Gastrointestinal agents

Inorganic chemistry

2. Gastrointestinal tract
•Gastrointestinaltract(GIT)isagroupoforgans.
•Itextendsfromtheesophagustotheanus.
•Theentrancetothesystemisthebuccalcavity.
•Themainportionsofinclude:stomach,smallintestine(duodenum,jejonum,
andileum),largeintestine(caecum,ascending,transverseanddescending
colons)andtherectumwiththeexitanus.
Functionsofstomach:Digestionofproteinsinacidicmediumtakesplacewith
pepsinenzymeacid(HCl).
Functionsofsmallintestine:Digestionofproteins,Digestionofcarbohydrates
andlipidsandAbsorptionofdigestedfoods,vitaminsandminerals.

3. ACIDIFYING REAGENTS OR ACIDIFIERS
These are the drugs which are able to increase the acidity, in GIT.
Types of acidifiers:
•Gastric acidifies:These are the drugs which are used to restore temporarily
the acidity of the stomach in patients suffering from achlorhydriaor
hypochlorhydria.
•Urinary acidifiers:These are the drugs which are used to render acidic urine
to enable treatment of some types of urinary tract disorders.
•Systemic acidifiers:These are the drugs which are able to neutralisethe
alkaline body fluids particularly blood, in patients who are suffering from
systemic alkalosis.
•Acids:These are used as pharmaceutical aids in the preparation, laboratory
quality control, etc.

4. Ammonium chloride
Molecular Formula: NH
4Cl
Molecular weight: 53.49
Synonym: Ammonium muriate
It contains not less than 99.5% of ammonium chloride, calculated with reference
to dried substance.
Methods of Preparation:It is prepared by neutralizing hydrochloric acid with
ammonia.
The resulting solution of ammonium chloride is evaporated to dryness.
NH
3+ HCl NH
4Cl
It is also prepared by treating ammonium sulpahte with sodium chloride.
2NaCl + (NH
4)
2SO
4 2NH
3+ 2HCl + Na
2SO
4
2NH
3+ 2HCl 2NH
4Cl
PhysicalProperties:Itisawhite,finecrystallinepowder.Itisodourlessandhas
coolingsalinetaste.Itishygroscopicinnature.Itisfreelysolubleinwaterbut
slightlysolubleinalcohol.Its0.8%w/vsolutionisisotonicwithserum.

5. PhysicalProperties:Itisawhite,finecrystallinepowder.Itisodourlessandhas
coolingsalinetaste.Itishygroscopicinnature.Itisfreelysolubleinwaterbut
slightlysolubleinalcohol.Its0.8%w/vsolutionisisotonicwithserum.
ChemicalProperties:Initsvapourform,itdissociatesinammoniaand
hydrochloricacid.NH
4Cl NH
3+HCI
Assay:Itisassayedbyacid-basetitrations.Theneutralformaldehydesolutionso
thatammoniumchloridewillbeconvertedtomethanimineandhydrochloricacid.
Theliberatedacidistitratedwith0.1NNaOHusingphenolphthaleinasan
indicator.
Identification tests:
•It gives the reactions of ammonium salts and chlorides.
•Afewmgofthesubstanceisheatedwithsodiumhydroxidesolution,leading
totheevolutionofammoniagas,whichisrecognizablebyitsodourandby
itsactiononmoistredlitmuspaper.

6. TestforPurity:Thesampleistestedforthepresenceoffollowingimpurities
likeArsenic,Sulphate,calcium,IronandHeavymetals.Lossondryingshould
notbemorethan1%.
Uses:Itishelpfulinproducingmildacidosisatadoseof2gorally.Itgets
rapidlyabsorbedandconvertedintoureaintheliver,thedecreaseinpHof
urineoccursduetoliberationofitsanionintothebloodstreamand
extracellularfluids.Itisalsouseasaningredientinexpectorantcough
mixturesindosesof300mgto1g.Itisgivenforitsdiureticactionespecially
tohelptheexcreationofoverdosageofbasicdrugssuchasamphetamineand
inthetreatmentofleadpoisoningbyincreasingitsextraction.

7. Dilute hydrochloric acid
MolecularFormula:HCl
Molecularweight:36.46
Itcontains10%w/wofHCl(limit9.5to10.5%)
Preparation:Hydrochloricacid(274g)isaddedgraduallytowater(726g)
andmixed.
Properties:Itiscolourlessliquid.Itisstronglyacidicandhasabout1.04–
1.05specificgravity.
Identification:
a)Afterneutralization,itgivesreactionswhicharecharacteristicsofchloride.
b)WhenitisaddedtoKMnO
4soluiton,chlorinegasisliberated.
c)Weightpermla25°Cis1.04to1.05g.
Testforpurity:IthastobetestedforAs,heavymetals,bromide,iodide,sulphiteand
freechlorine.

8. a)BromideandIodide:5mlofhydrochloricacidisdilutedwith10mlofwater.
Toit1mlofchloroformandsolutionofchlorinatedlimeareaddeddropby
dropwithconstantshaking.Thechloroformlayershouldnotbecomebrownor
violet.
b)Sulphite:1mlofhydrochloricacidisdilutedwith10mlofwater.Toit5
dropsofbariumchloridesolutionand0.5mlof0.001Niodineareadded.The
colourofiodineshouldnotgetdischarged.
c)Freechlorine:5mlofhydrochloricacidisdilutedwith10mlofwater.Toit
1mlofcadmiumiodidesolutionand1mlofchloroformareaddedwith
shaking.Thechloroformlayershouldnotbecomevioletwithin1min.
Assay:anaccurateamount,about10gofHClistransferredtoastoppered
flaskwhichishaving40mlofwater.Thesolutionistitratedwith1Nsodium
hydroxide,usingmethylorangeasanindicator.
NaOH+ HCl NaCl+ H
2O
Each ml of 1 N NaOH0.03646 g of HCl

