Police Violence Experienced by Black Gay and Bisexual Men: The Effects on HIV Care Engagement and Medication Adherence

Black men face high rates of police violence, including direct victimization and indirect exposure to or knowledge of harmful policing. This violence can result in death and physical harm, as well as in numerous poor mental health outcomes. There has been little research examining experiences of police violence experienced by Black gay and bisexual men or the effects of police brutality on HIV continuum of care outcomes. To address this important gap, in this exploratory study, we examined the effects of police brutality on engagement in HIV care and adherence to antiretroviral medications. Cross-sectional survey data were collected from 107 Black gay and bisexual men living with HIV. The path analysis showed that men with greater exposure to police violence had increased symptoms of post-traumatic stress disorder and were more likely to have missed HIV care appointments in the past year. Additionally, there was a significant indirect effect of exposure to police violence on missed medication doses via PTSD symptoms.

An exploratory study of community violence and HIV care engagement among Black gay and bisexual men

This study examined the relationship between exposure to community violence and HIV care engagement among 107 Black gay or bisexual men living with HIV in Chicago. Measures assessed the importance of demographic covariates (age, annual income, health insurance status, and years living with HIV), community violence exposures, mental health, social support, in explaining variations in missed doses of antiretroviral therapy (ART) medication and missed HIV care appointments. Results showed that participants who reported higher rates of exposure to community violence were two times more likely to have missed ART doses and HIV care appointments. Participants who reported depression scores were two times more likely to have greater non-ART adherence. Finally, older participants were more likely to report fewer missed ART doses. More research is needed to clarify the mechanisms between age or depression and ART adherence given community violence exposure. Health care providers should screen for depression when attempting to promote better ART adherence and keeping HIV care appointments for Black gay and bisexual men living with HIV. Younger Black gay and bisexual men living with HIV may be more vulnerable than older men for missed ART doses and may require additional screening and follow-up.

The Inherent Violence of Anti-Black Racism and its Effects on HIV Care for Black Sexually Minoritized Men

The goal of this study was to examine the effects of racial discrimination, depression, and Black LGBTQ community support on HIV care outcomes among a sample of Black sexually minoritized men living with HIV. We conducted a cross-sectional survey with 107 Black sexually minoritized men living with HIV in Chicago. A path model was used to test associations between racial discrimination, Black LGBTQ community support, depressive symptoms, and missed antiretroviral medication doses and HIV care appointments. Results of the path model showed that men who had experienced more racism had more depressive symptoms and subsequently, missed more doses of HIV antiretroviral medication and had missed more HIV care appointments. Greater Black LGBTQ community support was associated with fewer missed HIV care appointments in the past year. This research shows that anti-Black racism may be a pervasive and harmful determinant of HIV inequities and a critical driver of racial disparities in ART adherence and HIV care engagement experienced by Black SMM. Black LGBTQ community support may buffer against the effects of racial discrimination on HIV care outcomes by providing safe, inclusive, supportive spaces for Black SMM.

Understanding the impact of police brutality on Black sexually minoritized men

Young Black gay, bisexual, and other sexually minoritized men (SMM) face high levels of police brutality and other negative, unwarranted encounters with the police. Such interactions have known health consequences. The purpose of this study was to understand the health, mental health, and social consequences of police brutality experienced by young Black SMM. We conducted in-depth interviews with 31 Black, cisgender men, ages of 16-30 and analyzed the data using thematic analysis. Our primary results are summarized in four themes: 1) Police brutality is built into the system and diminishes trust; 2) Videos and social media make visible violence that has long existed; 3) Police brutality contributes to anxiety and other psychosocial effects; and 4) Violence reduces feelings of safety and contributes to avoidance of police. Our results highlight the direct and vicarious police brutality participants are subjected to and sheds light on the effects of such violence on trust, perceived safety, anxiety, and trauma symptoms. Results from this study contribute to the needed public health conversation around police brutality against Black men, specifically shedding light on the experiences of Black SMM.

