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Novel formulations of donepezil (DNP)-loaded microspheres based on a bio-degradable polymer of poly(lactic-co-glycolic acid) (PLGA) with a one-month duration of effect were developed, aimed at reducing dosing frequency and adverse effects and improving patient adherence. The spherical and monodispersed DNP-loaded microspheres were precisely fabricated by the Inventage Lab Precision Particle Fabrication method (IVL-PPFM®) based on micro-electromechanical systems (MEMS) and microfluidic technology. The types of polymers and end-groups, the drug/polymer ratio (DPR), and the routes of administration for DNP were studied to ensure an effective concentration and desired duration. Laser-light particle size analysis and scanning electron microscopy were used to characterization. Also, non-clinical animal models of beagle dogs are used to optimize DNP formulations and evaluate their pharmacokinetic properties. The PK results showed that the DPR was a critical factor in determining the exposure level and duration of DNR release. Furthermore, the lactide ratio, which varied depending upon the type of polymer, determined the hydrophobic interaction and was also an important factor affecting the desired DNP release. Since DNP shows a large inter-species variation between dogs and humans, PK modeling and simulation of the reference drug (i.e., Aricept®) and DNP-loaded microspheres were used for formulation development to overcome and interpret these variations. In addition, the developed PK model was extrapolated to humans using the estimated PK parameter and published clinical pharmacology data for DNP. The predicted PK profile of the DNP-loaded microsphere in humans showed that the formulation with PLGA 7525A and the DPR of 1/9 could maintain drug concentration for a month and could control initial burst release. The data obtained from the study could be used as scientific evidence for decision-making in future formulation development.

A controlled drug release formulation based on the subcutaneous injection of poly (lactic-co-glycolic acid) (PLGA) microspheres loaded with finasteride was prepared and evaluated for monthly delivery. After selection of biodegradable polymer and polymer-to-finasteride ratio, the formulation was characterized. Scanning electron microscopy (SEM) and laser-light particle size analysis were used to examine the morphology, surface structure, and particle size. High‑performance liquid chromatography (HPLC) was used to determine the drug loading, while liquid chromatography with tandem mass spectrometry (LC-MS/MS) was employed to analyze plasma finasteride concentrations. Results showed that the PLGA microspheres were spherical and of an appropriate size. The formulation stably releases the drug from the microspheres and the release sustained for a month without burst release, which was the desired duration. In vivo pharmacokinetic-pharmacodynamic (PK-PD) studies were conducted in beagle dogs through the administration of PROPECIA® (as a reference drug) per oral and subcutaneous injection of the long-acting injectable microsphere formulation (LAIF) loaded with five different doses of finasteride. From the acquired plasma data, PK-PD models for both PROPECIA®-administered group and LAIFs-injected groups were developed and validated. PK-PD profiles of both groups were predicted for up to one month. The predicted PK-PD profile of all LAIFs showed the achievability of monthly delivery and pharmacological effects without burst release, compared to the simulated PK-PD profile of PROPECIA®. According to the predicted PK-PD profiles, the formulation loaded with 16.8 mg of finasteride was determined to be the optimal dose. The data obtained from the PK-PD model could be used as the basis for the estimation of a first-in-human dose of the formulation.

Age-related macular degeneration (AMD) is wearing down of macula of retina, causing a blur or loss of vision in the center of the visual field. It can be categorized into dry or wet AMD. Until now, medical treatments for dry AMD have not been developed yet. The aim of this study was to evaluate pharmacokinetics (PKs) and tissue distribution of CK41016, a novel candidate for dry AMD, after intravenous (IV) or eye drop administration in rats and rabbits. In addition, a simple and sensitive bioanalytical method for CK41016 using ultra performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) was developed. PK parameters were estimated by compartmental analysis using a WinNonlin&reg, software version 8.1 (a Certara&trade, company). A PK model of CK41016 was well-described by the two-compartment model. The tissue-to-plasma partition coefficient (Kp) of CK41016 was the highest in the vitreous humor of rats and the cornea of rabbits after eye drop administration. In addition, the Caco-2 cell transporter assay confirmed that CK41016 was not an active substrate for the efflux transporter. In summary, the PKs and tissue distribution of CK41016 were successfully evaluated and investigated whether this drug was a substrate of efflux transporters.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have been used in various industrial applications for many years. Long-chain PFASs are ubiquitous in wildlife and are reported to have a long elimination half-life in biological systems. Moreover, significant gender difference exists in the elimination of PFASs, where less is eliminated in male than in female. Recently, PFASs manufacturers and agencies have tried to replace the use of long-chain PFASs with short-chain PFASs, since they are expected to exhibit less bioaccumulation potential. Nevertheless, the potential risk and the pharmacokinetic (PK) characteristics of the short-chain PFASs still remain unknown. This study aims to fill the knowledge gap on short-chain PFASs, perfluoropentanoic acid (PFPeA), in terms of its PK properties using non-linear mixed-effect modeling and to explore gender differences in rats. Animal studies were carried out following oral or intravenous administration of PFPeA in male and female rats at a dose of 0.5–10 mg/kg. Plasma, urine, feces and nine tissues were collected and analyzed using ultra-performance liquid chromatography–tandem mass spectrometry. PK findings revealed that the clearance and the inter-compartmental clearance were 1.75 and 3.12 times higher in female rats than in male rats, respectively. According to the result, PFPeA is eliminated more rapidly in female rats than in male rats. Also, the tissue distribution study confirmed that distribution characteristics exhibited gender difference. This study provides scientific evidence for conducting further investigation into short-chain PFASs, biomonitoring plans and decision making regarding human health risk assessment.

