Chapter 1 notes Part-2 (One Page Note) Error and limit test .pdf

This is short note for the quick revision of the chapter-1 of D.Pharm or any other pharmacy course syllabus.
It includes
-accuracy, precision and significant figures.
-Impurities (definition, sources and effects)
- Limit test (definition)
-Limit test for chlorides
-Limit test for sulphates.

1. Accuracy, Precision and significant figures
Prepared By –Kartik Tiwari (Lecturer)
HygiaCollege of Pharmacy, Lucknow(U.P)
Content as Per D. Pharm Syllabus
Accuracy Precision Significant figures
Accuracyistheclosenessof
agreementbetweenameasured
valueandatrueoracceptedvalue
(measurementerrorrevealsthe
amountofinaccuracy).
Accuracy =
Observed value
Exact value
* 100
Precisionisameasureofthedegree
ofconsistencyandagreementamong
independentmeasurementsofthe
samequantity(alsothereliabilityor
reproducibilityoftheresult).
Significantfiguresarethedigitsofvalue
whichcarrymeaningtowardsthe
resolutionofthemeasurement.Significant
figuresarethenumberofdigitsnecessary
toexpresstheresultofameasurement
compatiblewiththemeasuredprecision.
Impurities
Anyunwantedforeign-matterpresentina
compoundwhicharedifferfromtheactual
molecularformula.
Impurities:
Sources of impurities
1.During manufacturing.
From Raw materials
Reagents used in the manufacturing process
Solvent used in the manufacturing process
Reaction equipment
Manufacturing Hazards
2.During purification and processing.
Reagent used to remove other impurities
Solvents used in the process of purification
Contamination due to vessels and equipment(
filters, centrifuges, dryers etc.) used for purification
3. During storage.
Errors in packaging materials
Faulty packaging process
Microbial contamination
Impuritiescouldmaketheoriginalsubstanceincompatibleand
speedupthedeteriorationofthesubstance.Some
contaminantsactivelyparticipateinthechemicalprocess,
alteringthechemicalpropertiesoforiginalsubstances.
Theimpuritieseffecton
Potency
Selflifeofdrug
Therapeuticvalue
Itoccursdueto
Oxidationofthedrug
Temperature
Humidity
Effects of impurities
Limittestisdefinedasquantitativeorsemi-quantitativetest
designedtobeidentifiesandcontrolsmallquantitiesof
impuritywhichislikelytobepresentinthesubstance.
Limittestincludeschloride,sulphate,iron,heavymetalsand
Arsenic.
Limit Test:
Limit Test (Principle, Chemical reaction, Procedure and Observation)
LIMIT TEST FOR CHLORIDES LIMIT TEST FOR SULPHATES
Principle:Itisbaseduponthechemicalreactionbetween
silvernitrateandsolublechloridetoobtainedsilverchloride
inthepresenceofnitricacid.Thetestsolutionbecomes
turbidduetothesilverchloridethatisproducedwhendilute
nitricacidispresent.
Procedure:
Observation:Turbidityofthetestsolutionshouldbeless
thanstandardsolution.
Principle: The limit test of sulphate is based on the chemical
reactions between barium chloride and soluble sulphate in
the presence of acetic acid.
Procedure:
Observation:Turbidityofthetestsolutionshouldbeless
thanstandardsolution.
Test solution Standard solution
1.Specificweight of compound is
dissolved in water or solution is
prepared as directed in the
pharmacopoeia and transfer to
nessler cylinder
2.Add 0.15 ml of 5M acetic acid
3.Add 2.5 ml of barium sulphate
4.Add sufficient distilled water to
Produce 50 ml.
1.Mix 15 ml of sulphatestandard
solution and 15 ml of distilled
water in a nessler cylinder.
2.Add 0.15 ml of 5M acetic acid
3.Add 2.5 ml of barium sulphate
4.Add sufficient distilled water to
Produce 50 ml.
Test solution Standard solution
1. Specific amount of compound
dissolve in a distilled water and
solution is prepared according to
Pharmacopoeia and transfer to
nessler cylinder.
2. Add 1ml of dil. HNO
3
3. Dilute to 50 ml of water
4. Add 1ml of AgNO
3
1. Take 10 ml of chloride standard
solution (25ppm Cl) and 5 ml of
water.
2. Add 1ml of dil. HNO
3
3. Dilute to 50 ml of water
4. Add 1ml of AgNO
3