Evaluating the Bioavailability of Carbamazepine Using a Novel SNEDDS Formulation

Carbamazepine (CBZ) is an anticonvulsant drug primarily used to treat epilepsy, bipolar disorder, trigeminal and glossopharyngeal neuralgia. CBZ is a lipophilic, poorly soluble drug that belongs to the class-2 category according to the Biopharmaceutics Classification System. As a class-2 drug, the plasma concentration of CBZ is limited by its ability to diffuse across biological membranes. To increase its bioavailability, different methods such as crystal modifications, particle size reduction, amorphization, cyclodextrin complexation, pH modification, and self-emulsification were explored. Of these methods, Self Nano Emulsifying Drug Delivery Systems (SNEDDS) have shown to reduce particle size of CBZ molecules and improve its solubility. However, the bioavailability of CBZ administered as SNEDDS are not yet investigated. Given this background, the current study proposes to evaluate the bioavailability of these novel drug delivery systems using a rat model. The study is designed as a randomized controlled crossover experiment using 10-12 Sprague-Dawley rats divided equally into two groups. For this study, blood samples will be collected at 5, 10, 15, 20, 30, 45, 60, 90, and 120 minutes after administering two different formulations of CBZ nanoemulsions and stored at -20°C until ready for analysis. Plasma concentrations of CBZ will be determined by HPLC method. An unpaired t-test will be used to compare the significance between the two sets of data

Evaluating the Bioavailability of Carbamazepine Using a Novel SNEDDS Formulation

Central to the mechanism of how drugs work are the concepts of solubility and bioavailability. Drugs enter the body via absorption into the bloodstream, arrive at the target location, and bind to receptors to cause an effect. Drugs need to be soluble enough to pass through the cell membrane to enter and exit the bloodstream. Higher solubility generally correlates to higher bioavailability. Additionally, the smaller the particle size, the easier the drug will pass through the membrane into the blood plasma. Researchers have designed a system to categorize solubility class: Class I being high permeability and high solubility, Class II high permeability and low solubility, Class III low permeability and high solubility, and Class IV low permeability and low solubility. The study will use a Class II anticonvulsant, carbamazepine (CBZ). CBZ is a suitable candidate for this study because it requires a higher bioavailability due to its need to cross the blood brain barrier and act on the trigeminal nucleus. To increase bioavailability researchers have tried crystal modifications, particle size reduction, amorphization, cyclodextrin complexation, pH modification, and self-emulsification. These methods have been successful at increasing bioavailability, but this experiment will focus on reducing particle size into a new self-emulsifying formulation. In particular, the formulation of CBZ in this study is a self nano-emulsifying drug delivery system (SNEDDS), which shows more promise than previous methods to increase bioavailability. This study will create a SNEDDS formulation as a nasal nebulizer mist delivery and compare it to a FDA approved oral suspension using a crossover rat model design. Sixteen Sprague-Dawley rats will be ordered through Central State University and normalized to the study environment for a minimum of one week. Pending IACUC approval from Central State University, the tail vein method will be used to collect blood samples. The samples will be stored until needed for analysis using ELISA, enzyme-linked immunosorbent assay, which will be used to determine the concentration of CBZ in blood plasma

Jinwon Byun

https://digitalcommons.cedarville.edu/white_coat_ceremony_gallery_2013/1021/thumbnail.jp

Design of a circular dual-loop antenna for a GPS array element using an extended cavity structure

This article proposes a circular dual-loop antenna for a very small Global Positioning System array with an extended cavity structure. The antenna element consists of lower and upper circular loops printed on a high-dielectric ceramic substrate and an extended cavity structure above the ground plane to improve the isolation characteristic. To demonstrate the suitability of the proposed antenna, antenna characteristics are measured in a full-anechoic chamber, and its performances such as bore-sight gain, mutual coupling, and near-field as a function of extended cavity height are analyzed. The results confirm that the proposed antenna structure can minimize the gain degradation by improving the isolation characteristic and is therefore suitable for use in very small arrays

The Analgesic Efficacy of the Single Erector Spinae Plane Block with Intercostal Nerve Block Is Not Inferior to That of the Thoracic Paravertebral Block with Intercostal Nerve Block in Video-Assisted Thoracic Surgery

This monocentric, single-blinded, randomized controlled noninferiority trial investigated the analgesic efficacy of erector spinae plane block (ESPB) combined with intercostal nerve block (ICNB) compared to that of thoracic paravertebral block (PVB) with ICNB in 52 patients undergoing video-assisted thoracic surgery (VATS). The endpoints included the difference in visual analog scale (VAS) scores for pain (0–10, where 10 = worst imaginable pain) in the postanesthetic care unit (PACU) and 24 and 48 h postoperatively between the ESPB and PVB groups. The secondary endpoints included patient satisfaction (1–5, where 5 = extremely satisfied) and total analgesic requirement in morphine milligram equivalents (MME). Median VAS scores were not significantly different between the groups (PACU: 2.0 (1.8, 5.3) vs. 2.0 (2.0, 4.0), p = 0.970; 24 h: 2.0 (0.8, 3.0) vs. 2.0 (1.0, 3.5), p = 0.993; 48 h: 1.0 (0.0, 3.5) vs. 1.0 (0.0, 5.0), p = 0.985). The upper limit of the 95% CI for the differences (PACU: 1.428, 24 h: 1.052, 48 h: 1.176) was within the predefined noninferiority margin of 2. Total doses of rescue analgesics (110.24 ± 103.64 vs. 118.40 ± 93.52 MME, p = 0.767) and satisfaction scores (3.5 (3.0, 4.0) vs. 4.0 (3.0, 5.0), p = 0.227) were similar. Thus, the ESPB combined with ICNB may be an efficacious option after VATS

