Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BPH > D1: Medicines: Their Structure, Ingredients and Design > Flashcards

D1: Medicines: Their Structure, Ingredients and Design Flashcards

1
Q

Drug

A

Pure active chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Medicine

A

Dosage form administered to the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Dose

A

Amount of medicine.drug taken on one occasion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Frequency

A

How often the dose is taken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Local

A

Medicine that acts in the area where it is supplied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Systemic

A

Drug enters bloodstream and can act anywhere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Oral

A

Swallowed by mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Topical

A

Applied to a surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Parenteral

A

Injected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do Medicines contain

A

Drugs, excipients + structure

  • drug = active substances
  • medicine = non-active ingredients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Legal requirements of medicines and drugs by Human Medicines Regulations 2012

A

All medicines must have proven:

  • efficacy = effective for the medical condition claimed
  • safety = safe to use by patient
  • quality = broadest sense
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does quality include

A

‘Dose uniformity’ = Accurate dose of drug every time
‘Patient acceptability’ = Pleasant and easy to use
‘Stability’ = A long shelf life
‘Directions’ = Clear instructions how to take it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Good medicine design is…

A

Tailored to the body site, is essential for patient safety and successful treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

General design principles of Medicines

A
  • Optimum drug release rate
  • Stability to chemical, physical, and
    microbial degradation so it has a long shelf life
  • High patient acceptability and ease of use
  • Easy to manufacture as a quality product
  • Uniformity – must give the same dose every time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Types of bulk powders

A

Oral bulk powders
Dusting powders
Powders for reconstitution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Types of single dose powders

A

Sachets + wrapped powders
Capsules - hard + soft
Tablets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Types of tablets

A 
Dispersible
Immediate release
Delayed release
Extended release
Special routes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Dispersible tablet

A

Dissolve in water before taking, or on tongue with no water.

Most rapid drug release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Immediate release tablet

A

Disintegrates in stomach,rapidly releasing the drug. These are the ‘normal’ tablets we all take

Fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Delayed release tablet

A

Releases whole dose further down the GI tract ‘Gastro-resistant’ or ‘Enteric coated’

Delayed. Whole dose released in the intestine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Extended release tablet

A

Slow drug release over 8 to 24 hr

Prolonged action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Special route tablet

A 
Sublingual = Under the tongue
Vaginal = Body cavity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Excipients in bulk powders

A 
Bulking agents - diluents
Effervescent mixtures
Flavouring, sweeteners, colours
Granulating agents (binders)
Flow aids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Example of bulking agents

A

Sugars, sorbitol, salts, talc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Example of Effervescent mixtures

A

Citric or other fruit acids with carbonates or bicarbonates. React to release CO2 in water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Example of granulating agents

A

Polymers such as PVP and pregelled starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Example of Flow aids

A

Colloidal silicon dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Stability problems of powder medicines

A

1) Sensitivity to moisture
2) Flow
3) Mixing + separation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Why does powder unmix during movement

A

As they move, small particles fall through spaces between the big ones.
Separation due to size, shape, density differences.

• Vibration.
• Transport.
• Mixing & pouring.
‘Rolling plane surfaces’ within moving containers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How do we prevent powder separation

A

Granulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Granulation

A 
Mix powders (drug, diluent, disintegrate)
- Dry granulation = by roller compaction
- Wet granulation = wet powder mixture with a solution of polymer 'binder' then sieve + dry
Form granules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Granules

A

Particles glued together with water-soluble PVP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Advantage of granules

A

Structured mixture - permanent + cannot unmix
Large size - flows well into packing machines
Crunchy - compresses into tablets easily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Manufacturing tablets

A

Compression of granules or powder mixtures on a tablet press

  • granules / powder mixture
  • mix with a lubricant
  • exact amounts
  • compress on a tablet press machine
  • incited tablets
  • coating machines
  • coated tablets
  • packaged tablets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Ingredients in tablets + capsules

A
  • Granuating agents (binders)
  • Bulking agents
  • compression aids
  • lubricant
  • disintegrants
  • flow aid
  • tablet coat
  • capsule shell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Example of tablet coat

A

Polymers, colours, TiO2

Film coat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Example of capsule shell

A

Gelatin shell, colours, TiO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Example of flow aid

A

Colloidal silicon dioxide

Helps granule/powder flow into tablet die for a more consistent fill

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Example of disintegrants

A

Starch, Croscarmellose, Sodium starch glycollate, L-HPC

Swelling or wicking action
Breaks up tablet in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Example of lubricant

