Dosage forms - solids, liquids Flashcards

1
Q

What is a dosage form?

A

the physical form in which a drug is produced for administration to the recipient

  • the physical form of the oral dosage form will influence absorption rate and onset of action
  • range of dosage forms for the same route of administration to optimise the delivery of the API
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2
Q

What are tablets? How can they be prepared?

A

tablet are solid preparations prepared by
- compression

  • moulding
    = mixing the API with a diluent. the diluent serves as a base and must be readily water soluble. liquid added to moisturise it so that it will adhere to the mould cavities
  • lyophilisation
    = freezes the product, placed in a vacuum, temperature and pressure is lowered, ice is removed by sublimation and leaves behind the tablet
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3
Q

What are the different tablet excipients? What is their purpose?

A

filler

  • bulks up the tablet to the required weight
  • saccharides = lactose, sucrose, mannitol

disintegrant

  • helps break down the tablet into smaller pieces after ingestion = absorbs water from surroundings to increase its size and start breakdown
  • polymer based = starch, cellulose

solution binder

  • helps bind the ingredient together
  • polymer based = starch, sucrose, gelatin

glidant

  • prevents powder from sticking together, facilitates flow
  • magnesium stearate

lubricant

  • prevents sticking to the die
  • magnesium stearate, steric acid

anti-adherent

  • prevent powder sticking to the machine
  • magnesium stearate
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4
Q

How are tablets manufactured? What are the processes?

A

single press punch

  • small scale production
  • one pair of punches and die

rotary press

  • high scale/industrial production = large
  • 3-60 dies and set of punches

hydraulic press

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5
Q

What are the types of tablet?

A

immediate release
- designed to disintegrate when swallowed, dissolve and be absorbed

delayed release = m/r or s/r

  • designed to release the drug after a time lag, or slowly for a prolonged drug release or sustained drug action
  • must be swallowed whole not chewed

effervescent
- dissolved in water before administration, solution is usually a flavoured bubbling drink

soluble/dispersible
- dissolved in water, ease of swallowing

chewable
- produce pleasant tasting residue in the mouth when chewed, no bitter or unpleasant after taste

buccal or sublingual

  • small and flat
  • not to be swallowed whole

sugar coated or film coated
enteric coated
lozenges
pastilles

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6
Q

How do sugar coated and enteric coated tablets work?

A

sugar coated or film coated

  • coat protects tablet from environmental damage
  • to mask an unpleasant drug taste
  • aid identification of tablet
  • enhance its appearance

enteric coated

  • protects drug from the acid conditions of the stomach
  • prevent tablet from dissolving until it reaches the small intestine
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7
Q

What are lozenges and pastilles?

A

lozenges
- drug incorporated in flavoured base
- dissolve or disintegrate slowly in mouth, releasing medication generally for localized effect
example - antiseptics for sore throat.
- lozenges can also produce systemic effect
example - nicotine lozenges

pastilles - glycerol and gelatin base

  • sweetened ,flavoured and medicated
  • sucked = popular for soothing coughs/sore throats.
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8
Q

What are capsules?

A

made with hard or soft gelatin shell of various sizes
- drugs are enclosed within a gelatin container

when swallowed the gelatin shell is dissolved by gastrointestinal fluids releasing contents

soft gelatin capsules
- one piece capsules containing a liquid or semi-solid fill
= cod liver oil

hard gelatin capsules
- two piece capsules shells filled with powders, pellets, semi-solids or liquids

various types of capsules e.g. capsules delayed release pellets, inhalers.

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9
Q

What are the types of oral powders and granules? What is their purpose?

A

bulk powders = undivided powders
- useful for non-potent bulky drugs with large dose

individually wrapped doses - divided powders
- useful for potent drugs, accuracy of dose is important.

granules/powders
- for reconstitution before dispensing

effervescent granules
- masks taste of salty or bitter medications

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10
Q

What are the advantages of oral powders and granules?

A

solid preparations are more stable than liquid preparations
- longer shelf life

powders and granules are convenient forms in which to dispense drugs with a large dose

orally administered powders and granules which are mixed with water prior to taking are useful for patients who have difficulty swallowing or where absorption of the drug is required

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11
Q

What are the disadvantages?

