Spring 2017 - Current Topic
FINDING THE GOOD IN GOOD SCIENCE
Note: This document expresses Dr. Jenke’s personal views and opinions and is not a position established and supported by Triad Scientific Solutions, LLC. This document is not professional advice and does not constitute a professional service provided by either Dr. Jenke or Triad Scientific Solutions.
When members of the E&L community gather to develop standards, guidelines and best demonstrated practice recommendations, there are three principles they should obey:
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The standards must be based on “good science”,
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The standards must be effective and efficient, and
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The standards must fit every conceivable circumstance well.
It is the inability to achieve these principles that makes the generation of standards, guidelines and recommendations so frustratingly challenging.
Consider the last principle, for example. It is intuitively obvious in a diverse field such as pharmaceuticals that this principle is impossible to achieve as it is clear that a rigorous standard (which is specified set of tests coupled to a specified set of acceptable test results) cannot fit all the diverse circumstances equally well. It is the same problem as trying to design a glove that fits every human being. If the underlying purpose of the glove is “to keep one’s hands warm”, then a standardized glove can be designed that will address this requirement, to some degree, for most people. However, because the glove must keep everybody’s hands warm, it is logical that there will be design tradeoffs which will mean that while it keeps everyone’s hands warm, it does not keep everyone’s hands as warm as they would personally like it. Furthermore, there may be other trade-offs, such as “these gloves are not very sexy”, or “these gloves do not match my coat” or “these gloves make my hands itch”.
While the challenges in making standards that are generally applicable in the greatest number of circumstances are considerable, this is not the point that I want to address in this discussion. Rather, I want to address the challenges associated with good science.
Good science suffers from with the same problem as designing a standardized glove. As good scientists, we learned and we understand that there are very few universal scientific truths; rather, a scientific truth is a truth only under the rigorously defined set of circumstances upon which it is based. When we perform an experiment and draw a conclusion from that experiment, we understand the conclusion is only perfectly valid for the set of defined experimental circumstances we started out with. Extension of that same conclusion to other circumstances involves a certain measure of risk, specifically the risk that in changing the circumstances we have invalidated (knowingly or unknowingly) some fundamental principle that defines the applicability of our conclusions. Thus, we understand that there is an inherent trade-off when we make scientific generalizations and put them into standards, guidances and recommendations. That is, we sacrifice some of the good in good science for the sake of providing a direction that is generally right in the greatest number of circumstances.
The challenge we face as practitioners of good science is not in recognizing good science per say but recognizing the boundaries that differentiate between good science properly applied and good science improperly applied. When we are tempted to use a standard, or leverage a “rule of thumb” or “do this because everybody else is doing it”, as good scientists we must ask ourselves “am I taking a good idea in certain circumstances and applying it to the wrong circumstances?”. If the answer is yes, then surely this is as bad as using “bad” science in the first place.
Let me illustrate this with an example. I use this as an example not because it a particularly bad practice but because it effectively illustrates my point. The following, taken from the PQRI OINDP Best Practice recommendations, is well known and commonly applied in the E&L community.
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The Working Group recommends that analytical uncertainty be evaluated in order to establish a Final AET for any technique/method used for detecting and identifying unknown extractables/leachables.
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The Working Group proposes and recommends that analytical uncertainty in the estimated AET be defined as one (1) standard deviation in an appropriately constituted and acquired Response Factor database OR a factor of 50% of the estimated AET, whichever is greater.
The question I would ask you to consider is “where is the good science and the not so good science in these recommendations?”
Here is my answer. It is well known that response factors will vary among the universe of compounds that could be extractables and leachables. Thus, it is good science that a general concept such as the AET, which presumably is applicable to all possible extractables/leachables, take this variation into account. Furthermore, we all understand that basing actions on relevant and sufficient data is the cornerstone of good science, and thus that the requirement to consider “an appropriately constituted and acquired Response Factor database” is a requirement to do good science. However, it must be obvious that the direction to universally “use a factor of 50%” is not necessarily good science. While the derivation of the 50% is itself good science, as it was based on a response factor database (which is somewhat small in the context of the databases available today), it is obvious that the 50% is only relevant for the compounds in that database and the analytical method with which the data was generated. Universal and unquestioned application of the factor of 2 rule to compounds that were not in the original database and to analytical methods other than the method used to generate the data is not the best science; rather, it is poor science, not because the science itself is bad but because the good science aspects are being applied out of context.
To a good scientist, arguments such as “it is better than nothing” or “everybody else is doing it” are inexcusable. Certainly, the idea that “it is better than nothing” has to be examined objectively and harshly. The improper application of science is not guaranteed to be better than doing nothing because it is not the case that the improper application of science will always make things better. In fact, the history of improper application of good science is littered with examples of bad outcomes derived from applying good sciences incorrectly.
Listen, nobody said doing good science was easy. We understand that part of the driving force for recommending that the factor of 2 be universally applied is that back then few people could access a database. Thus, it was nearly impossible to practice the good science required in the recommendation and people, rather than do nothing, gravitated to the other part of the recommendation. However, today, it is virtually impossible to run into a reputable E&L laboratory that is not eager to talk about their database. Thus, in this case, our ability to do good science has finally caught up with our responsibility to do good science. It is proper that we accept that responsibility and be held accountable for meeting that responsibility.
This is true not only to adjusting the AET for analytical uncertainty but in numerous other places where our current capabilities enable our ability and address our responsibility to practice and preach a higher degree of good science than has ever been possible. Currently applied recommendations, standards, guidelines and practices must be adjusted, as appropriate, to leverage this new and higher degree of good science and new recommendations, standards and guidelines must be drafted to reflect this new and higher degree of science. We aspire to better science because we are capable of better science. More importantly, if we are going to talk the talk, we best start walking the walk.