9. Uses:Itisuseasanacidifier.
Storage:Itisstoreinwellclosedcontainers.
Dose:0.6to8ml.

10. ANTACIDS
Thesearethedrugswhichareusuallyalkalinesubstancesandusedforneutralising
excessacidinthestomachofpatientssufferingfromhyper-chlorhydria
(hyperacidity).Thesedrugsgivereliefofpainduetohyper-chlorhydria.
Antacidsmaybeclassifiedas:
a)Systemic(absorbable)antacids:Thesearesoluble,readilyabsorbableand
capableofproducingsystemicelectrolyticalterationsandalkalosise.g.sodium
bicarbonate.
b)Non-systemic(non-absorbable)antacids:Thesearenotabsorbedtoa
significantextentandthusdonotexertanappreciablesystemiceffect.Thisgroup
isfurthersub-dividedasfollows:

11. i.Aluminiumcontainingantacids:Examplesarealuminiumhydroxide,
aluminiumphosphate,dihydroxyaluminiumaminoacetate,dihydroxyaluminium
sodiumcarbonate,basicaluminiumcarbonate(gel).
ii.Calciumcontainingantacids:Examplesarecalciumcarbonate,tribasic
calciumphosphate.
iii.Magnesiumcontainingantacids:Examplesaremagnesiumcarbonate,
magnesiumcitrate,magnesiumhydroxide,magnesiumoxide,magnesium
phophate,magnesiumtrisilicate.
iv.Combinationantacidpreparations:Examplesarealuminiumhydroxidegel
andmagnesiumhydroxide,aluminiumhydroxidegelandmagnesiumtrisilicate,
magaldrate(monoaliumhydrate;hydratedmagnesiumaluminate),simethicone
(defoamingagent)containingantacids,calciumcarbonatecontainingantacid
mixtures,alginicacid-sodiumbicarbonatecontainingantacidmixtures

12. Theidealrequirementsofanantacid:
a.Itshouldbeinsolubleinwaterandhasfineparticleform.
b.Itshouldnotheabsorbableorcausesystemicalkalosis.
c.Itshouldbeabletoexertitseffectgraduallyandoveralongperiodoftime.
d.Itshouldnotbealaxativeorcauseconstipation.
e.Itshouldnotcauseanysideeffects.
f.Itshouldbestableandreadilyavailable.
g.Thereactionbetweenantacidandgastrichydrochloricacidshouldnot
producelargevolumeofgas.
h.TheantacidshouldbufferinthepHrange4to6.
i.Theantacidshouldprobablyinhibitpepsin,theproteolyticenzyme.

13. ALUMINIUM COMPOUNDS AS ANTACIDS
Aluminum hydroxide gel
Itisanaqueouswhiteviscoussuspensionofhydratedaluminiumoxidehaving
varyingamount,ofbasicaluminiumcarbonate.Thepreparationcontainsnotless
than3.5percentandnotmorethan14percentw/wofaluminiumoxide(A1
3O
3).
Preparation:It is prepared by adding a hot solution of potash alum slowly with
constant stirring to sodium carbonate. After complete removal of carbon dioxide
the precipitated aluminiumhydroxide is filtered. It is washed thoroughly with hot
water until it becomes free from sulphateion and the precipitate is suspended in
distilled water to the required strength.
3Na
2CO
3+ 2KAl(SO
4)
2+ 3H
2O 3Na
2SO
4+ K
2SO
4+ 2Al(OH)
3+ 3CO
2

14. Properties:Itisawhiteviscoussuspension.Aclearliquidgetsseparatedwhenit
iskeptstanding.Aluminiumhydroxidegelgivesastringentaluminiumchloride
hydrochloricacid.Thisresultsintonausea,vomitingandconstipation.
Al(OH)
3+ 3HCl AlCl
3+ 3H
2O
Identification:Asolutioninhydrochloricacidgivesreactionswhichare
characteristicofaluminium.Whenanequalvolumeofgelisdilutedwithdistilled
water,thepHofthesolutionshouldnotbemorethan7.5.
a)Testsforpurity:Ithastobetestedforalkalinity,ammoniumsalts,arsenic,
chloride,sulphateandacidconsumingcapacity.
b)Testforchloride:Itiscarriedoutbydissolving0.5gofgelin5mlofdiluteHCl
followedbyboilingandcoolinganddilutingthesolutionto100mlwithwater
andtaking25mlofdilutedsolutionafterfiltrationforcarryingoutthelimittest
forchloride.

15. a)Testforsulphate:Itiscarriedoutbydissolving5gofgelin5mlofdilutenitric
acid,followedbyheating.Thesolutionisdilutedaftercoolingwith200mlof
water.Thesolutionismixedwellandfiltered,ifnecessary.10mlofthefiltrateis
takenandafteradding2mlofHClthesolutionisusedforcarryingoutlimittest
forsulphateandthetestshouldcomply.
b)Acid-consumingcapacity:Anaccuratelyweighedquantityofgel(1.5ml)is
takeninaflask.Toit50mlof0.1Nhydrochloricacidisadded.Thecontentsare
shakenat37°Cfor1hour.Thesolutionisthentitratedforexcessofhydrochloric
acidwith0.1Nsodiumhydroxideusingbromophenolblueasanindicator.
1gofgelshouldconsumenotlessthan12.5mlandnotmorethan25mlof0.1
hydrochloricacid.

