Nitrile valve or meter valve is a type of primary packaging material. A nitrile valve consists of three elastomeric components, a metal spring, a metal ferrule, and the remaining component, which can be metal or molded plastic. A nitrile valve adjusts the cap and a cap seal is positioned between the cap and canister to provide a sealed canister.
A molded plastic that allows for increased flexibility in part design compared to the drawing process used for metal components.
A metal component includes lower cost, temperature, recycling effects and reduced moisture ingress into the formulation for metal valve stems. Its materials use the uniformity of the dose and extractable and leachable have resulted in a change in the material used in valve component.
So, the nitrile valve/meter valve has an important role in the meter-dose inhaler, its quality better follows some testing parameters,
1. Description:
Metered Valve 50 MCL OR other MCL with pre-ring inverted position.
2. Dimension
- The outer diameter of aluminium ferrule: take 5 selected samples in the lot. Measure the nitrile valve and the outer diameter of aluminium ferrule with the help of a Vernier caliper. Take reading and note down it
- Ferrule/cap diameter: take 5 samples of nitrile valve in lot. Measure the nitrile valve of ferrule/cap diameter with a Vernier caliper. Take reading and record it reading.
- Cap without upper stem: take 5 samples in lots. Measure the nitrile valve of the cap without upper stem with the Vernier caliper. Take reading and record the reading
3. Shot weight test
- take a filled aerosol canister along with an actuator and dust cap
- First of the prime the inhaler, the cap off the mouthpiece and shake the inhaler well.
- Then spray the inhaler into the air, away from your face, avoid spraying in your eyes
- Shake and spray the inhaler like this 3 more times to finish priming it
- Weight the inhaler without the dust cap with using of balance, note down the weight of the filled aerosol canister
- Tare the weighing balance and spray the inhaler into the air away from the face
- Note down the 1st shot weight
- Repeat the same process 10 times to check the shot weight.
4. Leakage test
- Selected 12 filled propellant canisters.
- Take the weight of each container to the nearest in mg and record the weight in the mg each as W1
- Allow the canister to stand in an upright position at a temperature of 250 C Record the date and time to the nearest half hour. For not less than 3 days (72 hours)
- After 3 days again weigh each container, record the weight in mg of each as W2, and Record the date and time to the nearest half hour.
- Determine the time T in hours during which the canisters were under test.
- Calculate the leakage rate, in mg per year of each canister taken by the formula
(365)(24/T)(W1-W2)
T= 3 Day (3x 24=72 hours)
W1= Initial weight
W2= final weight
- The requirements are met if the average leakage rate per year for the 12 canisters is not more than 3.5% of the net fill weight.
- None of the container lakes more than 5.0% of the net fill weight per year.
- If 1 canister leaks more than 5.0% per year, and if none of the canister leaks more than 7.0% per year.
- Determine the leakage rate of the additional 24 canisters a direction in herein, not more than 2 of the 36 canisters leak more than 5.0% of the net fill weight per year.
- None of the 36 canister containers leaks more than 7.0% of the net fill weight per year.
- Where the net fill weight is less than 15g and the label and expiration date the requirement are Mets
- If the average rate of the 12 canister is not more than 525mg per year.
- None of the canisters leaks more than 750 mg per year,
- If the canister leaks more than 1.1gm per year
- Determine the leakage rate of an additional 24 canisters as directed herein
- Not more than 2 of the 36 canisters leak more than 750 mg per year.
- None of the 36 canister leak more than 1.1gm per year
- This test is in addition to the customary in-line leak testing of each canister
5. Silicon test
Silicon is commonly used in nitrile valves as a lubricant utilized in meter dose inhalers. It is between 50 to 350 micrograms per nitrile valve. Silicon is impacting the overall performance of the meter dose inhaler.
Silicon reduces the friction and drug deposition in HFA formulation using metal and plastic nitrile valves. In a study, the change in particle size distribution over time was attributed to the drug product having an increased propensity to aggregate in the presence of silicone oil.
The efficient particle capture coats the particle collection surface of each stage with silicone, deposited from a volatile solvent
6. Check for contamination
should be free from dirt foreign matter or any other contamination both inside and outside.
I am Maneesh Maurya a professional pharmaceutical blogger from India having rich experience in the pharmaceutical Quality control field.
[…] The Canister for use in meter dose inhalers (MDI)especially a canister that may contain and dispense pressurized formulations of pharmaceutical substances in propellant for example hydrofluroalkane propellants. It contains a nitrile valve (meter valve). it is a complete set connected to the actuator. meter dose inhaler is divided into parts the actuator, canister, and meter valve. […]
[…] inhaler packaging of the actuator is used in meter dose inhalers. It has three parts, a canister, a metering valve, and an actuator. The meter-dose inhaler actuator for pressurized aerosol containing a formulation […]