A

Magnesium stearate

Help machine eject tablet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Example of compression aids

A

Microcrystalline cellulose

Deforms under pressure
Gives harder tablet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Example of Bulking agents

A

Sugar, lactose, dicalcium phosphate, mannitol, talc

Adds bulk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Example of granulating agents

A

Polymers such as PVP, pregelled starch

Binds powders together during wet granulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How do tablets release drug into body

A

Disintegrant absorbs water + swells tablet

  • Disintegration
  • Dissolution (drug in solution)
  • Absorption (across gut wall into bloodstream)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How do capsules release drug into body

A

Capsule shell (soluble polymer) dissolves
Powder contents are released + dissolve
( A disintegrate is sometimes used, if so disintegration is next)
Dissolution (drug in solution)
- Absorption (across gut wall into bloodstream)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Types of liquid medicines

A

Solutions
Suspensions
Emulsions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Solutions

A

All ingredients dissolved and therefore present as single molecules within the liquid ‘vehicle’.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Suspension

A

Insoluble solid particles dispersed in the liquid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Emulsion

A

Insoluble liquid droplets dispersed in the liquid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Excipient classes common in liquid medicines

A
  1. Vehicles
  2. Preservatives
  3. Stabilisers
  4. Colours
  5. Flavours
  6. Buffers
  7. Sweeteners
  8. Solubility enhancers
  9. Thickening agents
  10. Emulsifying agents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

E number list

A

This lists excipients (‘Additives’) approved for foods in EC.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Vehicle

A

Main liquid ingredient

  • Water
  • Sweetening/flavouring vehicles
  • Other liquids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Water used in medicines must be…

A

BP quality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Preservatives

A

Inhibit growth of dangerous microorganisms

  • Prevent poor poisoning in oral liquids
  • Prevent bottle contamination
  • Prevent microbes degrading medicine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What other excipients can act/ aid as preservatives

A

Sulphite antioxidants
Glycerol, syrup, sorbitol in very high concentration
Alcohol > 10%
Disinfectants (hypochlorites)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Internal preservatives

A

Sorbates
Benzoates
Chloroform
Methyl, ethyl, propyl parahydroxybenzoate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

External preservatives

A 
Benzalkonium chloride
Benzethonium chloride
Thiomersal, Borates,
Chlorocresol, Chlorbutanol 
Bronopol (Boots)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

2 types of stabilisers

A

Antioxidants + chelating agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Antioxidants

A

Reducing agents that react with dissolved oxygen?act as free radical scavengers
- prevent oxidation by being more easily oxidised than the drug / foodstuff they are protecting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Water-soluble antioxidants

A 
Ascorbic acid (Vitamin C)
Sulphur dioxide Sulphites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

2 types of antioxidants

A

Water-soluble + oil-soluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Oil-soluble antioxidants

A 
Tocopherol (Vit E)
Butylated hydroxyanisole (BHA)
Butylated hydroxytoluene (BHT)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What formulations are oil-soluble antioxidants used in

A

Formulations that contain fatty ingredients (emulsions, creams, ointments, foods) to prevent fat oxidation ‘rancidity’.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Chelating agents

A

Molecules that complex with heavy metal ions in solution, reducing their ability to catalyse oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Example of a chelating agent

A

Disodium Edetate (EDTA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Clinical use of EDTA

A
  • EDTA infusion to remove excess calcium (Ca2+) from the blood in hypercalcaemia arising from bone cancer.
  • Radioactive 51Cr complex of EDTA is used to assess kidney
    function - filtration rate.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Types of colour sources

A

Synthetic
Inorganic
Natural

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Oral bulk powders

A
  • Disperse spoonfuls of powder in water or milk

* A good way to give a large dose (grams) by mouth e.g. Indigestion remedies, bulk laxatives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Dusting powders

A

External skin diseases e.g. Athletes foot powders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Powders for reconstitution

A

Useful when drug is chemically unstable in water
• Powder dispersed in water before giving to patient e.g. Antibiotic syrups in a pharmacy; Freeze dried injections
• Make sure it all dissolves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Hard Capsules

A

Two part, hard polymer shell filled with a powder mixture

  • Polymer is water-soluble = gelatin or methylcellulose-
  • Easy to swallow
  • Many different capsule sizes available
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Soft Capsule

A

Flexible shell of plasticised polymer .

