Sonographic Evaluation of the Placenta in Fontan Patients: A Case Series.

Due to the advancements in pediatric cardiothoracic surgery and medical management, more individuals with congenital heart disease are reaching reproductive age. It is well established that individuals with Fontan circulation are at an increased risk for maternal and fetal adverse outcomes including maternal cardiovascular complications, hypertensive disorders of pregnancy, preterm birth, and fetal growth restriction. Early onset of poor placental health likely related to chronically elevated central venous pressure/low cardiac output inherited to Fontan circulation may play a role in the development of these outcomes. In this case series, we present second-trimester placental imaging findings and pregnancy outcomes of three individuals with Fontan circulation who delivered at a tertiary center in the Southeastern United States.

Risk Factors for Adverse Maternal Outcomes following Expectantly Managed Preterm Prelabor Rupture of Membranes.

OBJECTIVE: We sought to characterize the incidence and risk factors associated with developing maternal morbidity following preterm prelabor rupture of membranes. STUDY DESIGN: Retrospective case-control study of patients with preterm prelabor rupture of membranes at a single institution from 2013 to 2019 admitted at ≥23 weeks gestational age. The primary outcome was a composite of maternal morbidity which included: death, sepsis, intensive care unit (ICU) admission, acute kidney injury, postpartum dilation and curettage, postpartum hysterectomy, venous thromboembolism, postpartum hemorrhage, postpartum wound complication, postpartum endometritis, pelvic abscess, postpartum pneumonia, readmission, and/or need for blood transfusion were compared with patients without above morbidities. Severe morbidity was defined as: death, ICU admission, venous thromboembolism, acute kidney injury, postpartum hysterectomy, sepsis, and/or transfusion >2 units. Demographics, antenatal, and delivery characteristics were compared between patients with and without maternal morbidity. Bivariate statistics and regression models were used to compare outcomes and calculate adjusted odd ratios. RESULTS: Of 361 included patients, 64 patients (17.7%) experienced maternal morbidity and nine (2.5%) had severe morbidity. Patients who experienced maternal morbidity were significantly (p < 0.05) more likely to be older, have private insurance, have BMI ≥40, have chorioamnionitis at delivery, and undergo cesarean or operative vaginal delivery when compared with patients who did not experience morbidity. After controlling for confounders, cesarean delivery (aOR 2.38, 95% CI[1.30,4.39]), body mass index ≥40 at admission (aOR 2.54, 95% CI[1.12,5.79]), private insurance (aOR 3.08, 95% CI[1.54,6.16]), and tobacco use (aOR 3.43, 95% CI[1.58,7.48]) were associated with increased odds of maternal morbidity. CONCLUSION: In this cohort, maternal morbidity occurred in 17.7% of patients with preterm prelabor rupture of membranes. Private insurance, body mass index ≥40, tobacco use, and cesarean delivery were associated with higher odds of morbidity. These data can be used in counseling and to advocate for smoking cessation. KEY POINTS: · 17.7% of patients with PPROM experienced maternal morbidity.. · BMI ≥40 was associated with higher odds of maternal morbidity.. · Tobacco use and cesarean delivery were associated with higher odds of maternal morbidity..

Experiences of Malawian Mothers During Their Infants' Hospitalization.

BACKGROUND: Hospitalization of a newborn infant is stressful for all mothers. Hospitals in Malawi have limited nursing staff and support, so mothers are the primary care providers for their hospitalized infants. Few studies have explored the experience of these mothers as both care providers and mothers. PURPOSE: The purpose of this study was to explore the experiences of mothers during the hospitalization of the infant. The goal was to increase knowledge of their primary concerns about the hospital stay. METHODS: This was a descriptive qualitative study conducted at Queen Elizabeth Central Hospital in Malawi. Mothers were interviewed prior to their infant's discharge. We used the directed content analysis approach to analyze our data. RESULTS: Twenty mothers of preterm or full-term infants were interviewed. The primary concerns were perinatal experiences, the infant's condition and care including breastfeeding, support from family members, and support and care from healthcare providers. Additionally, mothers of preterm infants were concerned about the burdens of kangaroo mother care. IMPLICATION FOR PRACTICE: In hospitals that provide limited nursing support to mothers and their infants, it is important to identify a support system for the mother and provide mothers with information on infant care. IMPLICATIONS FOR RESEARCH: Future research should identify specific supports and resources in the community and hospital settings that are associated with positive hospital experiences.

