A systematic review and meta-analysis of the association between eating disorders and bone density.

This meta-analysis investigates the effect of an eating disorder on bone mineral density in two eating disorder subtypes. Following conflicting findings in previous literature, this study finds that not only anorexia nervosa, but also bulimia nervosa has a detrimental effect on BMD. Key predictors of this relationship are discussed. This systematic review and meta-analysis investigates bone mineral density (BMD) in individuals with anorexia nervosa (AN) and bulimia nervosa (BN) in comparison to healthy controls (HCs). AN has been associated with low BMD and a risk of fractures and mixed results have been obtained for the relationship between BN and BMD. Deciphering the effect these two ED subtypes on BMD will determine the effect of low body weight (a characteristic of AN) versus the effects of periods of restrictive eating and malnutrition which are common to both AN and BN. We conducted a systematic search through the electronic databases MedLine, EMBASE and PsychInfo and the Cochrane Library to investigate and quantify this relationship. We screened 544 articles and included 27 studies in a random-effect meta-analysis and calculated the standardised mean difference (SMD) in BMD between women with a current diagnosis of AN (n = 785) vs HCs (n = 979) and a current diagnosis of BN (n = 187) vs HCs (n = 350). The outcome measures investigated were spinal, hip, femoral neck and whole body BMD measured by DXA or DPA scanning. A meta-regression investigated the effect of factors including age, duration since diagnosis, duration of amenorrhea and BMI on BMD. The mean BMI of participants was 16.65 kg/m(2) (AN), 21.16 kg/m(2) (BN) and 22.06 kg/m(2) (HC). Spine BMD was lowest in AN subjects (SMD, -3.681; 95 % CI, -4.738, -2.625; p < 0.0001), but also lower in BN subjects compared with HCs (SMD, -0.472; 95 % CI, -0.688, -0.255; p < 0.0001). Hip, whole body and femoral neck BMD were reduced to a statistically significant level in AN but not BN groups. The meta-regression was limited by the number of included studies and did not find any significant predictors. This meta-analysis confirms the association between low BMD and AN and presents a strong argument for assessing BMD not only in patients with AN, but also in patients with BN.

Childhood psychopathology in children of women with eating disorders.

OBJECTIVE: We aimed to investigate the effect of maternal eating disorders (ED) on childhood psychopathology, early delays in cognitive, motor and language development, mother and child relationship, and child temperament in a community-based cohort: the Danish National Birth Cohort (DNBC). METHOD: Data were obtained prospectively on 48 403 children at 18 months and 46 156 children at 7 years. Data on cognitive, motor and language development, temperament and attachment were obtained at 18 months; data on child psychopathology were obtained at 7 years of age, using the Strengths and Difficulties Questionnaire (SDQ). Children of mothers with lifetime diagnosis of anorexia nervosa (AN, n = 931), lifetime diagnosis of bulimia nervosa (BN, n = 906) and both (AN & BN = 360) were compared to children of mothers without an ED (n = 46 206). RESULTS: Girls of women with lifetime AN had higher odds of having emotional problems, and girls of women with lifetime BN of having conduct problems compared with children of healthy women. Boys of women with lifetime AN had higher odds of total, emotional and conduct problems; boys of women with lifetime BN had higher odds of total, conduct, hyperactivity and peer difficulties compared to children of women without an ED. Boys of women with lifetime AN and BN had higher odds of total, emotional and peer problems compared to children of healthy women. CONCLUSION: Maternal ED is associated with childhood psychopathology in both boys and girls. Boys seemed at higher risk for psychopathology in this sample. Associations between emotional disorders across genders in children of mothers with lifetime AN, and hyperactivity and peer difficulties in boys of mothers with lifetime BN confirm and extend previous findings and point to possible shared risk between ED and other psychopathology.

Size at birth and preterm birth in women with lifetime eating disorders: a prospective population-based study.

