Stability of Protein Pharmaceuticals: Recent Advances.

There have been significant advances in the formulation and stabilization of proteins in the liquid state over the past years since our previous review. Our mechanistic understanding of protein-excipient interactions has increased, allowing one to develop formulations in a more rational fashion. The field has moved towards more complex and challenging formulations, such as high concentration formulations to allow for subcutaneous administration and co-formulation. While much of the published work has focused on mAbs, the principles appear to apply to any therapeutic protein, although mAbs clearly have some distinctive features. In this review, we first discuss chemical degradation reactions. This is followed by a section on physical instability issues. Then, more specific topics are addressed: instability induced by interactions with interfaces, predictive methods for physical stability and interplay between chemical and physical instability. The final parts are devoted to discussions how all the above impacts (co-)formulation strategies, in particular for high protein concentration solutions.'

Uptake of screening and risk-reducing recommendations among women with hereditary breast and ovarian cancer syndrome due to pathogenic BRCA1/2 variants evaluated at a large urban comprehensive cancer center.

PURPOSE: Carriers of pathogenic variants in BRCA1/2 have an elevated lifetime cancer risk warranting high-risk screening and risk-reducing procedures for early detection and prevention. We report on prevention practices among women with pathogenic BRCA variants in order to document follow through with NCCN recommendations and to identify barriers to guideline-recommended care. METHODS: Our cohort included women who had genetic testing through a cancer genetic clinic and completed a 54-item questionnaire to measure socio-demographics, medical history, rates of cancer screening and risk-reducing surgery, disclosure of test results, and cancer worry. Outcomes included rates of completion of risk-reducing salpingo-oophorectomy (RRSO), risk-reducing mastectomy (RRM), and NCCN risk-reducing and age-dependent screening guidelines (version 3.2019). Multivariable logistic regression analyses were used to evaluate potential predictors of these outcomes. RESULTS: Of 129 evaluable women with pathogenic BRCA1/2 variants, 95 (74%) underwent RRSO and 77 (60%) had RRM, respectively, and 107 (83%) were considered adherent to NCCN guidelines. Women with a history of breast or ovarian cancer were more likely to have RRM (OR = 4.38; 95% CI 1.80-11.51; p = 0.002). Increasing age was associated with an increased likelihood of RRSO (OR = 1.05; 95% CI 1.01-1.09; p = 0.019) and decreased likelihood for RRM (OR = 0.95; 95% CI 0.92-0.99; p = 0.013). Women who had RRM were 3 times more likely to undergo RRSO (OR = 2.81; 95% CI 1.10-7.44; p = 0.025). Women who had genetic testing after June 2013 were less likely to have RRM than those tested before June 2013 (OR = 0.42; 95% CI 0.18-0.95; p = 0.040. None of the other measured factors were associated with rates of RRSO, RRM or follow through with NCCN recommendations. There was near universal (127/129) reported disclosure of genetic test results to family members, resulting in the discovery of a median of 1 relative with a pathogenic variant (range = 0-8). CONCLUSION: An evaluation of follow up practice in a cohort of women with pathogenic variants in BRCA1/2 revealed high rates of reported completion of screening and surgical risk-reducing recommendations. Educational efforts should continue to reinforce the importance of follow-through with guideline recommended care among this high-risk group.

Cognition and Wealth Changes in Mid-to-later Life: A Latent Class Trajectories Approach Using the Health and Retirement Study.

ObjectivesTo assess how cognitive trajectories from mid-to-later life relate to wealth change, overall and by mid-life income. Methods: Data were from participants (51-64 years) in the 2000-2018 U.S. Health and Retirement Study who were cognitively healthy at baseline (year 2000; unweighted n = 3821). Longitudinal latent class analyses generated cognitive and wealth trajectories, independently, and multinomial logistic regressions estimated the association between cognitive trajectories and wealth profiles, overall and by median income. Results: We identified three cognitive: cognitively healthy (CH), increasing cognitive impairment (ICI), and increasing dementia (ID) and four wealth profiles: stable wealth loss (SWL), delayed gradual wealth loss (DGWL), stable wealth gain (SWG), and gradual wealth gain (GWG). The ID group had higher probability of being in the SWL group and lower probability of SWG, which was more pronounced in respondents with greater median income. Discussion: Individuals with ID may be vulnerable to wealth loss, particularly for middle-class households.