"The Fight is Two Times as Hard": A Qualitative Examination of a Violence Syndemic Among Young Black Sexual Minority Men

Young Black men who have sex with men (YBMSM) are disproportionately impacted by violence, including violence rooted in anti-Black racism, sexual identity bullying, and neighborhood violence rooted in structural racism and inequities. These multiple forms of violence are frequently co-occurring and interactive creating syndemic conditions that can negatively impact HIV care. This qualitative study is based on in-depth interviews with 31 YBMSM, aged 16-30 years, living with HIV in Chicago, IL, to examine how violence has impacted their lives. Using thematic analysis, we identified five themes that reflect how YBMSM experience violence at the intersection of racism, homonegativity, socioeconomic status, and HIV status: (a) the experience of intersectional violence; (b) long histories of violence contributed to hypervigilance, lack of safety, and lack of trust; (c) making meaning of violence and the importance of strength; (d) normalizing violence for survival; and (e) the cyclical nature of violence. Our study highlights how multiple forms of violence can accumulate across an individual's life and contribute to social and contextual situations that further contribute to violence and negatively impact mental health and HIV care.

Conceptualizing the Effects of Continuous Traumatic Violence on HIV Continuum of Care Outcomes for Young Black Men Who Have Sex with Men in the United States

The United States (US) is on track to achieve the 90-90-90 targets set forth by UNAIDS and the National HIV/AIDS strategy, yet significant racial disparities in HIV care outcomes remain, particularly for young Black men who have sex with men (YBMSM). Research has demonstrated that various types of violence are key aspects of syndemics that contribute to disparities in HIV risk. However, little research has looked collectively at cumulative violent experiences and how those might affect HIV treatment and care outcomes. Drawing on extant literature and theoretical underpinnings of syndemics, we provide a conceptual model that highlights how continuous traumatic violence experienced by YBMSM may affect HIV outcomes and contribute to racial disparities in HIV outcomes. The findings of this focused review suggest a need for research on how continuous exposure to various types of violence influence HIV prevention and treatment outcomes for young Black MSM.

153 Multiparametric assessment of diastolic function in heart failure

Background

The assessment of diastolic function is still challenging in the setting of heart failure (HF). We tested the hypothesis that applying a machine learning algorithm would detect heterogeneity in diastolic function and improve risk stratification in HF population.

Methods

This study included consecutive 279 patients with clinically stable HF referred for echocardiographic assessment, for whom diastolic function variables were measured according to the current guidelines. Cluster analysis, an unsupervised machine learning algorithm, was undertaken on these variables to form homogeneous groups of patients with similar profiles of the variables. Sequential Cox models paralleling the clinical sequence of HF assessment were used to elucidate the benefit of cluster-based classification over guidelines-based classification. The primary endpoint was a hospitalization for worsening HF.

Results

Cluster analysis identified 3 clusters with distinct properties of diastolic function that shared similarities with guidelines-based classification. The clusters were associated with brain natriuretic peptide level (p < 0.001, figure A). During follow-up period of 2.6 ± 2.0 years, 62 patients (22%) experienced the primary endpoint. Cluster-based classification exhibited a significant prognostic value (c2 = 20.3, p < 0.001, figure B), independent from and incremental to an established clinical risk score for HF (MAGGIC score) and left ventricular end-diastolic volume (hazard ratio = 1.677, p = 0.017, model c2: from 47.5 to 54.1, p = 0.015, figure D). Although guideline-based classification showed a significant prognostic value (c2 = 13.1, p = 0.001, figure C), it did not significantly improve overall prognostication from the baseline (model c2: from 47.5 to 49.9, p = 0.199, figure D).

Conclusion

Machine learning techniques help grading diastolic function and stratifying the risk for decompensation in HF.

Abstract 153 Figure.

P1528 Prognostic impact of pulmonary arterial wave reflection in heart failure

Background

Pulmonary hypertension (PH) is prevalent and is associated with adverse outcomes in heart failure. The pathophysiology of PH is heterogeneous, including pre-capillary PH and combined pre- and post-capillary PH. The latter PH has been reported in experimental studies to cause wave reflection in pulmonary circulation, putting additional burden on right ventricle. This study tested the hypothesis that separating wave reflection would enhance risk stratification in heart failure.

Methods

This study included 152 patients with clinical stable heart failure associated with PH who were referred to echocardiography for hemodynamic assessment (age = 72 ± 13 years old, ejection fraction = 49 ± 21%). Pulmonary arterial wave reflection was characterised by separating PA pressure waveform into forward (Pf) and backward pressure (Pb) waves, based on the concept of wave intensity. PA pressure waveform was estimated from continuous Doppler tracing of tricuspid regurgitation. Flow velocity was measured by pulse Doppler at right ventricular outflow tract. Outcome data was obtained by reviewing medical charts. The endpoint was hospitalization for worsening heart failure (WHF).

