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McAuley A, Palmateer N, Goldberg DJ, Shivaji T, Ritchie T, Licence K, Carter D, Hutchinson SJ. Increased risk of non-fatal overdose associated with non-prescribed benzodiazepine use in Scotland, UK. THE INTERNATIONAL JOURNAL OF DRUG POLICY 2023:104236. [PMID: 37865531 DOI: 10.1016/j.drugpo.2023.104236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/26/2023] [Accepted: 10/09/2023] [Indexed: 10/23/2023]
Abstract
BACKGROUND Drug-related deaths (DRDs) in Scotland increased for seven years in a row between 2014 and 2020, consolidating Scotland's place at the top of the United Kingdom and European drug-related mortality charts. One of the defining features of this recent and rapid rise has been the role of benzodiazepines, which are now involved in the majority of all DRDs. These deaths are linked to use of non-prescribed, benzodiazepine-type novel psychoactive substances (NPS) which have been identified by the United Nations as a global threat to public health. This study aimed to estimate the prevalence and determinants of non-prescribed benzodiazepine use and its association with recent non-fatal overdose among a national sample of people who inject drugs (PWID). METHODS Data from the 2019-20 Needle Exchange Surveillance Initiative (NESI) was analysed using logistic regression. NESI is a voluntary, anonymous, biennial, cross-sectional, bio-behavioural survey of PWID attending community-based services providing injecting equipment in mainland Scotland. RESULTS Prevalence of non-prescribed benzodiazepine use in the past six months was 52% and significantly associated with age (aOR 0.97, 0.96-0.98), frequent incarceration (aOR 1.29, 1.07-1.57), recent public injecting (aOR 3.25, 2.33-4.55), a recent methadone prescription (aOR 1.87, 1.51-2.33), and a history of benzodiazepine prescription (aOR 1.92, 1.47-2.52). In addition, non-prescribed benzodiazepine use was significantly associated with non-fatal overdose in the past year among PWID (aOR 2.47, 1.90-3.21). CONCLUSION This study found a high prevalence of non-prescribed benzodiazepine use among a national sample of PWID in Scotland. Prevalence was highest among populations known to be at increased risk of drug-related death and use was strongly associated with overdose. These novel findings highlight the scale of the non-prescribed benzodiazepine issue Scotland faces, and the urgency required to expand its harm reduction infrastructure to address this unique element of its overdose crisis.
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Trayner K, Yeung A, Sumnall HR, Anderson M, Glancy ME, Atkinson A, Smith M, McAuley A. National increase in the community supply of take-home naloxone associated with a mass media campaign in Scotland: a segmented time series analysis. THE INTERNATIONAL JOURNAL OF DRUG POLICY 2023:104106. [PMID: 37563038 DOI: 10.1016/j.drugpo.2023.104106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/15/2023] [Accepted: 06/18/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND Take-home naloxone (THN) programmes have been associated with reductions in opioid-related mortality. In response to high rates of drug-related deaths in Scotland, the Scottish Government commissioned the 'How to save a life' (HTSAL) mass media campaign to: (1) increase awareness of drug-related deaths and how to respond to an overdose, and (2) increase the supply of THN. The aim of this study was to assess the effect of the campaign on the supply of THN. METHODS We used an interrupted time series design to assess the effect of the HTSAL mass media campaign on the national community supply of THN. The study time period was August 2020-December 2021. We modelled two key dates: the start of the campaign (week beginning (w/b) 30th of August 2021) and after the end of the main campaign (w/b 25th of October 2021). RESULTS The total number of THN kits distributed in the community in Scotland during the study period was 27,064. The mean number of THN kits distributed per week (relative to the pre-campaign period), increased by 126% during the campaign and 57% post-campaign. In segmented regression analyses, the pre-campaign trend in the number of THN kits supplied was increasing by an average of 1% each week (RR=1.01, 95% CI 1.01 to 1.01, p<0.001). Once the campaign started, a significant change in level was observed, and the number of kits increased by 75% (RR=1.75, 95% CI 1.29 to 2.40, p<0.001). The trend during the campaign was stable (i.e. not increasing or decreasing) but a significant change in level was observed when the campaign ended, and the number of THN kits supplied decreased by 32% (RR=0.68, 95% CI 0.46 to 0.98, p = 0.042). The trend during the post-campaign period was stable. CONCLUSIONS The HTSAL campaign had a short term, but large and significant impact, on the community supply of THN in Scotland. Mass media campaigns could be combined with other interventions and strategies to maintain the increased uptake of THN outside of campaign periods.
