Slower Absorption Rate Research Articles

Dopamine‐modified Highly Dispersed ZIF‐8 to Promote CO2 Absorption

AbstractCO2 capture technology has been widely used to reduce CO2 emissions, resulting in a variety of capture methods and materials. Among them, the more widely used is the chemical absorption method. However, the chemical absorption method has problems such as high energy consumption and slow absorption rate. In order to solve the above problems, we prepared an effective catalyst to improve the CO2 absorption rate. ZIF‐8 and hydrophilic ZIF‐8‐DA were prepared by in situ synthesis under ambient conditions. The catalytic effect of the hydration reaction of ZIF‐8 and ZIF‐8‐DA was tested using CO2 absorption regeneration experiments under aqueous and alkaline conditions, respectively. The results showed that the synthesized catalysts could significantly enhance the CO2 absorption in water and alkaline solution. The addition of 0.1 wt % of ZIF‐8 in alkaline solution increased the average CO2 absorption by 1.80–15.84 %, respectively, while the addition of 0.1 wt % of ZIF‐8‐DA increased the CO2 absorption by 7.01–25.36 %. In addition, both catalysts had excellent reusability and maintained high performance even after five absorption and regeneration cycles. Polymer dispersibility index (PDI) results showed that ZIF‐8‐DA dispersed more uniformly in aqueous solution.

Pharmacokinetic and Pharmacodynamic Interaction of Finerenone with Diltiazem, Fluconazole, and Ritonavir in Rats.

Finerenone, a novel selective non-steroidal mineralocorticoid receptor antagonist, has been indicated in chronic kidney disease associated with type 2 diabetes mellitus. Considering the potential complications of diabetes, finerenone can be co-administered with various drugs, including fluconazole, diltiazem, and ritonavir. Given that finerenone is a substrate of cytochrome P450 (CYP) 3A4, the concurrent administration of finerenone with CYP3A4 inhibitors (diltiazem or fluconazole or ritonavir) could potentially lead to drug interactions, which may cause adverse events such as hyperkalemia. No studies have investigated interactions between finerenone and diltiazem or fluconazole or ritonavir. Therefore, this study aims to investigate the pharmacokinetic interaction of finerenone with diltiazem or fluconazole or ritonavir and to evaluate the impact of fluconazole on the pharmacodynamics of finerenone. The pharmacokinetic study included four rat groups (n=8 rats/group), including a control group (finerenone alone) and test groups (finerenone pretreated with diltiazem or fluconazole or ritonavir) using both non-compartment analysis (NCA) and population pharmacokinetic (pop-PK) modeling. The pop-PK model was developed using non-linear mixed-effects modeling in NONMEM® (version 7.5.0). In the pharmacodynamic study, serum potassium (K+) levels were measured to assess the effects of fluconazole on finerenone-induced hyperkalemia. The NCA results indicated that the area under the plasma concentration-time curve (AUC) of finerenone increased by 1.86- and 1.95-fold when coadministered with fluconazole and ritonavir, respectively. In contrast, diltiazem did not affect the pharmacokinetics of finerenone. The pharmacokinetic profiles of finerenone were best described by a one-compartment disposition with first-order elimination and dual first-order absorption kinetics. The pop-PK modeling results demonstrated that the apparent clearance of finerenone decreased by 50.3% and 49.2% owing to the effects of fluconazole and ritonavir, respectively. Additionally, the slow absorption rate, which represents the absorption in the distal intestinal tract of finerenone, increased by 55.7% due to the effect of ritonavir. Simultaneously, a pharmacodynamic study revealed that finerenone in the presence of fluconazole caused a significant increase in K+ levels compared with finerenone alone. Coadministration of finerenone with fluconazole or ritonavir increased finerenone exposure in rats. Additionally, the administration of finerenone in the presence of fluconazole resulted in elevated K+ levels in rats. Further clinical studies are required to validate these findings.

A novel macroporous carboxymethyl chitosan/sodium alginate sponge dressing capable of rapid hemostasis and drug delivery

Carboxymethyl chitosan (CMCS) and sodium alginate (SA), which are excellent polysaccharide-based hemostatic agents, are capable of forming polyelectrolyte complexes (PEC) through electrostatic interactions. However, CMCS/SA PEC sponges prepared by the conventional sol-gel process exhibited slow liquid absorption rate and poor mechanical properties post-swelling. In this work, a novel strategy involving freeze casting followed by acetic acid vapor treatment to induce electrostatic interactions was developed to fabricate novel PEC sponges with varying CMCS/SA mass ratios. Compared to sol-gel process sponge, the novel sponge exhibited a higher density of electrostatic interactions, resulting in denser pore walls that resist re-gelation and swelling according to FTIR, XRD, and SEM analyses. Additionally, the liquid absorption kinetics, as well as compression and tension tests, demonstrated that the novel sponge had significantly improved rapid blood absorption capacity and mechanical properties. Furthermore, in vitro coagulation and drug release studies showed that the novel sponge had a lower blood clotting index and clotting time, along with a slower drug release rate after loading with berberine hydrochloride, showcasing its potential as a rapid hemostatic dressing with controlled drug release capabilities.