Results

Figure A compares PA pressure waveforms (total and separated waves) obtained from 2 patients with and without WHF event. The patient with event had higher total pressure associated with late peak than the patient without event. Pb appeared later than Pf; it was markedly higher in the patient with event than the patient without event, although Pf was similar between both patients. Kaplan-Meier analysis demonstrated a significant separation of survival curves stratified by Pb (chi-square = 25.1, p < 0.001, figure B). During follow-up period of 1.5 ± 1.8 years, 65 patients (43%) experienced the endpoint. Sequential Cox analysis revealed that PASP remained significant after adjusted for left ventricular ejection fraction and E/e’ (hazard ratio = 1.017, p = 0.019). Pb also remained significant after the same adjustment (hazard ratio = 1.066, p = 0.003); the addition of Pb to a baseline model resulted in greater increase in predictive power than the addition of PASP (model chi-square: from 27.4 (baseline), to 37.6 (p = 0.004) for Pb, to 31.6 (p = 0.027) for PASP, figure C)

Conclusions

Pressure wave reflection in pulmonary artery is associated with early decompensation in heart failure.

Abstract P1528 Figure.

P893 Left ventricular flow energetics predicts worsening heart failure in dilated cardiomyopathy

Background

Blood flows through healthy hearts form optimal flow structures; they store flow kinetic energy (KE) that can be used for ejection. In contrast, in failing hearts, intracardiac flows become disorganized so that they may be energetically inefficient. However, it remained unknown whether left ventricular (LV) flow energetics prognosticates in heart failure.

Methods

This study included 61 patients with dilated cardiomyopathy (DCM). The temporal change in KE during early diastole (ED), atrial contraction (AC) and isovolumic contraction (IVC) was measured using Vector Flow Mapping particle tracking (Hitachi, figure top). LV inflow (total flow) were divided, based on whether they were ejected (direct flow, DF) or stayed in LV (retained flow, RF) in the following systole. KE of DF can be made use of for ejection, whereas KE of RF is supposed to be wasted. Diastolic function was graded, according to current EACVI/ASE guidelines. The patients were followed up for three years. Primary endpoint was hospitalization for worsening heart failure (WHF).

Results

12 patients had hospitalizations for WHF in the follow-up period. KE of total flow did not show any significant difference through the cardiac cycle between patients with and without WHF. KE of DF was slightly, but not significantly, smaller (ED: p = 0.252, AC: p = 0.119, IVC: p = 0.122), and KE of RF was slightly, but not significantly, larger (ED: p = 0.971, AC: p = 0.085, IVC: p = 0.134) in patients with WHF than those without events. The ratio of DF and RF (DF/RF ratio) showed significant differences between these two groups, especially from AC through IVC (figure, bottom-left). Cox proportional hazard analyses demonstrated that DF/RF ratio during IVC showed a significant correlation with clinical outcomes (p = 0.033, hazard ratio = 0.067). It remained significant even after adjusted for diastolic function grade (p = 0.046, hazard ratio = 0.074). Kaplan-Meier analysis confirmed the above results (figure, bottom-right). Conclusion: Efficiency of KE recruitment for LV ejection during IVC is associated with clinical outcomes in DCM.

Abstract P893 Figure. LISA

No Safe Havens: Protective Parenting Strategies for African American Youth Living in Violent Communities

Africans American youth experience disproportionately high rates of exposure to community violence. Such exposures are associated with a myriad of physical and mental health challenges. However, few qualitative studies have examined the ways in which parental figures have attempted to manage youth exposure to violence. This study recruited 4 focus groups composed of the parents of African American youth (n = 54). Participants reported that (a) there were no safe places immune from community violence, (b) there were no populations or subgroups protected from community violence, and (c) strategies to manage exposure to violence were often defined by the gender of the child. Although common protective parental strategies included mixed benefits, they ranged from "sheltering" (keeping children off the streets), "chauffeuring" (transporting or accompanying children to and from places), "removal" (enrolling children in schools outside of the neighborhood), and attempting "to rebuild the village." However, several of these strategies had constraints including money, time, and child maturation. Based on these findings, we offer research, policy, and practice implications in response to community violence exposure among this population.