Changes in late-life assistance networks for Black and White older adults during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has disproportionately impacted older Black Americans. Given that assistance networks play a crucial role in older adults' ability to respond to challenges, we sought to investigate whether older adults' assistance network size changed during the COVID-19 pandemic and differed by race. METHODS: We analyzed data from the 2018-2020 rounds of the U.S. National Health and Aging Trends Study for Black and White adults aged 70 and older receiving help in the community or residential care settings. We used ordinary least squares regression to compare changes in assistance network size in the 2 years pre-COVID-19 (2018-2019, N = 3438) to changes in size at the onset of COVID-19 (2019-2020, N = 3185). RESULTS: Black older adults had larger assistance networks with a greater number of family helpers before and during the pandemic compared to their White counterparts. Assistance network size for older adults increased before but not during the pandemic mostly due to declines in unpaid nonrelative helpers and lack of increase in paid helpers. These effects did not differ by race. CONCLUSIONS: Black and White older adults experienced similarly sized reductions in their assistance networks as a consequence of the COVID-19 pandemic. Future research should investigate the relationship between these network changes and the unmet needs of older adults.

Application of Formulation Principles to Stability Issues Encountered During Processing, Manufacturing, and Storage of Drug Substance and Drug Product Protein Therapeutics.

The field of formulation and stabilization of protein therapeutics has become rather extensive. However, most of the focus has been on stabilization of the final drug product. Yet, proteins experience stress and degradation through the manufacturing process, starting with fermentaition. This review describes how formulation principles can be applied to stabilize biopharmaceutical proteins during bioprocessing and manufacturing, considering each unit operation involved in prepration of the drug substance. In addition, the impact of the container on stabilty is discussed as well.

Predictors of nonadherence to breast cancer screening guidelines in a United States urban comprehensive cancer center.

BACKGROUND: This study aimed to identify predictors of nonadherence to breast cancer screening guidelines in an urban screening clinic among high- and average-risk women in the United States. METHODS: We reviewed records of 6090 women who received ≥2 screening mammograms over 2 years at the Karmanos Cancer Institute to examine how breast cancer risk and breast density were associated with guideline-concordant screening. Incongruent screening was defined as receiving supplemental imaging between screening mammograms for average-risk women, and as not receiving recommended supplemental imaging for high-risk women. We used t-tests and chi-square tests to examine bivariate associations with guideline-congruent screening, and probit regression to regress guideline-congruence unto breast cancer risk, breast density, and their interaction, controlling for age and race. RESULTS: Incongruent screening was more likely among high- versus average-risk women (97.7% vs. 0.9%, p < 0.01). Among average-risk women, incongruent screening was more likely among those with dense versus nondense breasts (2.0% vs. 0.1%, p < 0.01). Among high-risk women, incongruent screening was more likely among those with nondense versus dense breasts (99.5% vs. 95.2%, p < 0.01). The significant main effects of density and high-risk on increased incongruent screening were qualified by a density by high-risk interaction, showing a weaker association between risk and incongruent screening among women with dense breasts (simple slope = 3.71, p < 0.01) versus nondense breasts (simple slope = 5.79, p < 0.01). Age and race were not associated with incongruent screening. CONCLUSIONS: Lack of adherence to evidence-based screening guidelines has led to underutilization of supplementary imaging for high-risk women and potential overutilization for women with dense breasts without other risk factors.

Message Framing for Men? Gender Moderated Effects of Culturally Targeted Message Framing on Colorectal Cancer Screening Receptivity among African Americans.

Receptivity to recommended colorectal cancer (CRC) screening can be enhanced by use of loss-framed health messaging that emphasizes possible consequences of failing to act. However, a simultaneous use of culturally targeted messaging may be needed to achieve effectiveness when loss-framed messaging is used with African Americans, especially to reduce racism-related cognitions aroused by standard loss framing that impede CRC screening receptivity. This study considered whether effects of stand-alone and culturally targeted message framing on CRC screening receptivity differ between African American men and women. African Americans eligible for CRC screening (Men=117, Women=340) viewed an informational video about CRC risks, prevention, and screening, and were randomized to receive a gain or loss-framed message about screening. Half of participants received an additional culturally targeted message. Using the Theory of Planned Behavior, we measured receptivity to CRC screening. We also measured arousal of racism-related cognitions. A significant three-way interaction suggested effects of messaging on CRC screening receptivity were moderated by gender. Participants were no more receptive to CRC screening when standard loss-framing was used, but were more favorable if loss-framing was culturally targeted. However, these effects were more pronounced among African American men. Contrary to prior findings, gender moderated effects of culturally targeted loss-framed messaging were not attributable to reducing racism-related cognitions. Findings add to growing recognition of important nuance in effective use of message framing to also include gender, while suggesting a critical need to explore gender-relevant mechanistic pathways, potentially including how health messaging activates masculinity-related cognitions among African American men.