OBJECTIVE: To investigate whether eating disorders are associated with lower size at birth, symmetric growth restriction, and preterm birth; and whether pregnancy smoking explains the association between anorexia nervosa and fetal growth. DESIGN: Longitudinal population-based cohort study. SETTING: Denmark. SAMPLE: Women from the Danish National Birth Cohort (n = 83 826). METHODS: Women with anorexia nervosa (n = 1609), bulimia nervosa (n = 1693) and both (anorexia + bulimia nervosa, n = 634) were compared with unexposed women (n = 76 724) (women with exposure data and singletons n = 80 660) using crude and adjusted linear and logistic regression models. MAIN OUTCOME MEASURES: Size at birth (birthweight, length, head and abdominal circumference and placental weight); gestational age; small- and large-for-gestational-age (SGA, LGA); ponderal index, abdominal/head circumference. RESULTS: Lifetime anorexia nervosa and lifetime anorexia + bulimia nervosa were prospectively associated with restricted fetal growth and higher odds of SGA [respectively, OR = 1.6 [95% CI 1.3-1.8] and OR = 1.5 [95% CI 1.2-1.9)] compared with unexposed women. Active anorexia nervosa was associated with lower birthweight, length, head and abdominal circumference, ponderal index, higher odds of SGA [OR = 2.90 (95% 1.98-4.26)] and preterm birth [OR = 1.77 (95% CI 1.00-3.12)] compared with unexposed women. Pregnancy smoking only partly explained the association between anorexia nervosa and adverse fetal outcomes. CONCLUSIONS: Maternal anorexia nervosa (both active and past) is associated with lower size at birth and symmetric growth restriction, with evidence of worse outcomes in women with active disorder. Women with anorexia nervosa should be advised about achieving full recovery before conceiving. Similarly, targeting smoking in pregnancy might improve fetal outcomes. TWEETABLE ABSTRACT: Anorexia nervosa predicts small size at birth, small-for-gestational-age and symmetric growth restriction.

Eating disorders in a multi-ethnic inner-city UK sample: prevalence, comorbidity and service use.

PURPOSE: No studies have investigated the prevalence of eating disorders (ED) according to DSM-5 criteria and few have explored their comorbidity and service use in the general population in the UK. We aimed to estimate the prevalence, comorbidity, and service use in individuals with ED in a multi-ethnic inner city sample. METHODS: A total of 1698 individuals (age 16/90) were screened for ED in the first phase of the South East London Community Health Study and 145 were followed up with a diagnostic interview. Data was weighed for survey design and Chi Square tests were used to investigate socio-demographic distribution, comorbidity and service use in participants with ED. RESULTS: The point prevalence of ED was 4.4 % (Binge Eating Disorder (BED) 3.6 %; Bulimia Nervosa (BN) 0.8 %) and 7.4 % when including sub-threshold diagnoses (Purging Disorder (PD) 0.6 %; Other Specified Feeding and Eating Disorders (OSFED) 2.4 %). No cases of AN were identified. Purging Disorder was the ED with the highest proportion of comorbid disorders. A minority of participants with ED had accessed specialist care services. CONCLUSIONS: ED are common, the comorbidity of ED was in line with previous studies and no ethnic differences were identified. Although PD is not a full diagnosis in DSM-5, we found some evidence of high comorbidity with other disorders, that needs to be replicated using larger samples. Service use was low across ED diagnoses, despite high levels of comorbidity.

Childhood risk factors for lifetime bulimic or compulsive eating by age 30 years in a British national birth cohort.