Publication List, Dennis R. Jenke
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D. Jenke. Anion peak migration in ion chromatography. Anal. Chem. 53: 1535-1536 (1981).
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D. Jenke and M.R. Hannifan. Determination of the moisture and volatile content in coal by pressure change and gas chromatography. Anal. Chem. 54: 843-845 (1982).
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D. Jenke and F.E. Diebold, Characterization of phosphorite ores. Anal. Chem. 54: 1008-1011 (1982).
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D. Jenke and R. Woodriff. Application of the Woodriff constant temperature graphite furnace atomizer to atomic spectroscopy. Am. Lab. 14: 14-26 (1982).
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D. Jenke and R. Woodriff. Direct aerosol introduction in constant temperature furnace atomic absorption spectroscopy. Appl. Spectrosc. 36: 657-661 (1982).
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D. Jenke and R Woodriff. Simultaneous emission/absorption analysis in constant temperature furnace atomic spectroscopy. App. Spectrosc. 36: 686-689 (1982).
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D. Jenke and G.K. Pagenkopf. Temperature fluctuations in non-suppressed ion chromatography. Anal. Chem. 54: 2603-2604 (1982).
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D. Jenke and R. Woodriff. Carbon furnace atomic emission spectrometry with a constant temperature atomizer. Spectrosc. Lett. 16: 22-231 (1983).
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D. Jenke and G.K. Pagenkopf. Behavior of cations in non-suppressed ion chromatography. Anal. Chem. 55: 1168-1169 (1983).
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D. Jenke, G.K. Pagenkopf and F.E. Diebold. Chemical changes in concentrated acidic metal bearing waste waters when treated with lime. Environ. Sci. Technol. 17: 217-223 (1983).
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D. Jenke and D.E. Dobb. Characterization of and correction for memory effects produced by pneumatic nebulizers used in inductively coupled plasma emission spectroscopy. Appl. Spectrosc. 37: 379-384 (1983).
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D. Jenke and M.R. Hannifan. Determination of the moisture and low temperature volatiles in solid fuels. Am. Lab. 15(7): 38-45 (1983).
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D. Jenke and F.E. Diebold. Recovery of metals from acid mine drainage by selective titration. Water Research. 17: 1585-1590 (1983).
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D. Jenke. Comparison of three methods for the extraction of selected anions from media used for the collection of airbourne particulates. J. Air Pollut. Control Assoc. 33: 765-767 (1983).
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D. Jenke and R Woodriff. Continued development of direct aerosol introduction in constant temperature atomic absorption spectroscopy. Appl. Spectrosc. 37: 470-472 (1983).
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D. Jenke and G.K. Pagenkopf. Modeling of analyte response to changing eluent composition in suppressed ion chromatography. J. Chromatogr. 269: 202-207 (1983).
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D. Jenke, P.K. Mitchell and G.K. Pagenkopf. Use of multiple detectors and gradient elution in non-suppressed ion chromatography. Anal. Chim. Acta. 155: 279-285 (1983).
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D. Jenke, P.K. Mitchell and G.K. Pagenkopf. Anion content of snow by suppressed and non-suppressed ion chromatography. J. Chromatogr. Sci. 21: 2487–2489 (1983).
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D. Jenke and G.K. Pagenkopf. Effect of analyte concentration on retention behavior in non-suppressed ion chromatography. J. Chromatogr. Sci. 22: 231-233 (1984).
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D. Jenke and G.K. Pagenkopf. Models for prediction of retention in non-suppressed ion chromatography. Anal. Chem. 56: 88–91 (1984).
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D. Jenke and G.K. Pagenkopf. Optimization of anion separation by non-suppressed ion chromatography. Anal. Chem. 56: 85–88 (1984).
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D. Jenke and F.E. Diebold. Electroprecipitation treatment of acid mine wastewater. Water Research. 18: 855–859 (1984).
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F.E. Diebold and D.R. Jenke. Investigation of the interaction between acid mine water and concentrator wastes. USBM Mining Research Contract Report. November, 1984.
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D. Jenke. Analytical and sampling methodology used for determining the impact of a MHD test facility. Analytical Letters. 17(A8): 735–755 (1984).
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D. Jenke. Standardization of transparent analyte response in indirect photometric chromatography. Anal. Chem. 56: 2468–2470 (1984).
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D. Jenke. Modeling of analyte behavior in indirect photometric chromatography. Anal. Chem. 56: 2674–2681 (1984).
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D. Jenke and F.E. Diebold. Computer simulation of an industrial wastewater treatment process. Water Research. 69: 719–724 (1985).
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D. Jenke and N. Raghavan. Application of indirect photometric chromatography to pharmaceutical analysis. J. Chromatogr. Sci. 23: 75–80 (1985).
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D. Brown, R. Payton and D. Jenke. Elimination of matrix interferences in indirect photometric chromatography. Anal. Chem. 57: 2264–2267 (1985).
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D. Jenke. Indirect determination of hydrogen peroxide by ion chromatography. J. Chromatogr. Sci. 24: 352–355 (1986).
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D. Jenke and G.K. Pagenkopf. Chapter 7: Retention and Detection in Ion Exchange Chromatography, in Chromatography: Theory and Basic Principles. J.A. Jonnson, Ed. (Marcel Dekker, New York, 1987) pp. 313 – 345.
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D. Jenke. Column poisoning by multivalent cations in ion chromatographic analysis for alkali metals. J. Chromatogr. 370: 419–426 (1986).
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D. Jenke. Determination of alkaline earth metals in samples containing a large excess of alkali by ion chromatography. Anal. Chem. 59: 624–628 (1987).