The Role of Family Members in Providing Support For Malawian Women With Preterm Infants During Infant Hospitalization.

Purpose: Family support is essential for women with preterm infants during hospitalization. In low-income countries, the additional burden of infant care due to shortages in nursing staff necessitates that family members (guardians) be physically present to care for woman and the infant. The purpose of this study was to explore the types of support that Malawian women of preterm infants need during hospitalization. Methods: This descriptive qualitative study was conducted at a tertiary level hospital in southern Malawi. We recruited 15 women with preterm infants during hospitalization and conducted in-depth interviews. Data was audio-recorded, transcribed, and analyzed using NVivo. Results: The postpartum women participating this study preferred females and members of the maternal side of their family for guardians. Participants' support needs included physical, financial, emotional, and spiritual support. Barriers such as financial constraints and the lack of accommodations for guardians had left the participants without support persons physically present to help them.

Obstetrics and Gynecology Residents Can Accurately Classify Benign Ovarian Tumors Using the International Ovarian Tumor Analysis Rules.

OBJECTIVES: Recognition of benign versus malignant tumors is essential in gynecologic ultrasound (US). The International Ovarian Tumor Analysis (IOTA) rules have been proposed as part of resident US training. The objective of this study was to examine whether they could be accurately used by obstetrics and gynecology residents in Rwanda. METHODS: Patients undergoing explorative laparotomy for adnexal masses at the University Teaching Hospital of Kigali were included. Before the study, a didactic lecture on the IOTA rules for classifying adnexal masses was performed. Preoperative transabdominal US examinations were performed by residents at different levels of training, who were blinded to the results of prior US examinations. The IOTA classification was compared to the final pathologic diagnosis. RESULTS: There were 72 patients who underwent 116 US examinations. Only 15.5% of US examinations were considered inconclusive. First-year residents (12) correctly diagnosed 18 of 20 masses (90%) as benign and 4 of 4 as malignant. Second-year residents (9) classified 29 of 29 masses correctly. Third-year residents (10) accurately identified 21 of 22 (95.5%) as benign and 5 of 5 as malignant. Fourth-year residents (13) accurately identified 11 of 12 (91.7%) as benign and 6 of 6 as malignant. Therefore, 74 of 78 tumors (94.9%) considered benign by IOTA rules were confirmed by histologic results. Similarly, all 20 tumors classified as malignant were confirmed. Overall, the sensitivities to diagnose benign and malignant tumors by the IOTA rules were 83.3% and 100%, respectively. The positive and negative predictive values were 100% and 94.9%. There were no significant differences noted between residency years. CONCLUSIONS: All levels of Rwandan obstetrics and gynecology residents were able to use the IOTA rules to accurately distinguish benign from malignant tumors.

An Observational Study on Early Dyadic Interactive Behaviors of Mothers With Early-Preterm, Late-Preterm, and Full-Term Infants in Malawi.

BACKGROUND: Mother-infant interactions are necessary for infant growth and development. However, preterm birth is associated with less positive mother-infant interactions than full-term birth. Malawi has the highest preterm birth rate in the world, but studies of the mother-infant relationship in Malawi are limited and studies that observed mother-infant interactions could not be located. PURPOSE: This study explored mother-infant interactions among Malawian mothers of early-preterm, late-preterm, and full-term infants. METHODS: This observational study explored maternal and infant interactive behaviors. We recruited 83 mother-infant dyads (27 early-preterm, 29 late-preterm, and 27 full-term dyads). FINDINGS: Mothers of early-preterm infants looked at and rocked their infants less, and their infants looked at their mothers less, than mothers of either late-preterm infants or full-term infants. The infants in all groups were asleep most of the time, which contributed to low levels of interactive behaviors. Factors that were related to infant behaviors included marital status, maternal occupation, maternal education, infant medical complications, infant gender, history of neonatal deaths, and multiple births. IMPLICATIONS FOR PRACTICE: Our findings provide evidence about the need to encourage mothers to engage interactive behaviors with their infants. IMPLICATIONS FOR RESEARCH: Future studies of factors that contribute to positive interactions in Malawi are needed.

Emotional distress in mothers of early-preterm infants, late-preterm infants, and full-term infants in Malawi.

