SUSPENSIONS

SUSPENSIONS are micro heterogeneous dispersion systems consisting from solid medicinal substances in the suspended state, which are in the liquid dispersion medium (water, non-aqueous solvents).

Suspensions are liquid medicinal forms containing one or some powdered

medicinal substances, as a disperse phasedistributed in the liquid dispersion

environment.

Advantages of suspensions• Fast and complete manifestation of the therapeutic

action because of the possibility of introducing solid insoluble substances into a liquid where they have a high degree of dispersion ability.

• Prolongation of the action and the possibility to regulate it duration by changing the particles size of a medicinal substance.

• The possibility of correcting an unpleasant taste, smell and colour of a medicinal substance due to introduction of correcting agents into the suspension’s composition.

• Simplicity and convenience of their application in pediatrics and gerontology.

Poisonous and strong-effective substances don’t used in suspensions, because difficult to dose of them.

Suspensions are formed:•when prescribing substances insoluble in

the formulated solvent•when prescribing soluble substances in

amounts exceeding the limit of their solubility in the given solvent

•a new compound insoluble in the given solvent is formed because of the chemical interaction of solutions with substances

•when the conditions of substances’ solubility are worsened as the result of mixing two solutions prepared with different solvents

STABILIZATION OF SUSPENSIONS • To increase of the aggregation stability of

suspensions with hydrophobic substances, which do not form protective hydrate layers on the surface, it is necessary to lyophilize them, i.e. to add hydrophilic colloidal substances (stabilizers). Natural or synthetic high-molecular compounds (HMC): proteins, gelatosa, vegetative slime, natural polysaccharide complexes, methylcellulose, sodium - carboxymethylcellulose, polyvinylpyrrolidon, polyglycine, tweens, spens, bentonites, etc. are applied as stabilizers.

• The stabilization of these substances consists of formation of hydrate layers on the surface of the suspension’s particles, as well as in spanning of these particles by long macromolecules.

The amount of a stabilizer for 1.0 g of a hydrophobic substance

The name of a stabilizer

The amount of a stabilizer per 1.0 g of the substance

with distinctly expressed hydrophobic properties:

camphor, menthol

with poor expressed hydrophobic properties:

terpin hydrate, phenylsalicylate, etc.

Gelatose 1.0 0.55 % methylcellulose solution

2.0 1.0

Tween-80 0.2 0.1

METHODS OF PREPARATION SUSPENSIONS Suspensions of medicinal substances are

prepared by two methods:•Dispersion- The method of obtaining

the certain degree of dispersion by powdering dry medicinal substances – Rough suspensions- The method of “making muddy”- for hydrophilic substances with a high density (basic bismuth nitrate)

•Condensation- The method of formation of large particles from molecules - aggregates, due to the chemical interaction or replacement of a solvent- Thin suspensions- Suspensions are formed:

•as a result of the chemical interaction;

•as a result of the solvent’s replacement

FORMULATION OF SUSPENSIONSBY THE DISPERSION METHODFormulation of suspensions with

hydrophobic substances•Stage I Triturate a dry medicinal substance in the

mortar•Stage IITriturate (according to the Deryagin rule) with

50% amount of the liquid (add 0.4-0.6 ml of a liquid (40-60%) for 1.0 g of the powdered substance)

•Stage III Mix and dissolve in water (add water gradually)

and transfer into the bottle for dispensing

Rp.: Zinci oxydi 10.0 Aquae purificatae 100 ml

Misce. Da. Signa. For washes.

WCP (front side)Date № Pr.

Zinci oxydi 10.0 Aquae purificatae 100 ml

m total = 110.0

Prepared by: (Signature)Checked by: (Signature)

Weigh 10.0 g of ZnO in the mortar, triturate it, measure 100 ml of the purified water using a cylinder, add approximately 5 ml of the purified water in the mortar according to the Deryagin rule, triturate and then add gradually the remaining quantity of water. Pour the suspension obtained into the bottle for dispensing.