Involvement in the Juvenile Justice System for African American Adolescents: Examining Associations with Behavioral Health Problems

While researchers have found that African American youth experience higher levels of juvenile justice involvement at every system level (arrest, sentencing, and incarceration) relative to their other ethnic counterparts, few studies have explored how juvenile justice involvement and number of contacts might be correlated with this broad range of problems. A convenience sample of 638 African American adolescents living in predominantly low-income, urban communities participated in a survey related to juvenile justice involvement. Major findings using logistic regression models indicated that adolescents who reported juvenile justice system involvement versus no involvement were 2.3 times as likely to report mental health problems, substance abuse, and delinquent or youth offending behaviors. Additional findings documented that the higher the number of juvenile justice system contacts, the higher the rates of delinquent behaviors, alcohol and marijuana use, sex while high on drugs, and commercial sex. These findings suggest that identifying and targeting youth who have multiple juvenile justice system contacts, especially those in low-resourced communities for early intervention services, may be beneficial. Future research should examine whether peer network norms might mediate the relationships between juvenile justice involvement and youth problem behaviors.

Do Sexually Oriented Massage Parlors Cluster in Specific Neighborhoods? A Spatial Analysis of Indoor Sex Work in Los Angeles and Orange Counties, California

OBJECTIVE

Social determinants of health may be substantially affected by spatial factors, which together may explain the persistence of health inequities. Clustering of possible sources of negative health and social outcomes points to a spatial focus for future interventions. We analyzed the spatial clustering of sex work businesses in Southern California to examine where and why they cluster. We explored economic and legal factors as possible explanations of clustering.

METHODS

We manually coded data from a website used by paying members to post reviews of female massage parlor workers. We identified clusters of sexually oriented massage parlor businesses using spatial autocorrelation tests. We conducted spatial regression using census tract data to identify predictors of clustering.

RESULTS

A total of 889 venues were identified. Clusters of tracts having higher-than-expected numbers of sexually oriented massage parlors ("hot spots") were located outside downtowns. These hot spots were characterized by a higher proportion of adult males, a higher proportion of households below the federal poverty level, and a smaller average household size.

CONCLUSION

Sexually oriented massage parlors in Los Angeles and Orange counties cluster in particular neighborhoods. More research is needed to ascertain the causal factors of such clusters and how interventions can be designed to leverage these spatial factors.

Financial Distress among Pacific Islanders in Southern California

Pacific Islanders experience enduring and growing poverty in the United States, yet our understanding of their financial distress and needs is limited. Financial institutions, government agencies, and community-based organizations in areas with large Pacific Islander communities need better information with which to develop tailored programs, improve outreach and education, and improve economic security for these and other underserved populations. This paper describes the results from a unique in-language survey that asked detailed questions regarding the financial knowledge, status, and needs of Pacific Islanders, including poverty and wealth questions beyond those in the Census, in Los Angeles, Orange, and San Diego counties of Southern California.

A community-based participatory research study of HIV and HPV vulnerabilities and prevention in two Pacific Islander communities: ethical challenges and solutions

We describe ethical issues that emerged during a one-year CBPR study of HIV and human papillomavirus (HPV) vulnerabilities and prevention in two Pacific Islander (PI) communities, and the collaborative solutions to these challenges reached by academic and community partners. In our project case study analysis, we found that ethical tensions were linked mainly to issues of mutual trust and credibility in PI communities; cultural taboos associated with the nexus of religiosity and traditional PI culture; fears of privacy breaches in small, interconnected PI communities; and competing priorities of scientific rigor versus direct community services. Mutual capacity building and linking CBPR practice to PI social protocols are required for effective solutions and progress toward social justice outcomes.

Abstract B14: Strengthening CBPR collaboration between Pacific Islander community and academic research partners

Community-based participatory research (CBPR), applied authentically according to its principles, is inherently conducive to empowerment and capacity building for academic and community partners by promoting egalitarian collaborations through all stages of research. During an intensive qualitative study exploring the intersection of HIV-HPV and cancer in the Pacific Islander (PI) communities of Southern California, we strengthen effective collaborations between an academic research team and two PI community-based organizations (CBOs). Responding to an NCI call for research exploring AIDS-related cancers, our CBOs worked closely with the academic team to examine HIV-HPV factors among Chamorro and Tongan young adults. Key informant and focus groups interviews were collaboratively chosen as the grounded theory research design. Community partners lead the process in: 1) determining most locally relevant and culturally appropriate point of entry for the study investigating HIV and its potential connections to HPV; 2) establishing and convening project specific community advisory board; 3) recruiting study participants; and 4) collecting data. The academic team conducted trainings on HIV, HPV, sampling, data collection, and analysis. Partners jointly lead dissemination efforts. The decision-making process incorporated culturally appropriate meeting protocols of sharing food and experiences through “talk story.” Through our successful CBPR collaboration, we ensured a shared discourse on cancer-related and comorbid topics, and we solidified and reaffirmed our relationship for ongoing and future projects. Thus, CBPR is critical, as the need to address cancer health disparities through collaborative research continues to play a key role in shaping the racial/ethnic minority and medically underserved healthcare landscape.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B14.

