Lab Final - Suspensions

two phased liquid prep made of undissolved drug/immiscible liquid (dispersed phase) distributed in a vehicle (dispersion medium)

disperse system in which a finely divided solid is dispersed in a continuous phase of solid, liquid, or gas

• single phase: <1 nm
• two phase: 10-50 μm

• dispersed particle (drug)
• liquid medium
• excipients

• wetting agents
• flocculating agent
• viscosity enhancer/suspending agent
• preservative (benzoic acid, sodium benzoate)
• flavoring agent

when the dispersed phase isn't easily penetrated by the vehicle (clumps or float)

displace the air making the powder more penetrable by dispersion medium

• alcohol
• glycerin
• other hygroscopic liquids

• dispersed particles form aggregates
• aggregates settle by dispersion
• cakes form that are difficult to resuspend

the settling velocity of a smooth, rigid sphere in a viscous fluid - sedimentation rate

• size of the particle (proportional to)
• density diff between the particle and liquid (proportional to)
• viscosity of the liquid (inversely proportional)

when the density of the particle is equal to the density of the liquid

• enhance particle dispersability
• negate the surface charge on the suspended particles
• allows the formation of loose networks of particles called "floccs/floccules" - easily re-dispersed by shaking

• clay
• surfactants

• natural hydrocolloids
• semisynthetic hydrocolloids
• synthetic hydrocolloids
• clays

• acacia
• tragacanth
• alginic acid
• carrageenana
• locust bean gum
• guar gum
• gelatin

• methylcellulose
• sodium carboxymethylcellulose

carbopol

• bentonite
• veegum

treating inflammation of eyes and eyelids when infection or risk of infection is present

anitbacterial and corticosteroid combo