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Impurities Source of impurities: 1.During synthesis 2.During manufacturing 3.During storage.

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Presentation on theme: "Impurities Source of impurities: 1.During synthesis 2.During manufacturing 3.During storage."— Presentation transcript:

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2 Impurities Source of impurities: 1.During synthesis 2.During manufacturing 3.During storage

3 Impurities Classification of chemicals : 1.Commercial chemicals 2.Pure chemicals 3.Analytical chemicals 4.Pharmaceutical chemicals

4 Pharmacopoeia A description of the article Tests for identity Physical constants Quantitative assay Limit test Storage conditions official = obey the requirement

5 Pharmacopoeia British pharmacopoeia (BP) European pharmacopoeia (Eu.Ph) United state pharmacopoeia (USP)

6 Limit test They are quantitative or semi-quantitative test designed to identify or control small quantities of impurity,these test should be specific and sensitive

7 Limit test Type: 1.Comparison method 2.Quantitative determination 3.Test in which there is no visible reaction

8 Limit test General principle If the sample is lighter than the standard solution then it is within the pharmacopeial limit (accepted) If the sample is darker/heavier than the standard solution then it is above the pharmacopeial limit (rejected)

9 Limit test NESSLER cylinder ( appendix VII A127) clear glasses with normal capacity 50ml, the overall height is about 15cm, the external height to the 50ml mark 11.0 to 12.4 cm,the thickness of the wall 1.0 to 1.5 mm and the thickness of the base 1.0 to 3.0mm the external heights to the 50 mark of cylinders used to test must not differ by more than 1 mm

10 Limit test General precaution 1.The liquid used must be clean and filtered if necessary 2.The Nessler cylinder must be made of colorless glass and of the same inner diameter 3.Detecting opalescence or color development must be performed in daylight 4.When comparing turbidity it should be done against black background 5.When comparing color it should be done against white background

11 Limit test

12 Limit Test for Ammonium Principle NH K 2 HgI 4 NH 2 Hg 2 I 3 10ml of standard NH4 + (1ppm) +5ml H2O Add dis. water to 50 ml 0.3ml Nessler reagent 15ml sample solution Add dist. water to 50 ml 0.3ml Nessler reagent

13 Limit Test for Chloride Principle: AgClCl - + AgNO 3 15ml sample 1ml HNO3 Dist. H2O to 50 ml 1ml AgNO3 10ml St Cl - (5ppm) +5ml H2O 1ml HNO3 Dist. H2O to 50ml 1ml AgNO3

14 Limit Test of Sulphate Principle: SO BaCl 2 BaSO 4 1ml 25%BaCl2 1.5ml ethanolic SO 4 standard MIX by rotation & wait for 1 minute 15ml Standard 15ml sample 15ml water Mix by rotation Add 0.5ml acetic acid(5M Complete volume with Dil.water to 50ml

15 Limit Test for Iron 5ml NH 4 SCN H 2 O to 50ml 5ml HNO 3 10ml sample 5ml NH 4 SCN H 2 O to 50ml 5ml HNO 3 10ml standard Principle: Fe +3 + NH 4 SCN Fe(SCN) 3 Procedure: Why we use nitric acid?

16 Limit Test of Calcium Principle: Ca +2 + (NH 4 ) 2 C 2 O 4 CaC2O4 CaC2O4 Procedure 0.2ml alcoholic calcium stander(100ppm) 1ml ammonium oxalate 1 MIN 2ml calcium stander (100ppm) 20 ml dist water Pipette 15 ml 1ml acetic acid to 50ml with dist water 10ml calcium stander (10ppm) 5 ml dist water

17 Aspirin Limit Test of Salicylic Acid 0.05 ml FeCl 3 to 50ml H 2 O 15 ml iced H 2 O 0.1ml acetic acid 0.1gm sample 5ml ethanol 0.05 ml FeCl 3 to 50ml H 2 O 15 ml iced H 2 O 0.1ml acetic acid 1ml salicylic acid 4ml ethanol

18 Limit Test of Heavy Metal 1.2ml thioacetamide mix 2ml acetate buffer 12ml sample 1.2ml thioacetamide mix 2ml acetate buffer 10ml standard Pb 2ml sample Principle: Pb+2 +NaS PbS Sample preparation 2.5g aspirin dissolve in 30ml acetone then complete to 50 ml with H 2 O

