bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing Bioequivalence of Antiepileptic Drugs: Are the Current Requirements too Permissive?
Authors: Rediguieri Camila F , Zeredo Jorge L 
Published: March 2016

Purpose: In order to evaluate the permissiveness of current bioequivalence requirements for antiepileptic drugs we investigated how accurate Cmax and AUC0-t of generic antiepileptic drugs approved in Brazil are in comparison to reference products. Methods: Data collected from assessment reports of approved bioequivalence studies archived in the Brazilian regulatory agency in 2007-2012 were: geometric mean ratios and 90% confidence intervals (CI) for Cmax and AUC0-t, intra-subject variability (CV) of Cmax and AUC0-t and number of subjects. Results: The average difference in Cmax and AUC0-t between generic and reference products was 5% and 3%, respectively. Maximum deviation from 1.00 of the CI of Cmax can achieve 15-20% (demonstrated in 27% of studies); for AUC0-t, 25% of studies showed the deviation can be >10%. All studies that used adequate number of subjects for a 90% CI of 0.90-1.11 complied with it for AUC0-t, except one of carbamazepine, but only 33% complied with it for both AUC0-t and Cmax. The CV was strongly correlated to the maximum CI deviation for AUC0-t (CV of approximately 15% corresponding to deviation of 10%). Studies that presented maximum CI deviation ≤ 10 % together with CV ≤ 15% for AUC0-t represented 65% of the total. Weaker correlation was observed for Cmax and no correlation was seen between maximum CI deviation and number of subjects. Conclusions: Modification in legislation for bioequivalence of antiepileptic drugs is suggested, not only with constraint of AUC0-t 90% CI to 0.90-1.11, but also with limitation of the CV to 15%, as to assure similar variance in pharmacokinetics and diminish the risk of critical plasma-level fluctuation when switching between generic and reference formulations. Although most generics presented differences ≤ 10% in AUC0-t compared to their references, some narrow therapeutic index drugs displayed differences that could be clinically significant after product substitution. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
Effects of Prescription Drug Reduction on Quality of Life in Community-Dwelling Patients with Dementia
Authors: Sakakibara Mikio , Igarashi Ataru , Takase Yoshimasa , Kamei Hiroyuki , Nabeshima Toshitaka 
Published: March 2016

Purpose: Due to the use of multiple drugs and prevalence of diminished cognitive function, community-dwelling elderly individuals are more likely to have drug-related issues. We examined changes in quality of life (QOL) and activities of daily living (ADL) 3 months and 6 months after reducing drug use of dementia patients who had newly begun community-dwelling care. Methods: Prescription drug use was reduced in the intervention group, whereas the non-intervention group continued their regimen or began using additional drugs. QOL and ADL were assessed with the Japanese version of the EQ-5D and the Barthel Index, respectively. Results: Subjects were 32 individuals aged ≥65 years who had begun community-dwelling between March and July 2014 and had received approval for long-term care insurance. On average, the intervention group (n = 19) stopped using 2.6 prescription drugs. After 6 months, the differences in the QOL and ADL scores in the intervention group were -0.03 ± 0.29 and 6.32 ± 18.6, respectively, while the differences in the QOL and ADL scores in the non-intervention group (n = 13) were -0.13 ± 0.29 and -2.69 ± 23.7, respectively. In the intervention group, ADL scores were significantly increased by 14.0 ± 11.1 6 months after reduced benzodiazepine use. Conclusions: QOL was maintained with reduced drug use, while ADL score was slightly increased. In addition, the reduction of benzodiazepine use significantly increased ADL. In order to reduce polypharmacy among community-dwelling elderly patients, it is necessary to create an opportunity for pharmacists to re-examine their prescriptions This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
QT Correction: Using an Observed Regression Factor Applicable to a Population Subset
Authors: Oo Charles , Kalbag Suraj S 
Published: March 2016

