Tandem Microfiltration for Recombinant Insulin Purification

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Solution Overview

Problem

Microfiltration processes in biopharmaceutical manufacturing face challenges in scaling up due to filter fouling and unpredictable performance, particularly in removing both soluble and insoluble impurities from recombinant insulin or insulin analogs, which affects the efficiency and purity of the final product.

Innovation Solution

A process involving two tandem microfiltration steps is implemented, where the first step precipitates the insulin or insulin analog, allowing for the removal of soluble impurities, and the second step solubilizes it, enabling the retention and removal of insoluble impurities, using pH adjustments and microfiltration with a 0.1 µm pore size membrane to achieve high purity and scalability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single microfiltration step is used, then the process is simple, but it cannot effectively remove both soluble and insoluble impurities

Engineering Contradiction:
Improvepurity of insulin productVSAvoidnumber of microfiltration steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The microfiltration process is divided into two sequential steps: first microfiltration to remove soluble impurities from precipitated insulin, and second microfiltration to remove insoluble impurities from solubilized insulin. This segmentation allows each step to target specific impurity types, achieving comprehensive purification that a single step cannot accomplish.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If microfiltration is used to remove impurities, then purity improves, but filter fouling increases and reduces productivity

Engineering Contradiction:
Improvepurity of insulin productVSAvoidprocessing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The process utilizes pH adjustments to change the solubility state of insulin between steps. By precipitating insulin at neutral pH and solubilizing at acidic pH, the process transforms the physical state of the product to facilitate different impurity removal mechanisms, reducing membrane fouling and improving processing efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The process employs periodic alternation between precipitation and solubilization phases. During precipitation phase, soluble impurities are removed; during solubilization phase, insoluble impurities are removed. This periodic action prevents continuous fouling and maintains sustained productivity throughout the purification process.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If pH adjustment is used to precipitate insulin, then soluble impurities can be removed, but additional process steps are required

Engineering Contradiction:
Improveremoval of soluble impuritiesVSAvoidnumber of process steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

pH adjustment serves multiple functions: it precipitates insulin for first microfiltration, enables solubilization for second microfiltration, and facilitates buffer exchange. This multi-functionality reduces the need for separate dedicated steps for each function, optimizing the overall process design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces both soluble and insoluble impurities, enhancing the purity of recombinant insulin or insulin analogs and facilitating their exchange into a suitable buffer for downstream purification, thereby improving the efficiency and scalability of the production process.

Implementation Method 1

applying the aqueous mixture to a surface of a microfilter having a pore exclusion size sufficient to retain the precipitated insulin or insulin analog thereto

Methodology Applied
Scientific EffectMicrofiltration: Filter (physical)

Implementation Method 2

permeating the soluble impurities that are smaller than the exclusion pore size of the microfilter through the microfilter

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 3

adjusting the pH of the aqueous solution from the digestion step to a pH sufficient to precipitate the insulin or insulin analog from the aqueous solution

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 4

adjusting the pH to a pH sufficient to solubilize the precipitated insulin or insulin analog

Methodology Applied
Scientific EffectSolubilization: Solvation

Data Source

PatentEP3268384B1Process for preparing recombinant insulin using microfiltration
Publication Date: 2021.11.03 MERCK SHARP & DOHME CORP
  • EP3268384B1 patent drawingFigure 1A
  • EP3268384B1 patent drawingFigure 1B
  • EP3268384B1 patent drawingFigure 2

AI summary

The use of two tandem microfiltration (MF) steps in a process for making recombinant insulin is described. The two MF steps in a single downstream purification unit operation reduce both soluble and insoluble impurities and exchange the insulin product into a suitable buffer for downstream purification.