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DRUG ASSAY
Presenter:
Madiha Moid(Pharmacist)
(I.B.B.P.S,DUHS,OJHA
ASSAY (DEFINITION)
Assay is analytical procedure for assessing the presence or amount of a target entity (the Analyte).
3 steps in processing of ASSAY :
Solution Preparation
Sample & Standard preparation
Instrumentation & Calculation
STEPS INVOLVED
DIFFERENT TECHNIQUES
• Chemical Assays: Coulimetry, Spectrophotometry, Spectrofluorimetry, Chromatography,
• Immunoassays
• Microbiological assays
DIFFERENT TECHNIQUES
ASSAY METHOD ADVANTAGES LIMITATION
COULIMETRIC Simple Semi-quantitative
Rapid Sample Pretreatment
Inexpensive
SPECTROPHOTOMETRIC Simple Semi-quantitative
Rapid Sample Pretreatment
Inexpensive
HPLC Reliable Expensive
High resolution Training of personnel
Accurate Sample Pretreatment
Methodology Sources
1. Official Compendia
2. Petition Methods (NDAs and ANDAs)
3. Pharmacopeial Forum
4. Code of Federal Regulations(Title 21 of the Code of Federal Regulations (CFR)
5. Journals and Other Literature Laboratory Information Bulletin, Journal of Pharmaceutical Sciences
6. Links to Scientific Sites CDER Medical Library web site
ASSAY METHOD
Diclofenac Sodium(Spectrophotometic Method)
50
Spectrophotometry (UV ,VIS & IR)
PRINCIPAL Instrument used to measure the absorbance of
light by compounds within a liquid
Based on the BEER-LAMBERT LAW – absorbance is proportional to concentration
UV Spectroscopy
Sample dissolved in liquid; placed in cuvette.
A range of UV light wavelengths are passed through solution.
Some light will pass through; some light will be absorbed.
ASSAY methodDiclofenac Sodium
(Spectrophotometic Method)
1. Solution Preparation:
0.01N NaoH
Dissolve 0.4gm of NaoH in Litre of Solution.
ASSAY methodDiclofenac Sodium(Spectrophotometic Method)
Weigh 50mg of standard in 100 vol. flask.
Make up vol with 0.01N NaoH & sonicate.
Filter above solution. Take 02ml of filtrate in 100ml
vol. flask. Make up volume with 0.01N
NaoH & sonicate.
2. Standard Preparation:
ASSAY methodDiclofenac Sodium(Spectrophotometic Method)
10 tablets were weighed individually.
# of Tablet Weight (in mg)
1 219.9
2 218.5
3 223.9
4 220.4
5 218.1
6 219.97 218.48
223.69 218.510 220.4Mean = 2201.6 / 10 =
220.16
3. Sample Preparation:
ASSAY methodDiclofenac Sodium(Spectrophotometic Method)
Powder tablets. Powder material equivalent to 50 mg disclofenac sodium was taken in 100 vol. flask and make up the vol with 0.01N NaoH & sonicate.
= Avg wt of tab x req. quantity label claim
= 220.16mg x 50mg 50mg = 220.16mg
ASSAY methodDiclofenac Sodium(Spectrophotometic Method)
Dilution: Filter the solution. Take 02ml from filtrate in 100ml
vol. flask. Make up the volume with 0.01N
NaoH & sonicate.
ASSAY methodDiclofenac Sodium(Spectrophotometic Method)
Absorbance of resulting solutions (Standard & Sample) measured at 236nm spectrophotometrically.
ASSAY methodDiclofenac Sodium(Spectrophotometic Method)
Absorbance: Standard: 0.3058 Sample: 0.2970 = Abs of Sample x wt. of STD x Avg. wt. of tablets x Potency of STD x 100 Abs of Standard x wt. of sample x C: wt. X 100
= 0.2970 x 50.4 x 2 x 100 x 100 x 220.16 x 99.5 x 100 0.3058 100 100 220.4 2 50 100
= 96.40 %
For mg/tablet:
%age x label claim / 100 96.04 x 50 /100 = 48.02mg/tablet