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Sumnall HR, Atkinson AM, Anderson M, McAuley A, Trayner K. How to save a life: Public awareness of a national mass media take home naloxone campaign, and effects of exposure to campaign components on overdose knowledge and responses. THE INTERNATIONAL JOURNAL OF DRUG POLICY 2023:104111. [PMID: 37563039 DOI: 10.1016/j.drugpo.2023.104111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 06/18/2023] [Accepted: 06/20/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND Take home naloxone (THN) programmes are effective at reducing opioid related mortality, but require high levels of distribution, including to the general public. Mass media campaigns can be effective in improving public understanding of a topic and encouraging behavior change. Whilst mass media campaigns focusing on naloxone have been developed internationally, there is a lack of research on their potential impact. We investigated the effects of components of a recent national mass media campaign (Scotland, UK) designed to improve public awareness of drug related deaths, and readiness to intervene. METHODS We undertook a cross-sectional online experimental study with a randomized design, conducted with a nationally representative sample. Participants (N = 1551; 52.6% female; age 46.1±16.5 years) were assessed on overdose knowledge and readiness to intervene after presentation of eight combinations of campaign components. RESULTS Compared to a basic campaign description, exposure to all types of campaign component were associated with higher overdose knowledge (p < .001), but not knowledge of what to do in response to an overdose (p = .374), or readiness to intervene (p= .286). The greatest effects were associated with a media rich audio-visual resource (animated video with a popular song on the soundtrack, and narrated by a well-known actor). CONCLUSION Our data suggest that harm reduction is an appropriate topic for large-scale mass media campaigns. However, effects may be limited to knowledge and awareness raising in the general public, and may be related to the types of media used. Audience segmentation is important and more general messaging about drug related deaths may be more appropriate for the majority of audiences.
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Wiessing L, Sypsa V, Abagiu AO, Arble A, Berndt N, Bosch A, Buskin S, Chemtob D, Combs B, Conyngham C, Feelemyer J, Fitzgerald M, Goldberg D, Hatzakis A, Patrascu RE, Keenan E, Khan I, Konrad S, Leahy J, McAuley A, Menza T, Merrick S, Metcalfe R, Rademaker T, Revivo S, Rosca P, Seguin-Devaux C, Skinner S, Smith C, Tinsley J, Wilberg M, Des Jarlais D. Impact of COVID-19 & Response Measures on HIV-HCV Prevention Services and Social Determinants in People Who Inject Drugs in 13 Sites with Recent HIV Outbreaks in Europe, North America and Israel. AIDS Behav 2023; 27:1140-1153. [PMID: 36367613 PMCID: PMC9651099 DOI: 10.1007/s10461-022-03851-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2022] [Indexed: 11/13/2022]
Abstract
HIV/HCV prevention among people who inject drugs (PWID) is of key public health importance. We aimed to assess the impact of COVID-19 and associated response measures on HIV/HCV prevention services and socio-economic status of PWID in high-HIV-risk sites. Sites with recent (2011-2019) HIV outbreaks among PWID in Europe North America and Israel, that had been previously identified, were contacted early May 2020. Out of 17 sites invited to participate, 13 accepted. Semi-structured qualitative site reports were prepared covering data from March to May 2020, analyzed/coded and confirmed with a structured questionnaire, in which all sites explicitly responded to all 103 issues reported in the qualitative reports. Opioid maintenance treatment, needle/syringe programs and antiretroviral treatment /hepatitis C treatment continued, but with important reductions and operational changes. Increases in overdoses, widespread difficulties with food and hygiene needs, disruptions in drug supply, and increased homelessness were reported. Service programs rapidly reformed long established, and politically entrenched, restrictive service delivery policies. Future epidemic control measures should include mitigation of negative side-effects on service provision and socio-economic determinants in PWID.