16. Assay:Nearly5gofsubstanceisaccuratelyweighedandtakeninaflask.Tothis
3mlofhydrochloricacidisadded.Thesolutionisnowwarmedonawaterbath.
Aftercooling,thisistransferredtoa100mlvolumetricflaskandthevolumeis
madeupto100ml.Now20mlofthesolutionistakenfromthevolumetricflask
intoaconicalflaskandexactly40mlof0.05disodiumedetateisaddedtoit,
followedbyabout80mlofwaterandafewdropsofmethylredsolution.Tothis
1Nsodiumhydroxidesolutionisaddedtoneutralisethissolution.Thiscanbe
recognisedbychangeofcolourfromredtoyellow.Nowtheflaskiswarmedona
waterbathforabout1/2hour.Tothis3gofheaxmineisadded.Also,the0.5ml
ofxylenolorangesolutionisaddedtoitasanindicator.Themixtureisnow
filteredwithastandard0.05Mleadnitratesolutionuntilavioletcolourappears
attheendpointduetotheformationofleadxylenolorangecomplex.
Factor:Eachmlof0.05MdisodiumEDTAisequivalentto0.002549gofAl
2O
3.

17. Storage:Itistobestoredinwell-closedcontainersandshouldnotbeallowedto
freeze.Forattractivenessitisusuallydispensedinblueorambercoloured
bottles.
Uses:Aluminiumhydroxidegelisaveryeffectiveslow-actingantacid.Itdoes
notgetabsorbedinalimentarycanalanddoesnotproducecarbondioxide.Itis
widelyusedintreatmentofintestinaltoxemiaandhyperchlorhydria.Itisableto
neutralizegastrichydrochloricacidandcausesabsorptionoftoxinsandgases.It
doesnotcausesystemalkalosis.
Dose:Itsdoseis7.5to15ml.Itcausesconstipationandisthereforeadministered
withmagnesiumsaltwhichisamildlaxative.

18. CALCIUM COMPOUNDS AS ANTACIDS
Calcium carbonate
MolecularFormula:CaCO
3
Molecularweight:100.09
Itishavingnotlessthan98.0%andnotmorethan100.5%ofCaCO
3.
Preparation:onacommercialscale,calciumcarbonateisobtainedbymixing
theboilingsolutionofcalciumchlorideandsodiumcarbonateandallowingthe
resultingprecipitatetosettledown.
CaCl
2+ Na
2CO
3 CaCO
3+ 2NaC1
The precipitate is collected on calico filter, and washed with boiling water, until it
become free from chloride ions. Finally, the precipitate is dried.

19. Properties:Itoccursasfine,white,micro-crystallinepowder.Itisodourlessand
tasteless.Itisalmostinsolubleinwaterandalcohol.Thewatersolubilityis
increasebypresenceofCO
2duetoformationofsolublecalciumbicarbonateand
alsobyammoniumsaltsduetoformationoffreecalciumions.
CaCO
3+ H
2CO
3 Ca (HCO
3)
2
CaCO
2+ 2NH
4
+
Ca
2
+
+ 2NH
3+ H
2O + CO
2
Calciumcarbonateneutralisesacidswitheffervescence.
CaCO
3+ 2HCl CaCl
2+ CO
2+ H
2O
Identification:Itgivesreactionswhicharecharacteristicofcalciumand
carbonates.
Testforpurity:IthastobetestedforAl,Fe,phosphateandmatterinsolublein
HCl,As,heavymetals,chloride,sulphate,Ba,solublealkaliandlossondrying.

20. Assay:Calciumcarbonatemaybeassayedbythecomplexometricmethod.
Directtitrationiscarriedoutinanalkalinemedium.1gofanaccuratelyweighed
sampleismoistenedwithsufficientquantityofwaterandHCltogetaclear
solution.Byaddingmorewater,thevolumeisincreasedto250ml.To50mlof
thissolution100mlofwaterisaddedanditspHisadjustedto12with15mlof
freshlyprepared1NNaOHsolution.40mgofmurexideand
3mlsolutionofnaphtholgreenareaddedandtitratedwith0.05MEDTA
solutionuntiladeepbluecolourisobtained.
Eachmlof0.05MEDTAW0.005005gofCaCO
3.

21. Uses:Theprecipitatedchalkfindsuseexternallyasadentifricebecauseitis
havingmildabrasivequality,Italsofindsuseinternallyasanantacid.Itisfound
thatitcanproducealkalosisinspiteofitswaterinsolubility.Itscontinueduseas
anantacidisnotadvisable.Itishavingatendencytocauseconstipationand
henceitisusuallyadministeredalternativelyoralongwithmagnesiumsalts.Itis
arapidlyactingnon-systemicantacid.Itneutralisesgastricacidandforms
calciumchloride.Thelatterisconvertedinintestinetoaninsolublecalciumsalt
whichtendstobeconstipating.Hencecalciumandmagnesiumantacidsare
usuallygivenincombination.
Dose:1-4grepeatedaccordingtoneed,usuallysixtimesaday.

22. MAGNESIUM COMPOUNDS AS ANTACIDS
Magnesium hydroxide
MolecularFormula:Mg(OH)
2
Molecularweight:58.32.Itishavingnotlessthan95.0percentandnotmore
than100.5percentofMg(OH)
2.
Preparation:Themagnesiumhydroxideobtainedinthepreparationofmilkof
magnesiaisevaporatedtodryness.Itisalsopreparedbytreatingseawateror
othernaturalbrineswithsufficientcalciumhydroxidetoprecipitatemagnesium
asmagnesiumhydroxide,thenwashinganddryingtheprecipitate.
Properties:Itisawhitefineamorphouspowder.Itisalmostinsolubleinwater
yieldingasolutionwhichisslightlyalkaline.Itdissolvesindilutemineralacids.
Itslowlyabsorbscarbondioxidefromatmosphere,Magnesiumhydroxideandits
tabletshavebeenofficialinN.F.

23. Assay:Anaccuratelyweighedamountofsampleistakeninaflask.Toit25ml
of1NH
2SO
4isadded.Theexcessofacidisbacktitratedwith1NNaOHusing
methylredasanindicator.Eachmlof1NH
2SO
40.02917gofMg(OH)
2
Uses:Itisusedasanantacid.

