Porcine Parvovirus Detection in Pancreatic Enzyme Preparations
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Solution Overview
Problem
Current methods for determining viral infectivity and content in pancreatic enzyme preparations, such as pancrelipase, are not reproducible and have low detection limits, making it difficult to accurately assess porcine parvovirus (PPV) contamination, which is a concern due to the complex nature of these products.
Innovation Solution
A method involving multiple chloroform extractions and polyethylene glycol (PEG) precipitations is used to clarify and purify samples, allowing for the detection of infectious PPV and measurement of its DNA content, using techniques like PCR for nucleic acid amplification and immunofluorescence to assess viral presence and quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional extraction methods (ultracentrifugation, single-step extraction) are used, then the process is simple, but the detection precision and reproducibility are low
Solution Approach 1:
The extraction process is divided into multiple sequential steps: initial chloroform extraction, PEG precipitation, resuspension in buffer, second PEG precipitation, and final resuspension in solution. Each step isolates and concentrates the viral material while removing different classes of contaminants, progressively improving detection precision through systematic segmentation of the purification process
Solution Approach 2:
The method systematically extracts viral material from the complex pancreatic enzyme preparation matrix using chloroform to separate viral particles from enzymes and other contaminants. The viral-containing upper phase is then selectively precipitated using PEG, effectively taking out the viral material from the complex mixture for concentrated analysis
2Measurement precision
If multiple extraction and precipitation steps are performed, then the detection sensitivity increases, but the processing time and operational complexity increase
Solution Approach 1:
The method performs preliminary concentration and purification actions before the actual infectivity detection assay. By pre-concentrating viral material through repeated PEG precipitations and removing inhibitory substances through chloroform extractions, the assay conditions are optimized in advance, enabling more sensitive and reliable detection without extending the critical assay time
Solution Approach 2:
The method changes physical-chemical parameters systematically: using chloroform to alter solubility and separate phases, using PEG to change precipitation conditions, and adjusting buffer compositions. These parameter changes enable selective concentration of viral material while removing contaminants, improving detection sensitivity through controlled physicochemical transformations
3Measurement precision
If sample concentration is increased to improve detection, then the sensitivity improves, but the toxic enzyme materials interfere with detection
Solution Approach 1:
The method selectively extracts viral material into the upper phase during chloroform extraction, leaving toxic enzyme materials in the lower phase or at the interface. Subsequent PEG precipitation selectively precipitates viral particles from the upper phase, effectively taking out the viral material while leaving behind the toxic enzyme contaminants that would otherwise interfere with detection
Solution Approach 2:
Chloroform acts as an intermediary solvent that facilitates selective partitioning of viral material from enzyme materials. PEG serves as an intermediary precipitating agent that selectively precipitates viral particles. These intermediary substances enable separation and concentration of viral material while removing or isolating toxic enzyme components, eliminating their interfering effects on detection
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 method significantly enhances the precision and reproducibility of viral content measurements, effectively eliminating toxic enzyme materials while preserving infectious viruses, thereby ensuring the safety and quality of pancreatic enzyme preparations.
Implementation Method 1
extracting a sample of the preparation at least two times with chloroform to produce a clarified sample with an upper phase and a lower phase
Implementation Method 2
precipitating an aliquot of the upper phase from step (a) with polyethylene glycol (PEG)
Implementation Method 3
performing nucleic acid amplification on an aliquot from the solution of step (e), and producing an amplification profile that indicates viral content of the preparation
Implementation Method 4
the presence of infectious virus can be determined by immunofluorescence, such as with a fluorescence-focus units system comprising a specific detection agent for the virus
Data Source
AI summary
The present invention provides methods for detecting viral infectivity and content in an enzyme preparation. In certain embodiments, the invention relates to methods for producing a pharmaceutical pancreatic enzyme composition. In additional embodiments, the invention relates to detecting infectious porcine parvovirus (PPV) and determining PPV content in pancreatic enzyme preparations (PEPs), including pancrelipase preparations.