7. Introduction to different dosage form part 7.ppt

pharmaceutics

1. INTRODUCTION TO DIFFERENT
DOSAGE FORMS
Presented by
Mr. Parimal Hadge
Datta Meghe Institute of
Medicinal Science(DU)
Salod(H);Sawangi(M); Wardha:

2. Learning objectives:
The learner will be able to learn:
•Different types of dosage form
•Needs of dosage form
•Detail account on Suspension dosage form

3. Biphasic liquid dosage forms
Theliquidwhichconsistoftwophasesareknownasabiphasicliquid
dosageforms.
Theyaresubcategorizedintotwodifferentformsnamelyas–
I)Emulsion
II)Suspension
Inemulsionbothphasesareavailableinliquidwhereasinsuspension,
finelydividedsolidparticlesaresuspendedinliquidmedium.

4. Suspension
Suspensionsarethebiphasicliquiddosageforms
ofmedicamentinwhichfinelydividedsolid
particlesrangingfrom0.5to5micronare
dispersedinaliquidorsemisolidvehicle,withaid
ofsingleorcombinationofsuspendingagent.
Inwhichsolidparticlesactsasdispersephase
whereasliquidvehicleactsascontinuousphase
Theexternalphase(suspendingmedium)is
generallyaqueousinsomeinstance,maybean
organicoroilyliquidfornonoraluse.
Theparticlesizefornonoralsuspensionisso
importanttoavoidgrittinesstoskin.

5. Advantage of suspension
Suspension can improve chemical stability of certain drug. E.g. Procaine
penicillin
Drug in suspension exhibits higher rate of bioavailability than other
dosage forms.
Solution > Suspension > Capsule > Compressed Tablet > Coated tablet
Duration and onset of action can be controlled. E.g. Protamine Zinc-
Insulin suspension.
Suspension can mask the unpleasant/ bitter taste of drug. E.g.
Chloramphenicol

6. Disadvantage of suspension
Physicalstability,sedimentationandcompactioncancausesproblems.
Itisdifficulttoformulate.
Uniformandaccuratedosecannotbeachievedunlesssuspensionare
packedinunitdosageform.
Allsuspensionsarerequiredtobeshakenbeforemeasuringofdose.
Thestorageofsuspensionmayleadtochangesindispersesystem
especially,whenthereisfluctuationsintemperatures.

7. Ideal qualities of good suspension
It should settle slowly & easily re –dispersed on shaking
It should readily & evenly pour from container.
It should be chemically inert.
It should not forms hard cake.
It should prevent degradation of drug or to improve stability of drug.
It should mask the taste of bitter of unpleasant drug.

8. Flocculated suspension
Inthistype,solidparticlesarelooselyaggregatesthemselves,means
individualparticlesarecomeincontactwitheachothertoformsnetwork
likestructurecalledasafloccules.
Theseflocsarelight,fluffyinnature,whichareheldtogetherbyweakvan
derwaalsforceofattraction.
Aggregationisachievedbyaddingflocculatingagent.
Thissuspensionwillreadilysediments.
Thissuspensionpossesbetterphysicalstabilitybutlessbioavailabilityas
comparedtodeflocculatedsuspensionduetodissolutionoffloccules.

9. Deflocculated suspension
Inthistypeofsuspension,individualparticleexitsasaseparateentity,
meansparticlescarryafinitechargesontheirsurface.Henceparticles
approacheseachother,theyexperiencerepulsiveforces.Thisforcecreate
ahighpotentialbarrier,whichpreventsaaggregationofparticles.
Duringstorage,thesesuspensionshowsasedimentationatslowrate,due
tothatparticlesformsaclosepackingarrangement.
Sothatitisdifficulttoredispersedonagitation&formsacakeorclaying
whichishardinnature.
Thistypeofsuspensionhaveshortershelflifebuthighbioavailabilityas
comparedtoflocculatedsuspension.

10. Difference between flocculated & deflocculated suspension
Flocculated Suspension Deflocculated suspension
Particles form loose aggregates & forms
network likestructure.
Particle exist as separate entities.
Particles experience attractive forces.Particles experience repulsive forces.
Supernatant liquid is clear. Supernatantliquid is cloudy.
The rate of sediment is high. The rate of sediment is slow.
Sediment is rapidly formed. Sediment is slowly formed.
sediment are looselypacked, hence
hard cake is not formed.
Sediments are closely packed, hence
hard cake is formed.
The sediment is easy to redisperseon
shaking.
Sediment is difficult to redisperse on
shaking. (due to formation of hard cake)
Bioavailabilityis comparatively less.Bioavailability is relatively high.
The suspension is not pleasing in
appearance.
The suspension is pleasing in
appearance.

11. References:
•R. M. Mehta text book for pharmaceutics I
•Lachman, A reference book for pharmaceutics
•Martin, A reference book for pharmaceutics

12. Thank you