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D. Jenke and G. Iwinski. Determination of alcohols in pharmaceuticals by ion exclusion chromatography. J. Chromatogr. 392: 397–405 (1987).
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D.S. Brown and D.R. Jenke. Determination of sulfite and hydrogen peroxide in pharmaceutical matrices via classical spectrophotometry and flow injection. Analyst. 112: 899–906 (1987).
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D.R. Jenke and D.S. Brown. Determination of cysteine in pharmaceuticals via liquid chromatography with post column derivatization. Anal. Chem. 59: 1509–1512 (1987).
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B.P. Downey and D.R. Jenke. Determination of oxalate in pharmaceutical matrices by indirect photometric chromatography. J. Chromatogr. Sci. 25(11): 519 –524 (1987).
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D.S. Brown and D.R. Jenke. Application of fast LC to pharmaceutical analysis: dopamine HCl. J. Chromatogr. Sci. 25: 494–500 (1987).
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D.S. Brown and D.R. Jenke. Determination of trace levels of oxytocin in pharmaceutical solutions by high performance liquid chromatography. J. Chromatogr. 401: 157-168 (1987).
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D. Jenke. Quantitation of oxalate and citrate by ion chromatography with a buffered, strong acid eluent. J. Chromatogr. 437: 231–237 (1988).
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E. Burke, S. Zimmerman, D. Brown and D. Jenke. On-line sample clean-up in the liquid chromatographic analysis of pharmaceuticals for citrate content. J. Chromatogr. Sci. 26: 527–532 (1988).
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D. Jenke. Drug delivery via ion exchange across a fiber membrane. Pharm. Res. 6: 96–99 (1989).
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D.S. Hayward, S.R. Zimmerman and D.R. Jenke. Drug stability testing by monitoring drug and degradate levels by liquid chromatography. J. Chromatogr. Sci. 27: 235–239 (1989).
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D.R. Jenke. Quantitation of sodium bisulfite in parenteral samples by flow injection analysis. Anal. Chim. Acta. 220: 281–285 (1989).
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L.A. Cruz and D.R. Jenke. Evaluation of assay specificity in non-suppressed ion chromatography. J. Chromatogr. 477: 271–276 (1989).
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D.R. Jenke. Effect of some operational variables on the efficiency of ion chromatographic separations. J. Chromatogr. 479: 387–400 (1989).
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D.R. Jenke. The chromatographic efficiency of several commercially available ion chromatography column. J. Liq. Chromatogr. 13: 135–148 (1990).
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D.R. Jenke, D.S. Brown and R. Wiegand. Instrumentation for High Pressure Liquid Chromatography in Analytical Instrumentation Handbook. G.W. Ewing, Ed. (Marcel Dekker, New York, 1990) pp. 745 – 842.
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D.S. Hayward, R.A. Kenley and D.R. Jenke. Interactions between polymer containers and parenteral solutions: The correlation of equilibrium constants for polymer-water partitioning with octanol-water partition coefficients. Int. J. Pharm. 59: 245–253 (1990).
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L.A. Cruz, M.P. Jenke, R.A. Kenley, M.J. Chen and D.R. Jenke. Influence of solute degradation on the accumulation of solutes migrating into solution from polymeric parenteral containers. Pharm. Res. 7( 9): 967– 972 (1990).
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R.A. Kenley and D.R. Jenke. Determination of solute-polymer interaction properties and their application to parenteral product container compatibility evaluations. Pharm. Res. 7(9): 911–918 (1990).
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D.R. Jenke, D.S. Hayward and R.A. Kenley. Liquid chromatographic measurement of solute solvent/solvent partition coefficients: Application to solute/container interactions. J. Chromatogr. Sci. 28(12): 609–612 (1990).
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D.S. Hayward and D.R. Jenke. Interactions between polymer containers and parenteral solutions: Correlating equilibrium polymer-water interaction constants with solute partition coefficients. Int. J. Pharm. 66(1-3): 87–96 (1990).
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D. Jenke. Additive model for the evaluation of interactions between aqueous solutes and multi-component container materials. J. Parenter. Sci. Technol. 45(5): 233–238 (1991).
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D.R. Jenke. Effect of solution phase composition on the interaction between aqueous model solutes and polymeric container materials. Pharm. Res. 8(6): 782–786 (1991).
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D.R. Jenke, R.A. Kenley and D.S. Hayward. Interactions between polymeric containers and their contained solution: Modeling of polymer-water solute partitioning via coupled solvent-water partition coefficients. J. Appl. Polymer Sci. 43: 1475–1482 (1991).
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D.R. Jenke. Solute migration through thin polypropylene blend films. J. Appl. Polymer. Sci. 44: 1223– 1231 (1992).
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D.R. Jenke, E.K. Chess, D.C. Zietlow and B.E. Rabinow. Model for estimating the accumulation of solutes leaching from polymeric containers into parenteral solutions. Int. J. Pharm. 78: 115–122 (1992).
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D.R. Jenke. Determination of solute/polymer interaction constants via chromatography with polymer capillaries. J. Chromatogr. 594: 29–36 (1992).
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D.R. Jenke, C.D. Baron and C.L. Mayers. Drug delivery via ion exchange across a micromembrane. Pharm. Res. 9(12): 1654-1658 (1992).
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D.R. Jenke. Modeling of solute sorption by polyvinyl chloride plastic infusion bags. J. Pharm. Sci. 82: 1-6 (1993).
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C.L. Mayers and D.R. Jenke. Stabilization of oxygen-sensitive formulations via a secondary oxygen scavenger. Pharm. Res. 10(3): 445–448 (1993).