Purpose. A QT interval correction to standardized heart rate (QTc) is essential to compare drug effect or to mitigate cardiac risk in clinical practice. Numerous empirical formulas for QTc have been proposed. However, an effective and readily comprehensible method has been elusive. As QTc is dependent on demographics, concomitant drugs, health status, autonomic and diurnal variation, the applicability of these methods hinge on the characteristics of a population that is assessed. An individual QTc is ideal, but it requires substantial baseline ECG data and is beyond the scope for initial evaluation. As a compromise, an approach for a ‘discontinuous’ population subset is suggested. In this article, we outline the challenges of QTc, and select a power function [QTc = QT/{(RR)a}] in which a regression factor a relevant to a particular population subset is used. The formula is similar to the one used in the Bazett’s (a=1/2) or Fridericia’s (a=1/3) method. The use of this approach is illustrated with two small population subsets separated by age and out- or in-patient status. This QTc approach is relatively simple to implement in drug development or by a busy practitioner within his/her institution. Nevertheless, in view of the limitations of the illustrative sample size and confounding factors of this proposal, additional studies will be necessary for further evaluation of QTc methods.This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
Pre-Clinical Pharmacokinetic and Pharmacodynamic Characterization of Selected Chiral Flavonoids: Pinocembrin and Pinostrobin
Authors: Sayre Casey L. , Alrushaid Samaa , Martinez Stephanie E. , Anderson Hope D. , Davies Neal M. 
Published: March 2016

Purpose: Delineate the stereospecific pharmacokinetics and pharmacodynamics of the chiral flavonoids pinocembrin and pinostrobin. Objective: Characterize for the first time the stereoselective pharmacokinetics of two flavonoids, pinocembrin and pinostrobin and their bioactivity in several in vitro assays with relevant roles in heart disease, colon cancer, and diabetes etiology and pathophysiology. Methods: Chiral flavonoids were intravenously and orally administered to male Sprague-Dawley rats. Concentrations in serum and urine were characterized via stereospecific HPLC or LC/MS. Pure enantiomeric forms of each flavonoid were tested, where possible, to identify the stereospecific contribution to bioactivity in comparision to their racemates. Results: Short half-lives (0.2-6 h) in serum were observed, while a better estimation of half-life (3-26 h) and other pharmacokinetic parameters were observed using urinary data. The flavonoids are predominantly excreted via non-renal routes (fe values of 0.3-4.6 %), and undergo rapid and extensive phase II metabolism. Chiral differences in the chemical structure of these compounds result in significant pharmacodynamic differences. Conclusion: The importance of understanding the stereospecific pharmacokinetics and pharmacodynamics of two chiral flavonoids were delineated.This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
In vitro controlled drug release from loaded microspheres - dose regulation through formulation
Authors: Waters Laura Jane , Pavlakis Evangelos 
Published: March 2016

ABSTRACT
PURPOSE: Drug release profiles were established for ibuprofen encapsulated within several types of microspheres and a range of dissolution buffer media to study the effect these variables have in controlling the rate and extent of drug release. METHODS: Fatty acid microspheres containing ibuprofen were prepared by a process previously developed and refined to produce microspheres of a known size and composition, namely 80-125 ?m diameter and an excipient to ibuprofen ratio of 3:1. Drug release profiles from these encapsulated formulations were compared with those obtained for the dissolution of ibuprofen alone under the same conditions. RESULTS: Stearic acid microspheres were found to only partially retard the release of ibuprofen over a twenty minute period compared with the dissolution of ibuprofen alone. However, a significant retardation of ibuprofen release was observed with cetostearyl alcohol microspheres over the same period of time. Secondly, drug release profiles for encapsulated ibuprofen were determined using five distinct dissolution buffer media; sodium phosphate, potassium phosphate, citric acid and phosphate mix, MOPS and tris. Significant differences in the extent and rate of drug release were recorded between the different dissolution buffer solutions. These differences were also shown to be independent of variations in pH, temperature, buffer concentrations and the type of cations present. CONCLUSIONS: The presence and choice of microsphere formulation, and the choice of buffer present in the dissolution solution, can influence drug release in vitro, i.e. it is possible to achieve controlled drug release from microspheres. To explain the control achieved through the choice of buffer in solution it is proposed that the buffer anion exerts a stabilising influence on the ibuprofen-microsphere matrix.
Applications of Polymeric and Lipid Nanoparticles in Ophthalmic Pharmaceutical Formulations: Present and Future Considerations
Authors: Almeida Hugo , Amaral Maria Helena , Lobão Paulo , Silva Ana C , Loboa José Manuel Sousa 
Published: March 2016

