ml of the filtrate to 50 ml with the same solution and measure the absorbance   of the resulting solution at 280 nm . Calculate the content of Nitrazepam taking 910 as the value of  A ( 1 % , 1 cm ) at 280 nm.

Calculation

% of Nitrazepam  =  Absorbance     x   100 / conc. In gm per 100 ml  x  910

Assay Method of 
 Nitazoxanide Tablet & PFS

Standard

Take 50 mg of working standard of Nitazoxanide in a 100 ml volumetric flask. Add 70 ml of 0.1 M NaOH  and shake for 25 minutes.  Adjust the volume to100 ml with 0.1 M NaOH. Take 2 ml of the solution in a 50 ml volumetric flask. Make the volume up to the mark (50ml) with 0.1 M NaOH. Take absorbance at 413 nm.   (Concentration = 0.002%). Use 0.1 M NaOH as blank

Sample

Reconstitute the powder with 20 ml of water.Take 2.5 ml of suspension  equivalent to 50 mg of Nitazoxanide in a 100 ml volumetric flask. Add 70 ml of 0.1 M NaOH and shake for 25 minutes. Adjust the volume to100 ml with 0.1 M NaOH & mix.  Filter the solution by Whatman filter paper. Take 2 ml of the filtrate in a 50 ml volumetric flask. Make the volume up to the mark (50 ml) with 0.1 M NaOH. Take absorbance at 413 nm. (Concentration = 0.002%). Use 0.1 M NaOH as blank

Assay Method of 
 Nortriptyline Tablet

Sample

Weigh and powder 20 tablets. To a quantity of powder equivalent to 50 mg of Nortriptyline add 75 ml of 0.1M hydrochloric acid, shake for 30 minutes , add sufficient 0.1M hydrochloric acid to produce 100 ml . Mix and filter . To 10 ml of the filtrate  in a 250 ml separating funnel add 5 ml of water & 1 g of sodium chloride , shake for 3 minutes & make alkaline with 5 M sodium hydroxide . Extract with two quantities, each of  40 ml  of ether & wash the combined extracts with two quantities each of 5 ml ,of a mixture of equal volume of a saturated solution of sodium chloride and water. Extract the ether  solution with  two quantities , each of 20 ml of 0.1M hydrochloric acid . Combine the extracts and add sufficient 0.1M hydrochloric acid to produce 50 ml. Dilute 5 ml  to 50 ml with  0.1M hydrochloric acid ,Measure the absorbance of the resulting solution at the maximum at 239 nm, Calculate the content of  Nortriptyline taking 517 as the value of A (1% , 1cm ) at the maximum 239 nm % of  Nortriptyline  =  Absorbance of sample   x   100 / conc (in g/100 ml )  x 517

Fluphenazine Hydrochloride

Palladium Chloride : Dissolve 100 mg of palladium chloride in a mixture of 50 ml of water and 1 ml of hydrochloride acid. Heat on a water bath until the solution is in effect. Cool and dilute to 100 ml with water. This should be stored in an amber colour bottle  and should be used within 30 days . On the day of use mix 5 ml of this solution with 10 ml of 10 % v/v hydrochloric acid  and dilute to 100 ml with water .

  Assay Method of 
 Noscapine Syrup

Standard

To 10 ml of the syrup add 10 ml of water , 1 g of sodium chloride and 1 ml of 5M sodium hydroxide . Extract with successive quantities of  50 , 50  and 25 ml of  ether, combine the extracts , wash with three 5 ml quantities of water and evaporate to dryness. To the residue add 25 ml of  0.1M hydrochloric acid , warm on a water-bath to dissolve and to remove any traces of ether  and dilute to 50 ml with water. Dilute 3 ml to 50 ml with water and measure the absorbance of the resulting solution at  the maximum  at 310 nm . Calculate the content of Noscapine taking 90.7 as the value of A ( 1%, 1 cm ) at the maximum  at 310 nm .  % of content        = Absorbance  x 100 / conc, in g per 100 ml x 90.7

Assay Method of
 Nitazoxanide Tablet & PFS

Sample

To 10 ml of the syrup add 10 ml of water , 1 g of sodium chloride and 1 ml of 5M sodium hydroxide . Extract with successive quantities of  50 , 50  and 25 ml of  ether, combine the extracts , wash with three 5 ml quantities of water and evaporate to dryness. To the residue add 25 ml of  0.1M hydrochloric acid , warm on a water-bath to dissolve and to remove any traces of ether  and dilute to 50 ml with water.Dilute 3 ml to 50 ml with water and measure the absorbance of the resulting solution at  the maximum  at 310 nm . Calculate the content of Noscapine taking 90.7 as the value of A ( 1%, 1 cm ) at the maximum  at 310 nm .

Calculation

% of content        =   Absorbance  x 100 / conc, in g per 100 ml x 90.7

Assay Method of 
 Nitrofurantoin Tablet & PFS

Reagent	Take 9 gm Sodium Acetate Trihydrate & 200 ml of Distilled water in a 500 ml Volumetric Flask and dissolve it by shaking. Take 0.7 ml of Glacial Acetic Acid and finally make the volume 500 ml with Distilled Water.
Sample	Weigh 10 tablets and make it powder. Take powder-containing equivalent to 12 mg of Nitrofurantoin into 100 ml Volumetric flask Add 5 ml of N,N Dimethylformamide  & shake  to dissolve it and dilute with 65 ml of Distilled water. Shake for 20 minutes &  make the volume up to mark(100 ml) with Distilled water& filter with Whitman filter paper .Take 1 ml of the solution in a 25 ml volumetric flask. Make the volume up to mark (25 ml) with Sodium Acetate solution. Measure the absorbance at 367 nm taking Sodium Acetate solution as blank. Calculate the content of Nitrofurantoin taking 765 as the value of A (1%, 1 cm) at the maximum at 367 nm. (Concentration of Sample 0.00048 %)
Calculation	Absorbance of Sample   x   100 / Concentration of Sample   x 765

Assay Method of 
 Nystatin Syrup

Standard	Prepare standard in the same way as sample preparation .Conc. 0.001 % of Nystatin WS .
Sample	Take sample equivalent to 500000 units ie 100 mg (5 ml) of Nystatin in a mixture of 5 ml of glacial acetic acid and 50 ml of methanol. Shake for 15 minutes. Add sufficient methanol to produce 100 ml. Mix and filter. Dilute 1 ml of the filtrate to 100 ml with methanol.1 mg  is equivalent to about 5000 units Measure the absorbance at 305 nm , against methanol as reagent blank.