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McDonald SA, McAuley A, Hickman M, Bird SM, Weir A, Templeton K, Gunson R, Hutchinson SJ. Increasing drug-related mortality rates over the last decade in Scotland are not just due to an ageing cohort: A retrospective longitudinal cohort study. THE INTERNATIONAL JOURNAL OF DRUG POLICY 2021; 96:103286. [PMID: 34011449 DOI: 10.1016/j.drugpo.2021.103286] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/16/2021] [Accepted: 04/23/2021] [Indexed: 01/12/2023]
Abstract
BACKGROUND In Europe, North America, and Australia, mortality due to drug-related (DR) causes amongst people who inject drugs (PWID) is a major issue. Our objective was to characterise temporal trends in DR mortality rates in a large cohort of PWID in Scotland over the past decade, all of whom had been diagnosed with hepatitis C virus (HCV) infection, and to investigate factors associated with DR mortality. METHODS Retrospective longitudinal cohort study linking Scotland's national HCV Diagnosis Database and deaths registry. The study cohort consisted of all individuals with likely injection drug use-related route of HCV acquisition, who had been diagnosed with HCV between 1991 and 2018, and were alive and aged under 65 years on 1 January 2009. We used Lexis expansion to adjust for ageing cohort effects and calculated the mortality rate from an underlying/contributing DR cause over the period 2009-2018. We fitted Poisson regression models to estimate the temporal trend adjusting for attained age, sex, referral setting, region, and viraemic status at baseline. RESULTS Amongst the study population (n = 35,065; 236,914 person-years), a total of 1900 DR deaths occurred; the DR mortality rate increased from 5.6/1000 [101 deaths] in 2009 to 12.4/1000 [342] person-years in 2018. Increasing trends were observed for all age-groups except 55-64 years. The overall DR mortality rate was highest for referrals for HCV testing from prison (11.0/1000) and hospital settings (10.0/1000). Mortality increased with calendar time period, with significantly raised adjusted rate ratios (RRs) from 2015 (RR=1.40, 95% CI:1.16-1.69) to 2018 (RR=2.23, 95% CI:1.88-2.64), compared with 2011-2012, for older age (35-44: RR=1.37, 95% CI:1.20-1.56; 45-54: RR=1.32, CI:1.14-1.53) compared with <35 years, for persons diagnosed with HCV since 2009 (RR=1.34, 95% CI:1.21-1.49), and for prison and hospital referrals (RRs of 1.30, 1.37) compared with GP referrals. CONCLUSION Increasing DR mortality rates in Scotland over the past decade are not just due to an ageing cohort. Harm reduction services will likely need to expand and adapt to reverse the recent upward trends in DR mortality in PWID.