24. SODIUM COMPOUNDS AS ANTACIDS
Sodium bicarbonate
MolecularFormula:NaHCO
3
Molecularweight:84.01
Synonym:Bakingsoda
Itcontainsnotlessthan99percentandnotmorethantheequivalentof100.5per
centofNaHCO
3calculatedwithreferencetothedriedsubstance.
Preparation:Onasmallscale,itispreparedbypassingCO
2gasthrougha
solutionofsodiumhydroxide.Thesolutionisconcentratedtogettheproduct.
2NaOH + CO
2 Na
2CO
3+ H
2O
Na
2CO
3+ H
2O + CO
2 2NaHCO
3

25. Assay:Anaccuratelyweighedamountofsampleistakeninaflask.Toit25ml
of1NH
2SO
4isadded.Theexcessofacidisbacktitratedwith1NNaOHusing
methylredasanindicator.Eachmlof1NH
2SO
40.02917gofMg(OH)
2
Uses:Itisusedasanantacid.

26. Properties:Itoccursinwhitecrystallineoramorphouspowderhavingasaline
taste.Itisfreelysolubleinwaterbutpracticallyinsolubleinalcohol.When
heatedto100°Citgetsconvertedintosesquicarbonate(Na
2CO
3,NaHCO
32H
2O).
Itgiveseffervescencewithacids.Itssolutionisalkalineinnature.
Identification:Itgivesthereactionsofsodiumandcarbonate.Its1percentw/v
solutionhasapHnotmorethan8.6.
Testsofpurity:Itistestedforalkalinity,Al,Ca,insolublematter,As,Fe,heavy
metals,chloride,sulphateandammoniumcompounds.
Clarityandcolourofsolution:Its5.0percentw/vsolutionisclearand
colourless.

27. Lossondrying:Itshouldnotbemorethan0.25percent.Itisdeterminedon4.0
gbydryingitoversilicagelforfourhours.
Ammoniumcompounds:When1giswarmedwith10mlofsodiumhydroxide
solution,noammoniashouldbeevolved.
Assay:Its1gisweighedaccurately.Itisdissolvedin20mlofwater.Nowitis
titratedwith0.5Nsulphuricacidusingmethylorangeasanindicator.Eachmlof
0.5NH
2SO
40.042gofNaHCO
3
Uses:Inmedicineitismainlyusedforitsacidneutralizingproperties.Iffinds
useasanantacidandtocombatwithsystemicacidosis.Itisalsousedfor
preparingbuffersolutions(NaHCO
3+H
2CO
3).Itsaqueoussolutionsareusedas
localapplicantsforburns,insectbitesetc.Itisalsoaconstituentofeffervescent
mixture.
Dose:300mgto2g.

28. COMBINATION OF ANTACIDS
Manypreparationswhicharehavingcombinationofantacidsarebeingmarketed.
Theideabehindsuchcombinationistocounteracttheconstipativeactionof
calciumandaluminium,containingantacidswithlaxativeeffectofmagnesium
containingantacid.
Sometimesthecombinationantacidpreparationishavingonewithrapidonsetof
actionwithantacidwithalongerdurationofaction.Inanothertype,theantacids
arecombinedwithsimethicontypeofcompoundswhicharehavingantiflatuluent
actionastheyareantifoamingagentsandcausedispersionofgases.

29. Aluminium hydroxide magnesium carbonate co-driedgel:It is a co-precipitate of
aluminium hydroxide and magnesium carbonate carefully dried to contain a critical
proportion of water for antacid activity. It acts as an antacid that is given in doses of
up to 1 g.
Algicon tablets:The tablets are chewable, prepared by aluminium hydroxide-
magnesium carbonate co-dried gel (360 mg), magnesium alginate (500 mg),
magnesium carbonate (320 mg) and potassium bicarbonate (100 mg).
Simeco tablets: It contain aluminium hydroxide-magnesium carbonate co-dried gel
(282 mg), magnesium hydroxide (85 mg) and activated dimethicone (25 mg)
Aluminium Hydroxie gel-Magnesium Trisilicate Combinations:This is one the
more common combinations. It has laxative, constipative and protective effect.

30. Magaldrate:It is a chemical combination of aluminum hydroxide and magnesium
hydroxide. It contains the equivalent of 28 to 39% magnesium oxide and 17 to 25%
of aluminium oxide. It occurs as a white, odourless, crystalline powder which is
insoluble in water and alcohol, but soluble in dilute solution of mineral acids.
Calcium carbonate containing antacid mixture:Calcium carbonate with
aluminum hydroxide gel yields product which have a rapid onset with prolonged
action. Three part combinations of calcium carbonate, aluminium hydroxide gel and
magnesium containing antacid are also available.

31. CATHARTICS
Catharticsmaybedefinedasthosedrugswhichbringaboutdefecation.Theyare
beneficialinconstipationandforexpulsionofintestinalparasites.Theyaregiven
forclearingbowelsbeforesurgery.
Purgativesarealsocatharticswhichactsimilarlybutaremildintheiraction.
Laxativesarethemildtypeofpurgatives.Boththesebringaboutthesameeffect
butvaryinandmechanismofaction.Laxatives,catharticsandpurgativesactby
retainingfluidinthebowel,Thesemaybeadministeredbyoralrouteorbyrectal
route.

32. Mechanismofcatharticsorpurgative
a)Stimulants:Ex:senna,rhubarb,cascara,podophyllum,castoroil,aloeetc.
belongstothisclass.
b)Bulkpurgatives:Examples:methylcellulose,sodiumCMC,gum,ispagoletc.
c)Lubricants:Substancessuchasliquidparaffin,glycerin,mineroilsetc.actas
lubricantsandcausesmoothclearanceofthefecalmaterial.
d)Salinecathartics:Theseactbyincreasingtheosmoticloadofintestineby
absorbinglargequantityofwaterandtherebystimulateperistalsis.Poorly
absorbablecationslikecalcium,magnesiumandanionslikephosphate,sulphate,
tartratearecontributingtothiseffect.