Medical mistrust, culturally targeted message framing, and colorectal cancer screening among African Americans.

Mistrust in the information and treatment provided by medical professionals and organizations hinders cancer screening among African Americans. However, its impact on responses to health messaging aimed at bolstering screening uptake is unknown. The present study examined the effects of medical mistrust on message framing and culturally targeted health messaging about colorectal cancer (CRC) screening. Screening eligible African Americans (N = 457) completed the Group-Based Medical Mistrust scale and then viewed an informational video about CRC risks, prevention, and screening, during which all participants received either a gain or loss-framed message about screening. Half of participants received an additional culturally targeted screening message. After messaging, all participants completed Theory of Planned Behavior measures of CRC screening receptivity, as well as items assessing expectations about experiencing racism when obtaining CRC screening (i.e., anticipatory racism). Hierarchical multiple regressions showed that medical mistrust predicted lower screening receptivity and greater anticipatory racism. Additionally, effects of health messaging were moderated by medical mistrust. Among participants high in mistrust, targeted messaging-regardless of message frame-bolstered normative beliefs about CRC. Additionally, only targeted loss-framed messaging bolstered attitudes toward CRC screening. Although targeted messaging reduced anticipatory racism among participants with high mistrust, anticipatory racism did not mediate messaging effects. Findings indicate medical mistrust may be an important culturally-relevant individual difference to attend to in addressing CRC screening disparities, including its potential to impact responses to cancer screening messaging.

Moderators of the effects of perceived racism and discrimination on cancer-related health behaviors among two samples of African Americans.

BACKGROUND: Assumptions regarding within-race variation in the associations between measures of discrimination racism and health-related behaviors among African Americans have been largely unexplored. METHODS: We conducted secondary analyses of two studies to examine support for a model which describes several theoretical moderators of the effects of discrimination and racism on health behaviors. The first study examined the effects of group-based behavioral information and racial identity on the association between perceived racism and requests for at home colorectal cancer screening tests among a sample of 205 geographically diverse African Americans who participated in an online experiment from 2019 to 2020. RESULTS: Group-based behavioral information attenuated the association between perceived racism and requests for at-home screening kit. In the absence of group-based behavioral information, perceived racism was positively associated with screening kit requests for African Americans with weaker racial identity and negatively associated with requests for African Americans with stronger racial identity. The second study examined the influence of personal and group-based perceived discrimination, and behavior-relevant affective information related to a breast cancer risk notification, on 89 Michigan dwelling African American women's self-reported physician communication from 2015 to 2016. Results showed that perceived group-based discrimination was positively associated with physician communication in the absence of negative affective information, and perceived personal discrimination was negatively associated with physician communication as positive affective information increased. CONCLUSIONS: Together, these results support our theoretical model highlighting variation in the effects of discrimination and racism on health behaviors among African Americans, and indicates group-relevant behavioral information, racial identity, behavior relevant affective information, and target of discrimination as moderators of the effect. Implications for conceptualizing the effects of racism and discrimination and for examining racially targeted interventions are discussed.

COVID-19-Related Changes in Assistance Networks for U.S. Older Adults With and Without Dementia.

OBJECTIVES: Prepandemic research suggests assistance networks for older adults grow over time and are larger for those living with dementia. We examined how assistance networks of older adults changed in response to the onset of the coronavirus disease 2019 (COVID-19) pandemic and whether these changes differed for those with and without dementia. METHODS: We used 3 rounds of the National Health and Aging Trends Study. We estimated multinomial logistic regression models to test whether changes in assistance networks during COVID-19 (2019-2020)-defined as expansion, contraction, and adaptation-differed from changes prior to COVID-19 (2018-2019). We also estimated ordinary least squares regression models to test differences in the numbers of helpers assisting with one (specialist) versus multiple (generalist) domains before and during COVID-19. For both sets of outcomes, we investigated whether pandemic-related changes differed for those with and without dementia. RESULTS: Over all activity domains, a greater proportion of assistance networks adapted during COVID-19 compared to the pre-COVID-19 period (relative risk ratio = 1.19, p < .05). Contractions in networks occurred for those without dementia. Transportation assistance contracted for those with and without dementia, and mobility/self-care assistance contracted for those with dementia. The average number of generalist helpers decreased during COVID-19 (ß = -0.09, p < .001). DISCUSSION: Early in the pandemic, assistance networks of older adults adapted by substituting helpers, by contracting to reduce exposures with more intimate tasks for recipients with dementia, and by reducing transportation assistance. Future research should explore the impact of such changes on the well-being of older adults and their assistance networks.

