OSCE Formulations

Question 1

Identify the excipient in Dentinol Colic Drops used as an emulsifier and explain how it works.

Answer 1

Carbomer.
Expands upon contact with water, increasing the viscosity of the formulation and allowing the dispersed phase to be retained in solution more evenly.

Question 2

Identify the excipients in Dentinol Colic Drops used to improve the palatability and explain how.

Answer 2

Sucrose- sweetener

Dill oil- masks smell

Question 3

Which excipient in Dentinol Colic Drops acts as a preservative? Describe its composition.

Answer 3

Nipasept is composed on benzoate compounds. These are paragons that exhibit antimicrobial properties (E numbers):
Methylhydroxybenzoate E218
Ethylhydroxybenzoate E214
Propylhydroxybenzoate E216

Question 4

What type of emulsion is Dentinol Colic drops? Why?

Answer 4

Oil in water.
When added to water, the water volume increases and a thin oil layer forms. Dimethicone makes up the oil phase as it is hydrophobic.

Question 5

How long should Selsun shampoo remain in contact with the skin?

Answer 5

2-3 minutes to allow the drug to have the desired effect without causing irritation.

Question 6

What advice should be given to patients who wish to colour their hair after using Selsun shampoo?

Answer 6

Selsun shampoo shouldn’t be used two days before or after applying colour to the hair. Patients should be advised that the medication can cause discolouration if used prior to dyeing. This is unlikely providing that they rinse their hair thoroughly after use.

Question 7

Which excipient in Slsun shampoo is used as a suspending agent? Can it be used in oral suspensions?

Answer 7

Bentonite.

Cannot be used internally but is found in many external suspensions.

Question 8

Which excipient in Selsun shampoo causes it to foam? What group of excipients do they belong to? How do they clean the scalp?

Answer 8

Monoethanolamine laurel sulphate and empigen BB.
They are both surfactants, helping to clean the scalp by forming a lather that allows the drug to be evenly distributed over a larger surface area.

Question 9

What is the normal dose of Nystan suspension for a child? How can this be measured?

Answer 9

1mL to administered 4 times daily. It can be measured accurately using the measuring dropper provided as this quantity cannot be precisely measured with a 5mL spoon.

Question 10

What flavour is Nystan suspension? Why is this important?

Answer 10

It is cherry flavoured making it more palatable. This is important in making the drug more appealing to the patient, unpleasant tastes can be off putting and may lead to non-adherence, especially in children.

Question 11

Identify the excipients in Nystan suspension used to increase viscosity? Why is this important?

Answer 11

Sodium carboxymethylcellulose E466 and glycerin.
Increasing viscosity allows the medication to remain in contact with the affected area for a longer period for this particular formulation. In suspensions, the viscosity is extremely important in order to maintain stability, drug particles sink to the bottom of the suspension over time. The less viscous the solution, the more accelerated this process is.

Question 12

Is Nystan suspension for local or systemic use?

Answer 12

Local for use in fungal infections of the mouth e.g. thrush. It should be applied to the affected area and remain in contact for as long as possible, it is unnecessary for the medicine to pass through the blood to reach its target location.

Question 13

How do Aspirin dispersible tablets dissolve?

Answer 13

They disintegrate into solution, they do not fizz.

Question 14

Identify the excipients in aspirin dispersible and co-codamol effervescent tablets used to improve palatability. how does this occur?

Answer 14

Aspirin- sodium saccharin is an artificial sweetener.
Co-codamol- sorbitol and sodium saccharin are artificial sweeteners. Dimeticone is an anti-foaming agent, breaking down gaseous bubbles formed during dissolution, reducing risk of bloating.

Question 15

Identify the excipient in aspirin dispersible tablets used to aid dissolution. What type of excipient is it? Explain its mechanism.

Answer 15

Starch.
Upon contact with water, the starch swells, overcoming the adhesiveness of other components and causing the tablet to fall apart.
Calcium carbonate reacts with citric acid upon contact with water producing carbon dioxide, aiding dissolution.

Question 16

What are the benefits of an aspirin dispersible formulation as opposed to standard tablets?

Answer 16

They can be given to patients who cannot or don’t like swallowing tablets, especially in the elderly. Also useful in exceptional cases in children, such as Kawasaki’s disease.

Question 17

Give examples of groups of people who would have difficulty administering Hypromellose eye drops.

Answer 17

Children, elderly, those with manual dexterity problems.

Question 18

What preservative is used in Hypromellose eye drops? Why is this important?

Answer 18

Benzalkonium Chloride.

Bacterial growth in medication can lead to infection.

Question 19

Are there any groups of people who are unable to use Hypromellose eye drops due to the addition of the preservative?

Answer 19

Those with hypersensitivity, people who regularly wear contact lenses, patients with chronic dry eyes as it can cause damage to the tear film and ocular surface.