The unique properties and characteristics of ocular tissues and the whole set of defence mechanisms of the ocular globe make the instillation of ocular drugs into a difficult task with a low rate of therapeutic response. One of the challenges for the new generation of ophthalmic pharmaceutical formulations is to increase the bioavailability of drugs administered by the ocular route and, therefore, their therapeutic efficacy. This can be achieved with the use of some strategies that provide an increase in the formulation pre-corneal residence time, mucoadhesion and penetration across the eye tissues. Colloidal carrier systems have been very successfully used for the selective and targeted delivery of drugs for several routes of administration. In this context, nanoparticles prepared with specific polymers or lipids and coated, dispersed or suspended in polymer solutions with mucoadhesion properties or in situ gelling properties will be an excellent strategy that deserves attention and further research. In this review, the characteristics and main properties of polymeric and lipid nanoparticles are discussed and examples and advantages of the application of these colloidal carrier systems for the ophthalmic administration of drugs are presented. The future directions of the research required in this specific field are also presented.This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
The Implication of the Polymorphisms of COX-1, UGT1A6, and CYP2C9 among Cardiovascular Disease (CVD) Patients Treated with Aspirin
Authors: Jalil Nur Jalinna Abdul , Bannur Zakaria , Derahman A. , Maskon O. , Darinah Noor , Hamidi Hamat , Gunasekaran Osama Ali , Rafizi Mohd , Azreen Nur Izatul , Kek Teh Lay , Salleh Mohd. Zaki 
Published: March 2016

PURPOSE: Enzymes potentially responsible for the pharmacokinetic variations of aspirin include cyclooxygenase-1 (COX-1), UDP-glucuronosyltransferase (UGT1A6) and P450 (CYP) (CYP2C9). We therefore aimed to determine the types and frequencies of variants of COX-1 (A-842G), UGT1A6 (UGT1A6*2; A541G and UGT1A6*3; A522C) and CYP2C9 (CYP2C9*3; A1075C) in the three major ethnic groups in Malaysia. In addition, the role of these polymorphisms on aspirin-induced gastritis among the patients was investigated. METHODS: A total of 165 patients with cardiovascular disease who were treated with 75-150 mg daily dose of aspirin and 300 healthy volunteers were recruited. DNA was extracted from the blood samples and genotyped for COX-1 (A-842G), UGT1A6 (UGT1A6*2 and UGT1A6*3) and CYP2C9 (CYP2C9*3; A1075C) using allele specific polymerase chain reaction (AS-PCR). RESULTS: Variants UGT1A6*2,*3 and CYP2C9*3 were detected in relatively high percentage of 22.83%, 30.0% and 6.50%, respectively; while COX-1 (A-842G) was absent. The genotype frequencies for UGT1A6*2 and *3 were significantly different between Indians and Malays or Chinese. The level of bilirubin among patients with different genotypes of UGT1A6 was significantly different (p-value < 0.05). In addition, CYP2C9*3 was found to be associated with gastritis with an odd ratio of 6.8 (95 % Cl OR: 1.39 – 33.19; P = 0.033). CONCLUSION: Screening of patients with defective genetic variants of UGT1A6 and CYP2C9*3 helps in identifying patients at risk of aspirin induced gastritis. However, a randomised clinical study of bigger sample size would be needed before it is translated to clinical use.
The Risk of Recrystallization: Changes to the Toxicity and Morphology of Pyrimethamine
Authors: Perold Zak , Caira Mino R , Brits Marius 
Published: March 2016