Addressing multilevel barriers to clinical trial participation among Black and White men with prostate cancer through the PACCT study.

BACKGROUND: Cancer clinical trial participation is low and inequitable. Partnering Around Cancer Clinical Trials (PACCT) addressed systemic and interpersonal barriers through an observational study of eligibility and an intervention to improve patient-physician communication and trial invitation rates. METHODS: Physicians at two comprehensive cancer centers and Black and White men with prostate cancer participated. Patients were followed for 2 years to determine whether they became potentially eligible for an available therapeutic trial. Potentially eligible patients were randomized to receive a trials-focused Question Prompt List or usual care. Patient-physician interactions were video-recorded. Outcomes included communication quality and trial invitation rates. Descriptive analyses assessed associations between sociodemographic characteristics and eligibility and effects of the intervention on outcomes. RESULTS: Only 44 (22.1%) of participating patients (n = 199) became potentially eligible for an available clinical trial. Patients with higher incomes were more often eligible (>$80,000 vs. <$40,000, adjusted OR = 6.06 [SD, 1.97]; $40,000-$79,000 vs. <$40,000, adjusted OR = 4.40 [SD, 1.81]). Among eligible patients randomized to the intervention (n = 19) or usual care (n = 25), Black patients randomized to the intervention reported participating more actively than usual care patients, while White intervention patients reported participating less actively (difference, 0.41 vs. -0.34). Intervention patients received more trial invitations than usual care patients (73.7% vs. 60.0%); this effect was greater for Black (80.0% vs. 30.0%) than White patients (80.0% vs. 66.7%). CONCLUSIONS: Findings suggest the greatest enrollment barrier is eligibility for an available trial, but a communication intervention can improve communication quality and trial invitation rates, especially for eligible Black patients.

Culturally targeted message framing and colorectal cancer screening preferences among African Americans.

OBJECTIVE: The current study investigated whether culturally targeted message frames alter preferences for specific colorectal cancer (CRC) screening modalities among African Americans. METHOD: African Americans who were eligible for CRC screening (N = 457) viewed a video about CRC risks, prevention, and recommended screening options. Participants then received a gain or loss-framed message about screening, with half of participants viewing an additional culturally targeted message about overcoming disparities in CRC through screening. Participants reported their desired thoroughness in CRC screening and preferences for being screened using colonoscopy, sigmoidoscopy, or stool-based fecal immunochemical testing. RESULTS: Relative to gain-framing, loss-framed messaging enhanced desired thoroughness in CRC screening. Targeted loss-framing enhanced preferences for colonoscopy and decreased preferences for stool-based FIT screening. CONCLUSIONS: Findings demonstrate that message framing and culturally targeted messaging can impact CRC screening preferences. Altering preferences may carry implications for reducing CRC screening disparities among African Americans. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Complex effects of racism and discrimination on African Americans' health and well-being: Navigating the status quo.

Most research on the effects of racism and discrimination on the health and well-being of African Americans utilize a deficit perspective, one that homogeneously paints African Americans as disadvantaged victims. Such approaches do little to highlight the variability in the effects of racism and discrimination on relevant outcomes, and the resources that African Americans have drawn upon to navigate an environment characterized by varying levels of racialized hostility. The goal of this special issue is to inspire more refined conceptualizations of how African Americans navigate an often-hostile status quo in service of their health and well-being. The articles in this special issue examine within-race heterogeneity in African Americans' responses to varying manifestations of racism and discrimination, as well as subsequent heterogeneity in the effects of racism and discrimination on African Americans' health and well-being at the individual level. The commentaries and articles address the goals of this special issue in three broad categories of health outcomes: biological/physiological, mind and brain, and health behavior. These contributions demonstrate several critical themes that can guide future work to achieve a more comprehensive understanding of the heterogeneity in the effects of racism and discrimination on health and well-being among African Americans.

