Development of an in vivo-relevant drug product performance method for an amorphous solid dispersion.

The purpose of this work was to develop a meaningful in vitro dissolution method for evacetrapib spray-dried dispersion (SDD) tablets that is discriminating for crystalline drug substance (DS) content. Justification of the method conditions included evaluation of dissolution media, rotation speed, surfactant selection and level of surfactant to achieve sink conditions. Discrimination was illustrated by testing SDD tablets spiked with 10%, 20%, and 30% crystalline DS. The results demonstrated a 13%, 22% and 32% drop in the dissolution end point, respectively, as compared to unspiked SDD tablets. Additionally, tablets containing crystalline DS and tablets containing SDD were tested in a relative bioavailability (RBA) study. Utilizing the proposed dissolution method, the dissolution end point of SDD tablets was determined to be approximately 4 fold higher than that of the tablets containing crystalline DS. These results compare favourably to the in vivo RBA study results where SDD tablets had a 4.6 fold increase in exposure compared to tablets containing crystalline DS.

Best Practices in Stability Indicating Method Development and Validation for Non-clinical Dose Formulations.

Non-clinical dose formulations (also known as pre-clinical or GLP formulations) play a key role in early drug development. These formulations are used to introduce active pharmaceutical ingredients (APIs) into test organisms for both pharmacokinetic and toxicological studies. Since these studies are ultimately used to support dose and safety ranges in human studies, it is important to understand not only the concentration and PK/PD of the active ingredient but also to generate safety data for likely process impurities and degradation products of the active ingredient. As such, many in the industry have chosen to develop and validate methods which can accurately detect and quantify the active ingredient along with impurities and degradation products. Such methods often provide trendable results which are predictive of stability, thus leading to the name; stability indicating methods. This document provides an overview of best practices for those choosing to include development and validation of such methods as part of their non-clinical drug development program. This document is intended to support teams who are either new to stability indicating method development and validation or who are less familiar with the requirements of validation due to their position within the product development life cycle.

Absolute bioavailability of evacetrapib in healthy subjects determined by simultaneous administration of oral evacetrapib and intravenous [(13) C8 ]-evacetrapib as a tracer.

This open-label, single-period study in healthy subjects estimated evacetrapib absolute bioavailability following simultaneous administration of a 130-mg evacetrapib oral dose and 4-h intravenous (IV) infusion of 175 µg [(13) C8 ]-evacetrapib as a tracer. Plasma samples collected through 168 h were analyzed for evacetrapib and [(13) C8 ]-evacetrapib using high-performance liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameter estimates following oral and IV doses, including area under the concentration-time curve (AUC) from zero to infinity (AUC[0-∞]) and to the last measureable concentration (AUC[0-tlast ]), were calculated. Bioavailability was calculated as the ratio of least-squares geometric mean of dose-normalized AUC (oral : IV) and corresponding 90% confidence interval (CI). Bioavailability of evacetrapib was 44.8% (90% CI: 42.2-47.6%) for AUC(0-∞) and 44.3% (90% CI: 41.8-46.9%) for AUC(0-tlast ). Evacetrapib was well tolerated with no reports of clinically significant safety assessment findings. This is among the first studies to estimate absolute bioavailability using simultaneous administration of an unlabeled oral dose with a (13) C-labeled IV microdose tracer at about 1/1000(th) the oral dose, with measurement in the pg/mL range. This approach is beneficial for poorly soluble drugs, does not require additional toxicology studies, does not change oral dose pharmacokinetics, and ultimately gives researchers another tool to evaluate absolute bioavailability.

Modernization of Physical Appearance and Solution Color Tests Using Quantitative Tristimulus Colorimetry: Advantages, Harmonization, and Validation Strategies.