OBJECTIVE: To examine whether previously identified childhood risk factors for bulimia or compulsive eating (BCE) predict self-reported lifetime BCE by age 30 years in a prospective birth cohort. METHOD: Using data from the 1970 British Cohort Study at birth, 5, and 10 years, associations between 22 putative childhood risk factors and self-reported lifetime BCE at 30 years were examined, adjusting for sex and socioeconomic status. RESULTS: Only female sex (odds ratio (OR): 9.2; 95% confidence interval (CI): 1.9-43.7; p = 0.005), low self-esteem (OR:2.9; 95%CI: 1.1-7.5; p = 0.03) and high maternal education (OR:5.4; 95%CI: 2.0-14.8; p = 0.001) were significantly associated with higher risk of BCE, whereas high SES at 10 years was significantly protective (OR:0.2; 95%CI: 0.1-0.8; p = 0.022) of BCE in fully adjusted multivariable logistic regression analysis. DISCUSSION: Our findings do not support a strong role for childhood weight status and eating behaviours in the development of bulimia and compulsive eating pathology, rather suggesting a focus on self esteem may have greater relative importance. Findings in relation to maternal education and SES need further exploration.

Adolescent eating disorder behaviours and cognitions: gender-specific effects of child, maternal and family risk factors.

BACKGROUND: Eating disorder behaviours begin in adolescence. Few longitudinal studies have investigated childhood risk and protective FACTORS. AIMS: To investigate the prevalence of eating disorder behaviours and cognitions and associated childhood psychological, physical and parental risk factors among a cohort of 14-year-old children. METHOD: Data were collected from 6140 boys and girls aged 14 years. Gender-stratified models were used to estimate prospective associations between childhood body dissatisfaction, body mass index (BMI), self-esteem, maternal eating disorder and family economic disadvantage on adolescent eating disorder behaviours and cognitions. RESULTS: Childhood body dissatisfaction strongly predicted eating disorder cognitions in girls, but only in interaction with BMI in boys. Higher self-esteem had a protective effect, particularly in boys. Maternal eating disorder predicted body dissatisfaction and weight/shape concern in adolescent girls and dieting in boys. CONCLUSIONS: Risk factors for eating disorder behaviours and cognitions vary according to gender. Prevention strategies should be gender-specific and target modifiable predictors in childhood and early adolescence.

Childhood hyperactivity/inattention and eating disturbances predict binge eating in adolescence.

BACKGROUND: Identifying childhood predictors of binge eating and understanding risk mechanisms could help improve prevention and detection efforts. The aim of this study was to examine whether features of attention-deficit/hyperactivity disorder (ADHD), as well as childhood eating disturbances, predicted binge eating later in adolescence. METHOD: We studied specific risk factors for the development of binge eating during mid-adolescence among 7120 males and females from the Avon Longitudinal Study of Parents and Children (ALSPAC), a cohort study of children in the UK, using data from multiple informants to develop structural equation models. Repeated assessment of eating disturbances during childhood (mid-childhood overeating, late-childhood overeating and early-adolescent strong desire for food), as well as teacher- and parent-reported hyperactivity/inattention during mid- and late childhood, were considered as possible predictors of mid-adolescent binge eating. RESULTS: Prevalence of binge eating during mid-adolescence in our sample was 11.6%. The final model of predictors of binge eating during mid-adolescence included direct effects of late-childhood overeating [standardized estimate 0.145, 95% confidence interval (CI) 0.038­0.259, p = 0.009] and early-adolescent strong desire for food (standardized estimate 0.088, 95% CI −0.002 to 0.169, p = 0.05). Hyperactivity/inattention during late childhood indirectly predicted binge eating during mid-adolescence (standardized estimate 0.085, 95% CI 0.007­0.128, p = 0.03) via late-childhood overeating and early-adolescent strong desire for food. CONCLUSIONS: Our findings indicate that early ADHD symptoms, in addition to an overeating phenotype, contribute to risk for adolescent binge eating. These findings lend support to the potential role of hyperactivity/inattention in the development of overeating and binge eating.

Do eating disorders in parents predict eating disorders in children? Evidence from a Swedish cohort.

