Week 7 dosage forms Flashcards
Delivery routes
There are numerous route via which drugs can be administered to the body
Different routes require different dosage forms
Dosage forms
When considering dosage forms, we should consider whether we are seeking SYSTEMIC drug delivery or LOCAL drug delivery
Systemic drug delivery
Where the drug reaches the site of action through the systemic
(cardiovascular) circulation
Oral dosage forms are the most common type of systemic dosage form
Local drug delivery
Drug is delivered directly to the site of action via the dosage form (or the action of the dosage form)
Oral dosage forms
-Tablets (and caplets)
-Capsules
-Powders and granules
-Solutions
-Suspensions
-Emulsions
Tablets (and caplets)
-Very widely used dosage form formed from compacted powders or granules
-Tablet must disintegrate in the gastro-intestinal (GI) tract and the drug then enter solution
Capsules
-Drug in loose powder form is held within a 2-piece hard-shelled gelatin (usually) capsule
-Capsule shell quickly dissolves in the stomach and releases the drug
-Liquids / emulsions / pastes may be incorporated in 1-piece soft gelatin capsules
Powders and granules
Typically mixed with water prior to taking
–> “Bulk” or “single-dose”
Solutions
->Single phase systems
-Drug and other excipients are completely dissolved, i.e. as
a molecular dispersion, in a liquid (solvent)
-Faster acting than an equivalent tablet formulation-disintegration and dissolution steps are absent
Suspensions
-Drug and/or other excipients remain as solid particles
dispersed in the “vehicle”
-Usually employ a suspending (thickening) agent to keep the particles dispersed
Emulsions
-Dispersions of (at least) two immiscible or partially miscible liquids
-Medicinal oils, supplements,
lipophilic drugs
Rectal and vaginal dosage forms
-Suppositories
-Enemas
-Foams
-Pessaries
-Vaginal creams and gels
Suppositories
-Drug is incorporated into a water-soluble/dispersible base or a base which melts at body temperature
-Once inserted the drug will be released to exert a local or (sometimes) systemic effect
Enemas
-Liquid preparations formulated for rectal delivery
Foams
-Two-phase system administered from a pressurised container
-Drug dissolved in the liquid phase
Pessaries
-Vaginal tablets, suppositories or capsules
Topical and transdermal dosage forms
-Creams
-Ointments
-Gels
-Pastes / sprays / lotions / foams
-Transdermal therapeutic systems (patches)
Creams
-Semi-solid emulsion preparations usually applied topically to the skin, but
formulated for other delivery routes
-May contain a drug or sometimes the cream “base” has a therapeutic effect
Ointments
-Single-phase semi-solid base in which a drug can be dispersed
-Have excellent emollient properties
Gels
-Single-phase semi-solid preparations, usually aqueous in nature
Transdermal therapeutic systems (patches)
-Applied to the skin but usually for a systemic effect
Parenteral dosage forms
Drug (or source of calories/ nutrients/ hydration) administered via a hollow metal needle
-Injections
-Infusions
Injections
-Sterile liquid preparation drawn up and injected from a vial, ampoule or pre-filled syringe
-Typically IV, IM or SC, but many other routes
-Can utilise a syringe driver (or pump)
Infusions
For delivery of larger volumes IV
-Source of calories/ nutrients/ hydration but drugs can also be added
-Can be solutions or emulsions, e.g. Intralipid®
Pulmonary drug delivery systems
-Inhalers
-Nebulisers
-Electronic cigarettes
Inhalers
-Large variety of different types of inhaler devices
-Pressurised metered-dose inhalers (pMDIs)
-Dry powder inhalers
Drugs are typically delivered for a local effect, e.g. salbutamol,
beclomethasone, but can also be given for a system effect
Nebulisers
-Convert liquids to aerosols (dispersion of a liquid or a solid in a gas)
-Useful for delivering larger doses of drug
Other common dosage forms
Advanced dosage forms and technologies
-Needle-free technology, e.g. jet injection systems and
microneedles
-Implantable delivery systems
-Nanotechnology
-Cell-based therapies