Color measurements, including physical appearance, are important yet often misunderstood and underappreciated aspects of a control strategy for drug substances and drug products. From a patient safety perspective, color can be an important control point for detecting contamination, impurities, and degradation products, with human visual acuity often more sensitive for colored impurities than instrumental techniques such as HPLC. Physical appearance tests and solution color tests can also serve an important role in ensuring that appropriate steps are taken such that clinical trials do not become unblinded when the active material is compared with another product or a placebo. Despite the importance of color tests, compendial visual tests are not harmonized across the major pharmacopoeias, which results in ambiguous specifications of little value, difficult communication of true sample color, and significant extra work required for global registration. Some pharmacopoeias have not yet recognized or adopted technical advances in the instrumental measurement of color and appearance, whereas others begin to acknowledge the advantage of instrumental colorimetry, yet leave implementation of the technology ambiguous. This commentary will highlight the above-mentioned inconsistencies, provide an avenue toward harmonization and modernization, and outline a scientifically sound approach for implementing quantitative technologies for improved measurement, communication, and control of color and appearance for both solutions and solids. Importantly, this manuscript, for the first time, outlines a color method validation approach that is consistent with the International Conference on Harmonization's guidance on the topic of method validation.

Integrating tristimulus colorimetry into pharmaceutical development for color selection and physical appearance control: a quality-by-design approach.

The color of pharmaceutical dosage forms can be an important aspect of product branding and patient compliance with a dosing regimen. During the development of drug products, it is important to understand the stability of not only the active pharmaceutical ingredient but also the color and appearance of the tablet or capsule. Currently, the most common method to ensure color stability is to conduct a visual test throughout a stability study. This visual test is subjective and can be expensive, especially if there is a failure late in development or after marketing approval. This work describes a series of studies using accelerated conditions (i.e., heat, humidity, and light) and logistic regression analyses that have been developed to determine the relative stability ranking of multiple color coatings early in development to provide an increased probability of technical success on long-term stability studies and to avoid coatings whose visual appearance may change over time. Once this relative stability ranking has been established, the stability advantages can be assessed versus any manufacturing/processing liabilities of the selected coating in order to make a data-driven decision around coating selection. This work reviews the basic fundamentals of colorimetry, followed by the description of a consistent experimental approach to correlate a visual rating with an instrumental measurement (e.g., dE(*) from a colorimeter) to remove the subjectivity from the assessment. This approach represents a novel strategy for establishing a probabilized correlation between the quantitative instrumental color measurement and the visual rating of the same color change.

The assessment of impurities for genotoxic potential and subsequent control in drug substance and drug product.

The strategies implemented at Eli Lilly and Company to address European Medicines Agency and US Food and Drug Administration requirements governing the control of genotoxic impurities (GTIs) are presented. These strategies were developed to provide understanding with regard to the risk and potential liabilities that could be associated with developmental and marketed compounds. The strategies systematize the assessment of impurities for genotoxic potential, addressing both actual and potential impurities. Timing of activities is designed to minimize impact to development timelines while building a data package sufficient to either discharge the risk of potential GTI formation or support the implementation of a specification necessary for long-term control. This article presents the background associated with GTI control, the types of impurities that should be assessed, and the actions to be taken when an impurity is found to be genotoxic. A systematic approach to define potential degradation products derived from stress-testing studies is outlined with a proposal to perform a genotoxic risk assessment on these impurities. Finally, an Arrhenius-based strategy is proposed for a rapid assessment of the likelihood of potential degradation impurities to form in the commercial drug product formulation. Importantly, this article makes a proposal for discharging the risk of a potential GTI with supporting data.

The effect of analyte acidity on signal suppression and the implications to peak purity determinations using atmospheric pressure ionization mass spectrometry.