OBJECTIVE: We investigated whether parental eating disorders (ED) predict ED in children, using a large multigeneration register-based sample. METHOD: We used a subset of the Stockholm Youth Cohort born 1984-1995 and resident in Stockholm County in 2001-2007 (N = 286,232), The exposure was a diagnosed eating disorder in a parent; the outcome was any eating disorder diagnosis in their offspring, given by a specialist clinician, or inferred from an appointment at a specialist eating disorder clinic. A final study sample of 158,697 (55.4%) had data on these variables and confounding factors and contributed a total of 886,241 person years to the analysis. RESULTS: We found good evidence in support of the hypothesis that ED in either parent are independently associated with ED in their female children (HR 1.97 (95% CI: 1.17-3.33), P = 0.01) and that ED in mothers are independently associated with ED in their female children (HR 2.35 (95% CI: 1.39-3.97) P = 0.001). Numbers were too low to permit separate analysis of ED in parents and their male children. CONCLUSION: Eating disorders in parents were associated with ED in children. This study adds to our knowledge about the intergenerational transmission of ED, which will help identify high-risk groups and brings about the possibility of targeted prevention.

Fertility treatment, twin births, and unplanned pregnancies in women with eating disorders: findings from a population-based birth cohort.

OBJECTIVE: To investigate fertility treatment, twin births, and unplanned pregnancies in pregnant women with eating disorders in a population-based sample. DESIGN: A longitudinal population-based birth cohort (Generation R). SETTING: Rotterdam, the Netherlands. SAMPLE: Women from the Generation R study who reported a history of (recent or past) anorexia nervosa (n = 160), bulimia nervosa (n = 265), or both (n = 130), and a history of psychiatric disorders other than eating disorders (n = 1396) were compared with women without psychiatric disorders (n = 4367). METHODS: Women were compared on the studied outcomes using logistic regression. We performed crude and adjusted analyses (adjusting for relevant confounding factors). MAIN OUTCOME MEASURES: Fertility treatment, twin births, unplanned pregnancies, and women's feelings towards unplanned pregnancies. RESULTS: Relative to women without psychiatric disorders, women with bulimia nervosa had increased odds (odds ratio, OR, 2.3; 95% confidence interval, 95% CI, 1.1-5.2) of having undergone fertility treatment. Women with all eating disorders had increased odds of twin births (anorexia nervosa, OR 2.7, 95% CI 1.0-7.7; bulimia nervosa, OR 2.7, 95% CI 1.1-6.6; anorexia and bulimia nervosa, OR 3.795% CI 1.3-10.7). Anorexia nervosa was associated with increased odds of unplanned pregnancies (OR 1.8, 95% CI 1.2-2.6) and mixed feelings about these pregnancies (adjusted OR 5.0, 95% CI 1.7-14.4). Pre-pregnancy body mass index did not explain the observed associations. CONCLUSIONS: Eating disorders are associated with increased odds of receiving fertility treatment and twin births. Women with anorexia nervosa were more likely to have an unplanned pregnancy and have mixed feelings about the unplanned pregnancy. Fertility treatment specialists should be aware that both active and past eating disorders (both anorexia nervosa and bulimia nervosa) might underlie fertility problems.

Prevalence and correlates of disordered eating in a general population sample: the South East London Community Health (SELCoH) study.

PURPOSE: Disordered eating has been shown to be more prevalent than full eating disorders diagnoses. However, research on its prevalence, socio-demographic, psychological correlates, and patterns of service use in multi-ethnic samples is still limited. This paper explores these associations in a South London-based (UK) sample. METHODS: The South East London Community Health (SELCoH) study is a general population survey (N = 1,698) of individuals aged 16+. Disordered eating was defined as ≥2 positive answers at the SCOFF questionnaire. Crude and adjusted logistic and multinomial logistic regression models were fit to investigate associations between socio-demographic characteristics, disordered eating, psychiatric comorbidity, and service use. RESULTS: A total of 164 (10 %) participants reported disordered eating and the majority were from ethnic minorities. In adjusted models, Asian ethnicity was associated with purging, loss of control eating and preoccupation with food. Individuals with disordered eating had higher odds of screening positive for post-traumatic stress disorder and personality disorders and of having anxiety/mood disorders, suicidal ideation/attempts, hazardous levels of drinking, and used drugs in the previous year. Only 36 % of individuals with disordered eating had sought professional help in the previous 12 months mostly through their general practitioner (27.4 %), followed by psychotherapists (12.8 %) and mental health specialists (5.5 %). CONCLUSION: This study found a high prevalence of disordered eating, especially amongst ethnic minorities, and associations with a number of psychiatric conditions. Overall few participants accessed specialist services. These findings suggest that both disordered eating manifestations amongst ethnic minorities and access to care need better investigation.

