Adult and pediatric physiologically-based biopharmaceutics modeling to explain lamotrigine immediate release absorption process

Physiologically-based biopharmaceutics modeling (PBBM) has potential to accelerate the development of new drug and formulations. An important application of PBBM is for special populations such as pediatrics that have pharmacokinetics dependent on the maturation process. Lamotrigine (LTG) is a Biopharmaceutics Classification System (BCS) II drug and is widely prescribed. Therefore, the goal of this study was to assess the biopharmaceutics risk of the low-soluble drug LTG when the ontogeny on gastrointestinal tract (GIT) physiological parameters are considered. An oral physiologically-based pharmacokinetic model and a PBBM were developed and verified using GastroPlus™ software for both adults and children (2-12 years old, 12-52 kg). The biopharmaceutics properties and GIT physiological parameters were evaluated by sensitivity analysis. High doses were simulated assuming a worst case scenario, that is, the dose of 200 mg for adults and 5 mg/kg (up to the maximum of 200 mg) for 2-year-old children. Although several authors have suggested that ontogeny may have an effect on gastrointestinal fluid volume, our study found no evidence of interference between fluid and dose volumes with in vivo dissolution of LTG. The most impactful parameter was found to be the gastric transit time. Therefore, the hypothesis is developed to examine whether LTG exhibits characteristics of a BCS II classification in vitro while showing BCS I-like behavior in vivo. This hypothesis could act as a base for conducting novel studies on model-informed precision dosing, tailored to specific populations and clinical conditions. In addition, it could be instrumental in assessing the influence of various release profiles on in vivo performance for both adult and pediatric populations.

Exploring in vitro solubility of lamotrigine in physiologically mimetic conditions to prospect the in vivo dissolution in pediatric population

Pediatric drugs knowledge still leaves several gaps to be filled, all the while many biopharmaceutic properties applied to adults do not work in pediatrics. The solubility in many cases is extrapolated to pediatrics; however, sometimes it may not represent the real scenario. In this context, the aim of this study was to assess the possibility of the extrapolation of the solubility data assumed for adults to children aged 2-12 years using lamotrigine (LTG) as a model. LTG showed that its solubility is dependent on the pH of the medium, no precipitate formation was seen, and biomimetic media showed a greater capacity to solubilize it. Based on the dose number (D₀ ) in adults, the LTG was soluble in acidic pH media and poorly soluble in neutral to basic. Similar behavior was found in conditions which mimic children aged 10-12 years at a dose of 5 and 15 mg/kg. The D₀ for 5-year-old children at a dose of 15 mg/kg showed different behaviors between biorelevant and pharmacopeial buffers media. For children aged 2-3 years, LTG appeared to be poorly soluble under both gastric and intestinal conditions. Solubility was dependent on the volume of fluid calculated for each age group, and this may impact the development of better pharmaceutical formulations for this population, better pharmacokinetic predictions in tools as PBPK, and physiologically-based biopharmaceutics modeling, greater accuracy in the justifications for biowaiver, and many other possibilities.

Model-Informed drug development of gastroretentive release systems for sildenafil citrate

Gastroretentive drug delivery systems (GRDDS) are modified-release dosage forms designed to prolong their residence time in the upper gastrointestinal tract, where some drugs are preferentially absorbed, and increase the drug bioavailability. This work aimed the development of a novel GRDDS containing 60 mg of sildenafil citrate, and the evaluation of the feasibility of the proposed formulation for use in the treatment of pulmonary arterial hypertension (PAH), for once a day administration, by using in silico pharmacokinetic (PK) modeling and simulations using GastroPlus^TM. The Model-Informed Drug Development (MIDD) approach was used in formulation design and pharmacokinetic exposure prospecting. A 2² factorial design with a central point was used for optimization of the formulation, which was produced by direct compression and characterized by some tests, including buoyancy test, assay, impurities, and in vitro dissolution. A compartmental PK model was built using the GatroPlus^TM software for virtual bioequivalence of the proposed formulations in comparison with the defined target release profile provided by an immediate release (IR) tablet formulation containing 20 mg of sildenafil administered three times a day (TID). The results of the factorial design showed a direct correlation between the dissolution rate and the amount of hydroxypropyl methyl cellulose (HPMC) in the formulations. By comparing the PK parameters predicted by the virtual bioequivalence, the formulations F1, F2, F3 and F5 failed on bioequivalence. The F4 showed bioequivalence to the reference and was considered the viable formulation to substitute the IR. Thus, GRDDS could be a promising alternative for controlling the release of drugs with a pH-dependent solubility and narrow absorption window, specifically in the gastric environment, and an interesting way to reduce dose frequency and increase the drug bioavailability. The MIDD approach increases the level of information about the pharmaceutical product and guide the drug development for more assertive ways.