BACKGROUND: Mothers of preterm infants, early or late, report more distress than mothers of full-term infants. Malawi has the highest preterm birth rate in the world, but nothing is known about the relation of preterm birth to maternal mental health. PURPOSE: To compare emotional distress among mothers of early-preterm, late-preterm, and full-term infants. METHODS: We recruited 28 mothers of early-preterm, 29 mothers of late-preterm, and 28 mothers of full-term infants. Emotional distress was assessed 24-72 hr following birth. One-way ANOVA and regression analysis were used to compare the three groups. FINDINGS: Mothers of early-preterm infants reported more distress symptoms than mothers of full-term infants, and scores of mothers of late-preterm infants fell between the other two groups. Having a support person present was associated with lower symptoms and caesarean birth was associated with more symptoms. DISCUSSION: Promoting maternal mental health is important following preterm birth and health care providers need to support mothers.

Addressing Maternal Deaths in North Carolina: Striving to Reach Zero.

Maternal mortality in North Carolina remains a challenge to families, health systems, and communities. The Maternal Mortality Review Committee is part of the process required to prevent these events. In this commentary, we present an abbreviated description of the 2014-2015 Maternal Mortality Review Committee report, set for publication in December, 2019.

Using fetal scalp stimulation with Doppler ultrasonography to enhance intermittent auscultation in low-resource settings: a diagnostic trial from Tanzania.

BACKGROUND: Hypoxia during labor contributes to 2.2 million intrapartum and early neonatal deaths each year. An additional 0.6-1.0 million cases of life-long disability occur because of fetal hypoxia during labor. It is known that fetal heart rate changes in labor correspond to hypoxia and neurologic compromise, but a reliable, low-cost method for detecting these changes is not available. In this study we sought to compare the ability of a handheld Doppler device to detect accelerations as part of the fetal scalp stimulation test and to compare the diagnostic performance of routine intermittent auscultation with auscultation that is augmented with fetal scalp stimulation. METHODS: This non-randomized, pre- and post-diagnostic trial was conducted with 568 maternal-fetus pairs at Kilimanjaro Christian Medical Center in Moshi, Tanzania. The first objective was to determine whether a handheld Doppler device could detect fetal accelerations in labor with reasonable accuracy as compared with a cardiotocography machine. We performed the fetal scalp stimulation test on 50 fetuses during labor using both a handheld Doppler and a cardiotocography machine and compared the outcomes for correlation using the kappa correlation coefficient. During the second objective, two groups of laboring women were monitored either with intermittent auscultation alone per routine protocol (N = 251) or with intermittent auscultation augmented with fetal scalp stimulation per study protocol(N = 267). Diagnostic accuracy of the monitoring method was determined by comparing umbilical cord blood gases immediately after birth with the predicted state of the baby based on monitoring. The analyses included sensitivity, specificity, and positive and negative predictive values. RESULTS: The prevalence of fetal acidemia ranged from 15 to 20%. Adding the fetal scalp stimulation test to intermittent auscultation protocols improved the performance of intermittent auscultation for detecting severe acidemia (pH < 7.0) from 27 to 70% (p = 0.032). The negative predictive value of intermittent auscultation augmented with the fetal scalp stimulation test ranged from 88 to 99% for mild (pH < 7.2) to severe fetal acidemia. CONCLUSIONS: The fetal scalp stimulation test, conducted with a handheld Doppler, is feasible and accurate in a limited resource setting. It is a low-cost solution that merits further evaluation to reduce intrapartum stillbirth and neonatal death in low-income countries. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT02862925 ).

Maternal near miss and mortality due to postpartum infection: a cross-sectional analysis from Rwanda.

BACKGROUND: The objective of this study is to evaluate 'near miss' and mortality in women with postpartum infections. METHODS: We performed a retrospective review of all patients referred to the University Teaching Hospital of Kigali (CHUK) between January 2012 and December 2013. We identified 117 patients with postpartum infections. Demographic data, length of admission, location of referral, initial surgery and subsequent treatment modalities including antibiotic administration and secondary surgery were recorded. The primary outcome of interest was a composite of maternal mortality and "near miss" defined as more than one laparotomy with/without hysterectomy and prolonged hospitalization. RESULTS: Diagnoses at CHUK were: pelvic peritonitis (56 %), deep surgical site infection including fasciitis (17 %), and endometritis (15 %). The primary procedures performed prior to transfer were: cesarean section (81 %), septic abortion management (12 %), and vaginal delivery (7 %). Antibiotics were initiated prior to transfer in 66 % of women. Surgery was required in 73 % of patients. Hysterectomies were performed in 22 % of patients. Maternal death occurred in 5 % of the patient population. The primary outcome of severe maternal morbidity and mortality occurred in 90 patients (77 %). CONCLUSION: Peritonitis-primarily as a result of cesarean deliveries-is associated with significant morbidity and mortality in our population.