The neuropsychological profile of children at high risk of developing an eating disorder.

BACKGROUND: There is a large body of evidence indicating that eating disorders (EDs) are characterized by particular neuropsychological profiles. We aimed to further explore whether impairments in neuropsychological functioning previously found in ED groups are present prior to onset, or are secondary to the disorder. Method This is the first study to explore neuropsychological functioning in children born to a mother with a lifetime ED, who are therefore at high risk of developing an ED, in a large cohort sample. We investigated intelligence and attention at age 8 years (n = 6201) and working memory (WM) and inhibition at age 10 years (6192) in children who are at high risk of developing an ED, compared to children who are not. RESULTS: The children of women with lifetime anorexia nervosa (AN) showed high full-scale and performance IQ, increased WM capacity, better visuo-spatial functioning, and decreased attentional control. The children of women with lifetime bulimia nervosa (BN) showed comparatively poor visuo-spatial functioning. CONCLUSIONS: Our findings suggest that high intelligence, increased WM capacity and impaired attentional control might be intermediate phenotypes on the pathway between genetic vulnerability and the development of an ED.

Perinatal outcomes and gestational weight gain in women with eating disorders: a population-based cohort study.

OBJECTIVE: To investigate adverse perinatal outcomes and gestational weight gain trajectories in women with lifetime (current/past) eating disorders (ED: anorexia nervosa [AN] and bulimia nervosa [BN]). DESIGN: A longitudinal population-based birth cohort. SETTING: Rotterdam, the Netherlands. SAMPLE: Women who enrolled prenatally, had complete information on exposure (lifetime ED), and gave birth to a live singleton (n = 5256). Four groups of exposed women: lifetime AN (n = 129), lifetime BN (n = 209), lifetime AN + BN (n = 100), other lifetime psychiatric disorder (n = 1002) were compared with unexposed women (n = 3816). METHODS: Perinatal outcomes and gestational weight gain were obtained from obstetric and midwifery records, self-report and objective measurements. Exposed women were compared with unexposed women within the cohort using linear, logistic regression and mixed models. MAIN OUTCOME MEASURES: Any pregnancy, delivery and postnatal complications. Birthweight adjusted for gestational age, prematurity (born <37 weeks), small-for-gestational age; maternal weight gain during pregnancy. RESULTS: Maternal AN was positively associated with suspected fetal distress. No differences were found in mean birthweight, prevalence of a small-for-gestational-age, or premature birth. Relative to unexposed women, women with AN had, on average, a lower body weight but a higher rate of weight gain subsequently; whereas women with BN had a higher body weight but a lower rate of weight gain. CONCLUSIONS: Maternal lifetime ED is associated with few adverse perinatal outcomes in this sample. Differential gestational weight gain patterns in women with AN and BN are consistent with possible biological compensatory mechanisms aimed at protecting the fetus.

Is childhood OCD a risk factor for eating disorders later in life? A longitudinal study.