• Stick the labels «External», «Shake well before use» and «Keep out of the reach of children».

FORMULATION OF SUSPENSIONS BY THE DISPERSION METHOD

Method of “making muddy” (“shaking”) is applied for preparing suspensions with hydrophilic substances characterized by a great density.

• Stage ITriturate a solid medicinal substance in the mortar.• Stage IITriturate (according to the Deryagin rule) with 50% amount

of the liquid calculated by the amount of a dry substance (add 0.4-0.6 ml of a liquid (40-60%) per 1.0 g of the powdered substance).

• Stage IIIAdd 5-10 % of the liquid to the mixture obtained, triturate,

allow to stand for 1-2 minutes.• Stage IVWhen the liquid is settled (the big particles settle at the

bottom and the thin particles are on the top of the surface), transfer it into the bottle for dispensing.

The stages III-IV are repeated until all precipitate is transferred into a thin dispersed state.

Rp.: Bismuthi subnitratis 2.0 Aquae Menthae 200 ml Misce. Da. Signa. 1

tablespoon 3 times a day.

FORMULATION OF SUSPENSIONS BY THE DISPERSION METHOD

Rp.: Therpini hydrati 2.0 Natrii hydrocarbonatis 1.0

Aquae purificatae 100 ml Misce. Da. Signa. 1 tablespoon

3 times a day.

• The mixture is a suspension with terpin hydrate, a substance with poor expressed hydrophobic properties. Therefore, the suspension with terpin hydrate differs by the tendency to flocculation and, as a result, the tendency to fast sedimentation.

• Measure 80 ml of the purified water and 20 ml of the 5% sodium hydrocarbonate solution into the bottle for dispensing. Triturate 2.0 g of terpin hydrate with 10 drops of alcohol (because terpin hydrate is a poorly powdered substance) in the mortar, then add 1.0 g of gelatose and 1.5 ml of the sodium hydrocarbonate solution (according to the Deryagin rule). Mix and triturate all ingredients thoroughly until a homogeneous mixture is obtained. Then add (by small portions) the sodium hydrocarbonate solution, mix and pour the suspension obtained into the bottle for dispensing.

WCP (front side) Date № Pr.

Aquae purificatae 80 mlSolutionis Natrii hydrocarbonatis 5% 20ml Therpini hydrati

2.0 Gelatosae

1.0 V total =

100 mlPrepared by: (signature)Checked by: (signature)

FORMULATION OF SUSPENSIONS BY THE CONDENSION METHOD

Rp.: Calcii chloridi 10.0Natrii hydrocarbonatis 4.0Aquae purificatae 200 mlMisce. Da. Signa. 1 tablespoon 3 times

a day.

СаCl2 + 2NaHCO3 = CaCO3↓ + H2O + 2NaCl

WCP (reverse side)Sol. Calcium chloride 50 % (1:2): 10.0 2

= 20 mlSol. Sodium hydrocarbonate 5 % (1:20): 4.0 20 = 80 ml

Purified water: 200 - (20+80) = 100 ml

•At first two solutions - calcium chloride solution and sodium hydrocarbonate solution – should be prepared and then mix these solutions. Measure 100 ml of the purified water into the bottle for dispensing, add 20 ml of 50 % calcium chloride solution and 80 ml of 5 % sodium hydrocarbonate solution.

Quality Control of SuspensionsThe following tests are carried out in the final quality control of

suspension: • Appearance Color, odor and taste • Physical characteristics such as particle size determination and

microscopic photography for crystal growth • Sedimentation rate and • Zeta Potential measurement• Sedimentation volume • Redispersibility and Centrifugation tests • Rheological measurement • Stress test pH • Freeze-Thaw temperature cycling• Compatibility with container and cap liner

Ideal Requirements of Packaging Material•It should be inert. •It should effectively preserve the product

from light, air, and other contamination through shelf life.

•It should be cheap. •It should effectively deliver the product

without any difficulty.

THANK YOU FOR ATTENTION!!!