Complex Custom Calculation

[mallorie.getzelman]

Hello,

I've been trying to get this calculation to work for a dissolution that we perform here. The problem is that I have a profile dissolution and the calculation requires to account for Percent removed for each pull. I know it will require quite a few custom fields and that's okay but If someone could help me out that would be so helpful. The calculation is as follows and I've also attached how i set up my alter sample. The initial 2 CS injections need to stay the same because I already have a Standard agreement calculation set up using that.

Concentration in vessel at each time point:
𝐶𝑛 = 𝑆𝑝𝑙 𝑎𝑟𝑒𝑎/𝑀𝑒𝑎𝑛 𝑆𝑡𝑑 2 𝐵𝑟 𝑥 𝑆𝑡𝑑 𝑤𝑡 𝑥 𝑆𝑡𝑑 𝑑𝑖𝑙𝑢𝑡𝑖𝑜𝑛 𝑥 𝑆𝑡𝑑 𝑃

% Dissoluton at 1st (n=1) time point:
C1xV1x100/LC

% Dissoluton at 2nd (n=2) time point:
[(𝐶2 𝑥 { 𝑉1 − 𝑉𝑠}) + (𝐶1 𝑥 𝑉𝑠)] 𝑥 100/𝐿𝐶

where Vs = 10 mL

% Dissoluton after 2nd (n≥3) time point:
[(𝐶𝑛 𝑥 { 𝑉1 − (𝑛 − 1)𝑉𝑠}) + ∑ (n-1),i=1)(𝐶𝑖 𝑥 𝑉𝑠)]x100/LC

[EmpowersBane]

Hello,

I have coded custom fields for dissolution testing in our lab, but we use the basic formula of, for each timepoint:

Amount of current timepoint + Correction_Factor*(Sum of Previous Timepoints Amount)
Correction_Factor = volume taken per sample divided by dissolution volume which in our case is 1.5 mls/300 mls. Is your set up similar?

Also, there is a dissolution module built into Empower projects as well, if you have that option. Right click the project..Properties and there you see the extra options like PDA, Dissolution etc. Tick Dissolution and use the sample set wizard to set up number of Baths, Paddles, Q Value, how many timepoints etc and Empower will automatically calculate % Amount at each timepoint and % Dissolved at each timepoint and graph this data also.

We use custom fields as we also need a Mass Balance calculation that Empower doesnt support so there are a couple of ways around this. It depends on what you are looking for.

[mallorie.getzelman]

In our case we remove 10 mL at each of the 5 pulls and the starting volume is 1000mL for this specific method - they all vary based on the method we are utilizing. the premise your calc seems to be similar to what I described. Unfortunately we don't have the option to use the dissolution feature

[EmpowersBane]

In that case I would set up your sample set as follows: Label all the 5 timepoint samples as U1 to U5, and repeat this for however many paddles/sets of samples you are running, so if running 6 sets of 5 timepoints they are labelled U1 to U5 for set 1, U1 to U5 for set 2....etc all the way to set 6.

Then create 2 component type custom fields called CF_One and CF_Two. In CF_One, enter the amount pulled which in your case is 10 (10 mls) and for CF_Two enter the overall volume which is 1000 (1000mls). The advantage to these custom fields is they are flexible and will allow you to change the pull volume and overall volume easily without having to make new custom fields.
Now this is the way I do it so see if there are any similarities you could copy. First I create a Peak, Real Calculated CF called Correction_Factor and the formula is simply CF_One/CF_Two. By the way I keep the sample and peak type to all, result set only search order and dont pick All or Nothing as that will negatively affect the custom fields. In our company we process sample sets to generate result sets and rarely process from Injections or Channels tab, plus manual integration isnt allowed in our SOPs.

My repsonse for Dissolution is Amount and I presume thats your one as well, if not substitute Amount for whatever value you use to measure dissolution.

First Timepoint-Label U1- value is just Amount since no correction has occurred
Second Timepoint -Label U2- amount in second timepoint +( Correction Factor*(U%..(Amount)))
Third Timepoint- Label U3- amount in third timepoint + ( Correction Factor*(U1.%.(Amount)+U2.%.(Amount)))
Fourth Timepoint -Label U4- amount in fourth timepoint +( Correction Factor*(U1.%.(Amount)+U2.%.(Amount)+U3.%.(Amount)))
Fifth Timepoint - Label U5- amount in fifth timepoint + (( Correction Factor*(U1.%.(Amount)+U2.%.(Amount)+U3.%.(Amount)=U4.%.(Amount)))

The CFs for above are coded as:

A_Disso_First: Amount+(Correction_Factor*(U%..(Amount)))
B_Disso_Second: Amount+(Correction_Factor*(U1.%.(Amount)+U2.%.(Amount)))
C_Disso_Third: Amount+(Correction_Factor*(U1.%.(Amount)+U2.%.(Amount)+U3.%.(Amount)))
D_Disso_Fourth: Amount +(Correction_Factor*(U1.%.(Amount)+U2.%.(Amount)+U3.%.(Amount)+U4.%.(Amount)))

Note: its best to label alphabetically as thats how CFs are calculated A before B before C etc. And the formula for Disso First isnt a typo, i coded it as U%..(Amount) and not U1.%.(Amount) to specifically "tell" Empower to only look for the previous sample labeled as U...

There are further CFs you can create based on above and one CF that will do the work of all the above too, But does that look like the way you calculate dissolution? If so, I can advise on further CFs. If not you may need to adjust the formula to your own requirements.

[mallorie.getzelman]

I think the added complexity of this calculation is that it requires the Bracketing CS injections to calculate each of the pulls.
Example Sample set
WS x 6
CS -1
CS -2
pull 1 v 1-6
CSBR1
Pull 2 v 1-6
CSBR2.
and so forth and so on.

Pull one is calculated against AVG of CS 2 and CSBR1 and so forth...