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McAuley A, Gousias P, Hasan T, Rashid L, Richardson C, Reid G, Templeton K, McGuire J, Wise H, McVicar L, Jenks S, Gunn R, Dickson E, Stock SJ, Stockton A, Waugh C, Wood R, McMenamin J, Robertson C, Goldberg DJ, Palmateer NE. National population prevalence of antibodies to SARS-CoV-2 among pregnant women in Scotland during the second wave of the COVID-19 pandemic: a prospective national serosurvey. Public Health 2021; 199:17-19. [PMID: 34517289 PMCID: PMC8364809 DOI: 10.1016/j.puhe.2021.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 08/05/2021] [Indexed: 11/24/2022]
Abstract
OBJECTIVES This study aimed to determine SARS-CoV-2 seroprevalence among pregnant women in the Scottish population during the second wave of the COVID-19 pandemic. STUDY DESIGN Prospective national serosurvey. METHODS We tested 13,428 residual samples retrieved from pregnant women participating in the first trimester combined ultrasound and biochemical screening for fetal trisomy across Scotland for SARS-CoV-2 antibodies over a 6-month period from November 2020 to April 2021. Seroprevalence estimates were adjusted for the sensitivity and specificity of the assays and weighted to reference populations. RESULTS Seroprevalence rates in the antenatal samples significantly increased from 5.5% (95% confidence interval [CI] 4.7%-6.5%) in the 5-week period up to and including International Organization for Standardization (ISO) Week 51 (w/b Monday 14 December 2020) to 11.3% (95% CI 10.1%-12.6%) in the 5-week period up to and including ISO Week 14 (w/b Monday 5 April 2021). Increasing seroprevalence trends across the second wave were observed among all age groups. CONCLUSIONS By the end of the second wave of the COVID-19 pandemic, approximately one in 10 women tested around the end of the first trimester of pregnancy had antibodies to SARS-CoV-2, suggesting that the vast majority were still susceptible to COVID-19 as they progressed to the later stages of pregnancy, when risks from infection are elevated for both mother and baby.
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McLeod A, Hutchinson SJ, Smith S, Leen C, Clifford S, McAuley A, Wallace LA, Barclay ST, Bramley P, Dillon JF, Fraser A, Gunson RN, Hayes PC, Kennedy N, Peters E, Templeton K, Goldberg DJ. Increased case-finding and uptake of direct-acting antiviral treatment essential for micro-elimination of hepatitis C among people living with HIV: a national record linkage study. HIV Med 2020; 22:334-345. [PMID: 33350049 DOI: 10.1111/hiv.13032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/28/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVES Micro-elimination of hepatitis C virus (HCV) in people living with HIV (PLHIV) and co-infected with HCV has been proposed as a key contribution to the overall goal of HCV elimination. While other studies have examined micro-elimination in HIV-treated cohorts, few have considered HCV micro-elimination among those not treated for HIV or at a national level. METHODS Through data linkage of national and sentinel surveillance data, we examined the extent of HCV testing, diagnosis and treatment among a cohort of PLHIV in Scotland identified through the national database of HIV-diagnosed individuals, up to the end of 2017. RESULTS Of 5018 PLHIV, an estimated 797 (15%) had never been tested for HCV and 70 (9%) of these had undiagnosed chronic HCV. The odds of never having been tested for HCV were the highest in those not on HIV treatment [adjusted odds ratio (aOR) = 7.21, 95% confidence interval (CI): 5.15-10.10). Overall HCV antibody positivity was 11%, and it was at its highest among people who inject drugs (49%). Most of those with chronic HCV (91%) had attended an HCV treatment clinic but only half had been successfully treated (54% for those on HIV treatment, 12% for those not) by the end of 2017. The odds of never having been treated for HCV were the highest in those not on HIV treatment (aOR = 3.60, 95% CI: 1.59-8.15). CONCLUSIONS Our data demonstrate that micro-elimination of HCV in PLHIV is achievable but progress will require increased effort to engage and treat those co-infected, including those not being treated for their HIV.