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D. Jenke. Evaluation of various solvent systems for modeling solute sorption by plasticized polyvinyl chloride materials. J. Pharm. Sci. 82: 617–621 (1993).
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D.R. Jenke, A.V. Martinez, L.A. Cruz and S.R. Zimmerman. Accumulation model for solutes leaching from polymeric containers. J. Parent. Sci. Tech. 47(4): 1–5 (1993).
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D.R. Jenke, E.K. Chess and G. Jakubowski. Modeling of the leachables impact on the engineering of parenteral product container systems. Int. J. Pharm. 108(1): 1–9 (1994).
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D.R. Jenke. Determination of solute/polymer interaction properties via two-stage extraction. Pharm. Res. 11: 774–775 (1994).
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D.R. Jenke. Drug binding by reservoirs in elastomeric infusion devices. Pharm. Res. 11: 984–989 (1994).
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D.R. Jenke. Prediction of retention characteristics of multi-protic anions in ion chromatography. Anal. Chem. 66: 4466–4470 (1994).
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D.R. Jenke. Chromatographic method validation: A review of current practices and procedures. I. General concepts and guidelines. J. Liq. Chromatogr. 19(5): 719–736 (1996). Also reprinted in Instrumentation Science and Technology. 25(4): 345–359 (1997).
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D.R. Jenke. Chromatographic method validation: A review of current practices and procedures. II. Guidelines for primary validation parameters. J. Liq. Chromatogr. 19(5): 737–757 (1996). Also reprinted in Instrumentation Science and Technology. 26(1): 1-18 (1998).
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D.R. Jenke. Chromatographic method validation: A review of current practices and procedures. III. Ruggedness, re-validation and system suitability. J. Liq. Chromatogr. 19(12): 1873-1891 (1996). Also reprinted in Instrumentation Science and Technology. 26(1): 19-36 (1998).
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D.R. Jenke. Practical examination of a non-porous silica stationary phase for reversed phase fast LC applications. J. Chromatogr. Sci. 34: 362–367 (1996).
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D.R. Jenke. Liquid chromatographic estimation of octanol/water partition coefficients with a high efficiency, non-porous ultra-small particle size reversed phase stationary phase. J. Liq. Chromatogr. 19(14): 2227–2246 (1996).
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D.R. Jenke. Behavior of weak acid anions in response to changing mobile phase pH in indirect photometric chromatography. J. Chromatogr. Sci. 34(9): 394–398 (1996).
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D.R. Jenke. Utilization of extraction profiles to estimate the accumulation of extractables from polymeric materials. J. Appl. Polymer Sci. 63: 843–848 (1997).
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D.R. Jenke. Development and validation of an Ion Exclusion chromatographic method for the quantitation of organic acids in complex pharmaceutical products. J. Chromatogr. Sci. 36(4): 179–186 (1998).
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D.R. Jenke. Material/Solution Compatibility: Interactions between Products and Plastic Materials in Parenteral Products: Development, Quality and Regulatory Issues. American Association of Pharmaceutical Scientists, Alexandria, VA, 1997, pp. 60–71.
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D.R. Jenke. Changes in retention and detector response for weak acid anions as a function of mobile phase pH in indirect photometric chromatography. J. Liq. Chromatogr. & Related Technol. 21(3); 315–329 (1998).
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D.R. Jenke. Evaluation of model solvent systems for assessing the accumulation of container extractables in drug formulations. Int. J. Pharm. 224: 51-60 (2001).
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M. Warnock, L. Nair, S. Sadain and D.R. Jenke. Evaluation of an Ion Exclusion/Direct Conductivity method for quantitating acetic and formic acids in pharmaceutical LVP base formulations. J. Liq. Chromatogr. & Related Technol. 25(4): 541-560 (2002).
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D.R. Jenke. Extractable/Leachable substances from plastic materials used as pharmaceutical product containers/devices. PDA J Pharm Sci Technol. 56(6): 332-371 (2002).
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D.R. Jenke. Nomenclature associated with the chemical characterization of, and compatibility evaluations for, medical product delivery systems. PDA J Pharm Sci Technol. 57(2): 97-108 (2003).
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D.R. Jenke. Chromatographic methods used to identify and quantify organic extractables from packaging materials. J. Liq. Chromatogr. & Related Technol. 26(15): 2449-2464 (2003). Also printed in the Encyclopedia of Chromatography (2003).
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D.R. Jenke. Chromatographic methods used to identify and quantify organic polymer additives. J. Liq. Chromatogr. & Related Technol. 26(15): 2417-2447 (2003). Also printed in the Encyclopedia of Chromatography (2003).
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D.R. Jenke, J. Brennan, M. Doty and M. Poss. Use of binary ethanol/water model solutions to mimic the interaction between a plastic material and pharmaceutical formulations. J. Appl. Poly. Sci. 89: 1049-1057 (2003).
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M. Poss, T. Couch, A. Odufu, J. Mellon, B. Melnick, J. McCann and D. Jenke. Determination of 1,4-Dioxane impurity in Triton X-100Ô raw material by gas chromatography with mass spectrometric detection (GC/MS). J. Chromatogr. Sci. 41(8): 410-417 (2003).
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S. Karmarkar and D. Jenke. Application of Ion Chromatography in pharmaceutical and drug analysis. Pharmacopeial Forum. 29(6): 2082-2108 (2003).
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D. Jenke, D. Zietlow and S. Sadain. Leaching of organic acids from irradiated EVA plastics as a function of solution pH and polarity. PDA J Pharm Sci Technol. 58(1): 24-31 (2004).
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D.R. Jenke. The Response Spectrum in Chromatographic Analysis. In the Encyclopedia of Chromatography (2004).