Abstract B86: HIV and HPV risk and prevention factors among Tongan and Chamorro young adults in Southern California: A qualitative assessment

Background: Racial/ethnic minority and medically underserved populations are at significant risk of the intersection of HIV/AIDS, HPV, and cancer. Little is known about the intersection of these public health issues in Pacific Islander communities.

Purpose: Establishing the ground work for understanding the intersection of these diseases, we assessed HIV and HPV risk and prevention factors among Chamorro and Tongan young adults in Southern California.

Methods: Under guidelines of CBPR, a qualitative study was implemented utilizing community based focus groups with male and female young adults, and parents (n=69); and key informant interviews with medical, mental health, and social service providers, and community leaders from social, youth, and faith-based groups (n=26).

Results: Utilizing grounded theory, common factors impacting HIV-HPV risk and prevention among young adults were identified: 1) religio-cultural taboos limit communication about sexual health between generations and from community leaders; 2) limited knowledge of HIV and particularly HPV engender misperceptions about disease transmission and prevention; 3) sexual abstinence, especially for young women, is promoted by parents and religious leaders; however, 4) the norm of expected abstinence leads to low levels of condom acceptance; and 5) collectivist notions of filial shame associated with HIV-HPV testing and utilization of other sexual health services, constrains prevention.

Discussion: Quantitative exploration of the relationship between factors identified and behavior, as well as research to identify HIV/HPV links to cancer in these communities is needed. Future consideration must include multigenerational, gender appropriate and cultural norms –especially related to religion and the interplay between individualism and collectivism.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B86.

Toward a conceptual model linking community violence exposure to HIV-related risk behaviors among adolescents: directions for research

PURPOSE

To present a conceptual framework which accounts for the relationship between community violence exposures (CVEs) and youth HIV risk behaviors.

METHODS

This article provides an overview of existing research on the links between CVE and HIV risk for youth and offers a conceptual framework for clarifying how CVE might contribute to HIV sexual risk behaviors.

RESULTS

Increasing empirical findings substantiate that the links between CVE and HIV risk behaviors among youth are mediated by psychological problem behaviors, low school success rates, and negative peer influences.

CONCLUSIONS

Researchers have identified the behaviors that place teens at risk for becoming infected with HIV. However, most scholars have overlooked the potential importance of CVE in influencing such behaviors. This article presents new directions for adolescent research and HIV interventions on the basis of an integrated conceptual framework.

The Solaar HIV prevention program for gay and bisexual Latino men: using social marketing to build capacity for service provision and evaluation

Community-researcher partnerships can be powerful mechanisms to understand and effectively address health and social problems such as HIV/AIDS prevention. When the partnership is a positive, productive one, the combined expertise and energy of both parties result in a more effective program and a better evaluation of its effects. This article describes one such partnership and how a program challenge provided the opportunity for both partners to develop new capacities and strengthen others. The program is Proyecto SOLAAR, a community-based and culturally-sensitive HIV prevention program for gay and bisexual Latino men. The program is an experiential, daylong retreat focused on personal aspects of the men (e.g., self-concept), ideas about and aspects of their relationship behavior (e.g., cultural misunderstandings, dating behavior), and HIV prevention; there is a follow-up reunion a month later to share experiences with other participants about new dating and HIV prevention behaviors. The article focuses in particular on how the partners built new capacity in the area of social marketing to address the challenge of participant recruitment and describes the components of the new campaign. These components included distinctive images in ads in publications read by the target population, a toll-free telephone number and Web site for easy initial contact with the program, phone cards and postcards featuring the specially created program image to reinforce a connection to the program, and other aspects. The article describes the partnership between the HIV service providers and the researchers and how the collaborative effort was key to understanding and addressing the recruitment problem, identifying potential solutions, and implementing the new social marketing strategy. This process resulted in four kinds of capacities that were built or strengthened, including program recruitment, program content and implementation, program evaluation, and the partnership itself. The article concludes with a discussion of the unexpected benefits of the capacity-building experience and of the antecedent conditions that fostered the positive partnership outcomes.

