A Knowledge Management Framework and Approach for Clinical Development.

A knowledge management (KM) framework enhances knowledge gathering, sharing, application, and retention within clinical development and enables the effective and successful implementation of a clinical quality management system (QMS). The goal of managing knowledge is to improve organizational performance by getting the right information to the right people at the right time. The concepts of KM have been around for decades but, to date, have not been widely adopted within the clinical development arena. Implementing a structured approach and strategy to managing knowledge can enable more timely and informed decision making, enhance quality and productivity, and ultimately support the delivery of new products to patients. This paper outlines in general terms key elements of a clinical knowledge management (CKM) framework to assist clinical development organizations in understanding its benefits and basic components. Ideas are provided at a high level for flexible approaches and solutions aimed to enhance knowledge gathering, sharing, application, and retention within clinical development.

Use of a quality-by-design approach to justify removal of the HPLC weight % assay from routine API stability testing protocols.

Due to the high method variability (typically > or = 0.5%, based on a literature survey and internal Merck experience) encountered in the HPLC weight percent (%) assays of various active pharmaceutical ingredients (APIs), it is proposed that the routine use of the test in stability studies should be discouraged on the basis that it is frequently not sufficiently precise to yield results that are stability-indicating. The high method variability of HPLC weight % methods is not consistent with the current ICH practice of reporting impurities/degradation products down to the 0.05% level, and it can lead to erroneous out-of-specification (OOS) results that are due to experimental error and are not attributable to API degradation. For the vast majority of cases, the HPLC impurity profile provides much better (earlier and more sensitive) detection of low-level degradation products. Based on these observations, a Quality-by-Design (QbD) approach is proposed to phase out the HPLC weight % assay from routine API stability testing protocols.

Evaluation of chiral purity for a substituted imidazole p38 MAP kinase inhibitor and its intermediates using a single chiral capillary electrophoresis method.

The chiral separation of a substituted imidazole p38 MAP kinase inhibitor and its intermediates was investigated using capillary electrophoresis (CE) with various sulfated cyclodextrins. After initial screens, a single CE chiral method with a randomly sulfated beta-CD was selected for the evaluation of chiral purity for all three compounds. Operational parameters, such as the concentration of the chiral selectors, background electrolyte (or mobile phase) pH, organic modifiers, and temperature were varied in order to achieve an optimized method. The optimal method was validated in terms of linearity, sensitivity, precision, ruggedness, and specificity.

Comparison study of Chiralpak AD-H with AD columns in chromatographic enantioseparation of dihydropyrimidinone acid and its methyl ester.

This paper reports a comparison study of the difference between Chiralpak AD-H and AD columns in enantioseparation of dihydropyrimidinone (DHP) acid and its methyl ester under normal phase LC conditions. Unlike those of the AD phase, the van't Hoff plots of retention factors for DHP acid on the AD-H phase were linear. The cyclic van't Hoff plots of selectivity factors for DHP acid on the AD-H phase were non-linear and slightly non-superimposable. No conformational transition was observed on the AD-H phase in the whole temperature range. A single-step temperature program on the AD-H phase showed that the selectivity factors of DHP acid only increased approximately 1.7% in 24 h (versus approximately 50% on the AD phase). For DHP ester, the single-step temperature program showed that the selectivity factors on the AD-H phase remained the same in 24 h while those on the AD phase increased around 3.1%. The enantioselectivity of DHP acid on the AD-H phase was lower than that on the AD phase while the enantioselectivity of DHP ester on the AD-H phase was higher than that on the AD phase. The resolution of DHP acid on the AD-H phase was about the same as that on the AD phase while the resolution of DHP ester on the AD-H phase was much higher than that on the AD phase. The results of DHP acid are opposite of what the vendor suggested while the results of DHP ester are the same as the vendor's application notes. This indicates that the differences between Chiralpak AD-H and AD columns are not only in their particle size, but also in the solvated conformations.

Characterization of a thermally induced irreversible conformational transition of amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase in enantioseparation of dihydropyrimidinone acid by quasi-equilibrated liquid chromatography and solid-state NMR.

A thermally induced irreversible conformational transition of amylose tris(3,5-dimethylphenylcarbamate) (i.e., Chiralpak AD) chiral stationary phase (CSP) in the enantioseparation of dihydropyrimidinone (DHP) acid racemate was studied for the first time by quasi-equilibrated liquid chromatography with cyclic van't Hoff and step temperature programs and solid-state ((13)C CPMAS and (19)F MAS) NMR using ethanol and trifluoroacetic acid (TFA)-modified n-hexane as the mobile phase. The conformational transition was controlled by a single kinetically driven process, as evidenced by the chromatographic studies. Solid-state NMR was used to study the effect of the temperature on the conformational change of the solvated phase (with or without the DHP acid enantiomers and TFA) and provided some viable structural information about the CSP and the enantiomers.