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Dickson E, Palmateer NE, Murray J, Robertson C, Waugh C, Wallace LA, Mathie L, Heatlie K, Mavin S, Gousias P, Von Wissman B, Goldberg DJ, McAuley A. Enhanced surveillance of COVID-19 in Scotland: population-based seroprevalence surveillance for SARS-CoV-2 during the first wave of the epidemic. Public Health 2020; 190:132-134. [PMID: 33453689 PMCID: PMC7685039 DOI: 10.1016/j.puhe.2020.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 11/17/2020] [Indexed: 12/04/2022]
Abstract
Objectives The impact of the COVID-19 pandemic in Scotland has been amongst the most severe in Europe. Serological surveillance is critical to determine the overall extent of infection across populations and to inform the public health response. This study aimed to estimate the proportion of people who have antibodies to SARS-CoV-2 (‘seroprevalence’) in the general population of Scotland and to see if this changes over time. Study design/Methods Between International Organization for Standardization (ISO) week 17 (i.e. week commencing 20th April) and ISO week 25 (week commencing 15 June), 4751 residual blood samples were obtained from regional biochemistry laboratories in six participating regional health authority areas covering approximately 75% of the Scottish population. Samples were tested for the presence of anti-SARS-CoV-2 IgG antibodies using the LIAISON®SARS-CoV-2 S1/S2 IgG assay (DiaSorin, Italy). Seroprevalence rates were adjusted for the sensitivity and specificity of the assay using Bayesian methods. Results The combined adjusted seroprevalence across the study period was 4.3% (95% confidence interval: 4.2%–4.5%). The proportion varied each week between 1.9% and 6.8% with no difference in antibody positivity by age, sex or geographical area. Conclusions At the end of the first wave of the COVID-19 pandemic, only a small fraction of the Scottish population had antibodies to SARS-CoV-2. Control of COVID-19 requires the ability to detect asymptomatic and mild infections that would otherwise remain undetected through existing surveillance systems. This is important to determine the true number of infections within the general population which, in turn, can help to understand transmission, inform control measures and provide a denominator for the estimation of severity measures such as the proportion of infected people who have been hospitalised and/or have died.
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Sumnall HR, Atkinson AM, Trayner KMA, Gage SH, McAuley A. Effects of messaging on public support for drug consumption rooms in scotland, UK. THE INTERNATIONAL JOURNAL OF DRUG POLICY 2020; 83:102855. [PMID: 32693322 DOI: 10.1016/j.drugpo.2020.102855] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 11/15/2022]
Abstract
BACKGROUND There is evidence to suggest that medically supervised drug consumption rooms (DCRs) may form part of responses to reduce drug-related harm. Although DCRs have been established globally, they are perceived by some to be a controversial approach in the UK, and Government has repeatedly rejected proposals to establish one in Glasgow, Scotland. As public support is an important component of policy development and enactment, we sought to investigate the effects of different types of message framing on public support for DCR. METHODS We undertook a cross-sectional online study with a randomised design, conducted with a nationally representative sample. Participants were randomised to one of six message conditions comprising combinations of four components. All conditions included i) a basic description of a DCR, and conditions included combinations of ii) factual information; iii) pre-emptive refutation of common public concerns about DCR; and/or iv) a sympathetic narrative describing a mother whose son died from a heroin overdose. After reading each message, participants completed a bespoke measure assessing support for DCR. Data were analysed using ANCOVA. RESULTS Complete data were obtained from 1591 participants (50.3% Female; mean age 44.9 ± 16.1 years). Compared to reading a basic description of DCR alone, there was greater support for DCR in participants receiving the refutation (p < .001); sympathetic + factual (p < .05); and sympathetic + factual + refutation (p < .001) message conditions. Presenting factual or sympathetic messages alone were not associated with increased support. CONCLUSION Our findings suggest that public support for DCRs is not improved through communication of factual statements outlining potential benefits of the intervention alone. Advocates seeking to foster public support, and thus influence policy making, should also consider communication campaigns that address common concerns that the public might have about DCRs, and present the intervention in relation to potential benefits that they hold for people indirectly affected by drug-related harm.
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McAuley A. Digital health interventions: widening access or widening inequalities? Public Health 2014; 128:1118-20. [PMID: 25458115 DOI: 10.1016/j.puhe.2014.10.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 07/17/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
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Khodadadi S, Clark NJ, McAuley A, Cristiglio V, Curtis JE, Shalaev EY, Krueger S. Influence of sorbitol on protein crowding in solution and freeze-concentrated phases. SOFT MATTER 2014; 10:4056-4060. [PMID: 24819334 DOI: 10.1039/c4sm00600c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Small-angle neutron scattering was employed to study protein crowding under freezing conditions that mimic those used in pharmaceutical processing. The results demonstrate that, although there is an increase in heterogeneity as the temperature is reduced, sorbitol reduces protein crowding in both solution and freeze-concentrated phases, thus protecting the protein from forming oligomers or irreversible aggregates.