Question 20

How long can Hypromellose drops be used for once opened? Why?

Answer 20

Can be used for up to 4 weeks, or the expiry date, whichever comes first. After opening, there is a risk of contamination and bacterial growth.

Question 21

Comparing Otrivine and Vicks, which delivers the most accurate dose? Why?

Answer 21

Otrivine- squeezable plastic bottle with spray opening, different pressures can result in dose variability.
Vicks- glass bottle with spray pump, pressurised aqueous solution that is more accurate as a single metered dose is administered each time.

Question 22

Which excipients in Vicks help to prevent bacterial growth? Why is this important?

Answer 22

Chlorhexidine gluconate and Benzalkonium chloride.

Bacterial growth in medication can lead to infection.

Question 23

What is the likely function of sodium hydroxide in Vicks? Why is this important in nasal sprays?

Answer 23

Forms a buffer with citric acid to maintain a constant pH, which in nasal sprays should be within the range pH 5.5-6.5. This is to avoid irritation of nasal mucosa, ensure normal mucociliary clearance is maintained, ensure the active substance solubility in unionised form is suitable for absorption, prevent pathogenic bacterial growth, maintain functionality of preservatives.

Question 24

Which excipient is most likely to be the vehicle in Vicks Sinex pump spray?

Answer 24

Purified water.

Question 25

Why is chewing Gaviscon tablets beneficial to their mode of action?

Answer 25

The tablet is broken down into smaller pieces, increasing its surface are and allowing it to have a more widespread effect in the stomach.

Question 26

Why can Gaviscon chewable tablets not be swallowed whole?

Answer 26

The tablet is too large, if a patient attempted to swallow it whole they would be at risk of choking as it is likely to get stuck in their throat.

Question 27

What are the functions of mannitol in Gaviscon chewable tablets?

Answer 27

Increasing palatability as an artificial sweetener.
Have a negative heat of solution, giving a cooling/soothing feeling in the mouth.
Acts as a filter/diluent, binding to the API and making up the bulk of the tablet, compressing ingredients and imparting its properties onto the rest of the granulation.
Improves solubility, dissolution and stability due to chemical inertness, it will not react with other excipients.

Question 28

What additional excipients are needed in chewable tablets? Identify these in Gaviscon chewable tablets.

Answer 28

Flavourings and sweeteners create a more pleasant taste as these tablets are not swallowed whole. Peppermint flavouring is used in Gaviscon and the sweeteners are mannitol, aspartame and acesulfame K.

Question 29

Which excipients in Bazuka gel are responsible for the drying effect?

Answer 29

Ethanol and ethyl acetate. They evapourate when applied to the skin so create a cooling effect.

Question 30

Identify and describe the excipient in Bazuka gel responsible for the colloidal nature of the product.

Answer 30

Proxylin.

A mixture of cellulose nitrates that produces a film over the area, forming an occlusive layer.

Question 31

What are the functions of camphor and castor oil in Bazuka gel?

Answer 31

They increase the viscosity of the gel, making it easier to apply. Camphor creates a waterproof coating protecting the skin and castor oil acts as a plasticiser making the film flexible.

Question 32

Does the patient require a plaster after applying Bazuka gel? Why?

Answer 32

No.

The gel forms a hard protective layer once dry due to its excipients meaning there is no need for a plaster.

Question 33

What type of product is Canesten pessary?

Answer 33

A compressed powder tablet pessary containing 100mg of clotrimazole. It is inserted into the vagina using an applicator.

Question 34

Describe what happens when Canesten pessary is added to water. Which excipients cause this? Why is this important?

Answer 34

Maize starch swells upon contact with water/moisture, causing the tablet to disintegrate and release the active ingredient. This ensures that the drug is released at the appropriate time.

Question 35

Can Canesten pessaries be used in pregnancy? Explain.

Answer 35

It may be used without the applicator if necessary, the active ingredient is not a problem in pregnancy but use of the applicator may disturb the foetus.

Question 36

What is the function of hypromellose in Canesten pessaries?

Answer 36

Acts as a binding agent, forming a film around the liquid to prevent it from flowing out before administration.

Question 37

How is the nozzle of Fleet Enema lubricated before insertion?

Answer 37

The nozzle sits in a sheath allowing it to be pre lubricated with white soft paraffin. This means that the patient does not have to lubricate it themselves.

Question 38

Why is it important not to refrigerate Fleet enema?

Answer 38

The product is formulated for use at room temperature, refrigeration may alter the stability of it. It also may be more uncomfortable for the patient to administer.

Question 39

What should the patient expect after using Fleet enema? What advice could be given?

Answer 39

The patient should be prepared to expect frequent loose bowel movements within 5 minutes of using the product so should be advised to remain near toilet facilities until the effects wear off.
They should drink plenty of fluids, approximately 250ml of water every hour until effects completely wear off to avoid dehydration.
Leakage is normal as there is a larger quantity of liquid being administered to the bowel, this will not affect the action of the medication.

