suppositories Flashcards

1
Q

suppositories

A

administration: generally for rectal administration
shape: cylindrical with one/both ends tapered
weight: 1-2g

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2
Q

pessary

A

administration: generally for vaginal administration
shape: oviform, cone-shaped
weight: 1g

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3
Q

nasal bougie

A

administration: generally for nasal administration
base: gelato-glycerin base
length: 9-10cm long
weight: 1g

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4
Q

urethral bougie

A

administration: generally for urethral administration
shape: pencil-shaed (3-6mm diameter, 80mm long)
weight: 1g

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5
Q

ear cone

A

administration: into the ear
base: oleaginous base

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6
Q

application of suppositories

A
  1. carry drug for action at site of placement (eg. emollients, astringents, antiseptics, local anaesthetics)
  2. carry drug for systemic action (eg. hypnotics, tranquilizers, antispasmodic, antipyretic, antiemetic)
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7
Q

when are suppositories recommended

A
  1. for patients who are unable to make use of oral route of drug administration (eg. unconscious, severe nausea, post op)
  2. drugs that are less suited for oral administration
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8
Q

disadvantages of suppositories for drug delivery

A
  1. strong feeling of aversion
  2. suppositories that can leak
  3. slow onset (~30min) and incomplete drug absorption
  4. considerable intersubject and intrasubject variation in drug absorption
  5. development of proctitis (infammation of tissue lining rectum)
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9
Q

desirable properties of suppository base

A
  1. can be moulded by pouring or compression
  2. stable if heated above MP
  3. does not adhere to mould
  4. release drug at desired rate
  5. keeps its shape when handled and easy to insert
  6. does not leak out of orifice into which it is inserted
  7. stable during storage
  8. non-toxic and non-irritating
  9. compatible with drug
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10
Q

types of bases

A

oleaginous, water soluble/miscible, emulsifying

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11
Q

oleaginous bases

A

oily/fatty bases

eg: theobroma oil, hydrogenated fatty acids of vegetable oils, monoglycerides of high MW fatty acids

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12
Q

theobroma oil

A

aka cocoa butter, composed of triglycerides of mainly oleic stearic and palmitic acid, occurs in three crystalline forms-

  1. alpha (unstable, MP 22-24)
  2. beta (stable, MP 24-36), note the use of low heat (40-50 degree) and slow cooling are crucial for direct recrystallisation to beta-crystals
  3. gamma (unstable, MP 18)
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13
Q

disadvantage of theobroma oil base

A
  • melting provess must be carefully monitored
  • theobroma oil tends to stick to the sides of the mould
  • theobroma oil tends to soften in tropical climate and when substances such as colatile oils, phenol or chloral hydrate are added
  • theobroma oil is difficult to administer as it will melt on finger tip
  • theobroma oil tends to leak out of orifice
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14
Q

water soluble/miscible bases

A

does not melt but dissolve slowly in biological fluid, and are commonly prepared from glycerinated gelatin or polyethylene glycols

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15
Q

what does glycerinated gelatin contains

A

gelatin- for hardness

glycerin- for hydrophilicity (allow base to attract water)

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16
Q

what are the two types of gelatin

A
  1. pharmagel A- cationic and incompatible with anionic compounds
  2. pharmagel B- anionic and incompatible with cationinc compounds
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17
Q

advantage of glycerinated gelatin base

A
  1. more prolonged drug release; commonly used in pessaries

2. more easily inserted; suitable for urethral administration

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18
Q

disadvantage of glycerinated gelatin base

A
  1. hygroscopic; dehydrating effect on mucous membrane

2. support growth of mould (need to be hygienically stored)

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19
Q

what are carbowaxes

A

Polyethylene glycols

20
Q

what are PEG general formula

A

HOCH2 (CH2OCH2)n CH2OH,

common MWL 200, 400, 600, 1000, 1500, 1540, 3350, 4000, 6000

21
Q

advantages of PEG bases

A
due to higher MP:
1. convenient storage
2. easy insertion
3. no leakage from orifice
due to varying solubilities:
4. control of drug release
22
Q

disadvantage of PEG bases

A
  1. incompatible with phenols

2. hygroscopic

23
Q

emulsifying bases

A

composed of triglycerides with one or more emulsifying agents

24
Q

witepsol

A

hydrogenated triglycerides of lauric acid with added monoglycerides

25
Q

massupol

A

glyceryl esters, chiefly lauric acid, with added glyceryl monostearate

26
Q

advanatage of emulsifying bases

A
  1. not adversely affected by overheating
  2. solidify rapidly at RTP
  3. do not adhere to mould
  4. non-irritating
27
Q

hot process of preparation of suppositories

A
  • fusion or melt moulding, unsuitable for thermolabile drug
  • more commonly employed than cold process
  • base is melted over hot water-bath, and drug is dissolved or dispersed in the molten base
  • molten mixture is poured into lubricated mould and allowed to set in the cold
  • suppositories formed are removed from the metal moulds or supplied in the disposable moulds
28
Q

cold process of preparation of suppositories

A
  • hand moulding (slow process for small scale production; base kneaded throughly with drug) or compression moulding (partially automated and relatively faster than hand moulding)
  • does not employ heat and is suitable for thermolabile drugs
29
Q

types of packaging of suppositories

A
  • partitioned boxes
  • screw-capped glass/ plastic containers
  • aluminum foil wrappings
  • disposable plastic moulds
30
Q

what packaging is suitable for suppositories that have tendency to fuse contact

A

partitioning boxes or disposable mould

31
Q

storage for each types of suppositories

A
  1. theobroma oil (<30 degree, in the fridge)
  2. glycerinated gelatin (<35 degree, dont need be in the fridge but just within suitable temp)
  3. PEG (can store at RTP due to higher MP)
32
Q

potential storage problems for different types of suppositories

A
  • theobroma oil: bloom effect- white powdery deposit due to effect of temperature fluctuation that causes unstable forms of theobroma oil to emerge on surface)
  • fat base: elevated MP
33
Q

factors of evaluation of suppositories

A
  • appearance
  • uniformity of weight*
  • uniformity of drug content
  • disintegration time*
  • drug release profile
  • mechanical strength
  • melting behaviour
34
Q

appearance of suppositories

A
  • color, surface condition, shape, uniformity of mix

- sliced lengthwise for examination

35
Q

uniformity of weight

A
  • BP method: take 20 suppositories at random from batch, weight individually, then calculate their ave weight
  • acceptance criteria: <=2 deviate from average weight by >5% AND none deviates by >10%
36
Q

uniformity of drug content

A

drug is extracted from base and assayed using appropriate methods; only for suppositories that need to comply w this test

37
Q

disintegration time test

A

disintegration affect rate of drug release, test determines whether suppositories disintegrate or soften within a prescribed time when placed in a liquid medium under prescribed experimental conditions; carried out on 3 separate suppositories

38
Q

results of disintegration test

A

complete if any one:

  • suppository is completely dissolved
  • suppository has dispersed into its component parts
  • suppository has become soft and mass has no solid core offering resistance to pressure with a glass rod
39
Q

acceptance criteria of disintegration test

A

fat base: disintegration time <=30min
water soluble: disintegration time <=60min
note: all 3 suppositories tested must pass

40
Q

drug release profile

A

obtained by determining the amount of drug release from the suppository to the external medium over time

41
Q

dissolution test

A
basket method
paddle method (dialysis membrane)
42
Q

mechanical strength

A

suppository should be strong enough to withstand the rigours of normal handling

43
Q

melting behaviour

A
  1. softening temperature: temp at which deformation occurs; indicates ease of insertion and physical stability of suppository during handling
  2. liquefaction temperature: temp at which melting occurs, affect drug release, only needed for oleaginous base
44
Q

physiochemical factors of suppositories that affect release of bioavailability of drugs

A
  1. chemical composition of base
  2. lower viscosity of base more bioavailable due (increase effective area of drug absorption)
  3. increase interaction bet drug and base (increase absorption)
  4. increase partition coefficient of drug btw base and rectal tissue (reduce tendency of leaving the base)
  5. increase drug particle size (increase extend of spreading)
  6. charge on drug molecule
  7. lipid solubility of drug (lipid solubility to permeate membrane)
  8. surface property of drug (greater wettability increases absorption)
  9. increase amt of drug (increase absorption)
  10. effect of supp on rectal tissue
45
Q

important properties of base

A
  • stability
  • compatibility with other components
  • viscosity
  • rate of drug release
  • temperature range btw melting and solidification
  • volume of contraction
  • brittleness
  • hygroscopicity
46
Q

important properties of drug

A
  • solubility
  • particle size
  • surface property
  • amount in base
  • displacement value
47
Q

displacement value

A

number of parts by weight of a drug which displace one part by weight of base