Are synergies continuously present in cyclical movements? An example with the basketball dribble task

In human movement, synergies occur when two or more variables co-vary to stabilize a performance goal. The concept of motor redundancy is associated with the existence of several strategies to complete the same task, which enables a movement system to adapt to an ever-changing environment. This feature provides the system with the ability of being flexible enough to produce adaptive movements, but also stable enough to produce acceptable outputs which is a key issue in motor performance. In a kinetic chain of movement, two proximal joints might reciprocally compensate to stabilize an end-effector (i.e., the most distal segment in the limb that interacts with the environment). End-effector variables are 'controlled', and directly linked to performance, whereas the task relevant elements are allowed by the system to have high variability, providing adaptability. In basketball dribbling, we hypothesized that shoulder and elbow variability contributes to stabilize the dribble height as an end-effector performance variable. A specific computational procedure based on the UCM (i.e., Uncontrolled Manifold) notion was used to capture synergies in two groups according to the experience level: amateurs and professionals. Results identified synergy presence during the basketball dribbling, which only occurred when the wrist reached its peak height. The control of the wrist peak height is achieved due to a reciprocal compensation between shoulder and elbow which stabilizes the dribbling height.

Hospitalization direct cost of adults with community-acquired pneumonia in Portugal from 2000 to 2009

INTRODUCTION

Hospitalizations due to community-acquired pneumonia (CAP) in mainland Portugal from 2000 to 2009 accounted for 3.7% of all hospital admissions in population with 18 or more years of age. There is no direct-cost data regarding these admissions.

METHODS

In this observational descriptive study all adult hospitalizations associated with CAP diagnosis were retrospectively analyzed for the period between 2000 and 2009. Patients under 18 years old, those with pneumonia as secondary diagnosis, patients with tuberculous or obstructive pneumonia, and immunocompromised patients were excluded from the study. The direct cost of hospitalization was calculated according to the diagnosis-related groups (DRG), established for the respective year of hospitalization.

RESULTS

There were 294,026 hospital admissions with an average annual direct cost of 80 million Euros, which almost doubled between 2000 and 2009. The average direct hospitalization costs per admission, including wards and Intensive Care Units (ICU), amounted to €2,707, with an increasing trend. The average hospitalization cost was €2,515 for admissions resulting in live discharge, and €3,457 for the deceased.

CONCLUSION

The average direct cost of adult hospitalizations associated with CAP amounted to €2,707 in mainland Portugal from 2000 to 2009, showing an increase of 37.5% in hospitalization cost of living and deceased patients. The economic impact of CAP-related hospital admissions justifies the need for better implementation of preventive measures.

Population pharmacokinetics of orally administrated bromopride: Focus on the absorption process

Bromopride is a prokinetic and antiemetic drug used to treat nausea and vomiting. Although its prescription is common in Brazil, there is a lack of studies about bromopride pharmacokinetics. Therefore, the aims of this study were to investigate the population pharmacokinetics of bromopride and to evaluate the influence of covariates on its absorption. This study is a retrospective analysis of data collected from bioequivalence studies. The data was modeled using MONOLIX 2018R2. Assuming one-compartment and linear elimination, the absorption phase was evaluated with different structural models. The model of sequential first- and zero-order with combined error and exponential inter-individual variability in all parameters best described the atypical absorption profile of bromopride. Population estimates were first-order absorption rate (ka) of 0.08 h ^- 1, fraction of dose absorbed by first-order (Fr) of 32.60%, duration of the zero-order absorption (Tk0) of 0.88 h with latency time (Tlag) of 0.47 h, volume of distribution of 230 l and clearance of 46.80 l h ^- 1. Bodyweight affects Tk0, dosage form was found to correlate with Tk0 and Tlag, while gender affects Tlag. However, simulations evaluating the clinical importance of these covariates on steady-state indicated minimal changes on bromopride exposure. The mixed absorption model was reasonable to describe the absorption process of bromopride because it had the flexibility to fit multiple-peaks profile and shows good agreement with physicochemical properties of drug.