- Used for oils, liquids, pastes (A paste is a concentrated powder in a liquid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What are Tablets?

A

Single dose of compressed powder
it contains:
- Printing/ Embossing
- Break line
- Coat
- Drug and excipients
Tablets differ in size, shape, colour etc; to aid identification and create a distinctive look (‘Market identity’).
Printing In edible ink or embossed (indentation)
Tablets can be uncoated, sugar coated or film coated.
- Film coat is the most common - thin layer of coloured or transparent polymer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Why are tablets so popular?

A 
• Small, Portable
• Convenient to take
• Stable
- no water present
- coating blocks light
- moisture proof packing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Sensitivity to moisture

A

HYGROSCOPIC - absorb moisture
DELEQUESCENT - absorb and dissolve in it (!) nasty mess
EFFLORESCENT – hydrate salts that lose water of hydration
CAKING - powder sticking together due to moisture

76
Q

Flow

A

Critical for processing and packing.
• Depends on size, shape, moisture, surface charge etc.
• Large particles flow better.
• Add a flow aid if needed, or granulate

77
Q

Mixing and separation

A
  • How to get an even mix ?
  • How to get small amounts evenly into a large bulk ?
  • Mixing depends on size, density, shape, surface moisture, static.
  • Unequal particles can separate.
  • Fine powders (<10 microns) can agglomerate and don’t mix in
78
Q

Solutions to mixing problem

A
  • Granulation (Common in large scale manuf. Fixes powders in space)
  • Ordered mixes
  • Equalise particle sizes by grinding/sieving
  • Mix equal amounts 50:50 = most efficient
  • Geometric mixing (small scale technique)
79
Q

Why is powder separation a big problem in factories

A

Powder mixes can unmix during movement

  • As they move, small particles fall through spaces between the big ones
  • Separation due to size, shape, density differences.
80
Q

Describe Granulation

A

Granulation prevents separation

1) Mix Drug, diluents + disintegrants powders
2)
- By DRY GRANULATION - by roller compaction
- By WET GRANULATION - Wet the powder mixture with a solution of polymer ‘binder’
- – then sieve and dry
3) Granules are formed (particles are glued together with a water-soluble polymer e.g. PVP)

81
Q

Advantages of Granules

A

Mixture now structured - permanent and cannot unmix
Large size - flows well into packing machines
Crunchy - compresses into tablets easily

82
Q

Manufacture of Tablets

A

Compressing granules or powder mixtures on a tablet press

1) you mix granules/powder mixture with a lubricant (Mg Stearate)
2) Make exact amounts
3) Compress on a tablet compression machine
4) Uncoated tablets
5) Coating machines
6) Coated tablets
7) Tablets are packaged

83
Q

Ingredients of tablets + capsules

A 
Granulating agents (binders)
Bulking agents (diluents)
Compression aids
Lubricant
Disintegrants
Flow aid
Tablet coat
Capsule shell
84
Q

Function of granulation agent (+ example)

A

Binds powders together during wet granulation

- Polymers such as PVP, pre-gelled starch

85
Q

Function of bulking agents (+ example)

A

Adds bulk

- sugar, lactose, dicalcium phosphate, mannitol, talc

86
Q

Function of compression aids (+ example)

A

Deforms under pressure. Gives harder tablet.

- microcrystalline cellulose

87
Q

Function of lubricant (+ example)

A

Helps machine eject tablet

- magnesium stearate

88
Q

Function of disintegrants (+ example)

A

Swelling or wicking action. Breaks up tablet in water.

Starch, croscarmellose, Nastarch glycollate, L-HPC

89
Q

Function of flow aid (+ example)

A

Helps granule or powder flow into tablet die for a more consistent fill.
Colloidal silicon dioxide

90
Q

Function of tablet coat (+ example)

A

Film coat

Polymers, colours, TiO2

91
Q

Example of capsule shell

A

Gelatin shell, colours, TiO2

92
Q

Physical types of colours

A

Soluble dyes

Lakes

93
Q

Soluble dyes

A

Water soluble.
Oil soluble
Soluble in polymers (plastics)

Extracts of natural materials

94
Q

Lakes

A

Dyes adsorbed onto aluminium salts to make insoluble coloured powders

Powdered, dried foods - No toxicity testing needed

95
Q

Why are colours attractive in medicine

A

Natural colours in foods are often good nutritionally
- Carotenoids are precursor of vitamin A; β-Carotene (orange) = Carotenoids widespread in fruit and vegetables
- Fruit colours are natural antioxidants or are involved in body metabolism; Anthocyanins (red, purple, blue) Blackcurrants, raspberries, blueberries are rich in these.
-

96
Q

Why are colours coloured

A

Double bonds absorb UV and visible light as electrons in the π bond jump to higher energy orbitals
Colours are complex molecules with an
extensively linked (conjugated) network of double
bonds
Molecules with more conjugated double bonds, absorb UV and visible light at longer wavelengths, therefore coloured organic compounds have highly conjugated structures.