Towards Robust Calculation of Interannual CO2 Growth Signal from TCCON (Total Carbon Column Observing Network)

The CO2 growth rate is one of the key geophysical quantities reflecting the dynamics of climate change as atmospheric CO2 growth is the primary driver of global warming. As recent studies have shown that TCCON (Total Carbon Column Observing Network) measurement footprints embrace quasi-global coverage, we examined the sensitivity of TCCON to the global CO2 growth. To this end, we used the aggregated TCCON observations (2006-2019) to retrieve Annual Growth Rate of CO2 (AGR) at global scales. The global AGR estimates from TCCON (AGRTCCON) are robust and independent, from (a) the station-wise seasonality, from (b) the differences in time series across the TCCON stations, and from (c) the type of TCCON stations used in the calculation (“background” or “contaminated” by neighboring CO2 sources). The AGRTCCON potential error, due to the irregular data sampling is relatively low (2.4–17.9%). In 2006–2019, global AGRTCCON ranged from the minimum of 1.59 ± 2.27 ppm (2009) to the maximum of 3.27 ± 0.82 ppm (2016), whereas the uncertainties express sub-annual variability and the data gap effects. The global AGRTCCON magnitude is similar to the reference AGR from satellite data (AGRSAT = 1.57–2.94 ppm) and the surface-based estimates of Global Carbon Budget (AGRGCB = 1.57–2.85). The highest global CO2 growth rate (2015/2016), caused by the record El Niño, was nearly perfectly reproduced by the TCCON (AGRTCCON = 3.27 ± 0.82 ppm vs. AGRSAT = 3.23 ± 0.50 ppm). The overall agreement between global AGRTCCON with the AGR references was yet weakened (r = 0.37 for TCCON vs. SAT; r = 0.50 for TCCON vs. GCB) due to two years (2008, 2015). We identified the drivers of this disagreement; in 2008, when only few stations were available worldwide, the AGRTCCON uncertainties were excessively high (AGRTCCON = 2.64 ppm with 3.92 ppm or 148% uncertainty). Moreover, in 2008 and 2015, the ENSO-driven bias between global AGRTCCON and the AGR references were detected. TCCON-to-reference agreement is dramatically increased if the years with ENSO-related biases (2008, 2015) are forfeited (r = 0.67 for TCCON vs. SAT, r = 0.82 for TCCON vs. GCB). To conclude, this is the first study that showed promising ability of aggregated TCCON signal to capture global CO2 growth. As the TCCON coverage is expanding, and new versions of TCCON data are being published, multiple data sampling strategies, dynamically changing TCCON global measurement footprint, and the irregular sensitivity of AGRTCCON to strong ENSO events; all should be analyzed to transform the current efforts into a first operational algorithm for retrieving global CO2 growth from TCCON data

In Situ Aircraft Measurements of CO2 and CH4: Mapping Spatio-Temporal Variations over Western Korea in High-Resolutions

A cavity ring-down spectroscopy (CRDS) G-2401m analyzer onboard a Beechcraft King Air 350, a new Korean Meteorological Administration (KMA) research aircraft measurement platform since 2018, has been used to measure in situ CO2, CH4, and CO. We analyzed the aircraft measurements obtained in two campaigns: a within-boundary layer survey over the western Republic of Korea (hereafter Korea) for analyzing the CO2 and CH4 emission characteristics for each season (the climate change monitoring (CM) CM mission), and a low altitude survey over the Yellow Sea for monitoring the pollutant plumes transported into Korea from China (the environment monitoring (EM) mission). This study analyzed CO2, CH4, and CO data from a total of 14 flights during 2019 season. To characterize the regional combustion sources signatures of CO2 and CH4, we calculated the short-term (1-min slope based on one second data) regression slope of CO to CO2 and CH4 to CO enhancements (subtracted with background level, present as ∆CO, ∆CO2, and ∆CH4); slope filtered with correlation coefficients (R2) (<0.4 were ignored). These short-term slope analyses seem to be sensitive to aircraft measurements in which the instrument samples short-time varying mixtures of different air masses. The EM missions all of which were affected by pollutants emitted in China, show the regression slope between ∆CO and ∆CO2 with of 1.8–6% and 0.3–0.7 between ∆CH4 and ∆CO. In particular, the regression slope between ∆CO and ∆CO2 increased to >4% when air flows from east-central China such as Hebei, Shandong, and Jiangsu provinces, etc., sustained for 1–3 days, suggesting pollutants from these regions were most likely characterized by incomplete fossil fuel combustions at the industries. Over 80% of the observations in the Western Korea missions were attributed to Korean emission sources with regression slope between ∆CO and ∆CO2 of 0.5–1.9%. The CO2 emissions hotspots were mainly located in the north-Western Korea of high population density and industrial activities. The higher CH4 were observed during summer season with the increasing concentration of approximately 6% over the background level, it seems to be attributed to biogenic sources such as rice paddies, landfill, livestock, and so on. It is also noted that occurrences of high pollution episodes in North-Western Korea are more closely related to the emissions in China than in Korea

Direct electron injection into an oxide insulator using a cathode buffer layer

interior, courtyar