Results of an African American-targeted norm-based colorectal cancer screening intervention: a pilot study.

Lower colorectal cancer screening rates among African Americans contribute to higher colorectal cancer incidence and mortality. We tested the effects of a racially-targeted messaging intervention that used favorable behavioral norm information to increase uptake of at-home Fecal Immunochemical Test (FIT) Kits. We expected stronger intervention effects among African Americans with stronger racial identity. Eligible African Americans were randomized to one of four intervention conditions: injunctive norm message, descriptive norm message, both messages, neither message. The norm-based messages were delivered via an animated video health message. Background variables, constructs defined by the theory of planned behavior, racial identity, screening modality preferences, and uptake and return of FIT Kits were assessed. Of 205 participants, 111(54%) requested FIT Kits. Contrary to hypotheses, multigroup path analyses indicated stronger effects of targeted messages among African Americans with weaker racial identity. Findings highlight the importance of within-race heterogeneity in the receptivity to racially-targeted health messages.

Characterization of Oligomer Formation of Surfactant Protein-D (SP-D) Using AF4-MALLS.

BACKGROUND: Surfactant protein-S (SP-D) is a naturally occurring lung protein with the potential to treat pulmonary infections. A recombinant surfactant protein-D (SP-D) has been produced and was previously found to exist in multiple oligomeric states. INTRODUCTION: Separation and characterization of interconverting oligomeric states of a protein can be difficult using chromatographic methods, so an alternative separation technique was employed for SPD to characterize the different association states that exist. METHODS: Samples of SP-D were analyzed using asymmetrical flow field-flow fractionation (AF4) using UV and multi-angle laser light scattering (MALLS) detection. The AF4 method appears to be able to separate species as small as the monomer up to the dodecamer (the dominant species) to much larger species with a molar mass greater than 5 MDa. RESULTS: Consistent elution of four distinct peaks was observed after repeated injections. The largest species observed under the last peak (labeled as Peak 4) were termed "unstructured multimers" and were resolved fairly well from the other species. The AF4-MALLS data suggest that only a small fraction of Peak 4 truly corresponds to high molar mass unstructured multimers. All other peaks demonstrated significant molar mass homogeneity consistent with AFM results. CONCLUSION: AF4-MALLS technology appears to be a powerful analytical approach to characterize the complex and dynamic interplay among different protein oligomeric species of SP-D in an aqueous solution.

Uptake of genetic counseling and testing in a clinic-based population of women with breast cancer.

BACKGROUND: The study was conducted to evaluate racial differences in referral and uptake of genetic counseling (GC) in a clinic-based population of women with breast cancer. METHODS: Medical records of 150 breast cancer patients at the Karmanos Cancer Institute were reviewed to determine eligibility for GC according to National Comprehensive Cancer Network guidelines, GC referral rates, and appointment completion rates. Logistic regression was used to assess the relationship between demographic and clinical factors and GC eligibility and referral. RESULTS: The mean age at diagnosis was 57.1 (SD 12.6) and 66% of the women were Black. There were 91 women (60.7%) eligible for GC and of those, 54 (61.4%) were referred. After multivariable analyses, factors associated with reduced eligibility were older age at diagnosis (OR = 0.91, 95% CI [0.87,0.95]) and Black race (OR = 0.37, 95% CI [0.15, 0.96]). After additional multivariable analysis, eligibility was associated with an increased likelihood of referral (OR = 5.97, 95% CI [2.29, 15.56]), however, Medicare versus private insurance was associated with a lower likelihood for referral (OR = 0.32, 95% CI [0.12-0.80]. Of those referred, 49 (76.6%) completed an appointment, and 47 had genetic testing. Women with Medicare were also less likely to complete an appointment. Race had no impact on referral or appointment completion. CONCLUSIONS: There were no racial differences in GC referral or appointment completion in a clinic-based sample of women with breast cancer. Further interventions are needed to promote increased referral and appointment completion for women with breast cancer who are eligible for GC.

Justice beliefs and cultural values predict support for COVID-19 vaccination and quarantine behavioral mandates: a multilevel cross-national study.