97
Q

Issues with colours

A

Toxicity - colours are not essential
Azodyes - bronchoconstriction in asthmatics especially if aspirin intolerant.
Tartrazine - immunological sensitivity reactions.
Natural colours are often less chemically stable
than synthetics. Changing pH can change the colour (ionise)

98
Q

Flavours

A

To taste (mask) drug

99
Q

Traditional pharmacy flavourings

A 
Oils
Spirits &amp; tinctures
Concentrated waters
Waters
Syrups
100
Q

Oils

A

Pure oil. Very concentrated

- e.g. Peppermint oil. Cinnamon oil.

101
Q

Spirits + tinctures

A

Conc. oils/flavours in alcohol

- e.g. peppermint spirit

102
Q

Concentrated waters

A

Conc. solution or emulsion in water

- e.g. Concentrated Peppermint water, Concentrated Chloroform water

103
Q

Waters

A

Usually the most dilute form
- e.g. Peppermint water, Chloroform water
(often made from Double strength waters)

104
Q

Syrups

A

A flavoured syrup

- e.g. Orange Syrup BP, Blackcurrant Syrup BP

105
Q

What is the function of menthol, thymol and eucalyptol as a flavour/aroma?

A

Decongestant ( eg‘Vicks Vaporub’)

Mildly antiseptic

106
Q

What is the function of chloroform as a flavour/aroma?

A

common flavour & preservative

107
Q

What are the term used on labels when they don’t want
to disclose the flavouring or scenting agents?
Where is the word parfum usually used?

A

Aroma + Parfum

Parfum is usually used on cosmetics

108
Q

Why is a bitterness flavour useful

What is the bitterest material in the world

A

Bitterness is useful as a WARNING and for AVERSION

Bitrex

109
Q

What is the general use of bitrex

A

Prevent poorly sighted people, children and animals (wild and domestic ) eating or drinking dangerous things. Used in pesticides & herbicides, automotive, cleaning fluids, denatured alcohol

110
Q

What is the pharmaceutical use of bitrex

A
  • Surgical spirit
  • Anti-nail biting liquids.
  • Matching the bitterness of drugs in
    clinical trial placebos.
  • Veterinary training products (e.g. dog chewing, tail biting)
111
Q

What is bitrex composed of

A

Lidocaine (local anaesthetic) with an added benzyl group

112
Q

Function of lidocaine

A

Local anaesthetic

Kills any sense of taste

113
Q

Common feature of both lidocaine and bitrex

A

Both have profound but opposite effects on the
sensory nerves involved in taste.
Receptor agonists and
antagonists often have closely related chemical
structures.

114
Q

Function of buffers

A

Stabilise pH

Mixtures of an acid and its salt (or a base + its salt)

115
Q

What is pH

A

The concentration of H+ ions in solution

116
Q

What is a pH range

A

Measures acidity or alkalinity in solution

117
Q

Why is pH important to us as humans? + How do we prevent it from happening?

A

If the concentration of H+ ions is too high or low it damages our bodies : denatures our proteins, messes up all sorts of biochemical reactions, kills our cells etc.

We have detectors for pH on the tongue (sour taste)
and in the body (pain) e.g. bee stings are low pH.

118
Q

Why is control of pH critical in medicines

A

1) Drug solubility - Some drugs only dissolve in a specific pH
2) Chemical stability - To prevent pH-sensitive ingredients changing/degrading
3) Effectiveness of critical excipients - benzoate preservatives effective pH 2-5
4) Prevent pH shift due to dissolving atmospheric CO2 - CO2 causes a shift to acid.
5) Prevent stinging (ouch!) - Eye/nose drops.
6) Prevent blood problems - Large volume injections.
7) Match flavour - e.g. Acid fruit flavours (lemon, strawberry)

119
Q

How do buffers control pH ?

