Rising Temperature Effects on Growth and Gastric Emptying Time of Freshwater African Catfish (Clarias Gariepinus) Fingerlings

The present study was carried out to analyse the effect of water temperature on two components: (1) growth performance, and (2) gastric emptying time (GET) of African catfish Clarias gariepinus fingerlings. After 70 days, it was observed that experimental temperatures had no significant effects on the growth performance parameters, except for food conversion ratio (FCR) and food conversion efficiency (FCE). GET observation through X-radiography denoted that the shortest GET (10 h) was observed in fish reared at 32 °C and the longest GET (16 h) was observed in fish reared at 26 °C. The rapid digestion rate coincides with the FCR and FCE obtained in this study. Considering the limited scope of our study, more extensive studies on the impact of water temperature on other fish physiological parameters should be pursued. A better understanding of this research topic would be beneficial for the growth of African catfish fingerling aquaculture.

Sizing Directional Pneumatic Valves Based on the Characteristic Dynamic Behavior of Linear Actuators

In this paper, a novel approach to size directional pneumatic valves based on the analysis of the characteristic behavior of pneumatic actuators applied for pick and place tasks is presented. The study evidences the existence of three characteristic times in the displacement of a standard pneumatic actuation system, which are the emptying time, the transient-state time, and the steady-state time. The results also indicate that there is a close correlation between the velocity profile and the relative size of the piston area, where the steady-state time might be negligible when the piston is correctly sized. The emptying time, characterized by the depressurization of the counterpressure chamber, occurs predominantly with choked mass flow rate and constant volume. In this way, an analytical equation to estimate the emptying time has been determined. Moreover, during the transient-state time, the velocity profile is similar to the characteristic behavior of a first order system, therefore, the transient-state time is estimated by the time constant of the system, which was obtained by a linear first order model developed using the fundamental equations that govern the system behavior. The total displacement time, which is a design requirement to size directional valves, can be expressed as the sum of the emptying and transient-state time. Consequently, a set of equations are proposed to size the directional valve using design parameters such as displacement time, piston volume, load force, and supply pressure. The proposed equations were evaluated along with simulation and experimental results, demonstrating their validity and accuracy.

Bioequivalence of Oral Drug Products in the Healthy and Special Populations: Assessment and Prediction Using a Newly Developed In Vitro System “BE Checker”

In order to assess and predict the bioequivalence (BE) of oral drug products, a new in vitro system “BE checker” was developed, which reproduced the environmental changes in the gastrointestinal (GI) tract by changing the pH, composition, and volume of the medium in a single chamber. The dissolution and membrane permeation profiles of drugs from marketed products were observed in the BE checker under various conditions reflecting the inter-patient variations of the GI physiology. As variable factors, initial gastric pH, gastric emptying time, and GI agitation strength were varied in vitro. Dipyridamole, a basic drug, showed rapid and supersaturated dissolution when the paddle speed in the donor chamber was 200 rpm, which corresponds to the high agitation strength in the stomach. In contrast, supersaturated dissolution disappeared, and the permeated amount decreased under the conditions with a slow paddle speed (100 and 50 rpm) and short gastric emptying time (10 min). In those conditions, disintegration of the formulation was delayed, and the subsequent dissolution of dipyridamole was not completed before the fluid pH was changed to neutral. Similar results were obtained when the initial gastric pH was increased to 3.0, 5.0, and 6.5. To investigate that those factors also affect the BE of oral drug products, dissolution and permeation of naftopidil from its ordinary and orally disintegrating (OD) tablets were observed in the BE checker. Both products showed the similar dissolution profiles when the paddle speed and gastric emptying time were set to 100 rpm and 10 or 20 min, respectively. However, at a low paddle speed (50 rpm), the dissolution of naftopidil from ordinary tablets was slower than that from the OD tablets, and the permeation profiles became dissimilar. These results indicated the possibility of the bioinequivalence of some oral formulations in special patients whose GI physiologies are different from those in the healthy subjects. The BE checker can be a highly capable in vitro tool to assess the BE of oral drug products in various populations.

Meta-Analysis of Food Effect on Oral Absorption of Efflux Transporter Substrate Drugs: Does Delayed Gastric Emptying Influence Drug Transport Kinetics?

The oral route of drug administration is the most convenient method of drug delivery, but it is associated with variable bioavailability. Food is one of the major factors that affect oral drug absorption by influencing drug properties (e.g., solubility and dissolution rate) and physiological factors (e.g., metabolism and transport across the gastrointestinal tract). The aim of this work was to investigate the effect of food on the high-affinity intestinal efflux transporter substrate drugs. We hypothesized that transport efficiency is higher in the fed state as compared to the fasted state because of the lower intestinal lumen drug concentration due to prolonged gastric emptying time. A systematic analysis of reported clinical food-effect (FE) studies on 311 drugs was performed and the association of the efflux transport efficiency was investigated on the FE magnitude, i.e., changes in maximal plasma concentration and area under the plasma concentration–time profile curve for both solubility and permeability-limited drugs. In total, 124 and 88 drugs showed positive and negative FE, respectively, whereas 99 showed no FE. As expected, the solubility-limited drugs showed positive FE, but interestingly, drugs with a high potential for efflux transport, were associated with negative FE. Moreover, a high-fat diet was associated with a higher magnitude of negative FE for high-affinity efflux transporter substrates as compared to a low-fat diet. To account for changes in drug absorption after food intake, the prolonged gastric emptying time should be considered in the physiologically based pharmacokinetic (PBPK) modeling of orally absorbed efflux transporter substrate drugs.

The Effect of Sagunja Decoction on Functional Dyspepsia - A Systematic Review and Meta-Analysis

Objectives: This study examines the effect of Sagunja-tang on functional dyspepsia (FD) through a systematic review and meta-analysis of a randomized controlled trial (RCT). Methods: A search for RCTs that tested the effect of Sagunja-tang on functional dyspepsia was conducted in Medline, Embase, PubMed, CENTRAL, CiNii, CNKI, NDSL, RISS, OASIS, and KISS databases on November 8, 2020, with no limit on the year of publication. A meta-analysis was performed by synthesizing the findings, including total efficiency, clinical symptom score, myosin light-chain kinase (MLCK) level (pg/mL, and gastric half-emptying time (min). RevMan 5.4.1 software was used for data analysis. The quality of the literature was evaluated using Cochrane’s risk of bias (RoB) tool. Results: A total of 14 RCTs met the selection criteria. As a result of the meta-analysis, the treatment group had higher total efficacy and MLCK levels (gastric antrum, jejunum) than the control group, and the clinical symptom score and gastric half-emptying time were lower. However, due to the low quality of the included RCT and the small sample size, the results may be slightly biased.