Comparison of the Trends in Risk Factors and Management of Severe Postpartum Hemorrhage Years 2000-2004 Versus 2005-2008.

OBJECTIVE: To compare trends in the etiology and management of severe postpartum hemorrhage (PPH) during 2 time periods: 2000-2004 (Period 1) versus 2005-2008 (Period 2). STUDY DESIGN: Medical records with a diagnosis of PPH were identified by ICD-9 codes for immediate, third-stage, delayed, and secondary. PPH and post- partum coagulation defect. Subjects having a PPH within 24 hours of delivery who also received blood component therapy (defined as severe PPH) during Period 1 were compared with those from Period 2. RESULTS: There were 109 and 119 cases identified from Periods 1 and 2, respectively. Uterine atony was the most common cause of severe PPH during both time periods. In the second time period women with severe PPH had a lower mean hematocrit (p<0.05), a greater mean BMI (p<0.05), and more induced labor (p<0.01) as compared to the first time period. A greater proportion of the women in the second time period received misoprostol (p<0.0001) and platelets (p<0.05). The proportions of other therapies and surgical interventions remained unchanged, as did the ultimate outcomes. CONCLUSION: At a single large institution over the course of a 9-year period the management of severe PPH changed to include a greater utilization of misoprostol and platelet therapy.

Bone turnover markers and pharmacokinetics of a new sustained-release formulation of the cathepsin K inhibitor, ONO-5334, in healthy post-menopausal women.

A sustained-release tablet (SRT) of ONO-5334 was compared to the immediate-release tablet (IRT) dose, which demonstrated effects on bone mineral density (BMD) comparable to those of therapy with alendronate. The single-dose phase was a randomized, partial single-blind, crossover study where 50-, 100-, and 300-mg SRTs and 300-mg IRTs were administered to nine post-menopausal women. The multiple-dose phase was a randomized, double-blind, placebo-controlled, parallel-group study where 100- and 300-mg SRTs, or placebo were administered to 24 women. After a single administration of a 300-mg SRT, mean C max was 3.3-fold lower, mean AUCinf was 0.83-fold lower and mean C 24h was 5.4-fold higher compared to the 300-mg IRT. Repeated SRT dosing did not significantly affect PK, although C 24h increased slightly. After a single ONO-5334 dose, serum CTX-I was suppressed by ~50 % within 1 h, reaching maximum suppression 6 h post-dose. Greater suppression was maintained longer by the 300-mg SRT vs. the 300-mg IRT. Second morning void and cumulative urine CTX-I showed clear dose-response effects at/over 24 h for SRT, with maximum suppression occurring at/over 24 h (except 50- and 300-mg cumulative urine). Repeated dosing suggested greater suppression of urine CTX-I. Compared with the IRT, the SRT showed reduced C max, greater C 24h, and slightly reduced AUCinf dose for dose. The SRT showed clear dose-response suppression on bone resorption and greater efficacy dose for dose vs. the IRT.

Maternal near miss and mortality in a tertiary care hospital in Rwanda.

BACKGROUND: To determine the prevalence and factors associated with severe ('near miss') maternal morbidity and mortality in the University Teaching Hospital of Kigali-Rwanda. METHODS: We performed a cross sectional study of all women admitted to the tertiary care University Hospital in Kigali with severe "near miss" maternal morbidity and mortality during a one year period using the WHO criteria for 'near miss' maternal mortality. We assessed maternal demographic characteristics and disease processes associated with severe obstetric morbidity and mortality. RESULTS: The prevalence of severe maternal outcomes was 11 per 1000 live births. The maternal near miss ratio was 8 per 1000 live births. The majority of severe obstetric morbidity and mortalities resulted from: sepsis/peritonitis (30.2%)--primarily following caesarean deliveries, hypertensive disease (28.6%), and hemorrhage (19.3%). Majority of our patients were found to be of lower socioeconomic status, refered from district hospitals to the tertiary care center, and resided in the eastern part of the country. CONCLUSION: The main causes associated with MNH were peritonitis, hypertensive disorders and bleeding. The high prevalence of peritonitis may reflect suboptimal intraoperative and intrapartum management of high-risk patients at district hospitals. Direct causes of severe maternal outcome are still the most prevalent. The study identified opportunities for improvement in clinical care to reduce potentially these adverse outcomes.