Mechanistic study of the enantiomeric recognition of a basic compound with negatively charged single-isomer gamma-cyclodextrin derivatives using capillary electrophoresis, nuclear magnetic resonance spectroscopy, and infrared spectroscopy.

The possible mechanisms for the chiral recognition of 2-(R)-N-[1-(6-aminopyridin-2-ylmethyl)piperidin-4-yl]-2-[(1R)-3,3-difluorocyclopentyl]-2-hydroxy-2-phenylacetamide (RR-M3), and its enantiomer (SS-M3) with octakis(2,3-di-O-acetyl-6-sulfo)-gamma-cyclodextrin (ODAS-gamma-CD) and octakis(6-sulfo)-gamma-cycöpdextrom enantiomer; (OS-gamma-CD), were investigated using capillary electrophoresis (CE), proton ((1)H), fluorine ((19)F) and carbon ((13)C) nuclear magnetic resonance spectroscopy (NMR), and infrared (IR) spectroscopy. Clear evidence for the formation of diastereomeric complexes between the enantiomers and the two CDs was observed. NMR spectra suggest that the phenyl and difluorocyclopentyl rings are involved in the complexation. The phenyl ring on the guest molecule is deeply penetrated into the cavity of OS-gamma-CD, but it is not included into the cavity of ODAS-gamma-CD. The continuous variation plots built based on the (1)H NMR and IR spectra indicate a 1:1 complex stoichiometric ratio of the M3 enantiomers for both CDs. The affinity of the enantiomers for the two CDs is opposite.

Determination and differentiation of surface and bound water in drug substances by near infrared spectroscopy.

Near infrared spectroscopy (NIRS) was utilized to determine the water content during the drying of a drug substance with Karl Fisher titration as the reference measurement. NIRS calibration models were built with Partial Least Squares (PLS) regression based on spectral region of 1822-1948 nm for samples with 1-40% (w/w) water from five batches. A standard error of prediction (SEP) of 1.85% (w/w) was obtained from validation of the model with additional batches. A second NIRS calibration model using PLS was constructed in the region of 1-10% (w/w) water with samples from the same five calibration batches. This calibration model improved the accuracy of the prediction in the critical region around the end point of drying and provided a standard error of prediction 0.42% (w/w). In addition, direct spectral analyses with Principal Component Analysis (PCA) and peak ratios were applied to distinguish between surface (unbound) water and bound water incorporated into the crystal lattice of the drug substance. Direct spectral analysis indicated the existence of significant numerical and graphical differences between samples containing both surface and bound water, and those containing bound water only. Applying this method to monitor an actual drying process with the graphical assistance of spectral analysis, the drying process can be controlled, and the end point of drying clearly determined to ensure the desired hydrate form of the product. This study has demonstrated the in-line monitoring capability of NIRS to differentiate the surface and bound water simultaneously in addition to the determination of the water level.

Mechanistic study of enantiomeric recognition with native gamma-cyclodextrin by capillary electrophoresis, reversed-phase liquid chromatography, nuclear magnetic resonance spectroscopy, electrospray mass spectrometry and circular dichroism techniques.

The possible mechanisms for the chiral recognition of 2(S)-(3,5-bis-trifluoromethyl-phenyl)-2-[3(S)-(4-fluorophenyl)-4-(1H-[1,2,4]triazol-3-ylmethyl)-morpholin-2(R)-yloxy]-ethanol (compound A) and its enantiomer with native gamma-cyclodextrin (gamma-CD) were investigated using capillary electrophoresis (CE), reversed-phase liquid chromatography (RPLC), proton (1H), fluorine (19F) and carbon (13C) nuclear magnetic resonance spectroscopy (NMR), electrospray mass spectrometry (ESI-MS) and circular dichroism (CD). All experiments provided clear evidence of the formation of diastereomeric complexes between the enantiomers and gamma-CD. Proton, fluorine and carbon NMR spectra suggested that both aromatic rings, with mono-fluoro and bis-tri-fluoro functional groups, on the guest molecule were partially included into the cavity of the gamma-CD. ESI-MS spectra indicated that the diastereomeric complexes have a 1:1 stoichiometric ratio. The binding constants of the diastereomeric complexes obtained by CE, RPLC and CD were compared. The effects of the gamma-CD concentration, organic modifiers and temperature on the CE-chiral separation were also investigated.

Unusual effect of column temperature on chromatographic enantioseparation of dihydropyrimidinone acid and methyl ester on amylose chiral stationary phase.