Physiologically-Based Pharmacokinetic Model on the Oral Drug Absorption in Roux-en-Y Gastric Bypass Bariatric Patients: Amoxicillin Tablet and Suspension

The potential of a physiologically-based pharmacokinetic (PBPK) model to predict oral amoxicillin bioavailability, by considering the physiological changes after "Roux-en-Y gastric bypass" (RYGB) surgery in bariatric patients, was evaluated. A middle-out approach for parameter estimations was undertaken using in vitro, in situ, and in vivo data. The observed versus predicted plasma concentrations and the model sensitivity of the simulated parameters of AUC_0-inf and C_max of amoxicillin (AMX) were used to confirm the reliability of the estimation. The model considers that a drug-transporter (Transp) in the initial segments of the normal intestine plays a significant role in the AMX absorption. A lower fraction absorbed (F_abs) was observed in RYGB patients (54.43% for suspension and 45.21% for tablets) compared to healthy subjects (77.48% capsule). Furthermore, the tablet formulation presented a lower dissolved fraction (F_d) and F_abs compared to the suspension formulation of AMX in RYGB patients (91.70% and 45.21% versus 99.92% and 54.43%, respectively). The AUC_0-inf and C_max were sensitive to changes in R_tintestine, Peff_AMX, and Transp for both healthy and RYGB models. Additionally, AUC_0-inf and C_max were also sensitive to changes in the t_lag parameter for tablet formulation in RYGB patients. The PBPK model showed a reduction in AMX bioavailability as a consequence of reduced intestinal length after RYGB surgery. Additionally, the difference in the predicted F_d and F_abs between suspension and tablet suggests that liquid formulations are preferable in postbariatric patients.

Rapid and efficient method for the quantification of lychnopholide in rat plasma by liquid chromatography-tandem mass spectrometry for pharmacokinetic application

Lychnopholide is a sesquiterpene lactone usually obtained from Lychnophora and Eremanthus species and has pharmacological activities that include anti-inflammatory and anti-tumor. Lychnopholide isolated from Eremanthus matogrossenssis was analyzed in this study. The aims of this study were to develop and validate an analytical methodology by LC-MS/MS and to quantify lychnopholide in rat plasma. Chromatographic separation was achieved on a C18 column using isocratic elution with the mobile phase consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.4 mL/min. The detection was performed in multiple-reaction monitoring mode using electrospray ionization in positive mode. The method validation was performed in accordance with regulatory guidelines and the results met the acceptance criteria. The linear range of detection was 10-200 ng/mL (r > 0.9961). The intra- and inter-day assay variability were <6.2 and <11.7%, respectively. The extraction recovery was approximately 63% using liquid-liquid extraction with chloroform. Lychnopholide was detected in plasma up to 60 min after intravenous administration in rats. This rapid and sensitive method for the analysis of the sesquiterpene lactone lychnopholide in rat plasma can be applied to pharmacokinetic studies of this compound. Copyright © 2016 John Wiley & Sons, Ltd.

The exposure to Trichilia catigua (catuaba) crude extract impairs fertility of adult female rats but does not cause reproductive damage to male offspring

ETHNOPHARMACOLOGICAL RELEVANCE

Trichilia catigua is broadly used in folk medicine due to its mental and physical tonic activities and stimulant effects. In animal models, its antidepressant-like effects have been associated with the dopaminergic (DA) system modulation, which has an important role on maternal behavior and male offspring reproductive development.

AIM OF THE STUDY

Since little is known about the adverse effects of the exposure to T. catigua crude extract (CAT) in rats, specially regarding maternal homeostasis and offspring development, the aim of the present study was to evaluate whether CAT exposure may influence maternal toxicity parameters and behavior or disrupt male offspring physical and reproductive development.