19 Quantitative Limit Test Determination of lead concentration in a sample of heavy metals Primary solution Auxiliary solution 1ml sample 2ml standard 3ml standard 4ml standard 3ml sample 5ml standard 1 ml NH4OH 5drops thioacetmide

20 Non Aqueous Acid-Base Titration Main reasons for non aqueous titration : Solubility: many organic compound (acid or base) sparingly soluble in water but readily soluble in organic solvent Too weak acid or base : they didnt give sharp end point in aqueous titration but can titrated accurately in suitable non aqueous solvent

21 Non Aqueous Acid-Base Titration Titration solvents ProticAprotic Inert neutral substance as :benzene, chloroform and hydrocarbon

22 Non Aqueous Acid-Base Titration Protic solvent : Amphiprotic : it self dissociation (autoprotolysis) which process acidic and basic properties e,g:H2O,AcOH, ALCOHOL and liquid ammonia 2H 2 O H 3 O + + OH - 2C 2 H 5 OH C 2 H 5 OH 2 + +C 2 H 5 O - Protogenic: they have stronger acidic than basic properties (more acidic than water) E,g: CH 3 COOH & H 2 SO 4 B + CH 3 COOH BH + + CH3COO -

23 Non Aqueous Acid-Base Titration Protic solvent : Protophilic : basic substance and react with acidic solute with the formation of solvated proton and conjugated base of acid (more basic than water) E,g :ether,ketone & amine HB +S HS + + B -

24 Non Aqueous Acid-Base Titration Type of Titrant: Perchloric acid (HClO 4 )Used for titration in acetic acid media, it is commonly use for titration of weak media Alkali metal bases: alcoholic potassium hydroxide or alcoholic sodium hydroxide they used for titration of moderately weak acid Quaternary ammonium hydroxide: tetra butyl ammonium hydroxide the most widely used titrant for acid in non aqueous titration

25 Non Aqueous Acid-Base Titration Advantage of These Titrant Excellent potentiometric curve using ordinary glass or calomel electrode The salt formed from this titration are soluble in the solvent commonly used

26 Titration of Adrenaline Principle HClO 4 + CH 3 COOH CH 3 COOH ClO CH 3 COOH CH 3 COO HClO 4 + ClO 4 -

27 Titration of Adrenaline Volumetric: 1.In dry conical flask weigh 0.2g adrenaline 2.Add 25ml glacial acetic acid 3.One drop crystal violet indicator 4.Titrate against perchloric acid Poteatiometric 1.In dry beaker 0.2g adrenaline 2.25ml glecial acetic acid 3.Titate against perchloric acid End point when greenish blue appear Add 0.5ml until near the E.P add 0.1ml

28 Titration of Adrenaline Calculation From the equivalent factor each ml of perchloric acid react with of C 9 H 13 NO 3 F= (molecular weight of sample*molarities of standard) 1000 Theoretical (equivalent point) 1ml of 0.1M HClO g adrenaline X ml the weighted amount of sample X= equivalent point 0.2g adrenaline

29 Titration of Adrenaline Calculation %of deviation= end point from the graph*100 equivalent point Limitation 101% -98,5%

30 Titration of Phenobarbitals Principle

31 Titration of Phenobarbitals Volumetric titration 1.In dry conical flask weight 0.5g Phenobarbital 2.Add 40ml neutralized alcohol 3.Add 20 ml water 4.Titrate against 0.1N NaOH using ph.ph as indicator Potentiometric titration 1.In a dry beaker weight 0.5g Phenobarbital 2.Add 40ml neutralized alcohol 3.Add 20 ml water 4.Titrate against 0.1N NaOH End point when fine pink color appear Add 3 drop of ph.ph to the alcohol then add sufficient amount of NaOH (0.02 or0.1N) TO produce PINK COLOR

32 Titration of Adrenaline Calculation 1ml 0.1N NaOH 23.22mg Phenobarbitals Limitation 101% -98,5%

33 potentiometric curve

34 Safety Crystal violet may cause cancer. Severe eye irritant. Harmful by inhalation, ingestion and through skin contact. Perchloric acid It is very corrosive to skin and eyes, It can also ignite or explode upon contact with organic material such as cloth or wood also Causes hypothyroidism digestive and respiratory tract burns& it is Corrosive to metal glacial acetic acid This material is strongly corrosive and causes serious burns. Very harmful if swallowed. Lachrymator


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