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D. Jenke, M. Poss, J. Story, A. Odufu, D. Zietlow and T. Tsilipetros. Development and validation of chromatographic methods for the identification and quantitation of organic compounds leached from laminated polyolefin material. J. Chromatogr. Sci. 42(7): 388-395 (2004).
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D.R. Jenke. Guidelines for the design, implementation and interpretation of validations for chromatographic methods used to quantitate leachables/extractables in pharmaceutical solutions. J. Liq. Chromatogr & Related Technol. 27(20): 1-36 (2004).
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D. Jenke, M.J. Garber, and D. Zietlow. Validation of a liquid chromatographic method for quantitation of organic compounds leached from a plastic container into a pharmaceutical formulation. J. Liq. Chromatogr & Related Technol. 28(2): 199-222 (2005).
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D. Jenke, M. Poss, S. Sadain, J. Story, W. Smith and D. Reiber. Identification of caprolactam oligomers and related compounds in aqueous extracts of Nylon 6. J. Appl. Poly Sci. 95: 1262 - 1274 (2005).
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D.R. Jenke, J.M. Jenne, M.Poss, J. Story, T. Tsilpetros, A. Odufu and W. Terbush. Accumulation of extractables in buffer solutions from a polyolefin plastic container. Int. J. Pharm. 297(1-2): 120-133 (2005).
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D.R. Jenke. Linking extractables and leachables in container/closure applications. PDA J Pharm Sci Technol. 59(4): 265-281 (2005).
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D. Jenke, S. Swanson, E. Edgcomb, T. Couch, M. Chacko, M.J. Garber and L. Fang. Strategy for assessing the leachables impact of a material change made to a container/closure system. PDA J Pharm Sci Technol. 59(6): 360-380 (2005).
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D.R. Jenke. Examination of data relating to the thermodynamic and kinetic interactions between non-volatile aqueous solutes and three ethylene vinyl acetate co-polymers. J. Applied Poly. Sci. 99(1): 253-259 (2006).
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D. Jenke, A. Odufu and M. Poss. The effect of solvent polarity on the accumulation of leachables from pharmaceutical product containers. Eur. J. Pharm. Sci. 27: 133-142 (2006).
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D. Jenke and T. Couch. A consideration of the impact of solution composition on the accumulation of organic substances leached from plastics used in container/closure systems. PDA J Pharm Sci Technol. 60(1): 60-71 (2006).
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D.R. Jenke, J. Story and R. Lalani. Extractables/Leachables from plastic tubing used in product manufacturing. Int. J. Pharm. 315 (1-2): 75-92 (2006).
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D.R. Jenke. Extractable substances from plastic materials used in solution contact applications, An updated review. PDA J Pharm Sci Technol. 60(3): 191-207 (2006).
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D. Jenke, S. Sadain, K. Nunez and F.K. Byrne. Performance characteristics of an ion chromatographic method for quantifying citrate and phosphate in pharmaceutical solutions. J. Chromatogr. Sci. 45(1): 50-56 (2007).
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D. Jenke. An extractables/leachables strategy facilitated by collaboration between drug product vendors and plastic material suppliers. PDA J Pharm Sci Technol. 61(1): 17-23 (2007).
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D. Jenke. Evaluation of the chemical compatibility of plastic contact materials and pharmaceutical products; safety considerations related to extractables and leachables. J. Pharm. Sci. 96(10): 2566 – 2581 (2007).
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D.R. Jenke, D. Zietlow, M.J. Garber, S. Sadain, D. Reiber and W. Terbush. Accumulation of organic compounds leached from plastic materials used in biopharmaceutical process containers. PDA J Pharm Sci Technol. 61(4): 286 – 302 (2007).
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D. Jenke. Suitability-for-Use considerations for Prefilled Syringes. Pharm. Technol. Drug Delivery Supplement: s30-s33 (2008).
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D.L. Norwood, D. Jenke, C. Manolescu, S. Pennino and N. Grinberg. HPLC and LC/MS analysis of pharmaceutical container closure system leachables and extractables. J. Liq. Chromatogr. Related Technol. 32(11-12): 1768-1827 (2009).
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D. Jenke. A discussion of the physicochemical factors that regulate the leaching of organic substances from plastic contact materials into aqueous pharmaceutical solutions. Am. Pharm. Rev. 2009. Available at http://www.americanpharamceuticalreview.com/ViewArticle.aspx?ContentID = 4162&ID = 4.
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D. Jenke, T. Couch, A. Gillum and S. Sadain. Modeling of the solution interaction properties of plastic materials used in pharmaceutical product container systems. PDA J Pharm Sci Technol. 63(4): 294 – 306 (2009).
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D. Jenke, A. Shaw and S. Beck. The ELSIE initiative; Role of extractables/leachables databases in safety assessment. 27 Am. Biotech. Lab. (9): 14-17 (2009).
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D. Jenke. Compatibility of Pharmaceutical Solutions and Contact Materials; Safety Considerations Associated with Extractables and Leachables. J.Wiley and Sons (New York, 2009).
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D. Norwood, M. Ruberto, F.L. DeGrazio, J. Castner, W. K. Wong and D. Jenke. Extractables and leachables from rubber materials used in pharmaceutical systems. Rubber and Polymer News. June 29, 2009; 15-19.
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D. Jenke, T. Couch and A. Gillum. Comparison of solute binding properties of plastic materials used in pharmaceutical product containers. PDA J Pharm Sci Technol. 64(1): 37-43 (2010).
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D. Jenke. Extraction of stearate salts from plastic materials used in pharmaceutical applications. PDA J Pharm Sci Technol. 64(3):200-210 (2010).