Understanding how individual beliefs and societal values influence support for measures to prevent SARS-CoV-2 transmission is vital to developing and implementing effective prevention policies. Using both Just World Theory and Cultural Dimensions Theory, the present study considered how individual-level justice beliefs and country-level social values predict support for vaccination and quarantine policy mandates to reduce SARS-CoV-2 transmission. Data from an international survey of adults from 46 countries (N = 6424) were used to evaluate how individual-level beliefs about justice for self and others, as well as national values-that is, power distance, individualism, masculinity, uncertainty avoidance, long-term orientation, and indulgence-influence support for vaccination and quarantine behavioral mandates. Multilevel modeling revealed that support for vaccination and quarantine mandates were positively associated with individual-level beliefs about justice for self, and negatively associated with country-level uncertainty avoidance. Significant cross-level interactions revealed that beliefs about justice for self were associated more strongly with support for mandatory vaccination in countries high in individualism, whereas beliefs about justice for others were more strongly associated with support for vaccination and quarantine mandates in countries high in long-term orientation. Beliefs about justice and cultural values can independently and also interactively influence support for evidence-based practices to reduce SARS-CoV-2 transmission, such as vaccination and quarantine. Understanding these multilevel influences may inform efforts to develop and implement effective prevention policies in varied national contexts.

Chemometric Study of the Relative Aggregation Propensity of Position 19 Mutants of Aß(1-42).

BACKGROUND: The importance of aromaticity vs. hydrophobicity of the central hydrophobic core (CHC, residues 17-20) in governing fibril formation in Aß(1-42) has been the focus of an ongoing debate in the literature. INTRODUCTION: Mutations in the CHC (especially at Phe19 and Phe20) have been used to examine the relative impact of hydrophobicity and aromaticity on the degree of aggregation of Aß(1-42). However, the results have not been conclusive. METHODS: Partial least squares (PLS) modeling of aggregation rates, using reduced properties of a series of position 19 mutants, was employed to identify the physicochemical properties that had the greatest impact on the extent of aggregation. RESULTS: The PLS models indicate that hydrophobicity at position 19 of Aß(1-42) appears to be the primary and dominant factor in controlling Aß(1-42) aggregation, with aromaticity having little effect. CONCLUSION: This study illustrates the value of using reduced properties of amino acids in conjunction with PLS modeling to investigate mutational effects in peptides and proteins, as the reduced properties can capture in a quantitative manner the different physicochemical properties of the amino acid side chains. In this particular study, hydrophobicity at position 19 was determined to be the dominant property controlling aggregation, while size, charge, and aromaticity had little impact.

Development and pilot test of a physician-focused cancer clinical trials communication training intervention.

Objective: We describe the development and pilot test of a physician-focused, web-based training module designed to improve physician communication related to clinical trials in a diverse cancer patient population. Methods: Researchers and stakeholders developed the training module, which included a video explaining patient-centered communication strategies for discussing trials, and re-enactments of actual clinical interactions. For the pilot test, the module was provided to physician participants in the Partnering Around Cancer Clinical Trials (PACCT) trial at two major urban cancer centers. Questionnaires assessed change in beliefs, behavioral attitudes, knowledge and comfort; and perceptions of the module. Results: Nineteen physicians participated in the pilot test. Most were experienced in discussing trials. Assessments of change were mixed regarding beliefs; they showed marginal improvement in attitudes, and significant improvement in knowledge, but no change in comfort. Feedback on the module was favorable. Conclusions: This stakeholder-developed physician communication training module was acceptable and effective, albeit in this small and highly-experienced physician sample. Future research should determine its effectiveness on communication in clinical settings. Innovation: This is the first physician training module to focus on communicating about clinical trials in a diverse patient population. It offers a web-based format and re-enactments of naturally-occurring clinical interactions.Trial Registration Number: NCT02906241.

Analysis of Peptides using Asymmetrical Flow Field-flow Fractionation (AF4).

While asymmetrical flow field-flow fractionation (AF4) has been widely used for separation of high molecular weight species and even particles, its ability to resolve lower molecular weight species has rarely been explored. Over the course of many projects, we have discovered that AF4 can be an effective analytical method for separating peptides from oligomers and higher molecular weight aggregates. The methodology can be used even for peptides as small as 2 kD in molecular weight. Using multi-angle laser light scattering (MALLS) detection, accurate masses of the parent peptide can be obtained, provided accurate extinction coefficients are provided. It was shown that AF4 can be stability-indicating, suggesting that AF4-MALLS may be a suitable alternative to the use of SEC to monitor the aggregation of peptides.