A

bulk powders or granules are less convenient to carry than a small container of tablets/capsules

masking of unpleasant taste may be a problem with this type of preparation

bulk powders or granules are not good method of administering potent drugs with low dose

powders and granules are not a suitable method of administration of drugs that are inactivated in the stomach
- should be enteric coated tablets

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12
Q

What are solutions?

A

oral solutions contain one or more ingredients dissolved in a suitable vehicle, usually solids dissolved in liquids

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13
Q

What are the different types of solutions?

A

syrups
- a concentrated, viscous solution containing one or more sugar components = mainly sucrose

elixirs

  • usually contain potent or unpleasant tasting drugs
  • the formulation is clear, and generally contains a high proportion of sugar or sweetening agent to mask nauseating tastes
  • generally non aqueous solvents (e.g. alcohol, glycerin) form a significant proportion of the vehicle

linctuses

  • viscous liquids used in treatments of cough
  • should be sipped and swallowed slowly and allowed to trickle down the throat in an undiluted form
  • contains sugar = simple linctus

mixtures
- term used to describe pharmaceutical oral solutions and suspensions

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14
Q

What are the advantages of solutions?

A

absorption of the medicine from the GI tract is rapid

easy to swallow for children and some adults
- especially the elderly

uniform distribution of medicament
- no need to shake

flexible dosing is possible

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15
Q

What are the disadvantages of solutions?

A

medicaments are less stable in solution than in a dry dosage form

unpleasant flavours may be difficult to mask

bulky to carry around

vulnerable to loss by breakage of container

a means of measuring the dose is required
- measuring spoon, syringe

measurement depends on the accuracy and reliability of the patient

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16
Q

What are suspensions?

A

a disperse system in which one substance (the disperse phase) is distributed in particulate form throughout another (the continuous phase)
- in a suspension at least one of the ingredients is not dissolved in a vehicle

the preparation will require shaking before a dose is administered
- phases can separate

17
Q

What are the advantages and disadvantages of suspensions?

A

advantages

  • insoluble drugs may be more palatable
  • absorption will be quicker than solid dosage
  • useful way of administering large amounts of drug which would be inconvenient to take in capsule or tablet form.

disadvantages

  • preparation requires shaking before use
  • accuracy of dose likely to be less than equivalent solution.
18
Q

What are emulsions?

A

emulsions are liquid preparation containing a mixture of oil and water
- emulsions foe external use are called lotions

emulsifying agent

  • ensures that the oil phase is finely dispersed throughout the water as minute globules
  • emulsifier arranges at the interface, anchoring its hydrophilic part into water and its lipophilic part into oil

oil in water emulsion
- oily phase (disperse phase) is dispersed through the aqueous phase (continuous phase)

generally all oral dose emulsions tend to be oil in water
must be shaken well prior to measuring a dose
convenient for administering oils and fats or oily solutions of unpalatable drugs of low aqueous solubility

19
Q

What type of dosage form has the highest bioavailability?

A

oral solutions

20
Q

What are ear drops?

A

drug/mixture of drugs is presented as a solution or suspension

vehicle may be water but glycerol and propylene glycol may also be used

designed to exert local effect in the ear
- to soften wax

to treat local inflammation and infection, or to relieve pain

drops are inserted in the ear, using a dropper
- means of use are required

21
Q

What are the dosage forms for eye?

A

must be sterile

  • no microbial = can lead to infections
  • require preservative

eye drops

  • sterile solutions or suspensions of one or more medicaments
  • drops can be supplied in single or multiple dose containers

eye lotions
- sterile aqueous solutions are used usually undiluted for bathing the eye

eye ointments

  • sterile applied to the eyelid margin/eye
  • disadvantage = can affect vision - blurred vision
22
Q

What are topical dosage forms?

A

application
- a liquid or semi-liquid preparation intended for application to the skin

collodions
- a liquid preparation for external use.
- liquid is painted on the skin, where it forms a flexible film
example - in treatment of corns contains salicylic acid

dusting powders
- a preparation consisting of one or more substances in fine powder for external use
- used to treat a variety of skin conditions, to soothe skin or for disinfection
example - anti-fungal powders for athletes foot

liniment

  • liquids for external use
  • used to alleviate discomfort of muscle strains and injuries
  • massaged on skin (stimulating types) or applied on a warm dressing or with a brush (analgesic or soothing type)