solid oral dosage forms

Question 1

what are disperse systems?

Answer 1

two phase systems in which an insoluble or immiscible dispersed phase (e.g solid particles or liquid droplets) is distributed through a continuous phase

Question 2

what are the different dispersed systems?

Answer 2

dissolved, single phase and dispersed

Question 3

what are the advantages of solid oral dosage forms?

Answer 3

-convenient and clean
-light and compact (economic) as they are easy to transport and store
-dry (stable)
-accurate dose
-may give controlled release
-can mask taste

Question 4

what are the disadvantages of solid oral dosage forms?

Answer 4

-difficult to swallow
-difficult to dilute
-difficult for liquid drugs

Question 5

what are tablets?

Answer 5

solid preparations each containing a single dose of one or more active substances
-they are intended for oral administration

Question 6

how are tablets obtained?

Answer 6

by compressing uniform volumes of particles
-they sometimes have different shapes and the size varies from 50mg to 500mg

Question 7

what are the general properties of tablets?

Answer 7

strength:to withstands shock during manufacturing, packing, shipping dispensing and use
-efficacy:drug content must be bioavailable,release must be reproducible
-safety:chemically and physically stable,uniform in weight and in drug content

Question 8

what are the different types of tablets?

Answer 8

uncoated or coated
-soluble/dispersible or orodispersible
-effervescent
-chewable
-buccal
-sublingual
-gastro-resistant or enteric coated
-modified or controlled release
-oral lyophilisates

Question 9

why does nothing happen when enteric coated tablets reach the stomach?

Answer 9

the coating is not soluble in the acidic pH

Question 10

what are the different types of tablet excipients?

Answer 10

-diluents-form the bulk of the tablet
-binders-for granulation
-disintegrating agents-for drug release
-glidants-promote granule flow
-lubricants
-coating agents-protection
-colouring-helps patients differentiate between different tablets
-flavouring

Question 11

what do lubricants do?

Answer 11

prevent tablet from sticking to the die wall or punches in the tablet press

Question 12

what do tablet coatings do?

Answer 12

-protects the active ingredients
-organoleptic-taste,colour,smell
-improves product quality
-aids identification (e.g colour)
-protects the tablet during packaging/storing
-prevents contamination and dust problems
-can control drug release

Question 13

what are the different types of tablet coating?

Answer 13

-sugar coating-excipient=sucrose
-film coating-excipient=HPMC-hydroxypropylmethylcellulose (or hypromellose)
-press coating

Question 14

what are the advantages of sugar coating for tablets?

Answer 14

the appearance-rounded,highly polished tablets are produced

Question 15

what are the disadvantages of sugar coating for tablets?

Answer 15

-Multistage (time consuming)
-Difficult to automate
-Not for controlled release.
-increase tablet size by 30 – 50 %
-Indented logos not feasible

Question 16

what are the advantages of film coating for tablets?

Answer 16

-Increase tablet size by 2-3%
Can be automated
-Single stage process
-Good for controlled release
-Indented logos can be used

Question 17

what are the disadvantages of film coating for tablets?

Answer 17

-Environmental – extraction of organics into atmosphere
-Safety – explosion / fire / & toxic hazards (expensive to deal with)
-Solvent residues must be investigated
-Alternative aqueous route: hydrolysis causes problems, heating can destroy drug, ‘lumpy’ tablets caused by

Question 18

what are the advantages of press coating for tablets?

Answer 18

-separates incompatible materials (one in layer,one in core)

Question 19

what are the disadvantages of press coating for tablets?

Answer 19

-they are based on compaction of coating around pre-formed core.

-requires relatively complex, specialist equipment

Question 20

what are the 2 functional coatings?

Answer 20

-enteric coatings
-controlled release

Question 21

describe enteric coatings…

Answer 21

-insoluble at low pH therefore not attacked by HCL in the stomach
-sharp increase in solubility at higher pH e.g 5.2 for cellulose acetate phthalate coating
-Other materials:
polyvinylacetate phthalate and acrylic derivatives

Question 22

describe controlled release coatings…

Answer 22

they are polymers with restricted water solubility or permeability

Question 23

what are the three mechanisms of controlled release?

Answer 23

-Diffusion control-rate of release controlled by the rate of diffusion of drug through the coating
-Erosion-coatings designed to erode gradually
-Osmosis-osmotic pressure used to control release of drug

Question 24

what is a capsule?