A

When H+ ions are added or removed they change the ratio of salt to acid and this keeps the pH the same.

  • If you add acidic substances (adds H+ ions) = Buffer soaks up the H+ ions by converting salt to acid
  • If you add basic substances (eg OH-) (removes H+ ions) = Buffer adds more H+ ions by converting acid to salt

The net result is H+ concentration in solution stays much the same.……..until you exceed the buffer capacity.

120
Q

What is pKa

A

The pH at which [salt] and [acid] are present in equal molar concentrations.

Buffers are effective at pH values ±1 of their pKa.

121
Q

Which pH is best for Ibuprofen oral liquid

A

Ibuprofen is a carboxylic acid - it ionises over pH 4-6

  • At a low pH, ibuprofen (-COOH) will be poorly soluble + an aftertaste if a little dissolves
  • At a higher pH, ibuprofen (-COO-NA+) will be soluble but tastes horrible
122
Q

Types of sweeteners

A 
Sugars
Sugar alcohol
Simple polyols
Artificial sweeteners
Miscellany
123
Q

Examples of sugars

A

Sucrose, glucose, fructose

124
Q

Examples of sugar alcohol

A

Sorbitol, maltitol, xylitol, mannitol

125
Q

Examples of simple polyols

A

Glycerol

126
Q

Examples of artificial sweeteners

A

Aspartame, Sucralose

127
Q

Examples of miscellany

A

Starch hydrolysates (corn syrup)

128
Q

Property + use of sucrose

A

Syrup BP Vehicle. Rots your teeth. (cariogenic)
66.7% sucrose, almost a saturated solution
Preserves by dehydration (like jam).

129
Q

Properties + use of glycerol

A

Glycerol BP Vehicle. Dehydration preservative

130
Q

Properties + use of sugar alcohol (Sorbitol)

A

Sorbitol BP = vehicle which is 70% sorbitol in water

  • Diabetics usually OK. Metabolised more slowly than sugar so no sudden increases in blood sugar.
  • Tooth decay avoided (non-cariogenic)
  • Calories lower than sugars. Often used in ‘Sugar free’ products but they’re not calorie free !
131
Q

Properties + use of synthetic/artificial sweeteners

A

Different taste. No calories or tooth decay.

Completely different ADME

132
Q

Whats the function of Solubility enhancers

A

Improve drug solubility

133
Q

Examples of solubility enhancers

A

Solubilisers, Cyclodextrins + Cosolvents

134
Q

What are the function of cosolvents + give an example?

A

Salicylic acid 17%
Alcohol 18%
Ether 53%
- to aid solubility

135
Q

Emulsions

A

Liquid medicines in which one insoluble liquid
is suspended as microscopic globules in another.
The two liquids don’t dissolve in each other
( ‘immiscible’).

136
Q

Which medicines are usually emulsions?

A

Cream - Free-flowing liquids
Liquid emulsions - Semi solid, thick consistency,
(because disperse phase is often a wax)

137
Q

What different types of emulsions are there?

A

o/w = oil in water (milky white)
w/o = water in oil (translucent)
w/o/w + o/w/o = multiple emulsions (droplets within droplets)

138
Q

Types of oils

A

Fixed = Vegetable oils (Triglycerides)
Mineral = Liquid paraffin (Hydrocarbon)
Volatile = Oils from plants (various complex structures)
- volatile is used for aroma + flavouring (peppermint oil, lemon oil)

139
Q

Types of instability emulsions suffer from

A

physical, chemical and microbiological instability.

140
Q

Describe the physical instability of emulsions. Explain why it happens.

A

‘creaming and cracking’
(coalescence of droplets leading to growth and separation of the disperse phase)
- creaming = Disperse phase droplets
coalesce (increase in size) and collect near surface.
- cracking = Phase separation. Disperse
phase forms large globules or separate layer on surface

141
Q

Why does ‘creaming and cracking’ happen

A

Emulsions are unstable…they want to separate because of:
1) droplet size = Smaller droplets = more stable.
Hand-made liquid emulsions Stable for 1 week ?
Commercial manufacture uses high shear mixers.
IV emulsion - Intralipid ® ~0.5 micron. Stable 2 years
2) Temperature = Warming or temperature fluctuation accelerates; Freezing/thawing causes rapid separation
3)Type = o/w more stable than w/o (Creams more stable than liquid emulsions)
4) Added ingredients = f interact with emulsifying agent, can destabilise.

