Assay Method (Q - R)

Assay Method of
 Quinine Dihydrochloride Injection

Standard

To a volume  equivalent to 0.120 g of quinine dihydrochloride, add 4.5 ml of water & 1.5 ml of  5 M sodium hydroxide, & extract with successive quantities, each of  20 ml , of chloroform until complete extraction of the alkaloid is effected ( 3 times ), washing each extract with the same two quantities, each of 5 ml , water. Remove the chloroform from the combined extracts, dissolve the residue in 25 ml of anhydrous glacial acetic acid, add 5 ml of acetic anhydride, and titrate with 0.1 N perchloric acid vs, using crystal violet as indicator. Each ml of 0.1 N perchloric acid vs is equivalent to 0.01987 g of quinine dihydrochloride.

Calculation

% of content    =      No. of ml of 0.1N PCAVS x F x 19.87 x 100 / Amount of Quinine Dihydrochloride.

Assay Method of
 Quinine Sulphate Tablet

Standard	Dissolve powdered sample equivalent to 100 mg Quinine Sulfate in previously neutralized 50 ml Acetic Anhydride using 0.5% crystal violet solution as indicator. Titrate with 0.1 M perchloric acid and determine the end point. Each ml of 0.1M perchloric acid VS is equivalent to 26.10 mg of Quinine Sulfate.
Calculation	% of content =   V x F x 26.10 x 100 / W

Assay Method of
 Rabeprazole Sodium Tablet

Solvent	0.1 M NaOH
Standard	25 mg ----® 100 ml amber flask ----® Take 2.5 ml ----® 50 ml amber flask (Shake – 15 minutes)
Sample	Same as standard. wavelength 292 nm

Assay Method of
 Ramipril Tablet

Mobile Phase	Dissolve 15.609 g Sodium dihydrogen Orthophosphate ( NaH2PO4 )in 500 ml of water and make up to 1000 ml with  water. Adjust pH of this solution to 2.2 ± 0.1with ortho phosphoric acid.  Mix five  parts of this buffer with five parts of Acetonitrile.  Filter through 0.45 m  membrane filter and degasses.
Standard	Weight and transfer about 50 mg working standard of Ramipril in a 50 ml volumetric flask. Add 5 ml water & shake for 10 minutes. Further add 35 ml of Methanol and shake for 20 minutes and dilute with Methanol up to the mark and mix well. Dilute 5 ml of this solution into  50 ml volumetric flask  & mix well .Filter this solution with 0.45 mm membrane filter before injection.
Sample	Take the weight of 20 tablets & determine the average weight. Crush the tablets into fine powder. Take an amount of powder sample equivalent to  5 mg Ramipril in a 50 ml volumetric flask. Add 5 ml water & shake for 10 minutes. Further add 35 ml Methanol and shake for 30 minutes and dilute with Methanol up to the mark and mix well. Filter the solution by whatman filter paper and finally filter this solution with 0.45 m  membrane filter before injection.
Condition	Waters Sphreisorb  ODS2 , 5 mm  150 x 4.6 mm / UV at 210 nm / 8 minutes. 4.2 minutes for Ramipril (approx.)

 

Assay Method of
 Ranitidine Tablet

Solvent	Methanol
Standard	50 mg ----® 100 ml ----® Take 1 ml ----® 50 ml (Shake – 15 minutes)
Sample	Same as standard. wavelength 320 nm

Assay Method of
 Ranitidine Injection

Solvent	Water
Standard	50 mg ----® 100 ml ----® Take 2 ml ----® 100 ml (Shake – 5 minutes)
Sample	Same as standard. wavelength 314 nm

Assay Method of
 Raubasine INN

Solvent	Ethanol
Standard	10 mg ---® 100 ml ---® take 2 ml ---® 50 ml (Shake – 15 minutes)
Sample	Same as Standard. Take absorbance at 226 nanometer.

Assay Method of
 Repaglinide Tablet

Buffer	Dissolve 2 gm of Di -ammonium Hydrogen Phosphate into 1000 ml volumetric flask & add    950 ml distilled water, adjust the pH 2.5 ± 0.05 with Ortho Phosphoric Acid & make   volume with distilled water up to 1000 ml. Filter through 0.45 m membrane filter and   degasses.
Ratio	Methanol ( 70% ) : Ammonium Buffer pH 2.5 ( 30% )
Diluent	Methanol ( 70% ) : Ammonium Buffer pH 4 ( 30% )    Dissolve 2 gm of Di -ammonium Hydrogen Phosphate into 1000 ml volumetric flask & add 950 ml distilled water, adjust the pH 4 ± 0.05 with Ortho Phosphoric Acid & make volume with distilled water up to 1000 ml.
Standard	Accurately weigh and transfer about 10 mg of working standard of Repaglinide into 100 ml volumetric flask. Add 70 ml of diluent & shake for 15 minutes and then up to the mark  100 ml with diluent and mix well. Filter this solution with 0.45 m membrane filter before injection.
Sample	Take about 1.0 gm sample powder equivalent to 5 mg of Repaglinide into 50 ml  volumetric flask. Add 30 ml of diluent & shake for 15 minutes and then up to the mark  50 ml with diluent and mix well. Filter this solution by Whattman filter paper and finally  with 0.45 m membrane filter before injection.
Condition	ODS2  , 10 m 4.6 x 250 mm / 400 C/ UV at 242 nm / 15 minutes