BACKGROUND: It has been suggested that childhood obsessive-compulsive disorder (OCD) may be a risk factor for the development of an eating disorder (ED) later in life, but prospective studies are lacking. We aimed to determine the prevalence of ED at follow-up and clinical predictors in a longitudinal clinical sample of adolescents/young adults diagnosed with OCD in childhood. METHOD: All contactable (n=231) young people with OCD assessed over 9 years at a national and specialist paediatric OCD clinic were included in this study. At follow-up, 126 (57%) young people and parents completed the ED section of the Developmental and Well-being Assessment. Predictors for ED were investigated using logistic regression. RESULTS: In total, 16 participants (12.7%) had a diagnosis of ED at follow-up. Having an ED was associated with female gender and persistent OCD at follow-up. There was a trend for family history of ED being predictive of ED diagnosis. Five (30%) of those who developed an ED at follow-up had ED symptoms or food-related obsessions/compulsions at baseline. A difference in predictors for an ED versus other anxiety disorders at follow-up was identified. CONCLUSIONS: This study provides initial evidence that baseline clinical predictors such as female gender and family history of ED might be specific to the later development of ED in the context of childhood OCD. Clinicians should be alert to ED subthreshold symptoms in young girls presenting with OCD. Future longitudinal studies are needed to clarify the relationship between childhood OCD and later ED.

Fertility and prenatal attitudes towards pregnancy in women with eating disorders: results from the Avon Longitudinal Study of Parents and Children.

OBJECTIVE: To study the effects of eating disorders (EDs) on fertility and attitudes to pregnancy. DESIGN: A longitudinal prospective birth cohort. SETTING: Avon area, UK. SAMPLE: A cohort of 14,663 women who enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC). Singleton and live births were included across four groups of women: lifetime anorexia nervosa (AN; n = 171); lifetime bulimia nervosa (BN; n = 199), lifetime anorexia nervosa and bulimia nervosa (AN + BN; n = 82); and the general population (n = 10,636). METHODS: Fertility problems, conception time and attitudes to pregnancy were investigated in women with AN, BN and AN + BN, compared with the remaining sample (general population). MAIN OUTCOME MEASURES: Having seen a doctor for fertility problems, time taken to conceive (>12 months, and >6 months), unplanned pregnancies, and attitudes to pregnancy at 12 and 18 weeks of gestation. RESULTS: Women with AN (OR 1.6, 95% CI 1.1-2.5; P < 0.021) and women with AN + BN (OR 1.9, 95% CI 1.1-3.4; P < 0.020) were more likely to have seen a doctor for lifetime fertility problems, and women with AN + BN were also more likely to take longer than 6 months to conceive (OR 1.9, 95% CI 1.0-3.5; P < 0.04), and to have conceived the current pregnancy with fertility treatment. Unplanned pregnancies were more common in the AN group compared with the general population. All ED groups more frequently experienced negative feelings upon discovering their pregnancy, which remained higher in the AN + BN group at 18 weeks of gestation. CONCLUSIONS: Lifetime EDs are associated with fertility problems, unplanned pregnancies and negative attitudes to pregnancy. Health professionals should be aware of EDs when assessing fertility and providing treatment for this.

Long-term outcomes of obsessive-compulsive disorder: follow-up of 142 children and adolescents.

BACKGROUND: Obsessive-compulsive disorder (OCD) often starts in childhood and adolescence and can be a chronic disorder with high persistence rates. There are few prospective long-term follow-up studies. AIMS: To follow up young people with OCD to clarify persistence rates and relevant predictors, presence of other psychiatric disorders, functional impairment, service utilisation and perceived treatment needs. METHOD: All young people with OCD assessed over 9 years at the National and Specialist Paediatric OCD clinic, Maudsley Hospital, London, were included. Sixty-one per cent (142 of 222) of all contactable young people and parents completed computerised diagnostic interviews and questionnaires. RESULTS: We found a persistence rate of OCD of 41%; 40% of participants had a psychiatric diagnosis other than OCD at follow-up. The main predictor for persistent OCD was duration of illness at assessment. High levels of baseline psychopathology predicted other psychiatric disorders at follow-up. Functional impairment and quality of life were mildly to moderately affected. Approximately 50% of participants were still receiving treatment and about 50% felt a need for further treatment. CONCLUSIONS: This study confirms that paediatric OCD can be a chronic condition that persists into adulthood. Early recognition and treatment might prevent chronicity. Important challenges for services are ensuring adequate treatment and a smooth transition from child to adult services.