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J. Story, M. Gill, N. Liu, Y. Hua and D. Jenke. Generation of the extractables profile of an elastomeric materials and investigation of the accumulation behavior of target leachables including Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Tinuvin 770) and a related substance. PDA J Pharm Sci Technol. 64(2): 101-112 (2010).
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D. Jenke, Y. Hua, M.J. Garber and M. Gill. Development and validation of an HPLC/MS/MS method for quantitating Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (Tinuvin 770) and a related substance in aqueous extracts of plastic materials. J. Chromatogr. Sci. 48(3): 200 – 207 (2010).
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D. Jenke. Application of quality by design (QbD) principles to extractables/leachables assessment. Establishing a design space for terminally sterilized aqueous drug products stored in a plastic packaging system. PDA J Pharm Sci Technol. 64(6): 527-535 (2010).
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D. Jenke, Y. Hua, M.J. Garber and M. Gill. Development and characterization of an LC/MS method for quantitating aqueous extractables, including Bisphenol A, 1-Formylpiperidine and Bis-(pentanamethylene)-urea, from plastic materials. J. Chromatogr. Sci. 49(3): 214-220 (2011).
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D. Jenke. A general assessment of the physiochemical factors that affect the leaching of organic substances from plastic contact materials into aqueous pharmaceutical solutions. PDA J Pharm Sci Technol. 65(2): 166-176 (2011).
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D. Jenke. Application of ion chromatography in pharmaceutical and drug analysis. J. Chromatogr. Sci. 49(7): 524-539 (2011).
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D. Jenke and A. Odufu. Utilization of internal standard response factors to estimate the concentration of organic compounds leached from pharmaceutical packaging systems and application of such estimated concentrations to safety assessment. J. Chromatogr. Sci. 50:206-212 (2012).
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D. Jenke. Essential aspects in assessing the safety impact of interactions between a drug product and its associated manufacturing system. PDA J Pharm Sci Technol. 66(1): 63-77 (2012).
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D. Jenke. A general overview of the suitability for intended use requirements for materials used in pharmaceutical systems. Chapter 3 in Leachables and Extractables Handbook; Safety Evaluation, Qualification, and Best Practices Applied to Inhalation Drug Products. J. Wiley and Sons (New York, 2012), pp. 21-36.
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T. Feinberg, D.L. Norwood, A.T. Granger and D. Jenke. Extractables: The controlled extraction study. Chapter 14 in Leachables and Extractables Handbook; Safety Evaluation, Qualification, and Best Practices Applied to Inhalation Drug Products. J. Wiley and Sons (New York, 2012), pp. 289-330.
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D. Jenke. A general strategy for the chemical aspects of the safety assessment of extractables and leachables in pharmaceutical drug products; The chemical assessment triad. PDA J Pharm Sci Technol. 66(2): 168-183 (2012).
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Y. Hua and D. Jenke. Increasing the sensitivity of an LC/MS method for screening material extracts for organic extractables via mobile phase optimization. J. Chromatogr. Sci. 50:213-227 (2012).
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D. Jenke, A. Odufu, T. Couch, M. Chacko, S. Strathmann and E. Edgcomb. Evaluation of the general solution compatibility of polymer materials used in medical devices such as syringes. PDA J Pharm Sci Technol. 66(4): 286 – 306 (2012).
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D. Jenke. The chemical safety assessment process for extractables and leachables associated with packaged pharmaceutical products. Eur Pharm Rev. 18(1): 16-19 (2013).
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D. Jenke. Insights gained into the identification, qualification, and utilization of CRO laboratories in extractables and leachables studies. Pharm. Outsourcing. 14(2): 20, 22, 24-26 and 14(3): 22, 24, 26, 28, 30 (2013).
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D. Jenke, C. Rivera, T. Mortensen, P. Amin, M. Chacko, T. Tran, and J. Chum. A compilation of metals and trace elements extracted from materials relevant to pharmaceutical applications such as packaging systems and devices. PDA J Pharm Sci Technol. 67(4): 354-375 (2013).
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D. Paskiet, D. Jenke, D. Ball, C. Houston, D.L. Norwood and I. Markovic. The Product Quality Research Institute (PQRI) leachables and extractables working group initiatives for parenteral and ophthalmic drug product (PODP). PDA J Pharm Sci Technol. 76(5): 430-447 (2013).
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D. Jenke, J. Castner, T. Egert, T Feinberg, A. Hendricker, C. Houston, D.G. Hunt, M. Lynch, A. Shaw, K. Nicholas, D.L. Norwood, D. Paskiet, M. Ruberto, E.J. Smith and F. Holcomb. Extractables characterization of five materials of construction representative of packaging systems used for parenteral and ophthalmic drug products. PDA J Pharm Sci Technol. 76(5): 448-511 (2013).
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D.R. Jenke, D.L. Norwood, and D.G. Hunt. USP Plastic Packaging Chapters – An Overview. Pharmacopeial Forum. 39(6): 1 – 29 (2013). Available at http://www.usppf.com/pf/pub/data/v396/GEN_STIMULI_396_S20045.xmL.
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D. Jenke and M. Ruberto. Using the correlation between material composition and extractables and leachables to forecast extractables and/or leachables profiles. Part 1: Concepts and Plasticized Poly-(vinylchlorde) Case Study. Pharm. Outsourcing. 15(1): 32, 34, 36, 38-41 (2014).
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D. Jenke, and M. Ruberto. Using the correlation between material composition and extractables and leachables to forecast extractables and/or leachables profiles. Part 2: Polyethylene and Bromobutyl Rubber Case Studies. Pharm. Outsourcing. 15(2): 22, 24, 26 - 31 (2014).