33. Mechanismofcatharticsorpurgative
a)Stimulants:Ex:senna,rhubarb,cascara,podophyllum,castoroil,aloeetc.
belongstothisclass.
b)Bulkpurgatives:Examples:methylcellulose,sodiumCMC,gum,ispagoletc.
c)Lubricants:Substancessuchasliquidparaffin,glycerin,mineroilsetc.actas
lubricantsandcausesmoothclearanceofthefecalmaterial.
d)Salinecathartics:Theseactbyincreasingtheosmoticloadofintestineby
absorbinglargequantityofwaterandtherebystimulateperistalsis.Poorly
absorbablecationslikecalcium,magnesiumandanionslikephosphate,sulphate,
tartratearecontributingtothiseffect.

34. Thesalinecatharticsarewatersolublemainlyinorganicchemicalsandtheyare
takenwithplentyofwater.Thisishelpfulrestrictingexcessivelossofbodyfluid
andreducesnauseaandvomiting.
Thesalinelaxativesarerelativelyfreefromside-effectswhentakenforbrief
periods.Patientsonlowsodiumdietshouldnotusethesodiumcontainingsaline
laxatives.Theymaybeadministeredbyoralroute(suspensionorpowder)orby
rectalroute(enemaorsuppository).
Examplesofsalinelaxativeandcatharticagentsaredifferentmagnesiumsalts
suchasmagnesiumhydroxide.magnesiumsulphate,etc.andtartratesaltsof
sodiumandpotassium.

35. Magnesiumsulphate
MolecularFormula:MgSO
4,7H
2O
Molecularweight:246.5
Synonym:Epsomsalt
Itishavingnotlessthan99.0%andnotmorethan100%ofMgSO
4calculated
inreferencetotheignitedsubstance.
Preparation:Itisobtainbytheactiononmagnesiumcarbonateormagnesium
oxideorfromnativecarbonate.
MgCO
3+ H
2SO
4 MgSO
4+ H
2O + CO
2
Thesolutionisfiltered.Thefiltrateisevaporatedtocrystallization.
Itismanufacturedbytheactionofsulphuricacidonthenativecarbonateoron
previouslycalcineddolomite.Whendolomiteisused,magnesiumsulphatepasses
intosolution,andsparinglysolublecalciumsulphateisdeposited.
MgCO
3 . CaCO
3+ 2H
2SO
4 MgSO
4+ CaSO
4+ 2H
2O + 2CO
2

36. Properties:Itoccursascolourlesscrystalshavingacool,salinebittertaste.It
efflorescesinwarmdryair.Itissolubleinwaterandsparinglysolubleinalcohol.
Whengentlyheated,itlosessomeofitswaterofhydrationandgetsconverted
intothemonohydrate(whitepowder)whichbecomesanhydrousat200°C.
Identification:Itgivesreactionswhicharecharacteristicofmagnesiumand
sulphate.
Testsforpurity:IthastobetestedforAs,Fe,Zn,heavymetals,andlosson
drying.
Lossonignition:Itisbetween48.0and52.0percentandisdeterminedon1g
bydryinginanovenat105°Cfortwohoursandignitingtoconstantweightat
400°C.

37. Clarityandcolourofsolution:5gofmagnesiumsulphateisdissolvedin
sufficientwatertoproduce50ml.Itshouldgiveaclearandcolourlesssolution.
Acidityoralkalinity:1gofmagnesiumsulphateisdissolvedin10mlofwater.
Thissolutionisneutraltolitmussolution.
Assay:0.3gofthesampleisweighedaccurately.Itisdissolvedin50mlof
water.Toit10mlofstrongammonia-ammoniumchloridesolutionisadded.Now
thissolutionistitratedwith0.05Mdisodiumethylenediaminetetraacetateusing
0.1gofMordantBlack11mixtureasindicatoruntilthepinkcolourgets
dischargedfromtheblue.
Eachmlof0.05mdisodiumethylenediaminetetraacetate0.00602gofMgSO
4.
ActionandUses:Magnesiumsulphateisgivenorallyindilutesolutions.About
5ggivesrisetolaxativeeffect.Duetobitterandnauseatingtasteitisgivenin
fruitjuices.Themechanismofactionisthatmagnesiumsulphatedoesnotget
absorbedfromintestinaltractandthusretainssufficientwaterwithinthelumen.
Thehydrostaticpressureisabletopromotemotoractivityorperistalsisofbowel.
Dose:10-15 g. It is to be used with care in patients with impaired renal function.

38. SodiumOrthophosphate
MolecularFormula:NaHPO
4.12H
2O
Molecularweight:358.14
Synonym:Disodiumhydrogenphosphate
Itcontainsnotlessthan98.5%andnotmorethan101%ofNa
2HPO
4,whichis
calculatedwithreferencetothesubstancedriedat130°C.
Methods of Preparation:It is sodium salt of orthophosphoricacid or phosphoric
acid. It is formed by the reaction of orthophosphoricacid with sodium hydroxide
in calculated amount. H
3PO
4 + 2NaOH Na
2HPO
4+ 2H
2O
Industrially, it is prepared in a two-step process by treating calcium biphosphate
(CaHPO
4) with sodium bisulphate (NaHSO
4) with precipitate calcium sulphateand
monosodium phosphate (NaH
2PO
4) remains in the solution form.