Answer 24

a capsule consists of a dose of a drug enclosed in a water soluble shell made of gelatin

Question 25

why is gelatine used in capsules?

Answer 25

because it is: non toxic soluble at body temp, has good film forming properties -changes from a gel to solid at temps just above room temperature

Question 26

what is a hard gelatine capsule?

Answer 26

hard capsule consists of gelatin and water with dyes and pigments to add colour -it comprises of a two piece shell (body and cap) which lock together

Question 27

what must the material going in a hard gelatine capsule need to be?

Answer 27

-accurately filled -not react with gelatin (must not contain aldehydes or water) -must not leak out of the shell

Question 28

what are the different fill materials?

Answer 28

-powders -Granules -Pellets -Tablets -Pastes -Low viscosity,non aqueous liquids

Question 29

what are soft shell capsules?

Answer 29

-capsules that consists of a solid flexible shell surrounding a liquid or semi-slid fill -permits liquids to be presented as solid dosage forms -the drug is protected from water and oxygen

Question 30

what does the shell of soft shell capsules comprise?

Answer 30

comprises gelatin,plasticiser (usually glycerol,sorbitol or propylene glycol),water,preservatives,dyes

Question 31

what are soft gelatine capsules (soft gels)?

Answer 31

-one piece sealed shells -they are round,oval,oblong or tubular in shape -they are formed,filled and sealed in one go

Question 32

how much non-aqueous liquid are soft gels filled with?

Answer 32

with 0.1 to 0,8mL of non-aqueous liquid -liquid can be hydrophilic (e.g polyols surfactants) or lipophilic (i.e mineral or natural oils eg cod liver oil) -hydrophilic oils can allow rapid attainment of therapeutic drug levels (e.g with temazepam)

Question 33

what are the liquids that soft gels can be filled with?

Answer 33

-the liquids can be hydrophilic (e.g polyols surfactants) or lipophilic (i.e mineral or natural oils eg cod liver oil) -hydrophilic oils can allow rapid attainment of therapeutic drug levels (e.g with temazepam)

Question 34

what are the problems with soft gels?

Answer 34

-migration of fill material through the capsule shell (sweating) -migration of shell contents the other way which can possibly cause instability -both soft and hard capsules are unstable for drugs that are unstable in the presence of moisture -moisture in atmosphere may cause the shell to soften and break -dry conditions may cause cracking

Question 35

what are the factors that can influence the choice of capsule or tablet?

Answer 35

-company policy -market research -competitor products -production preferences -equipment available -production costs -required unit dose -dissolution rate -compression characteristics -particle size -stability

Question 36

what are lozenges?

Answer 36

-they stay in the mouth for 10-15mins -often release an antibacterial or anaesthetic (local effect)

Question 37

what are chewable tablets/

Answer 37

tablets designed to be broken down rapidly in the buccal cavity by action of the teeth

Question 38

what are the properties of chewable tablets?

Answer 38

-mannitol is often used for a cooling taste -a flavouring agent is frequently used -no disintegrant -no need for all ingredients to be water soluble

Question 39

what are the properties of lozenges?

Answer 39

-they contain no disintegrate -diluents are selected for them to ensure they have a smooth texture and pleasant taste -sugars (e.g sucrose/glucose) are often used

Question 40

what are dispersible tablets?

Answer 40

tablets that must disintegrate rapidly in cold water to produce a suspension for ingestion -it is paramount the disintegrate is effective in water

Question 41

what are soluble tablets?

Answer 41

tablets that are formulated to dissolve in water, so all ingredients must be highly soluble

Question 42

what are orodispersible tablets?

Answer 42

tablets designed to disintegrate in the mouth

Question 43

what are effervescent tablets?

Answer 43

-tablets that give rapid disintegration -sucrose is hygroscopic therefore often used as a sweetener to increase stability

Question 44

why are standard lubricants not used for effervescent tablets?

Answer 44

because the lubricant magnesium stearate slows the access of water and leaves a scum on the surface of water so sodium lauryl sulphate is often used

Question 45

what are sublingual and buccal tablets?

Answer 45

tablets that are absorbed though the mucosa and passed to the jugular vein, hence bypassing the GI tract and liver

Question 46

what are the properties of sublingual and buccal tablets?

Answer 46

-the tablets should not disintegrate -rapid dissolution is required -they help to avoid unpleasant tastes