Social capital and hypertension in rural Haitian women.

Hypertension is a major global public health risk and significant precursor to cardiovascular disease, stroke, diabetes and maternal mortality. A possible strategy to reduce chronic disease in resource-poor areas is social intervention. Research into the possible relationship of social determinants and disease is needed to determine appropriate social interventions. This study aims to determine the association between social capital and hypertension in rural Haitian women. From June to August 2005, 306 women, ages 18-49, who attended one of Hôpital Albert Schweitzer's five rural dispensaries as patients or accompanying patients, were interviewed. Individual interviews on social capital, demographics and anthropometrics were conducted. SAS statistical package was used to analyze the data. Groups/networks, personal empowerment, collective action/cooperation and trust components significantly decreased the likelihood of hypertension in multivariate analysis. In an additive model, the ranked index of social capital indicated that each social capital component score above the conceptual midpoint showed a 41 % reduction in the likelihood of hypertension. The findings suggest that interventions aimed to increase components of social capital may significantly lower hypertension.

Predictors of failed trial of labor among women with an extremely obese body mass index.

OBJECTIVE: The purpose of this study was to examine predictors associated with cesarean delivery (CD) among extremely obese women undergoing a trial of labor (TOL). STUDY DESIGN: Using a delivery database, we identified all pregnant women delivering at our institution from Jan. 1, 2008, through July 31, 2010, weighing >275 lb at the time of delivery who attempted a TOL with a singleton gestation >34 weeks' gestation. Demographic and obstetrical factors were compared for those having a successful vaginal delivery to those having a CD. RESULTS: During the study period, there were 357 pregnant women who weighed >275 lb (all with body mass index [BMI] >40 kg/m(2)), and among these, 248 (69.5%) attempted a TOL. Women having a CD had a greater BMI (51.6 vs 49.9 kg/m(2), P = .038), were less likely to be parous (32.2% vs 65.8%, P < .0001), and were more likely to be induced (80.5% vs 57.8%) compared to those having a vaginal delivery. Using a multivariable logistic regression model, among nulliparous women, maternal age, parity, and cervical dilation at time of admission were independent predictors for CD. Furthermore, an increase in BMI of 10 kg/m(2) was associated with a 3.5 increased odds (P = .002) for CD. CONCLUSION: Among nulliparous extremely obese women attempting a TOL, BMI was an independent predictor of CD, with the rate of CD increasing further with increasing BMI. The underlying mechanisms for failed TOL in the setting of maternal obesity remain largely unknown.

Evaluating the Association Between Fibrinogen and Rotational Thromboelastometry and the Progression to Severe Obstetric Hemorrhage.

AIM: This study aims to investigate the ability of fibrinogen and rotational thromboelastometry (ROTEM) parameters measured at obstetric hemorrhage protocol initiation to predict severe hemorrhage. METHODS: In this retrospective study we included patients whose hemorrhage was managed with an obstetric massive transfusion protocol. Fibrinogen and ROTEM parameters EXTEM clotting time (CT), clot formation time (CFT), alpha angle, A10, A20, lysis index 30 min after CT (LI30), FIBTEM A10, A20, were measured at initiation of the protocol with transfusion based on a predefined algorithm. Patients were grouped into either severe or nonsevere hemorrhage based on: peripartum fall in hemoglobin ≥4 g/dL, transfusion of ≥4 units of blood product, invasive procedures for hemorrhage control, intensive care unit admission, or death. RESULTS: Of the 155 patients included, 108 (70%) progressed to severe hemorrhage. Fibrinogen, EXTEM alpha angle, A10, A20, FIBTEM A10, A20 were significantly lower in the severe hemorrhage group while the CFT was significantly prolonged in the severe hemorrhage group. In univariate analysis, predicted progression to severe hemorrhage yielded areas under the receiver operating characteristic curve (95% confidence interval [CI]) of: fibrinogen: 0.683 (0.591-0.776), CFT: 0.671 (0.553, 0.789), EXTEM alpha angle: 0.690 (0.577-0.803), A10: 0.693 (0.570-0.815), A20: 0.678 (0.563-0.793), FIBTEM A10: 0.726 (0.605-0.847), and A20: 0.709 (0.594-0.824). In a multivariable model, fibrinogen was independently associated with severe hemorrhage (odds ratio [95% CI] = 1.037 [1.009-1.066]) for every 50 mg/dL decrease in fibrinogen drawn at obstetric hemorrhage massive transfusion protocol initiation. CONCLUSION: Both fibrinogen and ROTEM parameters measured at the initiation of an obstetric hemorrhage protocol are useful parameters for predicting severe hemorrhage.

Serum and urine bone resorption markers and pharmacokinetics of the cathepsin K inhibitor ONO-5334 after ascending single doses in post menopausal women.

AIMS: To investigate the safety, pharmacokinetics and pharmacodynamics of the new cathepsin K inhibitor, ONO-5334. METHODS: A double-blind, placebo-controlled, randomized study was carried out in 52 healthy post menopausal females. Single ascending doses of ONO-5334 (3-600 mg) were evaluated in six cohorts. The effect of food was studied at ONO-5334 100 mg. RESULTS: Across the doses tested, mean ONO-5334 C(max) occurred 0.5-1.0 h after dosing and the the t(1/2) ranged from 9.1 to 22 h. Linear increases in C(max) and AUC(0,∞) were observed in the 3-300 mg and 3-600 mg dose range, respectively. After food, the geometric mean ratio (95% CI) C(max) and AUC(0,∞) for ONO-5334 were 0.78 (0.31, 1.94) and 0.95 (0.67, 1.35)-fold greater than fasted, respectively. ONO-5334 significantly reduced serum bone resorption markers within 4 h vs. placebo. Statistical significance was achieved for ONO-5334 doses ≥30 mg for C-terminal telopeptide of type 1 collagen (CTX) and ≥300 mg for N-terminal telopeptide of type 1 collagen (NTX). Statistical significance was still evident at 24 h for ONO-5334 100 mg with serum CTX and 600 mg with serum NTX. The maximum suppression in serum CTX occurred at 4 h post dose with difference compared with placebo of -32%, -59%, -60% and -66% for 30, 100, 300 and 600 mg ONO-5334, respectively. Second morning urine void 24 h post dose showed statistically significant suppression of urinary CTX and NTX at 100 mg and above vs. placebo. ONO-5334 600 mg showed statistically significant suppression up to 72 h for serum CTX, urinary CTX and urinary NTX and 48 h for serum NTX vs. placebo. Adverse events were transient with no evidence of dose relationship. CONCLUSIONS: ONO-5334 displayed linear plasma pharmacokinetics over the (predicted therapeutic) dose range, 3-300 mg, with clear suppression of urinary bone resorption markers at doses ≥100 mg for serum markers at 24 h. ONO-5334 was well tolerated up to 600 mg day(-1) when administered to healthy post menopausal women.

Unmet health needs identified by Haitian women as priorities for attention: a qualitative study.

This 2009 qualitative study investigated Haitian women's most pressing health needs, barriers to meeting those needs and proposed solutions, and how they thought the community and outside organizations should be involved in addressing their needs. The impetus for the study was to get community input into the development of a Family Health Centre in Leogane, Haiti. Individual interviews and focus group discussions were conducted with 52 adult women in six communities surrounding Leogane. The most pressing health needs named by the women were accessible, available and affordable health care, potable water, enough food to eat, improved economy, employment, sanitation and education, including health education. Institutional corruption, lack of infrastructure and social organization, the cost of health care, distance from services and lack of transport as barriers to care were also important themes. The involvement of foreign organizations and local community groups, including grassroots women's groups who would work in the best interests of other women, were identified as the most effective solutions. Organizations seeking to improve women's health care in Haiti should develop services and interventions that prioritize community partnership and leadership, foster partnerships with government, and focus on public health needs.

Dissolution parameters reveal role of structure and solvent in molecular gelation.

The relationship between thermodynamic dissolution parameters (enthalpy and entropy) and gelation ability was examined for two different classes of compounds in three different solvent systems. In total, 11 dipeptides and 19 pyridines were synthesized and screened for gelation in aqueous and organic solvents, respectively. The dissolution parameters were determined from the variable-temperature solubilities using the van't Hoff equation. These studies revealed that the majority of gelators had higher dissolution enthalpies and entropies compared to nongelators, consistent with the notion that gelators have stronger intermolecular interactions and more order in the solid state. The dissolution parameters were also found to be solvent-dependent, suggesting that solvent-solute interactions are also important in gelation. Overall, these results indicate that converting nongelators into gelators is attainable when structural modifications or a change in solvent lead to increases in the dissolution parameters.