Pharmaceutics Flashcards

1
Q

Which animal insulin is most similar to humans?

A

Porcine

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2
Q

How many amino acid differences are there between human and porcine insulin?

A

1

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3
Q

How many amino acid differences are there between human and bovine insulin?

A

3

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4
Q

How many amino acid differences are there between human and sheep insulin?

A

4

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5
Q

Who helped to solve the potency loss and solubility problems with insulin?

A

Walden

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6
Q

How did walden help to solve the potency loss and solubility problems with insulin?

A

Recognised the potent material was in a discarded precipitant. Led to process of isoelectric precipitation with standardised purity and potency

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7
Q

How was human insulin manufactured?

A

Combinations of A and B chains individually expressed in E. coli

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8
Q

Features of hexamer insulin?

A

Stable but not biologically active. Minimal diffusion into capillaries

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9
Q

Features of dimer insulin?

A

Biologically active but less stable then hexamer. Limited diffusion into capillaries

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10
Q

Features of monomer insulin?

A

Biologically active but not stable. Rapid diffusion into capillaries

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11
Q

What is NPH insulin?

A

Neutral protamine hagedorn

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12
Q

What causes NPH insulin to have a longer action?

A

Provided as a crystalline suspension of insulin with protamine and zinc

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13
Q

What is the only type of insulin which is typically cloudy?

A

Insulin NPH

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14
Q

Why is insulin NPH cloudy?

A

Due to added crystals

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15
Q

Why is zinc used in insulin?

A

Used as a delaying agent. Size of crystals is proportionate to duration of action

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16
Q

Why is insulin glargine long-acting?

A

One amino acid replaced by two a mini acids at the end of B chain.
Makes it more soluble at acid pH compared to physiological pH
Acid solution microprescipitates after injection due to reduced solubility
Crystals dissolve slowly to release insulin slowly

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17
Q

Why is insulin detemir long-acting?

A

One amino acid omitted from end of B chain and replaced with fatty acid.
Action is extended because it’s altered form make it stick to itself at the injection site.

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18
Q

Why is insulin lispro rapid acting?

A

Lysine and proline residues are switched on C-terminal of the B chain. Modification prevents dimers from forming so injection only contains monomers

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19
Q

How was insulin aggregation in continuous subcutaneous insulin infusions resolved?

A

Using less aggregating insulin such lispro

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20
Q

Inhaled insulin has a similar kinetic profile to what type of insulin?

A

Fast acting

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21
Q

Why was inhaled insulin removed from the market?

A

Poor sales volume due to cost

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22
Q

What is viscosity?

A

An expression of the resistance of a fluid to flow

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23
Q

What is a Newtonian fluid?

A

The viscosity does not change with the shear rate

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24
Q

Examples of Newtonian fluids?

A

Water
Honey
Pharmaceutical dosage forms with high water content

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25
Q

Why does the velocity change when it is close to a wall?

A

It is much lower due to intermolecular interactions (adsorption)

26
Q

Why is it only possible to manufacture certain concentrations of insulin?

A

The adsorption rate is inversely proportional to the insulin concentration. So if the concentration is too high more will adsorb to the surface of the syringe

27
Q

Reynolds’s three regions of flow?

A

Laminar flow
Turbulent flow
Transition flow

28
Q

What is laminar flow?

A

Seen in the low-velocity region
Dye formed thin, straight streak down the pipe with no mixing
All motion in axial direction
Pressure drop per unit length is proportional to flow rate

29
Q

What is turbulent flow?

A

In high-velocity region
Dye was rapidly mixed throughout the pipes
Rapid, haphazard motion in all directions along with the axial flow causes mixing of the dye

30
Q

What is transition flow?

A

Flow is either laminar or turbulent and alternates depending on conditions
Conditions can include roughness of pipe wall, equipment vibrations

31
Q

What two forces did Reynolds determine were acting on the flow of fluid?

A

Inertial (velocity)
Viscous

32
Q

What do inertial forces do in fluid flow?

A

Maintain flow and it’s general direction

33
Q

What do viscous forces do in fluid flow?

A

Retard the general motion of fluid and introduces eddies (swirls)

34
Q

What does a Reynolds number <2100 show?

A

Laminar flow

35
Q

What does a Reynolds number 2100-4000 show?

A

Transition flow

36
Q

What does a Reynolds number >4000 show?

A

Turbulent flow

37
Q

What factors does Reynolds number look at?

A

Density of fluid
Velocity of fluid
Diameter of pipe
Viscosity of liquid

38
Q

Reynolds number equation?

A

Fluid density x fluid velocity x diameter
——-————————————————
Fluid viscosity

39
Q

Which forces dominate with a high Reynolds number?

A

Inertial

40
Q

Which forces dominate with a low Reynolds number?

A

Viscous

41
Q

Why is Hagen-Poiseuille’s law relate to pharmacy?

A

A small increase in the radius of a needle can reduce the pressure required to deliver the drug

42
Q

What does a needle gauge need to consider?

A

A balance between insertion pain and force required to administer the dose effectively

43
Q

What does Hagen-Poiseuille’s law take into consideration?

A

Radius of capillary
Time of flow
Pressure difference
Length of capillary

44
Q

How to measure viscosity?

A

Use a capillary viscometer. The time is takes the solution to drop from the start point to the end point

45
Q

What is stability testing used for?

A

Evidence for how quality of product varies with time
Establishes shelf-life
Determines storage conditions
Determines suitability of containers

46
Q

Factors that can influence chemical stability?

A

Temperature
Light
Oxygen
Moisture
pH
Ionic strength
Excipients

47
Q

What does ICH stand for?

A

International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use

48
Q

What is the ICH?

A

committee that provides the pharmaceutical stability guidelines for industries

49
Q

What is long-term stability testing?

A

performed for a longer duration of the test period to allow significant product degradation under recommended storage conditions.

50
Q

What is accelerated stability testing?

A

a means of comparing alternative formula-dons, packaging materials, and/or manufacturing processes in short-term experiments. Usually high temperature studies

51
Q

Uses of accelerated stability testing?

A

Product development
Quickly predict shelf life
Variables can include temperature, light, humidity

52
Q

Purpose of the Arrhenius equation?

A

Explains the effects of temperature on a rate of reaction

53
Q

How much does the speed of a reaction increase with a 10°c rise in temperature?

A

~2/3 times

54
Q

What do peaks in a chromatogram show?

A

A separated component

55
Q

What is the time it takes for a sample to come off a chromatography column?

A

Retention time

56
Q

Two main ways to interpret a chromatogram?

A

1) peak height
2) peak area

57
Q

Five principles for the procurement and supply of specials?

A

1) understand the patient’s experience and make a shared decision
2) establish the optimal treatment
3) identify a preparation and supplier
4) monitor and review the need for the special
5) ensure effective governance

58
Q

What is the pharmacist responsible for when dealing with UK specials?

A

Assessing clinical suitability
Checking manufacturer has an appropriate license
Ensuring product meets purchasing specification
Assess evidence that supports the formulation and shelf life

59
Q

What is the pharmacist responsible for when dealing with extemporaneous preparations?

A

Assessing clinical suitability
Ensuring medicine is made in a registered pharmacy
Ensuring product meets purchasing specification
Assess evidence that supports the formulation and shelf life

60
Q

What is a normal phase HPLC assay?

A

Mobile phase is non-polar
Stationary phase is polar

61
Q

What is a reverse phase HPLC assay?

A

Mobile phase is polar
Stationary phase is non-polar