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Roberts PL, Dunkerley C, McAuley A, Winkelman L. Effect of manufacturing process parameters on virus inactivation by dry heat treatment at 80 degrees C in factor VIII. Vox Sang 2007; 92:56-63. [PMID: 17181591 DOI: 10.1111/j.1423-0410.2006.00845.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVES Dry heat treatment at 80 degrees C for 72 h is used as a virus inactivation step for some coagulation factor concentrates such as Bio Products Laboratory's (BPL) factor VIII 8Y. In the current study, the effect of this process has been tested on a range of viruses. In addition the effect of various manufacturing process parameters on virus inactivation has been investigated. MATERIALS AND METHODS Samples of product intermediate were obtained from manufacturing, spiked with virus and subjected to freeze drying and dry heat treatment. Virus inactivation was determined by infectivity assay. RESULTS Freeze drying followed by dry heat treatment was effective for inactivating a wide range of enveloped and nonenveloped viruses. Sucrose or protein concentration had no effect on virus inactivation. Product presentation or the interruption of heat treatment also had no effect. The inactivation of some of the viruses was greater at higher residual water content but under such conditions the stability of the product was reduced. CONCLUSION This virus inactivation step was effective for a wide range of viruses and over the range of process conditions encountered in manufacturing. This demonstrates the robustness of this process step.
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Chak BCM, McAuley A. The synthesis and characterization of the pendant-armed ligand N,N′-bis(2′-pyridylmethyl)-1,7-dithia-4,11-diazacyclotetradecane (L4) and crystal structures of L4 and the copper(II) complex [Cu(L4)](ClO4)2 Crystal structure of the nickel(II) complex of N-(2′-pyridylmethyl)-1,4,7-trithia-11-azacyclotetradecane (L2), [Ni(L2)(CH3CN)](ClO4)2·CH3CN. CAN J CHEM 2006. [DOI: 10.1139/v05-241] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The synthesis and characterization of the mixed donor ligand N,N′-bis(2′-pyridylmethyl)-1,7-dithia-4,11-diazacyclotetradecane (L4) containing two pendant pyridine arms is described. The macrocycle formation involves reaction of N-tosylbis(2-bromoethyl)amine with N-tosylbis(3-mercaptopropyl)amine at high dilution followed by detosylation at the nitrogen atoms using LiAlH4 in view of the presence of the thioether groups. An X-ray study of the ligand shows the sulphur atoms lie exo to the macrocyclic ring. The nickel(II) and copper(II) complexes of L4 have been characterized and the X-ray structure of the Cu(II) ion exhibits a five-coordinate copper ion despite the presence of six available donor atoms. In the case of ligand N-(2-pyridylmethyl)-1,4,7-trithia-11-azacyclotetradecane (L2), with a single pendant N donor, the Ni(II) complex is distorted octahedral with a molecule of acetonitrile in the sixth site. Details of UVvis, ESR spectra, and electrochemical studies on the complexes are presented.Key words: synthesis, pendant-armed, mixed donor S,N macrocycles, copper, nickel.