Assay Method of
 Rifampicin Capsule

Sample

Shake a quantity of mixed contents of 20 capsules. Containing 0.1 g of Rifampicin  add 80 ml of methanol .Shake for 15 minutes , add sufficient methanol to produce 100 ml . Mix  and filter. Dilute 2 ml of the filtrate to 100 ml with phosphate  Buffer pH 7.4 and measure the absorbance of the resulting  solution  at the maximum 475 nm,  Calculate the content of Rifampicin taking 187 as the   value of A ( 1%, cm ) at 475 nm. % of content  =  Absorbance  x 100 / conc. in g /100 ml x 187

Assay Method of
 Rifaximin Tablet

Ratio	Methanol 80% : Distilled Water 20%
Diluent	Methanol
Standard	Transfer about 50 mg of Rifaximin working standard into 100 ml volumetric flask. Add 70 ml of methanol & shake for 15 minutes and then up to the mark 100 ml with methanol and mix well. Filter this solution with 0.45 m membrane filter before injection.
Sample	Take about crushed sample powder equivalent to 50 mg of Rifaximin into 100 ml volumetric flask. Add 70 ml of methanol & shake for 15 minutes and then up to the mark 100 ml with methanol and mix well. Filter this solution by Whattman filter paper and finally  with 0.45 m membrane filter before injection.
Condition	Water Spherisorb C8 5 micron 4.6 x 250 / 400 C/ UV at 230 nm / 1 ml per minute / 10 micro liter / 5 minutes approx

Assay Method of
 Risperidone Tablet

Standard

Weigh accurately 10 mg Working Standard of Risperidone and transfer it into a 100 ml volumetric flask. Add approximately 70 ml of 0.1M HCl and shake for 20 minutes to dissolve completely.  Then adjust the volume up to the mark (100 ml) with the same solvent. Filter the solution by whatman filter  & take 5 ml of the filtrated solution in to another 50 ml volumetric flask and make the volume up to the mark (50 ml) with 0.1M HCl & mix well. Measure the absorbance of standard solution at wavelength 238 nm using 0.1M HCl as a blank.

Sample

Take the quantity of powdered sample equivalent to 10 mg of Risperidone in a 100 ml volumetric flask. Add 70 ml of 0.1M HCl and shake for 20 minutes to dissolve completely. Adjust the volume up to the mark (100 ml) with 0.1HCl. Filter the solution by Whatman filter paper. Again filter the filtrated solution by 0.20-micron membrane syringe filter.Then take 5 ml of this filtrate in another 50 ml volumetric flask and make the volume up to the mark (50 ml) with the same solvent & mix well. Measure the absorbance of sample solution at wavelength 238 nm using 0.1M HCl as a blank.

Assay Method of
 Rofecoxib Tablet

Mobile Phase	Transfer about 600ml of buffer in a glass beaker. Add about 400ml of Acetonitrile. Mix and filter through a 0.45-micron membrane filter and degas.
Buffer	Weigh accurately about 6.8045 g of potassium di-hydrogen phosphate and 0.8709 g of di-potassium hydrogen phosphate. Transfer in a suitable glass beaker. Dissolve in about 900ml of water. Adjust the pH of the solution to 7.0 ± 0.1 with 10% KOH solution and dilute to 1000 ml with water
Diluent	Mobile Phase
Standard	Dissolve 50 mg of Rofecoxib WS in 30 ml of mobile phase and dilute to 50 ml with the same solvent. Dilute 5 ml to 50 ml with mobile phase. Filter this solution with 0.45 m membrane filter before injection.
Sample	Shake a quantity of the powdered sample containing about 50 mg of Rofecoxib in 30 ml of mobile phase for 30 minutes, dilute to 50 ml with the same solvent and then filter. Dilute 5 ml filtrate to 50 ml with mobile phase. Filter this solution with 0.45 m membrane filter before injection.
Condition	C18 Column (4.6 mmx 25cm) & 5µm (ODS) / UV at 265 nm

Assay Method of
 Rosuvastatin Tablet

Buffer A A 0.2%	Transfer 2 ml Glacial Acetic Acid in a 1000 ml volumetric flask then mix and filter through a 0.45-micron membrane filter and degas.
Mobile Phase	Methanol 60% : 0.2% Acetic Acid 40%
Diluent	Mobile Phase
Standard	50 mg ---® 100 ml ---® Take 10 ml ---® 50 ml (Shake 20 minutes)
Sample	10 mg ---® 100 ml (Shake 20 minutes)
Condition	ODS1 10m Column 4.6 x 250 mm / 400 C/ 242 nm / 1 ml per minute / 20 micro liter / 5 minutes approx