The effect of a co-eluting halogenated phenol, spiked at 1% of the main analyte level, has been examined for a series of halogenated phenols using LC-MS techniques. Similarly, the effect of co-eluting anilines has been investigated. The purpose of the work presented here was to evaluate the degree of signal suppression for structurally similar halogenated phenols and for similar anilines utilizing atmospheric pressure chemical ionization (APCI) in the negative mode and electrospray (ESI) in positive mode, respectively. A correlation between the effects of analyte ionization efficiency resulting from co-eluting compounds (signal suppression) and pK(a) has been made for these compounds. It was found that minimal signal suppression occurs when the spiked impurity has a similar (Delta pK(a)<1.5) acidity when compared to the main peak it is co-eluting with. The degree of signal suppression sharply increases when the difference in pK(a)'s between the main peak and the spiked impurity was greater than 1.5 units. Thus, when the main peak is much less acidic (more than 1.5 pK(a) difference) than the co-eluting impurity, signal suppression of the latter would not occur in negative mode APCI. Similarly, when the main peak is much less basic than the co-eluting peak, signal suppression of the impurity will also not be found for aniline compounds in positive mode ESI. Furthermore, the degree of signal suppression decreases as a function of sample load such that injections of 3 microg or less show no discernible impact on the spiked impurity peak. Ultimately, these results indicate that the use of mass spectrometry (MS) in peak purity determinations requires numerous considerations prior to assessing main peak purity. The optimization of sample load during an impurities assay will maximize co-eluting impurity signal as purity determinations by mass spectrometry made at sample loads above the 3 microg (sample load) threshold increase the risk for false negative assessment of impurities.

Cleaning verification assays for highly potent compounds by high performance liquid chromatography mass spectrometry: strategy, validation, and long-term performance.

A cleaning-verification assay was validated for a highly potent family of compounds utilizing a swab-sampling procedure and high performance liquid chromatography mass spectrometry (LC-MS) for separation and detection of the analytes. Due to the high potency of the compound, the LC-MS method was validated at a level of 50 ng/25 cm(2) and 50 ng/100 cm(2) (which equates to 10 ng/ml after extraction in 5 ml of sample solvent, and 3 ng/ml after correction for sampling losses). This validation exercise included recovery estimates from all drug product contact surfaces within the clinical trial manufacturing equipment, namely, stainless steel, anodized aluminum, Rilsan coated aluminum, bronze, polyvinylchloride, and Oilon. The limit of detection for the LC-MS method was determined to be less than 0.5 ng/ml, or less than 0.1 ng/cm(2), of the analyte. This method does not employ an internal standard. Long-term performance of the validated method is also reported. The precision on replicate injections of the standard prepared in the range of 3-6 ng/ml was typically better than 8.0% relative standard deviation (R.S.D.) over the course of 1 year, which resulted from 10 cleaning-verification submissions. Those results were consistent with the data obtained during method validation.

Evaluation of a monolithic silica column operated in the hydrophilic interaction chromatography mode with evaporative light scattering detection for the separation and detection of counter-ions.

In this work a monolithic silica column operated in the hydrophilic interaction chromatography (HILIC) mode in conjunction with an evaporative light scattering detector (ELSD) was investigated. Lithium, sodium and potassium were used as the test counter-ions for this evaluation. Chromatographic properties of this column operated in the HILIC mode were determined by varying key mobile phase parameters, such as pH, flow rate, buffer strength, acid and organic modifier. As organic content was increased from 60 to 90% acetonitrile, retention time increased on average by a factor of seven for the test cations listed above. Buffer concentration and pH were also observed to have an effect, although not as significant as the HILIC effect that was observed by changing organic content. Flow rates up to 5 mL/min were utilized to perform counter-ion separations in less than 3 min. After examining the changes in retention, resolution, and peak shape an optimized method was established and then further evaluated for linearity, reproducibility, and limit of detection (LOD) for sodium. Linearity was acceptable with an R2 value of 0.999 across the working-standard range and a LOD of 0.1 microg/mL was calculated. The reproducibility on the counter-ion determination from pharmaceutical sodium salts was 1.6% R.S.D. on average, and the accuracy of the counter-ion prediction was approximately 3% from theory when salt content was corrected for potency.