MATERIAL AND METHODS

Dams were treated daily (by gavage) with 400mg/kg of CAT or vehicle (control=CTR) throughout pregnancy and lactation. Fertility and maternal behavior tests were conducted in dams. Male offspring reproductive and behavioral parameters were analyzed.

RESULTS

Dams exposed to CAT showed increased pre- and post-implantation losses rates when compared to CTR group. No significant changes regarding maternal behavior or male offspring parameters were observed.

CONCLUSION

In conclusion, maternal exposure to CAT interfered with implantation during the initial phases of pregnancy but did not induce changes on maternal behavior or male offspring reproductive and behavioral parameters.

Employing photoacoustic spectroscopy in the evaluation of the skin permeation profile of emulsion containing antioxidant phenolic-rich extract of Melochia arenosa

CONTEXT

Oxidative stress is an important factor modulating skin alterations. Melochia arenosa Benth. (Malvaceae) is a Brazilian plant with antimicrobial activity and antioxidant potential.

OBJECTIVE

The objective of this study is to develop a topical formulation containing antioxidant phenolic-rich extract of M. arenosa and to evaluate its skin permeation profile.

MATERIALS AND METHODS

Response surface methodology was used to maximize the total phenolic (TP) content of the extract and its antioxidant activity was evaluated by 2,2-diphenyl-1-picryl-hydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and respiratory burst methods. An emulsion containing 1% optimized extract (OE) was developed and employed photoacoustic spectroscopy (PAS) for the determination of its skin permeation profile. The morphology of the skin was studied in histological sections stained with hematoxylin-eosin.

RESULTS AND DISCUSSION

The optimum conditions predicted for the major extractive efficiency of the phenolics with 100% ethanol led extraction time 101 h and plant:solvent proportion 1:13.5 (w/v). OE presented TP = 724.6 ± 8.2 mg GAE/g extract and scavenging capacity of DPPH (IC50 value = 11.43 ± 0.14 µg/mL) and ABTS radicals (IC50 value = 35.42 ± 0.48 µg/mL). The production of ROS by neutrophils after stimulation with phorbol miristate acetate was lower when the OE was present in the reaction medium, endorsing its high antioxidant capacity. The data obtained by PAS indicated that the OE present in the emulsion has permeated and was distributed in the whole skin. No histopathological alterations were observed in the histological analysis.

CONCLUSION

The formulation developed is a promising tool for skin care and could prevent the damage caused by oxidative stress.

Clinicians' prescribing practices for bariatric surgery patients: is there an issue?

WHAT IS KNOWN AND OBJECTIVES

Patients undergoing Roux-en-Y gastric bariatric (RYGB) surgery present a reduced absorption site, and special attention should therefore be taken when prescribing oral-dosage forms. This study was carried out to investigate the extent to which non-bariatric clinicians are aware of this issue when prescribing medicines for this population, and what type of information is available to aid them in their decision-making.

METHODS

Two questionnaires were created, one for non-bariatric clinicians and another for their patients who had undergone RYGB surgery, to gather information about the prescription practices for this population. Additionally, a literature search of pharmacokinetic studies on bariatric patients and recommended prescription practices was carried out.

RESULTS AND DISCUSSION

Of the 62 non-bariatric clinicians surveyed, 50% believed RYGB surgery interferes with drug absorption; however, 68% still prescribed tablets as the first choice form of dosage. Young clinicians (35%) were less likely to believe that RYGB surgery could affect drug absorption than experienced clinicians (43%). The main reasons for changing dosage forms were patient complaints about efficacy or difficulty in swallowing tablets. Of the 73 patients, 43 were taking drugs in tablet form after the surgery, 24 of whom had health issues unrelated to the surgery. None of the journals read by the clinicians contained pharmacokinetics (PK) studies involving bariatric surgery patients or presented recommendations for the prescription of oral-dosage forms for this population. The literature search revealed a total of 22 drugs that had undergone PK studies in RYGB patients. Fifteen of them were reported to have decreased effects, 12 of which were administered as tablets.