Perinatal hypothalamic-pituitary-adrenal axis regulation among women with eating disorders and their infants.

BACKGROUND: Psychiatric illness is associated with heightened hypothalamic-pituitary-adrenal (HPA) axis activity during pregnancy which may have long term effects on infant stress regulation. HPA axis regulation has not previously been investigated in women with eating disorders (ED) or their infants during the perinatal period. METHODS: Women were recruited to a prospective longitudinal study in three groups: 1) current or active ED (C-ED=31), 2) past ED (P-ED=29) and healthy control (HC=57). Maternal psychopathology, diurnal cortisol levels, corticotropin-releasing hormone (CRH) and CRH binding protein (CRH-BP) were measured during the third trimester of pregnancy. At eight weeks postpartum infant cortisol was obtained before and after routine immunisations to determine infant hormonal response to a stressful situation. RESULTS: Women with current ED had a significantly lower cortisol decline throughout the day compared to HC, in both adjusted and unadjusted analyses. Lower cortisol decline among women with a current ED were associated with higher levels of psychopathology during pregnancy. Women's cortisol awakening response, CRH and CRH-BP levels did not differ across the three groups. Infants' stress response was also significantly higher among those in the C-ED group, although this effect was attenuated after controlling for confounders. CONCLUSIONS: During pregnancy women with ED have lower cortisol declines, suggestive of blunted diurnal cortisol rhythms. Postnatally, their infants also have a heightened response to stress. This is the first study to identify HPA axis dysfunction in pregnancy in women with ED, and to show an intergenerational effect. Since dysfunctions in HPA activity during childhood may represent a risk factor for psychological and physical health problems later in life, further investigation of the potential long-term implications of these findings is crucial.

Vortexes tune the chirality of graphene oxide and its non-covalent hosts.

Graphene oxide (GO) is one of the most appealing bidimensional materials able to interact non-covalently with achiral molecules and to act as chiral inducers. Vortexes can tune chirality and, consequently transfer a specific handedness to non-covalent host molecules, either when dispersed in water or when deposited on a solid surface.

Kinetic glass transition in a micellar system with short-range attractive interaction

We show that percolation and structural arrest transitions coexist in different regions of the phase diagram of a copolymer-micellar system and relate them to short-range intermicellar attraction. The intermediate scattering function shows a nonergodic transition along a temperature and concentration dependent line. Analyses show a logarithmic time dependence, attributed to a higher-order glass transition singularity predicted by mode-coupling theory, followed by a power law.

Simultaneous spectrophotometric determination in solid phase of aspirin and its impurity salicylic acid in pharmaceutical formulations.

We report the simultaneous determination of aspirin and its hydrolysis product, salicylic acid, in solid phase by fluorescence spectrophotometry. Aspirin is often the most labile component in a combination-type analgesic compound. Therefore, its stability is often the initial concern in any formulation-screening program. Preliminary screening of a large number of potential formulations can be arduous, because most current methods of analysis generally consist of several steps: extractions or column separations followed by UV, colorimetric, or gas-liquid chromatographic assays. The method proposed here is quite suited to large numbers of assays because it is not time consuming, it is straightforward, and it is not subject to interference from the substances present in the pharmaceutical formulations. In addition, the method is nondestructive, not dependent on the sampling procedure, and, above all, quite sensitive.

Variable pH kinetics: an easy determination of pH-rate profile.

The complete pH-rate profile of the hydrolysis reaction of aspirin, requiring many experiments in the past, was obtained by a single variable-parameter kinetic experiment carried out by varying the hydrogen ion concentration. The experiment was carried out spectrophotometrically, reading automatically absorbance, pH, and temperature inside the reaction vessel. The results obtained by the fast processing of the kinetic profile are identical to those obtained under the same conditions but using traditional constant-pH kinetic runs. This method provides the possibility of reducing the amount of time and chemicals usually spent in collecting kinetic data in such mechanistic studies by nearly two orders of magnitude.