Suspensions

A system containing an insoluble or immiscible drug distributed throughout a vehicle

Dispersed system

A non-homogeneous liquid dosage form

Suspension

A suspension is a _______ dispersion

Coarse

Particle size is greater than 500 nm; usually consists of two distinct phases

Coarse dispersion

Particle size ranges between 1 and 500 nm; can be one or two phases

Colloidal dispersion

Liquid preparations with finely divided solid drug particles uniformly distributed throughout a vehicle

Suspensions

In suspensions, the drug must exhibit only a minimum degree of _________ in the vehicle

Solubility

Suspensions help mask ______ taste since there is less dissolved drug to taste

Bitter

Suspensions can exist in ready-to-use form or as a _____ _________ for reconstitution

Dry powder

These are used for drugs with short stability once mixed with liquid

Dry powder for reconstitution

The pharmacist adds a designated quantity of purified ______ to the dry powder for reconstitution right before dispensing

Water

A term for some oral aqueous suspensions, usually of a white-inorganic compound

Milk

An older term for suspensions of inorganic solids that have a strong affinity for hydration, forming a gel-like system

Magma

A clay-like muddy substance that swells up when placed in water

Bentonite

Suspensions are commonly use in _________

Pediatrics

Can be used for antibiotics (e.g., Amoxicillin), antacids (e.g., Aluminum hydroxide, Calcium carbonate), Ibuprofen

Suspensions

________ can be used as skin protectants and astringents such as Calamine 

Suspensions

These are for intramuscular use only; they are not suitable for intravenous use due to particle size

Sterile suspensions for injection

Sterile suspensions for injection are often designed for ________ action

Extended

_______ dosage forms provide an ease of administration

Liquid

Liquid dosage forms allow for ________ of dose adjustment and compounding

Flexibility

Provides a liquid dosage form for drugs that are poorly water soluble and thus cannot be made into a solution

Suspension

Suspensions mask the bitter taste of _______ drugs

Soluble

Water-soluble drugs with a bad taste can be chemically converted into an _______ form to be prepared as a suspension

Insoluble

Good suspensions must demonstrate therapeutic _________

Efficacy

Good suspensions must maintain ________ ________ of the drug and all components

Chemical stability

Good suspensions must possess esthetic appeal, including __________ properties like taste, smell, texture, and appearance

Organoleptic

Suspended particles should settle ________-

Slowly

Suspended particles must be readily ___________ (easy to suspend with shaking)

Dispersible

The size of suspended particles should remain fairly __________ throughout the shelf-life to maintain physical stability

Constant

Suspensions must be readily and easily __________ from the container

Pourable

The ratio of particle settling is described by this equation, which is based on ideal conditions

Stokes’ Equation

Reducing _______ ________ can decrease the rate of settling

Particle diameter

Increasing ___________ can decrease the rate of settling

Viscosity

A _________ medium results in a slower rate of settling

Thicker

Making the density of the medium _______ to the particle’s density slows the settling rate

Closer

Dispersed phase control; yields particles 10-50 um

Micropulverization

Dispersed phase control; yields particles less than 10 um, which is necessary for parenteral or ophthalmic suspensions

Jet-milling

Used in suspensions to ensure a fairly uniform particle size

Sieving

_______-shaped asymmetrical crystals tend to produce a more tenacious cake (hard to re-disperse) than symmetric particles

Needle

Finer particles tend to settle and form a ________ _______ that is non re-dispersible

Compact cake

Loose aggregates of particles held by weak bonding forces

Flocculated dispersed phase

Flocculated particles are easily ___________ and result in a high sedimentation volume of loose sediment

Dispersible

Cause repulsion between particles, include electrolytes, surfactants, bentonite magma, and pH adjustments

Flocculating agents

Solution to prevent caking in suspensions

Flocculation

Added to slow down the settling rate of the flocculated particles, making the preparation more pharmaceutically elegant

Suspending agents

Suspending agents lend ________ to the medium and increase viscosity

Structure

Example of suspending agents

Cellulose derivatives

The agent must be chemically and biologically inert, and the amount used must be reasonable so the suspension is not too viscous to pour

Suspending agent

Added to increase the density of the dispersion medium

Densifier

Examples are sucrose, sorbitol, glucose, and glycerin

Densifiers

Suspensions; these are crucial when the drug powder has low affinity for the medium (it is hydrophobic)

Wetting agents

Allow the medium to penetrate the dispersed phase more easily and remove air pockets from the particle crevices and surface

Wetting agents

Examples are alcohol, glycerin, and propylene glycol in aqueous mediums; mineral oil; docusate sodium

Wetting agents

The typical order of addition is powder, wetting agents, and then _________ ________

Suspension medium

Soluble ingredients like colors, flavors, and preservatives are added to the ________ ________

Dispersion medium

Can be prepared in the pharmacy from commercial solid dosage forms

Suspensions

Commercially prepared __________ are commonly used for suspending and sweetening

Vehicles

Syrup suspension vehicle

Ora-Sweet

Oral suspending vehicle

Ora-Plus

Compounding vehicle, often sugar-free for diabetics

Suspondol-S

Suspensions are made in a ______ mortar and pestle and then brought to volume in the dispensing container

Glass

Sustained release suspensions are ________ due to stability issues

Limited

Examples are coated beads, drug-impregnated wax matrix, microencapsulation, or ion exchange resin technology

Sustained release suspensions

Uses the Pennkinetic delivery system; ionic drug molecule is complexed with ion exchange resin and the resulting complex particles are coated with ethylcellulose

Delsym

Uncoated particles release the drug rapidly in the stomach

Fast release

Polymer-coated particles provide sustained release in the intestine

Extended release

Suspensions use ____ mouth containers

Wide

Suspension containers must have adequate _____ above the liquid (headspace) to allow for proper shaking

Space

Must be protected from freezing, excessive heat, and light

Suspensions

It is critical to tell patients to ______ suspensions well before using to re-suspend the settled particles and ensure the patient receives the correct, uniform dose

Shake