39. CaHPO
4+ NaHS0
4 NaH
2PO
4+ CaSO
4
Inthesecondstep,theresultingsolutionofmonosodiumphosphateisneutralized
andfinallyresultsintheformationofsodiumorthophosphate.
NaH
2PO
4+ NaOH Na
2HPO
4+ H
2O
PhysicalProperties:Itoccursascolourless,odourless,transparentcrystals.Its
anhydroussaltishygroscopicinnature.Iteffervescenceinairwhenwarmed.Itis
insolubleinalcoholbutsolubleinwater.ItsaqueoussolutionhasapHbetween
8.0-11.0i.e.moderatelybasic.
ChemicalProperties:Onhydrolysis,ityieldssodiumhydroxideandphosphoric
acidbackfromwhichitformed.
Na
2HPO
4+ 2H
2O H
3PO
4+ 2NaOH
Onheating,itgivespyrophosphate.
2Na
2HPO
4 Na4P2O
7+ H
2O
Onheatingwithammoniumchloride,tablesaltisformed.
Na
2HPO
4+ NH
4Cl NaCl+ Na.NH
4HPO
4

40. Assay:Itisbasedonacid-basetitration.6gofthesaltisdissolvedin100mlof
waterwhichisthentitratedwith0.5NH
2SO
4usingbromocresolgreenasan
indicatorinatapHof4.5.Each1mlof0.5NH
2SO
40.07098gofNa
2HPO
4
IdentificationTests:To5mlneutralsolutionofsample,add5mlsilvernitrate
solution,alightyellowprecipitatesareformed,thecolourretainsevenon
boiling,whichisreadilysolublein10Mammoniasolutionandindil.nitricacid.
Testforpurity:Itistestedforalkalinity,arsenic,magnesium,heavymetals,
sulphateandlossondrying.
Uses:ItiswidelyusedascatharticsduetopoorabsorptionofHPO
4
2-
.Intheform
oforalsolution,itisalsousedasanti-hypercalcemic.Asapharmaceuticalaid,it
isusedasabufferingagentinvariouspreparations.Itisalsousedinconjunction
withtrisodiumphosphate,inwatersofteningtreatment.Itspresenceprevents
coagulation,inthepreparationofcondensedmilk.Infoodindustries,itisusedto
adjustpH.7.Itisusedtotreatconstipationortocleanthebowelbeforea
colonoscopy.Itisusedasananti-cakingadditiveinpowderedproducts.
Dose:2-16gindivideddosedaily.

41. Kaoline
MolecularFormula:Al
2O
3.2SiO
2.2H
2O
Molecularweight:258
Synonym:chinaclay,hydratedaluminiumsilicate
Preparation:Itisahydratedaluminiumsilicate,widelydistributedinprepared
whentherockismined,executed,theimpuritiesarewashedwiththeflowof
waterandthenpowdered.Kaolinisfoundintwoforms:HeavyKaolinandLight
Kaolin.Thereforetheelutriatedwithwaterandlargesizedparticlesareseparated.
Theturbidliquidisallowedtosettle,heavykaolincontaininglargeparticlesand
colloidalkaolinecontainingparticlesofsmallsizeareseparatedanddried.
PhysicalProperties:Kaolinisslightlyplasticlikeandisnormallywhitein
colour.Ithasanearthyorclayliketaste.impurities.Itissoapytotouchandits
surfacetakeshighpolishonrubbing.Itsfusionpointrangebetween1700-
1800°C.Whenmoistenedwithwater,itproducesadarkercolouranddevelops
markedclaylikeodour.

42. ChemicalProperties:Onheating,kaolinloseswatermolecules.Itis
decomposedbyprolongedboilingortreatmentwithconcentratedsulphuricacid.
TestforPurity:Developmentofpinkcolourduetoadditionofphenolphthalein
toanaqueoussuspensionindicatesthepresenceofalkalinenature.
Testforlead:Fordetermininglead,thesubstanceisdigestedwithnitricacid.
Thereactioniscentrifugedandinthesupernatantliquidlimitteatforleadis
carriedout.
TestforIron:Ironisdetectedbytrituratingkaolinwithwater,sodiumsalicylate
isadded,themixturedoesnotacquiremorethanaslightreddishtint.
Uses:Kaolinsareusedasadsorbent,antidiarrhoealandincreasethebulkof
faeces.Itadsorbstoxinsfromalimentarytractandisthusbeneficialindiarrhoea,
Kaolinhasalsobeenusedinthetreatmentofchroniculcerativecolitis.

43. Bentonite
MolecularFormula:Al
2O
3.4SiO
2.H
2O
Molecularweight:422.286
Synonym:Clay
BentoniteisanamegiventoaparticularclaythatwasoriginallyfoundinFort
Benton,EasternWyoming.ThenamewasgivenbyW.C.Knightin1898.
Previously,itwascalledTaylorite,whichwasnamedafterWilliamTaylor,who
firstbegantodrawattentiontothedaydeposits.
InIndia,BhavnagarandKachchhdistrictsofGujaratandBarmerdistrictof
Rajasthanaremajorproducersofbentonite.Thesodiumbentoniteminedin
Rajasthantendstothebeoflowerqualityandisusedasfoundrysand.Both
activatedandgranularbentoniteareproducedinthecountry.

44. PhysicalProperties:Itisahydratedmaterialhavingswellingandabsorptive
properties.Itspowdermaskhasabindingproperty.Ithasexcellentplasticityand
lubricity.Ithashighshearandcompressivestrength.Ithaslowpermeabilityand
lowcompressibility.Ithasgooddrysealingproperties.Bentoniteclayhas
negativelychargedmolecules,whichgiveadsorptivepropertiestoit.
Uses:Itisuseascatharticsduetoabsorptionproperties.Itcanremovetoxic
metalsandchemicalsfollowingradiationtreatment.Itpromoteshealthybacteria
balanceanddetoxifythedigestivesystem.Italsosupportindetoxification.Itis
alsouseasanantidoteinmercurypoisoning.Itishelpfulinremovingtheinternal
parasitesfromdigestivesystem.Itisactiveagainstfreeradicalsandcanbeused
asantioxidant.Italsohelpsincoloncleansing.Itsupportsinboostingimmune
system.