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D. Jenke, T.R. Couch, S.J. Robinson, T.J. Volz and R.H. Colton. The use of TOC reconciliation as a means of establishing the degree to which chromatographic screening of plastic material extracts for organic extractables is complete. PDA J Pharm Sci Technol. 68(3): 256-270 (2014).
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D. Jenke, D and V.J. Barge. Factors affecting the release of extractable acetic acid from multi-layered plastic films containing ethylene vinyl acetate (EVA) and polyethylene (PE) layers. Pharm Outsourcing. 15(3): 52, 54, 56 - 59 (2014).
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D. Jenke. Establishing the proper pH of simulating solvents used in organic extractables assessments for packaging systems and their materials of construction used with aqueous parenteral drug products. Pharm Outsourcing. 15(4):20, 22, 24-27 (2014).
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D. Jenke and T. Carlson. A compilation of safety impact information for extractables associated with materials used in pharmaceutical packaging, delivery, administration and manufacturing systems. PDA J Pharm Sci Technol. 68(5): 407-455 (2014).
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D. Jenke. Extractables and Leachables Considerations for Pre-filled Syringe. Expert Opinion on Drug Delivery. 11(1): 1 – 10 (2014).
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D. Jenke and V.J. Barge. Mathematical modeling of the extractables release from multi-layered plastic film used in drug product containers. J. App. Poly. Sci. 132(1): 120-. DOI: 10.1002/APP.41233. (2014)
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D. Jenke. Safety Risk Categorization of Organic Extractables Associated with Polymers used in Packaging, Delivery and Manufacturing Systems for Parenteral Drug Products. Pharm Res. 32(3): 1105-1127 (2015). DOI: 10.1007/s11095-014-1523-z.
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A. Teasdale, M. Jahn, S. Bailey, A. Feilden, G. Taylor, M.L. Corcoran, R. Malick, D. Jenke, C.L.M. Stults, and L.M. Nagao. Study Controlled Extraction Studies Applied to Polyvinyl Chloride and Polyethylene Materials: Conclusions from the ELSIE Controlled Extraction Pilot. AAPS PharmSciTech. 16(3): 664 – 674 (2015). DOI: 10.1208/s12249-014-0249-x.
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D. Jenke, M. Gill, J. Liu, S. Liao, and X. Huang. Application of quality by design (QbD) principles to extractables/leachables assessment for terminally sterilized aqueous parenteral solutions stored in a plastic packaging system. CNPPA Magazine: Pharmacy & Packaging. 36(6): 4-10 (2014) and 37(1): 5-10 (2015).
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D.R. Jenke, C.L.M. Stults, D.M. Paskiet, D.J. Ball, and L.M. Nagao. Materials in Manufacturing and Packaging Systems as Sources of Elemental Impurities in Packaged Drug Products: A Literature Review. PDA J Pharm Sci Technol. 69(1):1-48 (2015). doi:10.5731/pdajpst.2015.01005
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D. Jenke, N. Liu, Y. Hua, S. Swanson and R. Bogseth. A means of establishing and justifying binary ethanol/water mixtures as simulating solvents in extractables studies. PDA J Pharm Sci Technol. 69(3): 366-38 2(2015). Doi: 10.5731/pdajpst.2015.01046.
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D. Jenke, B.E. Rabinow and M. Chacko. Potential contribution of a plasticized PVC packaging material to the levels of elemental impurities in packaged drug products. Pharm Outsourcing. 16(2): 26, 28, 30, 32, 34, 35. (2015).
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D. Jenke. Considering the Standardization of Strategies for Establishing Extractables Profiles for Plastic Components Used in Drug Product Production Systems. Pharm Outsourcing. 16(3): 12-14 (2015).
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D. Jenke. Moving forward towards standardized analytical methods for extractables and leachables profiling studies. PDA J Pharm Sci Technol. 69(4): 471-476 (2015). Doi: 10.5731/pdajpst.2015.01089.
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D. Jenke. Development and justification of a risk evaluation matrix to guide chemical testing necessary to select and qualify plastic components used in production systems for pharmaceutical products PDA J Pharm Sci Technol. 69(6): 677-712 (2015). Doi: 10.5731/pdajpst.2015.01077.
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D. Jenke. Insights into elemental impurities. The Medicine Maker. 0616 (20): 34-37 (2016).
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D. Jenke and N. Liu. Chromatographic considerations in the standardization of liquid chromatographic methods used for extractables screening. J Liq Chromatogr Rel Tech. 39(13): 613-619 (2016).
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D. Jenke, T. Egert, A. Hendricker, J. Castner, T. Feinberg, C. Houston, D.G. Hunt, M. Lynch, L. Markovic, K. Nicholas, D.L. Norwood, D. Paskiet, M. Ruberto, E.J. Smith, and F. Holcomb. Simulated Leaching (Migration) Study for a Model Container-closure System Applicable to Parenteral and Ophthalmic Drug Products (PODPs). PDA J Pharm Sci Technol. 71(2): 68-87 (2017). Doi:10.5731/pdajpst.2016.007229.
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D.R. Jenke and B.E. Rabinow. Proper Accounting for Surface Area to Solution Volume Ratios in Exaggerated Extractions. PDA J Pharm Sci Technol. 71(3): 225-233 (2017). Doi:10.5731/pdajpst.2016.007195.
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D. Jenke. Strategic aspects of change control for packaging. Eur Pharm Rev. 22(2): 60-62 (2017).
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D. Jenke. Extractables – leachables correlations for packaging. Eur Pharm Rev. 22(4): 68-70 (2017).
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D. Jenke. Extractables Screening of Polypropylene Resins used in Pharmaceutical Packaging for Safety Hazards. PDA J Pharm Sci Technol. 71(5): 346-367 (2017).
