OOS Investigation case study-1 (Dissolution)

In Pharmaceutical Industries OOS investigation and root cause identification is very important topic. If you are not able to identify the exact root cause, then your effort should be looked in your investigation.
Here I am sharing case study to understand it in a better way-
Description of Event:
OOS result observed in dissolution test.
One unit result is 800% and other 5-units are well with in limit (about 98%) -Limit is NLT 75%(Q).

Preliminary investigation:
It is aberrant result (Not a true representative result), but no any obvious cause is identified.
Re-measurement:
Hypothesis testing is performed to rule out instrument error, vial filling error, dilution error.
But no any error is identified and all above possibilities are ruled out.

Now what is the next step. . .We know that this is a aberrant result, but we could not able to proove that.
We can not perform the Re-analysis by saying that this is a erratic result. Our effort to identify the root cause should be looked in our investigation.

Good investigator approach:
The next step of good investigator which he can take to make this investigation more adequate.
Step-1
Run the subject vial sample and one reference vial sample on PDA detector and check the peak purity and spectrum. 

Step-2
If peak purity of subject vial is failed and reference vial peak purity is passed. Then there is a chance of sample contamination with foreign materials, which give response at same retention time. 
Step-3
Now our next step to identify that from where this contamination come to the sample. There is a possibility that bowl was not properly cleaned and previous sample trace remains in the dissolution bowl.
To rule out this possibility we have to perform some experiments like previous product (about 20ppm solution) injection should be injected in same chromatographic system and if peak observed at same RT then this investigation looks better. But if no peak observed then we have to inject few more product solution based on possibility and evaluation of  our investigation.
Step-4
If no root cause is identified in step-3, then in step-4 we have to forward this investigation to manufacturing to rule out any product contamination (inject previous product on same chromatographic conditions) in manufacturing.
By all these efforts, if we will do the Re-analysis and release the batch. It will give confidence to auditor that there is no any issue with the product quality. 

Basic Knowledge of HPLC

 Liquid Chromatography 

The term liquid chromatography, as used in the compendia, is synonymous with high-pressure liquid chromatography and high-performance liquid chromatography. LC is a separation technique based on a solid stationary phase and a liquid mobile phase.

Stationary Phase: Separations are achieved by partition, adsorption, or ion-exchange processes, depending on the type of stationary phase used. The most commonly used stationary phases are modified silica or polymeric beads. The beads are modified by the addition of long-chain hydrocarbons. The specific type of packing needed to complete an analysis is indicated by the “L” designation in the individual monograph (see also the section Chromatographic Columns, below). The size of the beads is often described in the monograph as well. Changes in the packing type and size are covered in the System Suitability section of this chapter.

Chromatographic Column: The term columnincludes stainless steel, lined stainless steel, and polymeric columns, packed with a stationary phase. The length and inner diameter of the column affects the separation, and therefore typical column dimensions are included in the individual monograph. Changes to column dimensions are discussed in the System Suitability section of this chapter.  Compendial monographs do not include the name of appropriate columns; this omission avoids the appearance of endorsement of a vendor’s product and natural changes in the marketplace. See the section Chromatographic Columns for more information.

Mobile Phase: The mobile phase is a solvent or a mixture of solvents, as defined in the individual monograph.

Apparatus: A liquid chromatograph consists of a reservoir containing the mobile phase, a pump to force the mobile phase through the system at high pressure, an injector to introduce the sample into the mobile phase, a chromatographic column, a detector, and a data collection device.

Gradient Elution: The technique of continuously changing the solvent composition during the chromatographic run is called gradient elution or solvent programming. The gradient elution profile is presented in the individual monograph as a gradient table, which lists the time and proportional composition of the mobile phase at the stated time.

Procedure

1. Equilibrate the column and detector with mobile phase at the specified flow rate until a constant signal is received.
2. Inject a sample through the injector, or use an auto-sampler.
3. Begin the gradient program.
4. Record the chromatogram.
5. Analyze as directed in the monograph

• SYSTEM SUITABILITY
  System suitability tests are an integral part of gas and liquid chromatographic methods. These tests are used to verify that the chromatographic system is adequate for the intended analysis.
  The tests are based on the concept that the equipment, electronics, analytical operations, and samples analyzed constitute an integral system that can be evaluated as such.
  Factors that may affect chromatographic behavior include the following:
  • Composition, ionic strength, temperature, and apparent pH of the mobile phase
  • Flow rate, column dimensions, column temperature, and pressure
  • Stationary phase characteristics, including type of chromatographic support (particle-based or monolithic), particle or macropore size, porosity, and specific surface area
  • Reverse-phase and other surface modification of the stationary phases, the extent of chemical modification (as expressed by end-capping, carbon loading, etc.)