Evaluation of a single-pass intestinal-perfusion method in rat for the prediction of absorption in man

Prediction of the fraction of dose absorbed from the intestine (Fa) in man is essential in the early drug discovery stage. In-vitro assays in Caco-2 and MDCK cells are routinely used for that purpose, and their predictive value has been reported. However, in-situ techniques might provide a more accurate estimation of Fa. In this study, we evaluated a single-pass intestinal-perfusion (SPIP) method in the rat for its use in the prediction of absorption in man and compared it with a previous report using cell-based assays. Effective permeability coefficients (Peff) were determined in rats for 14 compounds, and ranged from 0.043x 10(-4) cm s(-1) to 1.67 x 10(-4) cm s(-1). These values strongly correlated (r2 = 0.88) with reported Peff values for man. In addition, the Spearman rank correlation coefficient calculated for in-situ-derived Peff and absorption in man was 0.92 while for the previously tested in-vitro Caco-2 and MDCK systems vs absorption in man, the correlation coefficients were 0.61 and 0.59, respectively. SPIP provided a better prediction of human absorption than the cell-based assays. This method, although time consuming, could be used as a secondary test for studying the mechanisms governing the absorption of new compounds, and for predicting more accurately the fraction absorbed in man.

Comparison of chromatographic and spectroscopic methods used to rank compounds for aqueous solubility

Rapid methods for ranking the solubility of compounds in aqueous media using commercial, 96-well ultraviolet-visible (UV-vis) and nephelometric plate readers are described. The methods were evaluated using commercially available compounds from a variety of structural classes as well as a series of structurally related compounds derived from combinatorial synthesis. Samples were predissolved in dimethyl sulfoxide (DMSO) and then added to the study solvent to attain a final concentration of DMSO in the aqueous solution of 5%. Comparison of filtration of the samples through nylon and poly(tetrafluoroethylene) (PTFE) membranes is also described. The solubility of the compounds determined using the UV-vis plate reader in the absorption mode (with samples filtered with the PTFE filter) as well as in the light scattering mode was in good agreement with that determined by high-performance liquid chromatography, with an average correlation of 0.95. Solubility data obtained using a 96-well nephelometer was also comparable (r(2) = 0.97). The nonequilibrium methods described in this study can be used to rapidly rank compounds from combinatorial libraries for solubility and can also give a general assessment of solubility prior to running additional high throughput screens in a drug discovery environment.

MDCK (Madin-Darby canine kidney) cells: A tool for membrane permeability screening

The goal of this work was to investigate the use of MDCK (Madin-Darby canine kidney) cells as a possible tool for assessing the membrane permeability properties of early drug discovery compounds. Apparent permeability (Papp) values of 55 compounds with known human absorption values were determined using MDCK cell monolayers. For comparison, Papp values of the same compounds were also determined using Caco-2 cells, a well-characterized in vitro model of intestinal drug absorption. Monolayers were grown on 0. 4-microm Transwell-COL membrane culture inserts. MDCK cells were seeded at high density and cultured for 3 days, and Caco-2 cells were cultured under standard conditions for 21 to 25 days. Compounds were tested using 100 microM donor solutions in transport medium (pH 7.4) containing 1% DMSO. The Papp values in MDCK cells correlated well with those in Caco-2 cells (r2 = 0.79). Spearman's rank correlation coefficient for MDCK Papp and human absorption was 0.58 compared with 0.54 for Caco-2 Papp and human absorption. These results indicate that MDCK cells may be a useful tool for rapid membrane permeability screening.

Quantitative determination of disodium edetate in ophthalmic and contact lens care solutions by reversed-phase high-performance liquid chromatography

A specific and sensitive HPLC method has been developed for the quantitative determination of disodium edetate (1) in a variety of ophthalmic and contact lens care solutions. Using this method, a common contaminant, nitrilotriacetic acid (2), is easily separated from 1. Sample preparation involves a single dilution step prior to mixing with an aqueous cupric nitrate solution to form a copper:EDTA complex for analysis. An aliquot of the resulting mixture is analyzed by HPLC using either a 10-microns styrene divinyl benzene column or, for separations requiring greater selectivity and resolution because of interfering components in the sample matrix, a 5-microns octadecyl column with a mobile phase of acetonitrile:0.006 M aqueous tetrabutylammonium phosphate, pH 6.5 (20:80). The column effluent is monitored by UV detection at 254 nm. The method is linear, quantitative, and reproducible for a wide variety of formulations. Using this method, the average recovery of 1 from spiked samples was 100%, with a relative standard deviation of less than 2%. The minimal quantifiable level of 1 was approximately 2.8 ng (equivalent to an analytical concentration of 1.5 microgram/mL).