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SuspensionSuspension

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Suspension: Suspension: A suspension is a two-phase system consisting of a finely divided solid particles dispersed in liquid, or gas.

AndAnd Pharmaceutical Suspension. A liquid Pharmaceutical Suspension. A liquid

preparation containing undissolved material. preparation containing undissolved material. A"SHAKE WELL" label is applied to the A"SHAKE WELL" label is applied to the containercontainer

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Parts of the SuspensionParts of the Suspension

Suspension is made of two Suspension is made of two phase system, consisting of a phase system, consisting of a finely divided solid particles finely divided solid particles (Dispersed phase) distributed in (Dispersed phase) distributed in a particular manner throughout a particular manner throughout another medium (Continuous another medium (Continuous phase).phase).

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SuspensionSuspension

Dispersed phase

Continuous phase(Dispersion medium)

Particle size of Dispersed phase Iess than 1 micrometer (µm) Particle size of Dispersed phase Iess than 1 micrometer (µm) ColloidColloidParticle size of Dispersed phase more than 1 micrometer (µm)Particle size of Dispersed phase more than 1 micrometer (µm)SuspensionSuspension

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Compositions Of Compositions Of Pharmaceutical SuspensionPharmaceutical Suspension

Insoluble particles Main parts Liquid medium

Suspending agent

Excipients

Surfactant

Viscosity enhancer

Preservative

Favoring agent

Sweetener

Colours

Buffers

Stabilizers

**The order in which these ingredients are blended is important to the stability of the The order in which these ingredients are blended is important to the stability of the preparationpreparation 55

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Pharmaceutical application of Pharmaceutical application of suspensionsuspension

Patients compliance Patients compliance Improve solubility Improve solubility Mask tasteMask tasteFast absorption Fast absorption Improve stability for drugsImprove stability for drugs

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Pharmaceutical Applications of SuspensionPharmaceutical Applications of Suspension Patients who have Patients who have problems in swallowingproblems in swallowing solid dosage forms solid dosage forms

require drugs to be dispersed in a liquid. require drugs to be dispersed in a liquid. Oral suspensions permit the formulation of Oral suspensions permit the formulation of poorly soluble poorly soluble drugs in drugs in

the form of liquid dosage form. the form of liquid dosage form. Drugs, which possess Drugs, which possess unpleasant tasteunpleasant taste in solution dosage form like in solution dosage form like

paracetamol, chloramphenicol palmitate etc. can be formulated as paracetamol, chloramphenicol palmitate etc. can be formulated as palatable suspension as they are suitable for administration to palatable suspension as they are suitable for administration to peadiatric patients. peadiatric patients.

The rate of The rate of absorptionabsorption of a drug from suspension is usually of a drug from suspension is usually fasterfaster than solid dosage form but slower than solution.than solid dosage form but slower than solution.

If drug is If drug is unstable unstable when in contact with vehicle, suspension should when in contact with vehicle, suspension should be prepared immediately prior to handing out to the patient in order be prepared immediately prior to handing out to the patient in order to reduce the amount of time that the drug particles are in contact to reduce the amount of time that the drug particles are in contact with dispersion medium. e.g Ampicillin suspension with dispersion medium. e.g Ampicillin suspension

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Routes of administration of suspensionRoutes of administration of suspensionExternal use (Topical )

Oral administration

Ophthalmic

Otic

Parenteral suspensions

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Routes of administration of Routes of administration of suspensionsuspension

External use (Topical): There consistency range from fluid to paste. e.g fluid suspension calamine lotion. Zinc cream consists of high percentage of powders dispersed in an oily (paraffin) phase.

Oral administration: non sterile dispersion Ophthalmic and Otic: sterile and possess very fine particles Parenteral suspensions: sterile e.g Vaccines formulated as

dispersions

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Injectable Suspensions Suspensions contain less than 5% of drug solid with mean

particle diameter within 5-10 µm.µm. Owing to the presence of particles in these formulations , Owing to the presence of particles in these formulations ,

these particles are more difficult to process and sterilize these particles are more difficult to process and sterilize than solution for injectionthan solution for injection

During the manufacture of suspension for injection the During the manufacture of suspension for injection the components are prepared and sterilized separately.components are prepared and sterilized separately.

They are then aseptically combinedThey are then aseptically combined

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The final product of injectable suspension The final product of injectable suspension can not be filter sterilized owing to the can not be filter sterilized owing to the presence of particles in the formulation.presence of particles in the formulation.

Powders for use in sterile suspensions can Powders for use in sterile suspensions can be sterilized by gas , but gas residues be sterilized by gas , but gas residues must be avoided.must be avoided.

Injectable Suspensions

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Suspensions are useful formulation for Inhalations

The volatile component are adsorbed onto the surface of the diffusible solid to ensure uniform dispersion throughout the liquid.

An example for a suspension used for inhalation is menthol and eucalyptus

These materials used as an adjunct to fluid replacement in acute diarrhea treatment

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Aerosols: another form for Aerosols: another form for pharmaceutical suspensionpharmaceutical suspension

**Aerosols are dispersions of a liquid or Aerosols are dispersions of a liquid or solid in airsolid in air..

**Many pharmaceutical aerosols consist of Many pharmaceutical aerosols consist of solids dispersed in a solids dispersed in a non-aqueous non-aqueous propellant or propellant mixturepropellant or propellant mixture..

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