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D. Paskiet, R. Janssen, D. Guazzo, D. Ball, M. Eakins, D. Hunt, D. Jenke, J. Kaufman, D. Kiehl, H. Kirchmeyer, P. LeGall, D. Norwood, M. Ruberto, J. Wong, and L. Yoest. The rationale and proposed changes to the revision of Elastomeric Closures for Injections <381>. Pharmacopeial Forum. 43(5): (2017).
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D. Jenke. Identification, Analysis and Safety Assessment of Leachables and Extractables. TrAC 101: 56-65 (2018).
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D. Jenke. Accounting for Risk when Designing Chemical Safety Assessments for Pharmaceutical Packaging Systems. Eur Pharm Rev. 23(1): 20, 22, 24 (2018).
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D. Jenke. How One Might Experimentally Determine if Container Closure Systems and their Components and Materials of Construction Contribute Elemental Impurities to Packaged Pharmaceutical Drug Products. PDA J Pharm Sci Technol. 73(2): 181-190 (2019).
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D. Jenke. Application of Arrhenius Kinetics to Acceleration of Controlled Extraction Studies. PDA J Pharm Sci Technol. 73(2): 135-168 (2019).
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D. Jenke, P. Christiaens, J.M. Beusen, P. Verlinde, and J. Baeten. Identifying and Mitigating Errors in Screening for Organic Extractables and Leachables: Part I; Introduction to Errors in Chromatographic Screening for Organic Extractables & Leachables and Discussion of the Error of Omission. PDA J Pharm Sci Technol; 74(1): 90-107 (2020).
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D. Jenke, P. Christiaens, J.M. Beusen, P. Verlinde, and J. Baeten. Identifying and Mitigating Errors in Screening for Organic Extractables and Leachables: Part 2: The Errors of Inexact Identification and Inaccurate Quantitation. PDA J Pharm Sci Technol. 74(1): 108-133 (2020).
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D. Jenke. Identifying and Mitigating Errors in Screening for Organic Extractables and Leachables: Part 3: Considering Errors of Implementation and the Use of a Database to Judge and Promote Good Science and Efficient Practices. PDA J Pharm Sci Technol. 74(1): 134-146 (2020).
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D. Jenke. Identification and quantitation classifications for extractables and leachables. PDA J Pharm Sci Technol. 74(2), 275-285 (2020).
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D. Jenke. Materials in Manufacturing and Packaging Systems as Sources of Elemental Impurities in Packaged Drug Products: An Updated Literature Review. PDA Journal of Pharm Sci Technol. 74(3): 324-347 (2020).
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D. Jenke. Correcting the Analytical Evaluation Threshold (AET) and Reported Extractable's Concentrations for Analytical Response Factor Uncertainty Associated with Chromatographic Screening for Extractables/Leachables. PDA Journal of Pharm Sci Technol. 74(3): 348-358 (2020).
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D. Jenke, T. Heise. The Implications of Chromatographically Screening Medical Products for Organic Leachables Down to the AET Adjusted for Response Factor Variation. PDA Journal of Pharm Sci Technol.273-288 (2021).
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Jenke, D.; Christiaens, P.; Baeten, J.; Verlinde, P.; Beusen, J-M, D’Autry, W.; Mullis, J. Good Identification Practices for Organic Extractables and Leachables Via Mass Spectrometry. ISBN 978-0-578-95605-3 (2021).
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D. Jenke. A Safety Risk-Based Extractables and/or Leachables Qualification Strategy for Packaged Drug Products. PDA Journal of Pharm Sci Technol. 75(6): 506-535 (2021).
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D. Jenke, P. Christiaens, P. Verlinde, J. Baeten, J.M. Beusen. Is Retention Time and/or Structure Matching a Solution to the Challenge of Providing Quantitative Data when Screening for Extractables and Leachables by GC/MS? PDA J Pharm Sci Technol. 76 (3): 236-247 (2022). DOI: https://doi.org/10.5731/pdajpst.2021.012673
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D. Jenke, P. Christiaens, J.M. Beusen, P. Verlinde, J. Baeten. A Practical Derivation of the Uncertainty Factor Applied to Adjust the Extractables/Leachables Analytical Evaluation Threshold (AET) for Response Factor Variation. PDA Journal of Pharm Sci Technol. 76 (3): 178-199 (2022). DOI: https://doi.org/10.5731/pdajpst.2021.012692
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D. Jenke. Extractables and Leachables: Characterization of Drug Products, Packaging, Manufacturing and Delivery Systems, and Medical Devices. J.Wiley and Sons (New York, 2022). ISBN: 978-1-119-60507-2.
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D. Jenke, J.M. Beusen, P. Verlinde, J. Baeten, P. Christiaens, D. Hunt, P. Gruddanti. Proposals for the Development, Composition, and Routine Use of System Suitability Standard Mixtures in Support of Chromatographic Screening for Organic Extractables and Leachables. Pharmacopeia Forum. 49(4). (2023). DOI: https://doi.org/10.31003/USPNF_S203084_10101_01.
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D. Jenke. Standardization of Chromatographic Screening Methods for Organic Extractables and Leachables by Managing Outcomes. PDA Journal of Pharm Sci Technol. 77(4): 329-338 (2023).
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D. Jenke. Insights into Practical Challenges Associated with Extractables Testing of Medical Devices. BioPharm Asia. 12(5): 18-25. (2023).
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D. Jenke. Accurate or Protective: What is the Goal of Non-targeted Extractables and Leachables Quantitation and Identification?. PDA Journal of Pharm Sci Technol. Accepted article, November 2023. pdajpst.2023.012868; DOI: https://doi.org/10.5731/pdajpst.2023.012868.