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Rodopoulos T, Ishihara K, Rodopoulos M, Zaworotko MJ, Maeder M, McAuley A. Synthesis and reactivity of the macrobicyclic complexes (1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane)cobalt(III) perchlorate ([Co(L 1)(ClO 4)](ClO 4) 2), [(chloro(1,4,8,11-tetraaza-17-oxabicyclo[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L 2)(Cl)](ClO 4) 2), (4,8-dimethyl-1,4,8,11-tetraaza-17-oxabicyclo[9.5.3]nonadecane)cobalt(III) perchlorate ([Co(L 3)(ClO 4)](ClO 4) 2), and (5,8-dimethyl-1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane)cobalt(III) perchlorate ([Co(L 4)(ClO 4)](ClO 4) 2) Crystal structure of the L 2 complex. CAN J CHEM 2005. [DOI: 10.1139/v05-089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1,5-diaza-8-oxacyclodecane with either 1,9-dichloro-3,7-diazanonane-2,8-dione, and subsequent reduction of the diamide (3), or with 1,9-dichloro-3,7-(dimethyl)diazanonane-2,8-dione and reduction (L3). A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1,4-diaza-7-oxacyclononane. The Co(III) complexes of these ligands and of 1,5,8,12-tetraaza-17-oxabicyclo[10.5.2]nonadecane (L1) have been prepared. Spectrophotometric determinations on the L1 complex ion confirm the presence of two hydrogen ion related equilibria, one of which (pK = 2.2 ± 0.2) is associated with the proposed replacement of the apical ether oxygen by a water molecule that is bound to the metal centre and hydrogen bonded to the ether. The species derived from L1 and L2 exhibit remarkable kinetic stability. Studies on the anation of the [Co(L1)(H2O)](ClO4)3 with chloride ions in acidic media are consistent with the reaction of both the proton-related complex and the [Co(L1)(H2O)]3+ ion. Whilst complex ions containing two secondary NH groups maintain the metalion coordination in strongly acidic media, corresponding species with ligands containing all four tertiary amine sites are subject to attack by protons leading to a relatively facile demetallation of the complexes. The latter finding is supported by kinetic studies and mass spectrometric fragmentation patterns of the ions. Key words: cobalt(III), macrobicycle, hydrolysis, anation, spectroscopic analysis.
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Brodovitch JC, McAuley A, Oswald T. Kinetics and mechanism of the oxidation of hydroquinone and catechol by [Ni(III)cyclam]3+ in aqueous perchlorate media. Inorg Chem 2002. [DOI: 10.1021/ic00139a035] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Fairbank MG, McAuley A. Kinetics and mechanism of the reduction of nickel(III) macrocyclic complexes by iodide ion. Inorg Chem 2002. [DOI: 10.1021/ic00264a025] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Chandrasekhar S, Fortier DG, McAuley A. Syntheses of chromium and copper complexes of hexaazamacrocycles. Crystal structures of chromium(III) complexes of 1,4,7,10,13,16-hexaazacyclooctadecane and 1,4,7,11,14,17-hexaazacycloeicosane. Inorg Chem 2002. [DOI: 10.1021/ic00060a017] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Chandrasekhar S, McAuley A. Syntheses and reactivity of nickel complexes of 8-aza-1,5-dithiacyclodecane and the macrobicyclic ligand 1,2-bis(8-aza-1,5-dithia-8-cyclodecanyl)ethane. Inorg Chem 2002. [DOI: 10.1021/ic00037a044] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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20
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McAuley A, Subramanian S. Synthesis, structure, and reactivity of the nickel(II) complex of 7-aza-1,4-dithiacyclononane. Inorg Chem 2002. [DOI: 10.1021/ic00340a022] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Chandrasekhar S, McAuley A. Syntheses, structure, and reactivity of cobalt and nickel complexes of 1,4,7-trithiacyclodecane: self-exchange rates for Co(S6)2+/3+ couples from cobalt-59 NMR spectroscopy. Inorg Chem 2002. [DOI: 10.1021/ic00029a026] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Macartney DH, McAuley A. Kinetics and mechanisms of the reactions of a nickel(IV) complex with iron(II), vanadium(IV), and nickel(II) cyclam ions in aqueous perchlorate media. Inorg Chem 2002. [DOI: 10.1021/ic00156a024] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Fairbank MG, McAuley A. Kinetics and mechanism of chloride and bromide substitution of diaquonickel(III) macrocyclic complexes. Inorg Chem 2002. [DOI: 10.1021/ic00228a032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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McAuley A, Whitcombe TW. Bis(1,4,7-triazacyclononane)palladium(III): characterization and reactions of an unusually stable monomeric palladium(III) ion. Inorg Chem 2002. [DOI: 10.1021/ic00291a010] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Brodovitch JC, McAuley A. Kinetics and mechanism of the oxidation of nickel(II)cyclam by aquocobalt(III) in aqueous perchloric acid. Inorg Chem 2002. [DOI: 10.1021/ic50220a009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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