PURPOSE. Pyrimethamine, an anti-malarial agent known to exhibit solid state polymorphism, may be purified by means of recrystallization. Recrystallization may alter the solid state chemistry of pharmaceuticals, which may impact the toxicity and/or manufacturability thereof. We evaluated the risks associated with the recrystallization of pyrimethamine. METHODS. Pyrimethamine was recrystallized using several organic solvents. X-ray diffraction, thermal analysis, infra-red spectroscopy, microscopy, flowability -, solubility and dissolution testing as well as computational work were employed to evaluate the recrystallized products. RESULTS. A toxic solvatomorph of pyrimethamine (Pyr-MeOH) was found to be the product from methanol recrystallization. The elucidation of – and the elaboration on the unique characteristics of Pyr-MeOH provides the pharmaceutical industry with several means to identify Pyr-MeOH and to distinguish it from the pharmaceutically preferred anhydrous form (Pyr). Thermal methods of analysis found that the toxicity of Pyr-MeOH may be reversed by overcoming a desolvation activation energy of 148 kJ/mol. In addition it was found that recrystallization altered the morphology of Pyr. Angle of repose and tapped density determinations identified that the different morphologies of Pyr displayed differences in powder flow and compressibility behaviour and In Silico calculations were successful in rendering morphologies resembling that found experimentally. CONCLUSION. We present a solvatomorph of pyrimethamine and provide several characteristic means to identify this unwanted toxic form and quantified the energy required to overcome its toxicity. In addition we describe that Pyr may present in different morphologies and show how it may impact the manufacturability thereof. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
The Efficacy and Tolerability of Exenatide in Comparison to Placebo; A Systematic Review and Meta-Analysis of Randomized Clinical Trials
Authors: Nikfar Shekoufeh , Abdollahi Mohammad , Salari Pooneh 
Published: March 2016

Recent investigations in finding new drugs in the treatment of diabetes have led to the discovery of several pathological pathways involved in diabetes. Exenatide a drug with incretin mimetic activity was studied in several in vivo and in vitro as well as human studies. It has shown promising results in controlling metabolic indices in type-2 diabetes and was approved by FDA but still there is an active safety alert on it. In this study we aimed to meta-analyze all placebo-controlled clinical trials on the efficacy or tolerability of exenatide in type 2 diabetes.
The literature search provided 1016 articles while only 14 articles were eligible to be included in the meta-analysis with a total of 2583 patients enrolled in the study. According to the wide variation in design of various studies, the study duration of 16 weeks and less or more and dose (5 μg bid versus 10 μg bid) were considered and analyzed.
The results of this meta-analysis show that exenatide decreases fasting plasma glucose and HbA1C significantly regardless of dose and study duration. The effect of exenatide on weight reduction was more prominent at the dose of 10 μg bid regardless of the study duration, however at the dose of 5 μg bid, significant results were observed after drug administration for more than 16 weeks. Exenatide usage decreased serum triglycerides indifferent to dose and study duration while its effect on cholesterol was not prominent. Along with these impacts, exenatide changed LDL and HDL cholesterol at the lower dose. The hemodynamic effect of exenatide was observed as significant decrements in systolic and diastolic blood pressure at the higher dose. The risk of nausea, vomiting and hypoglycemia was significant and indifferent to dose while headache and nasopharyngaitis were seen more at lower dose.
It is concluded that exenatide can be considered as a good hypoglycemic agent in type-2 diabetic patients with benefits on lipid profile and blood pressure with partially questionable tolerability.

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Understanding the Hysteresis Loop Conundrum in Pharmacokinetic / Pharmacodynamic Relationships
Authors: Louizos Christopher , Yáñez Jaime A , Forrest M Laird , Davies Neal M 
Published: March 2016

