# ANOVA and Test Method Validation for a Drug Delivery Device

S

#### stevoc

I've been tasked with validating a test method and would welcome any comments on the approach I've taken.

We've developed a drug delivery device that delivers a small dose of a gel lie substance from a manual pump. The dose specification is the weight of drug supplied by a full operation of the pump.

A manual dosing test has been developed and I now need to demonstrate that this method is valid.

I've had some testing done - 3X operators have taken 12X consecutive doses from each of 5 devices. I've been analysing the data using ANOVA.

I've compared the data sets for each operator with each other (at device level - so all the device 1 and also teh combined) and have calculated F values well below those from the tables.

Does that mean I conclude that there is no significant difference in the means?

thanks

Steve

R

#### RONQUILLO

Hello Steve,

Maybe I need more information about the test, however the F values calculated are well below compare with F critical (from tables) means that no significant difference that you said in others words with any operator the results are similar, the variations is for common variation not special; so you can use someone of them without affect the test.

S

#### stevoc

Maybe I should make it clearer what I'm trying to achieve. The device we're testing delivers a fixed volume of drug with each manual operation. The drug containers holds enough drug for multiple operations.

12 consecutive doses have been delivered from each of 5X devices

A1, A2, A3 ....A12
B1, B2, B3 .....B12

etc

These tests have been repeated by 3X operators.

When I use ANOVA to analyse the means from each operator (60 doses per operator), I get a F value of 1.254. When I look up the value for Fcrit from the distribution tables F(0.5,df2,df177) = 2.9957, so I conclude that there is no significant difference between the means and that my test method is valid?

I'd appreciate any comments on that approach

many thanks

Steve

Last edited by a moderator:
R

#### RONQUILLO

Steve,

Remember the Anova always use the initial hipotesis that:

Operator 1 = Operator 2 = Operator 3

I mean all the doses per operator not have variations by special causes, the variation are by comun causes that every operator can have, if F calculated was bigger that F critical (from tables), so you have the next case:

Operator 1 <=> (Different) Operator 2 <=> Operator 3 or at least two operators have significant differences; in this case you need to check the method; but you have the first case so your method is valid.

Kind Regards

Jaime Cort

S

#### stevoc

OK, I think I might need some help now. After getting positive results in preliminary testing, we've conducted the test in an official capacity and failed!

The test was modified slightly, 5 devices were operated 24 times by each of 3 operators. The results for each device were then compared between operators using ANOVA at a 95% confidence level - and for 4 of 5 devices it was shown that at least one of the means was different.

I can't see where to go here -there doesn't appear to be a lesser criteria that can be used? Even if we try to disprove the null hypothesis at a 99% confidence level, we still have a significant difference.

thanks

Steve

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