Question 40

What volume of liquid is inside Fleet enema? How much is inserted into the rectum? Why?

Answer 40

There is 133mL of liquid in the enema, only 118mL is generally delivered to the rectum due to leakage and a small remainder left in the bottle.

Question 41

What are Scopaderm patches used for? How long do they last? How is this useful for their application?

Answer 41

The indications for Scopaderm are travel sickness and vertigo. They can be left on the skin for up to 3 days (72 hours) which is beneficial as the patches are long acting, modified release so can be applied to combat indications over long periods such as long journeys.

Question 42

How long does it take for Scopaderm to become effective? Why?

Answer 42

It can take up to 6 hours after application for the patch to be effective. This is because the drug must cross the rate limiting membrane of the patch before absorption through the skin and into the blood. Therefore, it takes time for effective concentrations of the drug to be present in the bloodstream.

Question 43

Describe the appearance of Scopaderm patches and the drug delivery method.

Answer 43

The patches look like plasters and are skin coloured so very discreet upon application. This discretion however is limited to particular skin tones/ethnicities. It is a transdermal patch that delivers the drug, hyoscine, via absorption through the skin.

Question 44

IS it possible to bathe/swim whilst wearing Scopaderm patches? What should the patient do if the patch falls off?

Answer 44

Swimming and bathing are permitted however prolonged contact with water may cause the patch to fall off. If this occurs, it should be disposed of and a new patch applied if required.

Question 45

Comparing to E45 and Bongela, describe the look and feel of Doublebase gel.

Answer 45

Bongela- clear in appearance, water based so provides a cooling effect.
E45- white in appearance, heavy and oily making it hard to rub into the skin.
Doublebase- white in appearance, a cross between a gel and a cream, much lighter and easier to rub into the skin than E45.

Question 46

Which excipient is responsible for forming the gel in Doublebase? How?

Answer 46

Carbomer.
It is a polymer which absorbs water, giving the product a gel like consistency. It swells upon contact with water forming a gel matrix, this also increases the stability of the formulation.

Question 47

What is sorbitan laurate? Why is it used in Doublebase gel?

Answer 47

Sorbitan laurate acts as an emulsifying agent ensuring the water and oil phases mix together evenly.

Question 48

Describe the function of glycerol in Doublebase gel. Why is it important?

Answer 48

Acts as a humectant, reducing water loss in the product and maintaining its stability. It is also used for its emollient properties.

Question 49

There is no preservative in Simple eye ointment, explain why.

Answer 49

There is no need as the product does not contain any water, meaning little risk of bacterial growth.

Question 50

Identify the main excipient in simple eye ointment that may cause side effects. Why?

Answer 50

Anhydrous lanolin, wool fat, may cause skin irritation as it is a relatively common allergen.

Question 51

Describe disadvantages of Simple eye ointment compared to eye drops.

Answer 51

A thin line is harder control than a single drop.
Ointment may cause prolonged blurred vision.
As they are solely fat/oil based, ointments are harder to squeeze out because they are more viscous than eye drops.

Question 52

Describe advantages of Simple eye ointment compared to eye drops.

Answer 52

Lack of water means a longer shelf life and less risk of bacterial contamination.
Ointments contain fewer excipients so are much safer.
Ointments hold better within the eye, drops tend to run.
After application, ointments break into smaller drops which remain in the conjunctival sac for longer, thus increasing the bioavailability of the drug.

Question 53

What type of inhalers are Easibreathe and Autohaler? How are they different to standard MDIs?

Answer 53

Breath actuated MDIs are automated, they work in response to inhalation which triggers the operation of the device and release of the dose. They respond to inspiratory flow so the user simply needs to lift the lever and inhale into the device, automatically releasing a dose.

Question 54

Which patient groups may benefit from using Easibreathe/Autohalers?

Answer 54

Children and the elderly. Lack of coordination and manual dexterity can make using standard MDIs very difficult. Automated inhalers remove the need for coordination as the user doesn’t need to press to receive a dose.

Question 55

In the Autohaler, what is the function of the release slide on the bottom of the device? When should it be used?

Answer 55

The lever releases a dose of medication without breath-actuation. This is used to check whether the inhaler is empty/working correctly. Patients may use it to check if there are any doses left after prolonged use of if the inhaler hasn’t been used for a period of 2 weeks or more.

Question 56

Do Easibreathe/Autohalers require a propellant? Why?

Answer 56

Although breath actuated, so the breath draws in the drug, these inhalers do contain propellants. These allow the solid drug particles to be delivered as a fine mist. This increases the likelihood that the drug will reach its target location. At room temperature, the propellant is a gas, so the medication is stored in a small pressurised cannister.