Extrapolation of pharmacokinetic (PK) parameters from in vitro or in vivo animal to human is one of the main tasks in the drug development process. Translational approaches provide evidence for go or no-go decision-making during drug discovery and the development process, and the prediction of human PKs prior to the first-in-human clinical trials. In vitro-in vivo extrapolation and allometric scaling are the choice of method for projection to human situations. Although these methods are useful tools for the estimation of PK parameters, it is a challenge to apply these methods since underlying biochemical, mathematical, physiological, and background knowledge of PKs are required. In addition, it is difficult to select an appropriate methodology depending on the data available. Therefore, this review covers the principles of PK parameters pertaining to the clearance, volume of distribution, elimination half-life, absorption rate constant, and prediction method from the original idea to recently developed models in order to introduce optimal models for the prediction of PK parameters.

Perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), which are classified as perfluoroalkyl and polyfluoroalkyl substances (PFASs), have been widely used in industrial applications as a surface protectant. PFASs have been detected in wildlife and in humans around the globe. The purposes of this study are to develop and validate a physiologically based pharmacokinetic (PBPK) model for detecting PFNA and PFDA in male and female rats, and to apply the model to a human health risk assessment regarding the sex difference. A PBPK model of PFNA and PFDA was established based on an in vivo study in male and female rats. Analytes in biological samples (plasma, nine tissues, urine, and feces) were determined by ultra-liquid chromatography coupled tandem mass spectrometry (UPLC–MS/MS) method. PFNA and PFDA showed a gender differences in the elimination half-life and volume of distribution. The tissue–plasma partition coefficients were the highest in the liver in both male and female rats. The predicted rat plasma and urine concentrations simulated and fitted were in good agreement with the observed values. The PBPK models of PFNA and PFDA in male and female rats were then extrapolated to a human PBPK model based on human physiological parameters. The external doses were calculated at 3.35 ng/kg/day (male) and 17.0 ng/kg/day (female) for PFNA and 0.530 ng/kg/day (male) and 0.661 ng/kg/day (female) for PFDA. Human risk assessment was estimated using Korean biomonitoring values considering the gender differences. This study provides valuable insight into human health risk assessment regarding PFNA and PFDA exposure.

This study aimed to describe the occurrence and to evaluate the predictive factors of thrombocytopenia caused by parenteral linezolid in hospitalised patients without haemato-oncologic diseases. Using electronic medical records, a retrospective safety evaluation was performed among all hospitalised adult patients who received parenteral linezolid therapy between January 2005 and June 2016. Of all identified 264 patients with an average age of 63.4 (SD 15.8) years, thrombocytopenia occurred at a rate of 29.2% after an average of 11.2 (SD 7.4) days of the initiation of linezolid therapy. Significant predictive factors for thrombocytopenia included the duration of linezolid therapy longer than or equal to 7 days (adjusted odds ratios [ORs] 7.25, 19.51 and 28.80; 95% confidence intervals [CIs] 1.92-27.38, 4.76-79.95 and 6.48-127.92 for 7-13 days, 14-20 days and ≥21 days, respectively; P < 0.01 for all values), baseline platelet count

Background: Interest in pharmacist participation in the multidisciplinary intensive care team is increasing. However, studies examining pharmacist interventions in the medical intensive care unit (MICU) are limited in Korea. The aim of this study was to describe the current status of pharmacist interventions and to identify common pharmacologic problems requiring pharmacist intervention in the MICU. Methods: Between September 2013 and August 2014, a retrospective, observational study was conducted in the 22-bed MICU at a university hospital. Data were obtained from two trained pharmacists who participated in MICU rounds three times a week. In addition to patient characteristics, data on the cause, type, related drug, and acceptance rate of interventions were collected. Results: In 340 patients, a total of 1211 pharmacologic interventions were performed. The majority of pharmacologic interventions were suggested by pharmacists at multidisciplinary rounds in the MICU. The most common pharmacologic interventions were adjustment of dosage and administration (n = 328, 26.0%), followed by parenteral/enteral nutritional support (n = 228, 18.1%), the provision of drug information (n = 228, 18.1%), and advice regarding pharmacokinetics (n = 118, 9.3%). Antimicrobial agents (n = 516, 42.6%) were the most frequent type of drug associated with pharmacist interventions. The acceptance rate of interventions was 84.1% with most accepted by physicians within 24 hours (n = 602, 92.8%). Conclusions: Medication and nutritional problems are frequently encountered pharmacotherapeutic problems in the MICU. Pharmacist interventions play an important role in the management of these problems.