45. ANTIMICROBIAL AGENTS
Theagentswhichhelpinpreventingorreducinginfectionduetomicrobes.
Classification:
•Antiseptics
•Disinfectants
•Germicides
•Bacteriostatics
•Sanitizers

46. Idealpropertiesofantimicrobialagent:
Itshouldpossessantisepticorgermicideactivityandnotbacteriostaticactivity.If
themicro-organismsdonotgetkilled,theymayresumegrowthandbringabout
infections.
Itshouldhaverapidonsetandsustainedactivity.Thiswillbeabletoreduce
incidenceofresistance.
Itmustpossessgoodtherapeuticindexindicatingusefulnessintheconcentration
employed.
Itshouldnotcauselocalcellulardamageorshouldnotinterferewithbody
defenses.
Itshouldshownosystemictoxicityfromtopicalapplications.
Itshouldhaveingeneralbroadspectrumofactivityagainstbacteria,fungi,
protozoa,virusetc.
Thetopicalantimicrobialagentshouldhavefavorablelipid-Waterdistribution
coefficientsothatitseffectivenesshasbeenbest.

47. Mechanismofaction:
Themechanismofactionofantimicrobialagentsmayrangefromamild
astringenttopowerfuloxidativeprocesses.
•Oxidation:
•Halogenation:S
H
S
H
S

S

Oxidation
Protein
Altered protein H
NH
2
O
Amino acid - - Amino acid
OCl
-
Cl
NH
2
O
Amino acid - - Amino acid
Protein structure
Altered protein

48. Proteinprecipitation:Manymetalionsexhibitproteinbindingorprotein
precipitation.Thenatureofinteractionwithproteintakesplacethroughpolar
groupofproteinwhichactsasligandsandthisactioningeneralisnon-specific.
Proteinprecipitantsarenotabletodistinguishtheproteinofmicrobeandthatof
host.Germicidalactionresultswhentheconcentrationofionbecomessuchthat
reactiongetrestrictedlargelytotheparasitecell.

49. Potassiumpermanganate
MolecularFormula:KMnO
4
Molecularweight:158.03
Synonym:Permanganicacid
Itcontainsnotlessthan99%andnotmorethan100.5`%ofKMnO
4.
Preparation:Potassiumpermanganateispreparedbymixingasolutionof
potassiumhydroxidewithpowderedmanganesedioxideandpotassiumchlorate.
Themixtureisboiled,evaporatedtoyieldtheresidue.
6KOH + 3MnO
2+ KClO
3 3K
2MnO
4+ KCl+ 3H
2O
By passing chlorine gas through potassium permanganate solution.
2K
2MnO4 + 3Cl
2 6KMnO
4+ 6KCl

50. Properties:Itoccursintheformofdarkpurpleprismaticcrystalwithmetallic
lustre.Itisodourlessbutittastessweetandastringent.Itdecomposesathigher
temperature.
2KMnO
4 K
2MnO
4+ MnO
2+ O
2
Itisapowerfuloxidizingagent.
2KMnO
4+ H
2O + KI 2MnO
2+ 2KOH + KIO
3
Whenhydrochloricacidisaddedtothesolutionofpotassiumpermanganate,
chlorinegasisliberated.
2KMnO
4+ 16HCl 12KCl + 2MnCl
2+ 8H
2O + 5Cl
2
Assay:3gmofthesubstanceisdissolvedin100mlofwater.Take20mlofthis
solution,add1gmofKIand10mlof2NHClandtitratetheliberatediodine
with0.1MNa
2S
2O
3usingstarchsolutionasanindicator.
Each 1 ml of 0.1 M Na
2S
2O
3 0.003160 g of KMnO
4

51. IdentificationTests:Itgetsdecomposedonheating,ablackresidueisobtained
withevolutiongas.Theresiduegivespotassiumhydroxidewhenwaterisadded
intoit.TheresultingsolutiongivescharacteristictestofK
+
ion.
AsolutionofKMnOisacidifiedwithsulphuricacid,andthenheatedto70°C
decolorizedbythesolutionofhydrogenperoxide.
TestforPurity:KMnO
4isboiledwith95%aqueousalcoholtodestroythe
purplecoloursothatcolourshouldnotinterferewiththelimittest.
Theprecipitatedmanganesedioxideisremovedbyfiltration.
2KMnO
4+ 3CH
3CH
2OH 2KOH + 2MnO
2+ 3CH
3CHO + 2H
2O
Take 20 ml of filtrate and perform the limit test for chloride and sulphateand the
sample must comply the permissible limits.

52. Storage:Itshouldbestoredinairtightcontainers,toavoidcontactwithorganic
matter.
Caution:GreatcareshouldbetakeninhandlingKMnO4becausedangerous
explosionmayoccurifitisbroughtincontactwithorganicmatteroranyrapidly
oxidisablesubstance.
Uses:Itisatopicalanti-infective.Itssolutionisusedasanantisepticinmouth
washandforcleaningofulcers.Itisusedinthetreatmentofurethritis.Because
ofitsoxidizingproperty,itisusedasanantidoteinmanyvenoms,barbiturates,
alkaloidsetc.Itssolutionisusedinbathforeczemaandacutedermatoses
patients.Itiscommonlyusedasanantisepticinveterinarypractices.

53. Hydrogenperoxide
MolecularFormula:H
2O
2
Molecularweight:34.01
100mlofhydrogenperoxidesolutioncontainsnotlessthan26%w/wandnot
morethan28%w/wofH
2O
2,correspondingto100times,itsvolumeofavailable
oxygen.Itisanaqueoussolutionofhydrogenperoxide,itcontainsnotLessthan
6%w/wofhydrogenperoxide.
Preparation:
Itispreparedbytheactionofsulphuricacidonbariumperoxide.
BaO
2+ H
2SO
4 BaSO
4+ H
2O
2
Hydrogen peroxide solution may be prepared by reaction of barium peroxide with
phosphoric acid. Barium peroxide Barium phosphate is filtered.
2BaO
2+ 2H
3PO
4 Ba
3(PO
4)
2+ 3H
2O
2
It can also be prepared by treating sodium peroxide with sulphuricacid.
Na
2O
2+ H
2SO
4 Na
2SO
4+ H
2O
2

54. PhysicalProperties:Hydrogenperoxidesolutioniscolourlessandodourless.Its
tasteisslightlyacidic.Itreadilygetsdecomposedwhencomeincontactwith
oxidisableorganicmetal.Thedecompositionofhydrogenperoxideispromoted
bycatalystsCu,Feandetc.whilesmallquantityofsulphuricacid,phosphoric
acidandalcoholretardeddecompositionofhydrogenperoxide.Itisastrong
oxidizingagentandismisciblewithwater.
Testsforidentity:
a)Whenmadealkalineandheated,itgetsdecomposedwitheffervescence,evolving
oxygen.
b)To1drop,20mlofwater,1dropofpotassiumchromateand2mlofsolvent
etherareaddedandshaken,Then,etherlayerbecomesblue.