WHAT IS NEW AND CONCLUSION

There is still a relative lack of clinical evidence to guide clinicians when prescribing medicines for bariatric patients. It is therefore recommended that pharmacists should have greater participation in the prescription process to advise non-bariatric clinicians and educate RYGB surgery patients to help avoid therapeutic failure.

Consensus document for the prevention of respiratory infections in adults

Infectious diseases are one of the principle causes of morbidity, mortality and drain on health resources worldwide. In recent years there has been an increase in the impact of respiratory infections, particularly in the Portuguese population. It is for this reason that the Portuguese Respiratory Society has presented a series of recommendations for the prevention of respiratory infections in adults. These recommendations include both general measures and vaccinations for flu and pneumococcal pneumonia.

In vitro antifungal activity of the flavonoid baicalein against Candida species

The aim of the present study was to evaluate the in vitro activity of baicalein, the flavone constituent of Scutellaria baicalensis, and synergism of the combination of baicalein and fluconazole against Candida albicans, Candida tropicalis and Candida parapsilosis. The MIC(50) (lowest concentration at which there was 50 % inhibition of growth) of baicalein alone against six Candida strains ranged from 13 to 104 µg ml(-1). For the three species tested, exposure to baicalein at the MIC(50) concentrations obtained for each strain resulted in a high loss of viability. The fluconazole plus baicalein combination markedly reduced the MICs of both drugs for all three strains analysed. In addition, a synergistic effect between baicalein and fluconazole was observed for C. parapsilosis in terms of MIC(50) (fractional inhibitory concentration index = 0.207). Scanning electron microscopy analysis revealed that yeast cells exposed to baicalein at MIC(50) produced a profusely flocculent extracellular material, resembling a biofilm-like structure. In conclusion, these results showed the antifungal capability of baicalein against Candida species and highlight a promising role of baicalein when used in combination with fluconazole against Candida infections.

Human bocavirus in very young infants hospitalized with acute respiratory infection in northeast Brazil

A cross-sectional study was carried out over a period of 12 months to investigate the occurrence of human bocavirus (HBoV) infection in infants hospitalized for respiratory infections in a teaching hospital in Salvador, Brazil, and to describe the clinical manifestations of this infection. Nasopharyngeal aspirates were collected from the children and immunofluorescence and polymerase chain reaction were performed to investigate the presence of respiratory viruses. HBoV was detected in 4 out of 66 patients. Two of the HBoV-positive infants were co-infected with other viruses. The principal clinical findings in HBoV-positive children were: nasal obstruction, catarrh, cough, fever and dyspnea. This study revealed HBoV infection in children aged <2 months, suggesting that the infection may occur at a very early age.

In vitro study of mutagenic potential of Bidens pilosa Linné and Mikania glomerata Sprengel using the comet and micronucleus assays

Teas of Bidens pilosa and Mikania glomerata are popularly consumed to medicinal ends. The capacity to induce DNA damages and mutagenic effects of these teas were evaluated, in vitro, on HTC cells, with comet assay and micronucleus test. The teas tested at various doses were prepared differently: infusion of Mikania glomerata (IM) and Bidens pilosa (IB), macerate of Mikania glomerata in 80% ethanol (MM80) and decoction of Bidens pilosa (DB). In IM and MM80, the quantity of coumarin was determined by high-performance liquid chromatography (HPLC) with UV detection. Methylmethanesulfonate was utilized as positive control, phosphate-buffered saline as negative control, 80% ethanol as solvent control and 2-aminoanthracene as drug metabolism control. The comet assay demonstrated genotoxic effects for both plants. The genotoxic potential of IB was upper than DB, showing dose-response. In the MN test, excepting IM 40 microL/mL, all treatments was not mutagenic. The effects did not show direct relation with cumarin quantity present in IM and MM80. The results demonstrated DNA damages at the highest concentrations of alcoholic macerate (10 and 20 microL/mL) and infusion of Mikania glomerata (20 and 40 microL/mL) and of Bidens pilosa infusion (40 microL/mL). Thus, both dose and preparation-form suggest caution in the phytotherapeutic use of these plants.