Investigation tools for root cause analysis

In Pharmaceutical Industries generally following investigation tools are used by investigator-

Different Investigation tools:
A-5W and 1-How:

Ask five “W” and one “H” as mentioned below,
1) What?? 
2) Where?? 
3) When? ?
4) Who?? 
5) Why?? 
6) How?? 
Observe the problem first hand, personally (not to rely on the report of other).

Talk to those at the sharp end (counselling).
Explore the contributing visible and invisible factors.
Analyze each factor and conclude probability.

2- Brain storming
This is one of the best Technique i.e. “Brainstorming” may be used to identify the root cause of the problem. The details of Brainstorming are mentioned below-
Brainstorming: One of the creative problem solving method that allows the people to come-up with suggestion / ideas that could solve the problem or help to identify the root cause of the problem.
A meeting with Cross Functional team may be called to brain storm on problem / situation.
Relevant people shall ask to think and share their views / suggest ideas to overcome the problem.
All views and suggestions shall analyse to identify the cause of problem.

3-Third technique “Six-M Framework” (Ishikava diagram) using Fish bone diagram may be used to
identify the root cause of the problem The steps to use “Six M framework” are given below.
Pictorial presentation of fish bone diagram of Root cause analysis includes,
Head of Fish: Problem of Effect
Bones of the Fish: “Six –M” i.e. Major Causes: Man, Machine/Equipment, Material, Method/Process,
Measurement and Environment/Define your problem from the following source:

• Internal: OOS Reports, Self Inspection, Deviations, Trend analysis. 

Root Cause Analysis team should involve those who are most familiar with the processes and systems and include participation of the Department Head, Quality Assurance.
Label each “bone of the fish” The major categories typically utilized are: Man, Machine/Equipment, Material, Method/Process, Measurement and Environment/Mother Nature. The team should identify probable causes, these could be Man,Machine/Equipment, Material,
Method/Process, Measurement and Environment/Mother Nature.Analyze the information and identify the actual or hypothesis. Analysis of data must be objective and logical.

5 Why root cause analysis use in OOS Investigation.

In Pharmaceutical Industries most of the investigators are using 5-Why root cause analysis tools to identify the exact root cause of the events.

For example, OOS observed in Assay test. 

Result:79.0% (Limit- 95.0 to 105.0%) 

Remeasurment performed.

Same vial:79.0%

Refilled vial:79.0%
Re-dilution from stock:99.5%.
From above Re-measurement testing root cause is identified as sample dilution error.

5-Why root cause analysis for above case study. 

1-Why--Problem
OOS (79.0% result) observed in assay test
2-Why 79.0% result. 
Analyst had done wrong sample dilution (prooven in hypothesis testing)
3-Why analyst had done wrong sample dilution.
During investigation it has been observed that analyst had 2 pipettes (4ml and 5ml) in his working tray. Hence analyst had used 4ml pipette for sample dilution instead of 5ml pipette, resulting 20% lower Assay.
4-Why analyst had 2 pipettes in his tray.
Analyst have 2 different products for analysis and he had kept all preparations in a same tray.
5-Why.....Not applicable.

So from above investigation exact root cause is identified in 4th-Why only.
Based on root cause, proper and effective CAPA should be taken.

Investigation (OOS/OOT/Deviation/Incident)tools selection

Many of Pharmaceuticals organization received 483 due to selection of improper investigation tools.

For example, system suitability is not achieved (bracketing RSD failed) and investigation started through lab incident without ensuring the test results. The result is OOS, but considering first observation (RSD failure) laboratory iniciated investigation through Incident. FDA may consider this a major 483 for hiding a failure result. 

Any non conformance of specification should be handled through OOS only. 

If result is not OOS or OOT and system suitability parameters are failed, then only it should be handle through laboratory Incident. 

Systematic Root cause Analysis

During investigation do not directly conclude the root cause based on your immediate observation. There may be the some other reasons too.
For example, if any failure observed in unknown impurity due to instrument error (pressure fluctuations) . Based on this observation generally investigator consider this as an obvious root cause and  missed to rule out other possible reasons like extraneous peak or product contamination.
Force degradation study data is very helpful to rule out and to prove that this failure is not a product issues, or subjected impurity peak due to degradation due to improper sample preparations.
Before saying this failure due to instrument malfunction only we have to rule out all other possible reasons through SYSTEMATIC ROOT CAUSE ANALYSIS (Write all possible reasons of failure and  rule out this one by one till final root cause). This is the most recent expectation of auditor.