142
Q

Describe the chemical instability of emulsions. Explain why it happens.

A

Internal oil phases are sensitive to chemical degradation
- Internal phase has a HUGE SURFACE AREA = high surface area for oxygen + light-catalysed reactions so increased rate of fat oxidation (rancidity)

143
Q

How do we prevent chemical degradation

A

Oil soluble antioxidant

  • Tocopherols (Vit E)
  • BHA (butylated hydroxyanisole)
  • BHT (butylated hydroxytoluene)
144
Q

Describe the microbiological instability of emulsions. Explain why it happens.

A

Emulsions can grow microorganisms

1) o/w = bugs grow well in the continuous water phase. Use oil droplets as food.
2) temperature = temperature dependent
3) preservatives = add for longer term stability
- – interact with emulsifier = destabilise emulsion
- –partition into the oil phase - ineffective

145
Q

Use of oral liquid emulsions

A

Oral liquid emulsions used to administer oils by mouth

  • more palatable = taste better
  • easier to administer
  • more digestable (oil as fine droplets has a high surface area so is digested faster by GI Lipases)
  • more effective (liquid paraffin - not absorbed, more effective as a laxative as a emulsion
146
Q

Use of topical emulsions

A

Topical emulsions - soothe inflamed skin + administer drugs topically

  • hair lotions + shampoos
  • skin infections ( emulsion bases to use as emollients + antipruritics)
  • irritating skin conditions (drugs to treat fungal + parasite)
  • topical lotions + creams (lice, dandruff)
147
Q

What is a Suspensions

A

Liquid medicines in which insoluble solids (usually drug)

are dispersed as fine particles.

148
Q

How does a suspension look under the microscope

A

Vehicle = liquid in which the particles are suspended

Suspended particles = disperse phase

149
Q

What are the main problems of suspensions ?

A

Physical signs of instability are

  • Separation = particles fall due to density differences (redisperse by shaking)
  • Caking = high density sediment of particles (difficult to redisperse)

a UNIFORM suspension will allow the patient to get the same dose of drug every time they pour the medicine = patient gets better

with a SEPARATED/CAKED suspension, an early dose wont work. Later doses will overdose patient + they may need resuscitation.

150
Q

How do we prevent these caking/separation ?

A

1) Shake it - if particles redisperse easily, you can pour accurate dose.
2) Thickening agents - 3 types (Entangling/gelling soluble polymers, colloidal polymers + minerals, colloidal silicon dioxide in an oil)
3) Flocculation - flocs are loose, weakly-bonded, particle aggregates (2 types)
- —adding a surfactant = absorbs + adds surface charge; add salt to adjust charge to get flocs
- — add soluble polymer which absorbs to the particle surface

Shake bottle; flocs break up on shaking + particles redisperse to uniform suspension; flocs re-form on standing to prevents caking

151
Q

Function of thickening agents

A

Substance that increases the viscosity of a liquid without substantially changing its other properties.

152
Q

Entanglement

A 
Polymer chains are extremely long and will entangle each
other. 
In dilute solution this
increases the viscosity of the vehicle.
Concentrated solutions are
commonly called gels
153
Q

Entanglement with junction zones

A

Bonds or ordered structures form between the chains. These ‘ junction zones’ act as molecular cross-links, making the gel stronger and more rubbery.
This structure is a ‘true’ gel to a polymer or food scientist.

154
Q

Colloidal polymers/minerals

A

Very small plate-like particles finely dispersed in the liquid
They thicken by ‘charge dispersal’ = Particles are charged. Repulsion keeps particles at a distance from each other, so the whole liquid resists movement.

Examples = Carbomer (synthetic polymer), Bentonite (clay), ‘Veegum’ Aluminium mag. silicate
(mineral), Colloidal silicon dioxide.