This paper reports an unusual effect of column temperature on the separation of the enantiomers of dihydropyrimidinone (DHP) acid and its methyl ester on a derivatized amylose stationary phase by normal-phase liquid chromatography. The separation of the DHP acid enantiomers was investigated using both carbamate-derivatized amylose and cellulose stationary phases (Chiralpak AD and Chiralcel OD) with an ethanol-n-hexane (EtOH-n-Hex) mobile phase. On the amylose phase, the van 't Hoff plot of the retention factor of the S-(+)-DHP acid was observed to be non-linear while that of R-(-)-DHP acid was linear. Likewise, the van 't Hoff plot for DHP acid enantioselectivity was non-linear with a transition occurring at approximately 30 degrees C. Furthermore, the van 't Hoff plot for the DHP acid enantioselectivity factor for data taken when heating the column from 5 to 50 degrees C was not superimposable with the same plot prepared with data from the cooling process from 50 to 5 degrees C. This observation suggested that the stationary phase was undergoing a thermally induced irreversible conformational change that altered the separation mechanism between the heating and cooling cycles. Similar phenomena were observed for the separation of the enantiomers of the DHP ester probe compound. The conformational change of the AD phase was shown to depend on the polar component of the mobile phase. When 2-propanol (2-PrOH) was used as the modifier instead of EtOH, the van 't Hoff plots for DHP acid were linear and thermally reversible, suggesting that no such irreversible conformational change occurs with this modifier. Conversely, when the AD phase was pre-conditioned with a more polar methanol (MeOH) or water containing mobile phase, thermal irreversibility of DHP acid enantioselectivity was once again observed. Interestingly, when the stationary phase was changed to its cellulose analogue, the Chiralcel OD, all van 't Hoff plots for the retention and selectivity of DHP acid were thermally reversible for both EtOH-n-Hex and 2-PrOH-n-Hex mobile phases.

Evaluation of the origins of the selectivity of polymers imprinted with a HIV protease inhibitor using infrared spectroscopy and high performance liquid chromatography.

This work investigates the origins of enantioselectivity of polymers imprinted with the HIV protease inhibitor, Indinavir. For the preparation of imprints of the drug, the critical interactions between the functional monomer, methacrylic acid, and Indinavir were characterized by infrared (IR) spectroscopy to explore the optimum functional monomer concentration for the polymerization. It was shown that a polymer with high selectivity and minimum non-selective binding for Indinavir was obtained when prepared with enough functional monomer to hydrogen bond with all of the functional groups of the drug without using an excess of monomer. This observation is explained in terms of a balance that is achieved in the monomer-template equilibrium during the polymerization that yields a polymer with highly selective sites and minimal non-selective sites. This paper further demonstrates that IR spectroscopy can be a valuable tool in the design and syntheses of molecular imprinted polymers.

Examination of rofecoxib solution decomposition under alkaline and photolytic stress conditions.

Rofecoxib is a highly active and selective cyclo-oxygenase II inhibitor. A stability-indicating method for the assay of rofecoxib has been developed using reverse-phase high-performance liquid chromatography (HPLC). Stress testing of rofecoxib was conducted during the method development and validation. HPLC analysis of rofecoxib solutions stressed under alkaline and photolytic conditions revealed the presence of several degradates. Two main degradates were determined to be the cyclization product formed by photo-cyclization and the dicarboxylate formed by ring opening in the presence of base and oxygen. The identities of these degradates were confirmed by comparison of UV spectra and HPLC retention time with the independently synthesized products. The mechanistic pathways for the formation of these degradates are discussed. Further improvement of the HPLC method's ruggedness has been made based on these studies.

Enantiomeric separation of a thiazolbenzenesulfonamide compound using packed-column subcritical fluid chromatography.

Separation of enantiomers of a thiazolbenzenesulfonamide compound was performed on a Chiralpak AD column using subcritical fluid chromatography. Effects of alcohol modifier and temperature on the separations were studied. The results revealed that while the main adsorbing interactions were between the hydroxyl group of the analyte and the carbamate group of the stationary phase, chiral discrimination was achieved through an inclusion mechanism within the chiral cavity created along the amylose chains. Analogs and synthetic precursors of the thiazolbenzenesulfonamide studied were also investigated so as to understand the effect of functional groups and configuration of the analyte molecule upon chiral recognition.

A strategic approach to the development of capillary electrophoresis chiral methods for pharmaceutical basic compounds using sulfated cyclodextrins.

Enantioseparations of basic pharmaceutical compounds were investigated using different types of sulfated cyclodextrins as chiral selectors. A general strategy for method development was described, together with enantiomeric separations of a number of pharmaceutical related compounds. Based on this strategy, systematic method development approaches for several selected compounds were performed by modifying method parameters, such as the concentration of the chiral selectors, buffer pH, type of organic modifiers, buffer type, temperature and applied voltage. The results of the investigation elucidated the separation mechanism. Many practical aspects were also discussed through several specific examples in order to demonstrate how to develop and validate a precise, sensitive, accurate and rugged separation.