Permeability profile estimation of flavonoids and other phenolic compounds by biopartitioning micellar capillary chromatography

This paper points out the usefulness of biopartitioning micellar chromatography (BMC) using capillary columns as a high-throughput primary screening tool providing key information about the oral absorption, skin permeability, and brain-blood distribution coefficients of 15 polyphenols (6 flavones, 2 flavonols, a flavanone, 2 flavan-3-ols, 3 phenolic acids, and a phloroglucinol) in a simple and economical way. For the compounds studied, except vicenin-2, rutin, chlorogenic acid, p-hydroxycinnamic acid, and 4-hydroxybenzoic acid, maximal oral absorption (>90%) can be expected, if there are not solubility problems or metabolic processes. On the other hand, the most retained compounds in BMC, that is, 5-hydroxyflavone, flavone, and flavanone, show the highest brain-blood distribution coefficients and skin permeability coefficients.

A nutritional profile of non-pregnant women from the slums of Dinajpur, Bangladesh

The health and nutritional status of many urban slum dwellers in the developing world is said to be deteriorating. The nutritional profile of 328 adult, non-pregnant women from the slums of Dinajpur, Bangladesh, confirms this. Results of a cross-sectional survey showed that approximately half the women were acutely malnourished and all but six were anaemic. This, despite the fact that the slums of Dinajpur are considered relatively 'better-off' than many in the developing world; most families having permanent land tenureship, and access to basic education and health services.

Treatment for iron deficiency anaemia with a combined supplementation of iron, vitamin A and zinc in women of Dinajpur, Bangladesh

OBJECTIVE

The study was set up to determine to what extent the addition of a supplement of vitamin A alone or in combination with zinc would improve standard iron treatment and correction of iron deficiency anaemia.

DESIGN

216 non-pregnant anaemic women of 15-45 years of age with haemoglobin levels < or = 100 g/l were randomly assigned to three treatment groups. One group (A) received iron alone, a second group (B) received iron and vitamin A, and a third group (C) received iron, vitamin A and zinc. Every woman was given one iron capsule per day for 60 days as FeSO4 containing 60 mg of elemental iron. In addition, groups B and C received 200,000 i.u. of vitamin A, given as a supervised dose, on the first day of the treatment after collection of the blood sample. Group C received one zinc tablet per day for 60 days as zinc gluconate containing 15 mg of elemental zinc.

SETTING

The north-western part of Bangladesh in the urban slums of Dinajpur district between February and August 1995.

SUBJECTS

To select women with a haemoglobin level of < or = 100 g/l, all the women of four randomly selected municipal slums of the district in the targeted age group (328) were invited to take part in the study. Blood samples were analysed for haemoglobin, serum iron, total iron binding capacity (TIBC), ferritin, retinol and zinc.

RESULTS

Out of the 328 women screened, 254 (77.5%) had a haemoglobin level < or = 100 g/l and 322 (98%) < or = 120 g/l. The three treatment schedules significantly increased haemoglobin levels and improved iron parameters, except for serum iron in the group who received iron alone. The group who received iron, vitamin A and zinc responded best with an increase in haemoglobin of 17.9 g/l as compared to the group receiving iron alone (13.4 g/l). Iron and vitamin A treatment gave an intermediate response of 15.9 g/l. However, these differences are only statistically significant only for the group who received iron, vitamin A and zinc and only for the increase in haemoglobin, P = 0.03.

CONCLUSION

The results are suggestive that the addition of vitamin A and zinc to the treatment for anaemia can increase haemoglobin levels more than with iron alone.

Antimicrobial activity of Guinea-Bissau traditional remedies

The ethanolic extracts of twelve plants selected through ethnomedical survey in Guinea-Bissau were investigated for their in vitro antimicrobial properties over ten bacteria and Candida albicans, using agar diffusion and dilution methods. All the tested extracts showed some activity against at least one of the bacteria. Most of the extracts (79%) showed activity against Staphylococcus aureus and only one (Cryptolepis sanguinolenta) against Escherichia coli. Cryptolepis sanguinolenta and Terminalia macroptera root extracts showed some activity against Candida albicans as well as showing an interesting profile of activity against most of the enteropathogen microorganisms. Inhibition zones against Staphylococcus aureus were localised on extract chromatograms by bioautographic techniques.