155
Q

Colloidal silicon dioxide

A

For gelling oil
Very small particles that form linked networks in the oil
Network breaks up when stirred (gel gets thinner)
Reforms on standing (gel thickens). This is called Shear thinning behaviour

e.g. xanthan gum

156
Q

Properties + use of thickening agen

A

At low concentration = increase vehicle viscosity, keep drugs suspended + maintain dose uniformity in suspensions

At high conc = semi-solid gels; transparent gel base for pharmaceuticals + cosmetics

Thicken liquids for greater residence time at site of action (e.g. eyedrops, teething + mouth ulcer gels)

157
Q

What are the different categories of thickening agents

A

Entanglement/gelling polymers + minerals
Colloidal soluble polymers
Colloidal silicon dioxide

158
Q

What is a Cream

A

Creams are emulsions
in which one phase is a
semisolid/wax

159
Q

Types of creams

A

o/w cream

w/o creams

160
Q

O/W creams

A

Water is the continuous phase

  • cream can mix with wound exudates
  • feel cool as water phase evaporates
  • allow wounds to dry
  • used in acute conditions as not occlusive
  • acceptable to patients
  • less greasy /sticky than ointments
  • rub-in well into the skin
161
Q

W/O creams

A

Oil is the continuous phase:

  • ‘Oily creams’
  • Tend to be ‘occlusive’ (see ointments)
  • Make dry skin more supple : ‘moisturising’.
  • Protect against water : nappy rash, sun/sea
162
Q

Use of Skin creams

A
  • Common as cosmetics.
  • Deliver a wide range of drugs to skin :
    antibiotics, antivirals steroids,antifungals
    Fungal infections of damp areas
    eg miconazole creams for athletes foot,
    sweat rash, jock itch, nail infections
163
Q

Use of common creams for body cavities

A

Clotrimazole Combi-packs for vaginal thrush

  • 10% cream for intravaginal use in an applicator
  • 2% cream for outside
  • 2% cream for partner

Rectal cream for haemorrhoids (piles)
e.g. Anusol cream – tube with long applicator

164
Q

What is an ointment

A

Spreadable greasy semi-solids, which may contain:

  • dispersed powders
  • small amounts of aqueous liquids

The base (vehicle) is
- a mixture of waxes, fats and oils (triglycerides)
- usually hydrophobic (water repellent)
The base is a uniform mixture has the wax, fats + oils dissolve in each other when melted

165
Q

What is a paste

A

Ointments with a high powder content

166
Q

Name some ointment ingredients and how they differ

A

Hydrocarbons (Paraffins)

  • unreactive
  • different forms (smaller mw = liquids, longer mw = light paraffin)

Fatty alcohols, acids and esters

167
Q

Uses of creams

A

Skin creams

Common creams for body cavities

168
Q

Triglycerides

A

Triglycerides are esters of long chain fatty acids with glycerol.

  • Common as animal and vegetable fats and oils
  • Vegetable oils have more unsaturated bonds. (e.g. Sunflower oil is a ‘polyunsaturate’) => animal fats tend to be saturated

When unsaturated bonds oxidise and ester groups oxidise, it forms short-chain fatty acids which are very smelly.
- ‘RANCIDITY’ = degradation of fats & oils

169
Q

Uses of ointments

A

Occlusives

Protectives and Emollients

170
Q

Occlusives

A

Trap sweat and water vapour under the skin to increase
skin hydration
• Make dry skin more supple.
• Soften the Stratum Corneum.
• Used in Chronic dry skin disorders. eg eczema.
- prevents skin cracking

171
Q

Protectives + emollients

A

Barrier to protect against water and wind
– Cracked lips = Lip Balm
– Nappy rash = Ointments, w/o creams
– Emollients = skin itching e.g. in eczema

172
Q

Problems with ointments

A
  • Greasy & messy
  • Stains clothing and not easily removed from skin.
  • Not for acute inflammation (oozing, red, infected) as these require:
  • – Drying and cooling
  • – o/w creams
  • – Aqueous lotions
If you occlude a wound it :
• Prevents drying
• Raises skin temp
• Bacteria grow
• Difficult to clean the lesions
173
Q

Structure of the nose

A
  • olfactory area = area of smelling receptors
  • turbinate bodies
  • – Humidify and warm air to lungs.
  • – Rippled - large surface area.
  • – Lots of blood vessels near surface.
  • mucosal surface
  • – Mucus traps particles.
  • – ‘Cilated’ epithelium - yellow area
  • –‘Mucociliary clearance’ in 10-20 min
174
Q

Structure of the eye

A
  • eyelids + glands = eye creams + ointments
  • cornea
  • anterior chamber
  • lens, iris, muscles
    (cornea, anterior chamber + lens, iris + muscles use eyedrops)
  • posterior (back of the eye) = Systemic drugs or direct injection
175
Q

What type of medicines do we use to deliver drugs to different parts of each organ?