55. Testsforpurity:Ithastobetestedforacidity,preservative,lossonevaporation,
bariumandstability.
Acidity:10mlofhydrogenperoxideisfirstofalldilutedwith20mlofwater.
Then,itistitratedwith0.1Nsodiumhydroxide,usingmethylredasanindicator.
Notlessthan0.2mlandnotmorethan1mlof0.1NNaOHshouldnotbe
required.
Testsforbarium:Itisbasedupontreating,theH
2O
2withdiluteH
2SO
4no
turbidityshouldproduce.

56. Assay:Hydrogenperoxideandacidifiedpotassiumpermanganate,bothare
oxidisingagents.Theytwooxidisingagentsreduceoneanotherwiththe
evolutionofgaseousoxygen.HydrogenperoxidereducesKMnO
4solutionand
causesitsdecolouration.Attheendpoint,excessdropsofKMnO
4givespink
colour.Potassiumpermanganateitselfactsasanindicator.
Theassayofhydrogenperoxideiscarriedoutbythepermanganatemethod.10ml
ofsampleisdilutedto250mlinavolumetricflaskwithpurifiedwater.to25mlof
thissolution,10mlof5Nsulphuricacidadded.Thenthecontentaretitratedwith
0.1Npotassiumpermanganatesolution,untilafaintpinkcolourisobtained.
Each ml of 0.1N KMnO
40.001701 g of H
2O
2
Uses:Hydrogenperoxideisastrongoxidizingagentandyieldsnascentoxygen,
andhenceusedforbleaching.Itactsasanantisepticandagermicideandhenceis
usedforcleaningcutandwounds.Itiseffectiveantidoteforphosphorusand
cyanidepoisoning.Itisalsouseasadeodorant.Theliberationofgaseousoxygen
isabletoexertanadditionalcleansingactiononcutsandwounds.Itisusefor
bleachingthehair.

57. Chlorinatedlime
MolecularFormula:Ca(OCl)Cl,CaOCl
2
Molecularweight:136.98
Synonym:Bleachingpowder,chlorineoflime
Chlorinatedlimeshouldcontainnotlessthan30%w/wofavailablechlorine.
Preparation:Itispreparedbytheactionofchlorineoncalciumhydroxide.
Calciumhydroxideisspreadontheshelvesinasuitablecontainer.Thechlorine
gasisintroducedatthetopofthechamber.
Ca(OH)
2 + Cl
2 Ca(OCl)Cl+ H
2O
Thisprocesstakesabout12-24hrs.

58. Properties:Itisadullwhitepowderwithcharacteristicodour.Whenexposedto
air,itabsorbsmoistureandgraduallydecomposed.Itisslightlyacidicinwater
andalcohol.Whenbleachingpowderisputinwater,hypochloritegoesoutin
solution,becauseofthisbleachingandoxidizingproperty.
2Ca(OCl)Cl+ CO
2+ H
2O CaCO
3+ CaCl
2
ModeofAction:Itworksbychlorinationofmicroorganism'sprotein,which
ultimatelyleadstothedestructionofproteinandcelldeath.
IdentificationTest:WhenthesampleistreatedwithconcentratedHCl,chlorine
gasisevolvedinlargeamount.

59. Assay:Itsassayisbasedonredoxtitrationmethod.Chlorinatedlimeliberatesthe
availablechlorineasCl
2gasbytheactionofacid.Then,thisfreechlorineis
allowedtoreactwithpotassiumiodidetoliberateiodine,thequantityofliberated
iodineisthenestimatedbytitrationwith0.1NSodiumthiosulphate.
CaOC1
2+ 2CH
3COOH Ca(CH
3COO)
2 + H
2O + CO
2
Procedure:Take4gofchlorinatedlimewithsmallquantityofwaterand
transferitmakeitto1Lflaskandmakeupthevolumetothemark.Measure100
mlofthissuspensionandtransferinanotherflask.Thenitistitratedwith3gm
KIsolution,acidifiedwith5mlaceticacid,theliberatediodineistitratedagainst
0.1Nsodiumthiosulphateusingstarchsolutionasanindicator.
Each1mlof0.1NNa
2S
2O
30.003545gofavailablechlorine.

60. Testforpurity:Ithasbeentestedforitsstabilitybyheatingitat100°Cfor2hrs.
Itmustnotlosemorethan3%w/wofavailablechlorine.
Uses:Chlorinatedlimehasthebactericidalaction.Itisalsousedasdisinfectant
inwounds.Itisusedasacleansingagentforwaterclosets(toilets),drainsand
effluents.Itisalsousedasaningredientinthepreparationofdetergents.Itisa
powerfulbleachingagent.

61. Testforpurity:Ithasbeentestedforitsstabilitybyheatingitat100°Cfor2hrs.
Itmustnotlosemorethan3%w/wofavailablechlorine.
Uses:Chlorinatedlimehasthebactericidalaction.Itisalsousedasdisinfectant
inwounds.Itisusedasacleansingagentforwaterclosets(toilets),drainsand
effluents.Itisalsousedasaningredientinthepreparationofdetergents.Itisa
powerfulbleachingagent.

62. THANK YOU