Hysteresis loops are phenomena that sometimes are encountered in the analysis of pharmacokinetic and pharmacodynamic relationships spanning from pre-clinical to clinical studies. When hysteresis occurs it provides insight into the complexity of drug action and disposition that can be encountered. Hysteresis loops suggest that the relationship between drug concentration and the effect being measured is not a simple direct relationship, but may have an inherent time delay and disequilibrium, which may be the result of metabolites, the consequence of changes in pharmacodynamics or the use of a non-specific assay or may involve an indirect relationship. Counter-clockwise hysteresis has been generally defined as the process in which effect can increase with time for a given drug concentration, while in the case of clockwise hysteresis the measured effect decreases with time for a given drug concentration. Hysteresis loops can occur as a consequence of a number of different pharmacokinetic and pharmacodynamic mechanisms including tolerance, distributional delay, feedback regulation, input and output rate changes, agonistic or antagonistic active metabolites, uptake into active site, slow receptor kinetics, delayed or modified activity, time-dependent protein binding and the use of racemic drugs among other factors. In this review, each of these various causes of hysteresis loops are discussed, with incorporation of relevant examples of drugs demonstrating these relationships for illustrative purposes. Furthermore, the effect that pharmaceutical formulation has on the occurrence and potential change in direction of the hysteresis loop, and the major pharmacokinetic / pharmacodynamic modeling approaches utilized to collapse and model hysteresis are detailed. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
Enhancement of Skin Penetration of Hydrophilic and Lipophilic Compounds by pH-sensitive Liposomes
Authors: Tokudome Yoshihiro , Nakamura Kaoru , Itaya Yurina , Hashimoto Fumie 
Published: March 2016

PURPOSE: Enhance skin penetration of hydrophilic and lipophilic compounds using liposomes that are responsible to the pH of the skin surface. METHODS: pH-sensitive liposomes were prepared by a thin layer and freeze-thaw method with dioleoyl phosphatidyl ethanolamine and cholesteryl hemisuccinate. Liposomal fusion with stratum corneum lipid liposomes was measured using fluorescence resonance energy transfer. Particle diameter and zeta potential of the liposomes after fusion were measured by dynamic light scattering and electrophoresis. RESULTS: Under neutral pH conditions, the diameter of the pH-sensitive liposomes was 130 nm and their zeta potential was -70 mV. In weakly acidic conditions, the diameter was larger than 3,000 nm and the zeta potential was -50 mV. In contrast, the particle diameter and the zeta potential of the non-pH-sensitive liposomes remained constant under various pH conditions. A skin penetration study was performed on hairless mice skin using vertical diffusion cells, showing that the fusion ability of pH-sensitive liposomes was higher than that of non-pH-sensitive liposomes. In the skin penetration study was carried out using hydrophilic (calcein) and lipophilic (N-(7-nitrobenz- 2-oxa-1,3-diazol-4yl)-PE) (NBD-PE) model compounds which were applied to the skin with pH-sensitive liposomes as carrier. The fluorescent compounds contained within the pH-sensitive liposomes permeated the skin more effectively than those within non-pH-sensitive liposomes, and this ability was further enhanced with the lipophilic compound. CONCLUSION: These studies suggest that pH-sensitive liposomes have potential as an important tool for delivery of compounds into the skin. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
Pluronic® F-127 and Pluronic Lecithin Organogel (PLO): Main Features and their Applications in Topical and Transdermal Administration of Drugs
Authors: Almeida Hugo , Amaral Maria Helena , Lobão Paulo , Lobo José Manuel Sousa 
Published: March 2016

Topical drug treatment aims at providing high concentrations of drugs at the site of application so as to avoid adverse systemic effects associated with oral administration. Smart polymers, or stimuli-responsive polymers, are able to respond to a stimulus by showing physical or chemical changes in their behaviour as, for example, the delivery of the drug carried by them. The thermo-responsive nature of Pluronic® F-127 (Basf, Ludwigshafen, Germany) makes it an excellent candidate for the delivery of drugs at various application sites. In recent years, PF-127, and later, Pluronic lecithin organogels (PLO), have attracted particular interest in the design of dermal and transdermal delivery systems with a view to promoting, improving or retarding drug permeation through the skin, bearing in mind that for topical delivery systems, accumulation in the skin with minimal permeation is desired, while for systemic delivery, the opposite behaviour is preferred.
In this review, we discuss the properties and characteristics of PF-127 and Pluronic lecithin organogels (PLO), and present many examples and advantages of the application of these polymeric systems in topical and transdermal administration of drugs.

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