A

Creams and ointments - For external parts
(Areas where the surface structure is skin)

Drops / nasal sprays - For areas they can access.
Drugs can be absorbed through thin membranes like the cornea but don’t expect them to penetrate deeply.

Systemic therapy - For areas drops can’t access.
Drugs by mouth or injection. Drug reaches the organ by
diffusing into tissues from the bloodstream.

176
Q

What things do we need to consider when formulating liquids for use in these areas?

A

Isotonic with blood
pH adjusted
Irritancy tested
— Disease state can make eyes and nose extremely sensitive to stinging.
Low cilia toxicity - To be healthy, nose needs good muco-ciliary clearance
Vehicle - Prevents ‘Swimmers ear’
Polymer thickeners - Help retain drops at site. May be muco-adhesive
Preservatives - Prevents re-infection from the dropper tip.
Sterile (no microbes) - the dropper tip. Damaged eye has particularly poor immune defences against infection.

177
Q

What types of injections are there ?

A

Large volume infusions

  • 100ml to 3L bags
  • Fluid replacement
  • Parenteral nutrition emulsions

Small volume infusions

  • single injections = Pre-filled syringes are supplied to wards
  • multidose injections - reconstituted in pharmacy sterile unit
178
Q

Main routes of injection

A 
IV Intravenous = Vein
IM Intramuscular = Muscle
SC Subcutaneous = Under the skin
ID Intradermal = Into the dermis
IT Intrathecal = Spinal fluid
179
Q

What things do we need to consider when formulating liquids for use as injections?

A
  • Sterile (no microbes) = prevents infection
  • No microbial waste products (Pyrogens) = prevents rise in body temperature
  • IV particle free unless emulsion = prevents clotting
  • Isotonic with blood = prevents stinging
  • pH adjusted (pH 7.4 best) = blood is a good buffer
  • Preservatives = Multidose injections
  • Irritancy = Irritant drugs can cause tissue damage (necrosis) e.g. anticancer drugs
  • Solubilisers, stabilisers, cosolvents = maintain drug solubility + stability
180
Q

What problems do we have with the public perception of excipients ?

A 
Excipients are known to the public as:
• Additives
• E-numbers
• Artificial ingredients
• Chemicals

They have had A Bad Press, Big-time !
• Lots of ‘Scare stories’ - Foods and medicines
• People are confused
• What is safe and what is not ?

181
Q

How can the Pharmacist play a role in making the public accept excipients?

A

Advise the public when they are worried or misinformed

All excipients in medicines have a function
• Maintain chemical stability of the drug
• Prevent microbial growth in the medicines
• Ensure homogeneity - same dose everytime
They have been tested for toxicity.
Some people may react
Only a few excipients have been linked with adverse reactions
• But there are lots of scare stories.
• Which ones are true ?

182
Q

What is emulsifierss ?

A

Prevent droplet coalescence

183
Q

What molecular characteristic do all emulsifiers possess?

A 
Hydrophobic tail (dissolves in oil)
Hydrophilic head (dissolves in water)

These molecules locate at oil/water or air/water interfaces

184
Q

What types of emulsifier are there ? Name an example of each type.

A

Anionic (negative) = Sodium dodecyl (lauryl) sulphate
Cationic (positive) = Cetrimide (CTAB)
Non-ionic = Cetostearyl alcohol

185
Q

Explain the different ways emulsifiers can work

A 
Surfactants
• Accumulate at water oil interface.
• Form an interfacial barrier.
• But charged molecules repel. – only a thin layer
• Not good for stabilising emulsion

Polymers and proteins

  • Proteins have hydrophilic and hydrophobic areas and are amphiphilic.
  • Adsorb at interface, meaning, they’re good emulsifying agents.
  • They can bridge between droplets. OIL and therefore act as suspending/flocculating agent
186
Q

Why does using a mixture of emulsifiers often result in a better emulsion than a single charged one ?

A

Mixed emulsifier surfactants
• Mix of hydrophilic + more lipophilic ampiphiles
• Denser interfacial film.
• Excellent for stablising emulsions.
• Widely used in creams (concentrated emulsions)
— e.g. emusifying wax BP (Sodium dodecyl sulphate (charged) with cetostearyl alcohol (non-ionic); Instant stable emulsions and creams (just add oil and water)

187
Q

Name a natural emulsifier

A

Lecithin (egg yolk) - phospholipid

Whey proteins.- Milk is a stabilised emulsion

BPH (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions