Clinical Pharmacology

Solanum melongena L. Extract Promotes Intestinal Tight Junction Re-Assembly via SIRT-1-Dependent Mechanisms

Tight junction disruption can lead to pathogenesis of various diseases without therapeutic strategy to recover intestinal barrier integrity. The main objective of this study is to demonstrate the effect of Solanum melongena L. extract (SMLE) on intestinal tight junction recovery and its underlying mechanism. Intestinal barrier function is attenuated by Ca2+ depletion. SMLE treatment increased TER value across T84 cell monolayers. Permeability assay reveals that Ca2+ depletion promotes 4-kDa FITC-dextran permeability, but not 70-kDa FITC-dextran. SMLE suppresses the rate of 4-kDa FITC-dextran permeability, indicating that SMLE inhibits paracellular leak pathway permeability. SMLE-mediated TER increase and leak pathway suppression are abolished by neither calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ) inhibitor nor AMP-activated protein kinase (AMPK) inhibitor. Furthermore, mammalian target of rapamycin (mTOR) and extracellular signal-regulated kinase (ERK) inhibitors have no effects on SMLE-mediated TER increase and leak pathway suppression. Interestingly, SMLE is unable to enhance TER value and diminish leak pathway permeability in T84 cell monolayers pre-treated with sirtuin-1 (SIRT-1) inhibitor. Immunofluorescence staining reveals that SMLE enhances re-assembly of tight junction proteins, including occludin and ZO-1 to intercellular space but this effect is abolished by SIRT-1 inhibitor. These data suggest that SMLE promotes intestinal tight junction re-assembly via SIRT-1-dependent manner.

Sauropus androgynus (L.) Merr.: a multipurpose plant with multiple uses in traditional ethnic culinary and ethnomedicinal preparations

Various plants form the basis of multiple traditional ethnic cuisines and ethnomedicinal practices across the globe. The ethnic cuisines cater to the nutritional, dietary and medicinal requirements of the tribal and rural communities even today. Using literature from various scholarly databases, this study was conducted to consolidate a comprehensive review on the use of Sauropus androgynus (L.) Merr. in various traditional ethnic cuisines and ethnomedicinal preparations across the globe. The survey shows that it is used in multiple ethnic cuisines and is variously known in different countries and among the communities. Further, it possesses multiple nutritional and ethnomedicinal properties. Considering its importance in ethnic foods and ethnomedicinal preparations, it is important to investigate the nutritional composition, phytochemical constitution and pharmacological basis of ethnomedicinal uses. Therefore, we further compiled this information and found that it is a rich source of both micro- and macronutrients and packed with several bioactive compounds. Survey of pharmacological studies on its traditional medicinal uses supports its ethnomedicinal properties. Despite its importance in traditional food and ethnomedicinal systems, it remains underexplored. Limited information on the toxicity of its various extracts shows that further studies should be conducted to understand its safety aspects. Further clinical studies to prospect possible drug candidates from it should be attempted.

Evaluation of subacute toxicity and herb-drug interaction potential of an herbal Arishta formulation

Background Arishta technology is an age-old heritage and uses herbal decoctions to prepare self-generated alcoholic medicines. In Ayurveda, Arishta preparations are widely used as a remedy for metabolic disorders. However, their safety and influence on herb metabolism pathways were not yet explored. Aim: To study the subacute toxicity of a polyherbal Arishta formulation (coded as DB-07) in rats and to evaluate its potential for inhibition of the drug-metabolizing enzyme (Cytochrome P450 3A4). Methodology Experimentally naive rats were treated with graded oral doses of DB-07 (10 and 20 mL/kg/day) for 28 days. During the course of the experiment, all the animals were closely observed for apparent behavioural abnormalities and mortalities. Tissue histology was performed to assess any sign of toxicity. In addition, in vitro CYP3A4 inhibition assay was performed to study the effect on drug metabolism pathways. Results Animals did not show any change in body weight, organ toxicity and food consumption throughout the dosing period of 28 days. Pathophysiological, behavioural status and locomotor activity were not altered. DB-07 did not inhibit CYP3A4 enzyme and drug metabolism pathway in-vitro. Gallic acid and quercetin were identified as phytomarker from the formulation that may be responsible for its activity related safety issue. Conclusion These results indicate that use of DB-07 may be safe with no sign of toxicity for up to 28 days in rats. Further, CYP3A4 inhibition assay indicated that DB-07 is less likely to have herb-drug interactions when concomitantly administered with CYP3A4 inhibitors or inducer.

Safety assessment of Oryeong-san, a traditional herbal formula: Study of subacute toxicity and influence of cytochrome P450s and UDP-glucuronosyltransferases

Oryeong-san is a traditional herbal formula that is used for the treatment of common genitourinary diseases in Korea and other Asian countries. However, little is known about its safety and influence on drug metabolism. In the present study, we investigated the subacute toxicity of an Oryeong-san water extract (OSWE) in rats and its effects on activities of drug-metabolizing enzymes. Subacute toxicity was modeled in animals exposed to treatment with the extract at multiple doses. Rats were given OSWE by oral gavage at 0, 1000, 2000 and 5000 mg/kg/day for 4 weeks. We checked general observations and investigated any changes of body/organ weight, food consumption, hematology, serum biochemistry, and urinalysis in vivo; and the activities of human microsomal cytochrome P450s (CYP450s) and UDP-glucuronosyltransferase (UGT) isozymes in vitro. We found that OSWE caused no significant toxicological changes at the doses tested. Therefore, the no observed adverse effect level of OSWE was more than 5000 mg/kg/day for male and female rats. OSWE inhibited the activities of CYP2C19 (IC₅₀: 737.69 μg/mL) and CYP2E1 (IC₅₀: 177.77 μg/mL). These results indicate that OSWE may be safe with no drug-related toxicity for up to 4 weeks and provide useful information concerning its potential to interact with conventional drugs or other herbal medicines.

Adverse Drug Reactions in Patients Receiving Systemic Antifungal Therapy at a High-Complexity Hospital

The aim of the present study was to determine the frequency of adverse drug reactions (ADRs) associated with the use of systemic antifungal drugs in patients hospitalized at a high-complexity hospital. In addition, factors associated with ADRs were investigated. This cross-sectional retrospective study involved the investigation of 183 medical records of patients receiving systemic antifungal therapy. Antifungal drugs were classified using the fourth level of the Anatomical Therapeutic Chemical System. ADR causality was classified using the Naranjo algorithm. Drug interactions were assessed using DRUG-REAX software. Data were analyzed with descriptive statistics and univariate and multivariate logistic regression. A total of 53 patients (29.0%) had at least 1 ADR involving antifungals. Ninety-six ADRs were detected. The main ADRs observed were an infusion reaction in 24 patients (25.0%), hypokalemia in 22 (22.9%), nephrotoxicity in 18 (18.7%), and hepatotoxicity in 15 (15.6%). Amphotericin B and voriconazole were associated with ADRs of major clinical impact. Eleven of the ADRs (11.4%) were related to drug interactions. The following 3 factors were contributors to the multivariate model for the occurrence of ADRs caused by antifungal drug use: neoplasm diagnosis (odds ratio [OR], 3.9; 1.9-7.9), length of hospital stay (OR, 2.2; 1.1-4.5), and the use of ≥13 drugs (OR, 3.4; 1.6-7.2). Our study revealed positive associations between the occurrence of ADRs and diagnosis of a neoplasm, the length of stay, and the use of multiple drugs concomitant with antifungals. These risk factors should be considered in antifungal stewardship, among other actions, to promote the rational use of antifungal agents.

Special population considerations and regulatory affairs for clinical research

Special populations, including women (non-pregnant and pregnant), pediatrics, and the elderly, require additional consideration with regard to clinical research. There are very specific regulatory laws, which protect these special populations, that need to be understood and adhered to in order to perform clinical research. This review provides a broad overview of some of the physiological differences in special populations and discusses how these differences may affect study design and regulatory considerations. These various special populations, with respect to regulatory affairs, are clearly defined within the Code of Federal Regulations. The definition of "special population" exists to provide enhanced awareness of their vulnerabilities, thereby allowing the creation of regulatory guidance aimed to decrease injury or outright harm. Currently, progress is being made to be more inclusive of special populations in clinical trials. This reflects changing attitudes towards drug information, with it being more representative of those patients that will ultimately be prescribed or exposed to the therapy. However, all research undertaken in these populations should be performed in a manner that ensures all protections of each participant are upheld.

Computer aided identification of sodium channel blockers in the clinical treatment of epilepsy using molecular docking tools

Phenytoin (PHT) and Carbamazepine (CBZ) are excellent sodium channel blockers administered in clinical treatment of epileptic seizures. However, the narrow therapeutic range and limited pharmacokinetics of these drugs have raised serious concerns in the proper management of epilepsy. To overcome this, the present study attempts to identify a candidate molecule with superior pharmacological profile than PHT and CBZ through In silico approaches. PHT and CBZ served as query small molecules for Tanimoto based similarity search with a threshold of 95% against PubChem database. Aided by MolDock algorithm, high affinity similar compound against each query was retrieved. PHT and CBZ and their respective similar were further tested for toxicity profiles, LC 50 values and biological activity. Compounds, NSC403438 and AGN-PC-0BPCBP respectively similar to PHT and CBZ demonstrated higher affinity to sodium channel protein than their respective leads. Of particular relevance, NSC403438 demonstrated highest binding affinity bestowed with least toxicity, better LC 50 values and optimal bioactivity. NSC403438 was further mapped for its structure based pharmacophoric features. In the study, we report NSC403438 as potential sodium channel blocker as a better candidate than PHT and CBZ which can be put forth for pharmacodynamic and pharmacokinetic studies.

ABBREVIATIONS

AEDs - Antiepileptic drugs, BLAST - Basic Local Alignment Search Tool, CBZ - Carbamazepine, GEFS+ - Generalized Epilepsy with Febrile Seizures Plus, GPCR - G Protein Coupled Receptor, Nav - Sodium channel with specific voltage conduction, PDB - Protein Data Bank, PHT - Phenytoin, PIR - Protein Information resources, SAVES - Structural Analysis and Verification Server, VGSC - Voltage-gated Sodium channels.

Pharmacokinetics of orally administered duloxetine in children and adolescents with major depressive disorder

BACKGROUND

Duloxetine, a selective serotonin (5-hydroxytryptamine) and norepinephrine reuptake inhibitor, has been approved since 2004 for the treatment of adults with major depressive disorder (MDD). It is currently not approved for use in pediatric patients (aged <18 years) with MDD. The clinical development program for duloxetine in the pediatric MDD population, which consisted of three clinical studies, provided extensive data on the safety, tolerability, and pharmacokinetics of duloxetine across a wide dose range in pediatric patients of differing ages, sex, body weights, and sexual maturation.

OBJECTIVES

The objectives were to characterize the pharmacokinetics of duloxetine based on population modeling following daily oral administration in children and adolescents aged 7-17 years diagnosed with MDD; to estimate the magnitude of between- and within-patient variability; to identify potential patient factors affecting duloxetine pharmacokinetics, and to compare duloxetine pharmacokinetics in the pediatric population with those characterized in adults.

METHODS

The analyses meta-dataset was created from pharmacokinetic and demographic data available from one phase II (open-label) and two phase III (randomized, double-blind) clinical trials of duloxetine in children and adolescents. Patients received 20-120 mg of oral duloxetine once daily. Duloxetine concentrations (a total of 1,581 concentrations) were obtained from 428 patients: 34% were children (aged 7-11 years) and 66% were adolescents (aged 12-18 years). Population modeling analyses were performed using nonlinear mixed-effects modeling and the first-order conditional estimation method with interaction. Patient factors were assessed for their potential influence on duloxetine apparent clearance (CL/F) and apparent volume of distribution (V d/F). Duloxetine pharmacokinetic parameters and model-predicted duloxetine concentrations at steady state in the pediatric population were compared with those in adults.

RESULTS

Duloxetine pharmacokinetics in pediatric patients was described by a one-compartmental model. Typical values of CL/F, V d/F, and half-life (t 1/2) at 60 mg/day of duloxetine were 79.7 L/h, 1,200 L, and 10.4 h, respectively. The between-patient variability in CL/F and V d/F was 68 and 87%, respectively, while within-patient variability was 57% (proportional error) and 2.04 ng/mL (additive error). Body surface area (BSA), dose, and race had a statistically significant effect on duloxetine pharmacokinetics. With a 2.2-fold increase in BSA, the CL/F increased about twofold. A sixfold increase in dose (20 to 120 mg) decreased CL/F by 32%. In American Indian patients, V d/F was 131% higher than the other races combined. Age, sex, body mass index, serum creatinine, cytochrome P450 2D6 predicted phenotype, and menarche status did not have a statistically significant effect. Estimates of CL/F and V d/F were higher in the pediatric population than in adults; subsequently, the average steady-state duloxetine concentration was approximately 30% lower in the pediatric population than in adults.

CONCLUSIONS

Duloxetine pharmacokinetics was similar in children and adolescents with MDD. The statistically significant effects of dose, BSA, and race on duloxetine pharmacokinetics in pediatric patients did not appear to be clinically meaningful. At a given dose, the typical steady-state duloxetine concentrations in the pediatric population were lower than in adults, and the distribution of steady-state duloxetine concentrations in pediatric patients were typically in the lower range of concentrations in adults.

Detection of pharmacovigilance-related adverse events using electronic health records and automated methods

Electronic health records (EHRs) are an important source of data for detection of adverse drug reactions (ADRs). However, adverse events are frequently due not to medications but to the patients' underlying conditions. Mining to detect ADRs from EHR data must account for confounders. We developed an automated method using natural-language processing (NLP) and a knowledge source to differentiate cases in which the patient's disease is responsible for the event rather than a drug. Our method was applied to 199,920 hospitalization records, concentrating on two serious ADRs: rhabdomyolysis (n = 687) and agranulocytosis (n = 772). Our method automatically identified 75% of the cases, those with disease etiology. The sensitivity and specificity were 93.8% (confidence interval: 88.9-96.7%) and 91.8% (confidence interval: 84.0-96.2%), respectively. The method resulted in considerable saving of time: for every 1 h spent in development, there was a saving of at least 20 h in manual review. The review of the remaining 25% of the cases therefore became more feasible, allowing us to identify the medications that had caused the ADRs.

An open-label safety and pharmacokinetics study of duloxetine in pediatric patients with major depression

OBJECTIVE

This preliminary, 32-week study assessed the safety, tolerability, and pharmacokinetics of duloxetine in pediatric patients (aged 7-17 years) with major depressive disorder.

METHODS

Patients received flexible duloxetine doses of 20-120 mg once daily, with dose changes made based on clinical improvement and tolerability. Pharmacokinetic samples were collected across all duloxetine doses, and data were analyzed using population modeling. Primary outcome measures included treatment-emergent adverse events (TEAEs), vital signs, and Columbia-Suicide Severity Rating Scale (C-SSRS).

RESULTS

Of the 72 enrolled patients, 48 (66.7%) completed acute treatment (18 weeks) and 42 (58.3%) completed extended treatment. Most patients (55/72; 76%) required doses ≥ 60 mg once daily to optimize efficacy based on investigator judgment and Clinical Global Impressions-Severity score. Body weight and age did not significantly affect duloxetine pharmacokinetic parameters. Typical duloxetine clearance in pediatric patients was ≈ 42%-60% higher than that in adults. Four patients (5.6%) discontinued due to TEAEs. Many (36/72, 50%) patients experienced potentially clinically significant (PCS) elevations in blood pressure, with most cases (21/36, 58%) being transient. As assessed via C-SSRS, one nonfatal suicidal attempt occurred, two patients (2.8%) experienced worsening of suicidal ideation, and among the 19 patients reporting suicidal ideation at baseline, 17 (90%) reported improvement in suicidal ideation.

CONCLUSION

Results suggested that pediatric patients generally tolerated duloxetine doses of 30 to 120 mg once daily, although transient PCS elevations in blood pressure were observed in many patients. Pharmacokinetic results suggested that adjustment of total daily dose based on body weight or age is not warranted for pediatric patients and different total daily doses may not be warranted for pediatric patients relative to adults.

The value of population pharmacokinetics and simulation for postmarketing safety evaluation of dosing guidelines for drugs with a narrow therapeutic index: buflomedil as a case study

Population pharmacokinetics and simulation techniques currently play an important role in new drug development. This paper illustrates the potential value of those methods in postmarketing safety assessment, using buflomedil in elderly patients as an example. We retrospectively assessed the risk of buflomedil overdosing associated with the latest dosing recommendations of the French Drug Agency (AFSSAPS). First, buflomedil concentrations measured in 24 elderly patients were analysed with a nonparametric population approach. Then, the pharmacokinetic model was used to perform a 1000-patient Monte Carlo simulation for the two recommended buflomedil dosage regimens. The maximum concentrations calculated after 10 days of therapy were compared with levels observed in reported cases of toxicity to assess the probability of overdosing. A three-compartment model best fit concentration data. Population predictions showed little bias (-0.14 mg/L) and good precision (8.73 mg(2) /L(2)). Overall results of the simulation study showed that the application of the two recommended dosage regimens of buflomedil was associated with overdosing (C(max) > 10 mg/L) and potential toxicity in 2.9% of geriatric patients. In patients with mild renal impairment, who may receive the higher-dosage regimen by therapeutic error, the probability of overdosing was 6.2%. Despite specific dosing recommendations in case of renal impairment, this study shows that the use of buflomedil could be associated with significant risk of overdosing in geriatric patients. Such results might have enhanced decision-making when buflomedil safety was reassessed by AFSSAPS in 2006. The retrospective case of buflomedil illustrates how these methods may be valuable in postmarketing safety evaluation of potentially toxic drugs.

Predicting the clinical relevance of drug interactions from pre-approval studies

Drug interactions (DIs) may result in adverse drug events that could be prevented, but in many cases the available information on potential DIs is not easily transferable to clinical practice. The majority of studies date from preclinical or premarketing phases, using animals or human-derived sources that may not accurately reflect the growing clinical complexity of high-risk populations, such as the elderly, women, children, patients with chronic disease, polytherapy and impaired organ functions. Thus, at the time of approval of a new drug the information in the summary of product characteristics refers to potential DIs, but lacks specific management recommendations and is of limited clinical utility. Therefore, we set out to review in vitro and in vivo methods to predict and quantify potential DIs, to see whether these studies could help the physician tackle daily problems of the assessment and choice of combined drug therapies, and to propose, from a clinical point of view, how premarketing studies could be improved so as to help the physician at the patient's bedside. Preclinical and premarketing study design needs to be improved to make information easily accessible and clinically transferable. Studies should also take into account appropriate sample size, duration, co-morbidity, number of coadministered drugs, within- and between-subject variability, specific at-risk populations and/or drugs with a relatively narrow therapeutic window, and clinical endpoints. After premarketing development in situations where there is potential high risk of serious adverse events, specific phase IV studies (and/or active pharmacovigilance studies) should be required to monitor and quantitatively assess their clinical impact.

Pharmaceutical research in paediatric populations and the new EU Paediatric Legislation: an industry perspective

A large proportion of medicines used in children are prescribed off-label, and children have often been denied access to new or innovative medications. Because such situation is unethical, the need to obtain paediatric information for medicines used in children seems nowadays a matter of consensus on a global basis. Based on this, it was clear in EU, like what has happened in the US, that there was a need for a legal obligation for Pharmaceutical Companies to perform studies. This new European Paediatric Regulation that entered into force in 2007 opens a new era of European drug regulatory history and will offer a major opportunity to improve children's health through advancements in research by providing a new framework for evaluating the efficacy and safety of medicines for children. But, paediatric development remains challenging and the hurdles of conducting research in paediatric population are numerous. The article presents the new European Paediatric Regulation, illustrates its rationale through paediatric psychopharmacology, and discusses some of its consequences on paediatric research from an industry perspective. Recommendations for further international collaboration are also suggested to make global paediatric development plans.

On pharmaceutical risk minimization

Current regulatory guidelines related to pharmaceutical risk minimization put most emphasis on risk communication and control of the use of drugs. Little, if any, consideration is given to those aspects of an adverse drug reaction that ultimately determine whether the risk can be minimized. However, this limited scope is unfortunate and could prevent risk minimization activities from improving drug use safety. This article attempts to present an overview of possible elements of pharmaceutical risk minimization and to place these in a framework. The promotion of drug safety through risk communication and control of use should be advanced, with more attention to actionable and evidence-based guidance relating to the 'pretreatment evaluation', and in particular the 'on-treatment management' of the patient.

Pharmacovigilance in developing countries

Requires collaboration between stakeholders to develop novel models of funding

The relevance of pharmacokinetic studies in designing efficacy trials in juvenile major depression

INTRODUCTION

Identifying evidence-based dosing strategies is a key part of new drug development in pediatric populations. Pharmacokinetic (PK) studies can provide important information regarding how best to dose medications in children and adolescents. Utilizing scientifically supported dosing strategies provides the best chance for any given drug to demonstrate both efficacy and acceptable tolerability in definitive, placebo-controlled studies.

METHODS

Results of both PK studies and randomized, placebo-controlled efficacy trials (RPCTs) in juvenile major depressive disorder (MDD) are reviewed. The degree to which the medication dosing strategies that were employed in the efficacy studies were supported by the extant PK data is considered. Medications that are reviewed include fluoxetine, sertraline, paroxetine, citalopram, escitalopram, venlafaxine, nefazodone, and mirtazapine.

RESULTS

In many instances, the dosing paradigms that were used in the RPCTs differed, sometimes substantially, from the dosing strategies that would have been supported based on the results of PK studies.

CONCLUSIONS

Medication dosing regimens may have contributed to the failure of several RPCTs to show drug efficacy in the treatment of pediatric MDD. In addition, the doses of medication used in these RPCTs may also have contributed to the safety and tolerability concerns that have been raised with these drugs. PK and dose-ranging studies should be performed prior to the initiation of definitive efficacy trials so that empirically supported dosing strategies can be incorporated into the design of RPCTs of antidepressants in children and adolescents suffering from MDD.

Adverse reactions related to drugs for headache treatment: clinical impact

OBJECTIVE

To assess the clinical impact of adverse reactions related to drugs for primary headache treatment.

METHODS

We examined the adverse reactions to 360 medications prescribed by the specialists of the Headache Centre of the University of Modena and Reggio Emilia to 256 consecutive outpatients (214 female, 42 male; mean age: 38.88 +/- 14.06 years; range 10-72 years). Adverse reactions were reported by patients during scheduled follow-up visits, classified by specialists and reassessed by a clinical pharmacologist.

RESULTS

Adverse reactions with a causal relationship classified as definite/probable/possible were 202 (56%): 62% (80/129) were due to acute treatments and 53% (122/231) to prophylactic treatments (chi2 test, P = 0.115 ns). More than 90% of the adverse reactions were of limited intensity [mild (58%) or moderate (36%)]. Only 5% were severe, and two reactions (1%) were serious. The most affected apparatus was the nervous system (41%). Of these adverse reactions, 43% caused the discontinuance of the treatment, especially of prophylaxis (54%). Patients evaluated 70% of the medications as effective, but, at the same time, they considered most of the adverse reactions (69%) unacceptable.

CONCLUSION

Adverse reactions related to headache medications have a strong impact on patients' management, even if their real intensity and severity are usually very limited. Drugs for headache treatment are still far from being ideal drugs. To prevent the discontinuance of effective medications, the physician, prior to prescribing, should assess, together with the patient, the acceptability of the more common adverse drug reactions.