Mass transfer and kinetic measurement and modeling for CO2 absorption into aqueous EAE and water-lean EAE/NMP solvents

Chemical absorption using amine solvent is currently available technology for CO2 capture from post-combustion flue gas. It is hindered by high operating cost and high capital cost due to high regeneration energy and slow CO2 absorption rate of amine solvent. Water-lean solvent of 2-(ethylamino) ethanol (EAE)/1-methyl-2-pyrrolidinone (NMP)/water could be a potential solution as it achieved significantly low regeneration energy of 2.3 GJ/tCO2 tested in a pilot plant. However, kinetics of CO2 reaction with EAE and mass transfer rate of CO2 absorption into EAE/NMP solvent are not fully understood. In this work, kinetics of CO2 absorption into unloaded aqueous EAE in 1–5 mol/L at 300–313 K and mass transfer of CO2 absorption into CO2-loaded EAE/NMP water-lean solvent in 5 mol/L with equilibrium CO2 partial pressure (PCO2*) range of 0.3–7 kPa at 312 K were studied in a wetted wall column. Kinetic data of aqueous EAE is interpreted by zwitterion mechanism, and the reaction is of first order with respect to EAE concentration in 1–5 mol/L at 300–313 K. CO2 absorption rate (kg’) of EAE/NMP water-lean solvent is 1.3–2.1 times greater than aqueous EAE due to the greater CO2 physical solubility. At lean and rich loading conditions, 5 M EAE in 3NMP/1water and 9NMP/1water show 2–7 times faster kg’ than 30 % MEA, and 1.4–2.5 times faster kg’ than 30 % PZ. It is found that EAE activity coefficient may increase in the presence of NMP in the solvent, and the estimated EAE activity coefficient in 1NMP/1water, 3NMP/1water, and 9NMP/1water are 2.13, 3.50, and 4.72, respectively. CO2 capacity of EAE/NMP solvent is 2–3.7 times greater than 30 % MEA and 1.2–2 times greater than 30 % PZ.

Structural investigation of aqueous amine solutions for CO2 capture: CO2 loading, cyclic capacity, absorption–desorption rate, and pKa

Understanding the CO2 capture performance of individual amines based on their structure is essential for efficient CO2 capture. In this study, the effects of the molecular structure of amine on CO2 loading, cyclic capacity, absorption–desorption rate, and pKa were investigated, and promising candidates for CO2 capture, along with an amine blending strategy, were proposed. The results showed that electron-donating alkyl groups increased the CO2 loading by increasing the electron density and pKa of the amino groups, whereas the electron-withdrawing hydroxyl group exhibited the opposite effect. Thirty amines were tested and categorized into Group A, B, C, and D based on CO2 absorption rate and cyclic capacity. Amines in Group B had a slow absorption rate but high cyclic capacity and included sterically hindered primary or secondary amines (2-amino-2-methyl-1-propanol, 2-(isopropylamino)ethanol, and 2-(tert-butylamino)ethanol) and sterically hindered tertiary amines with one hydroxyl group on the β–carbon (1-dimethylamino-2-propanol, 1-(2-hydroxyethyl)piperidine, N,N-diethylethanolamine and 1-diethylamino-2-propanol). The best-performing amines, Group A, were primarily multiamines (1-(2-hydroxyethyl)piperazine, 2-methylpiperazine, 2-(2-aminoethylamino)ethanol, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-diaminopropane, hexamethylenediamine, diethylenetriamine, and 3,3’-diamno-N-methyldipropylamine) and included a sterically hindered heterocyclic secondary amine (2-piperidineethanol) with a hydroxyalkyl substituent on the α–carbon. Thus, amines in Group A are promising absorbents for CO2 capture, and blending amines in Group B with amines that have a high CO2 absorption rate (e.g., Group A) can also be a potential strategy for efficient CO2 capture.

Enhancing solar-driven atmospheric water harvesting by a bilayer macroporous hydrogel

The adsorption-based atmospheric water harvesting technique has shown great potential in providing clean water. An ideal device for atmospheric water harvesting should enable the massive and quick release of water after it is rapidly absorbed by the moisture adsorbent. At present, however, the moisture adsorbent still experiences issues such as a slow water absorption rate, hampered adsorption–desorption kinetics, and a low total water yield. In this paper, a bilayer moisture adsorbent (BMA), which glues a hydrophilic macroporous layer for rapid water adsorption and a carbonized sunlight-absorbing layer for both water harvesting and desorption acceleration, is introduced. Further evidence suggests that it is the stable, fluffy, and rough porous structure of the BMA that helps to harvest atmospheric water efficiently. The fully carbonized BMA exhibits a water absorption capacity of up to 396% at a relative humidity of 90%, which is 20% higher than a monolayer sample. More importantly, the desorption efficiency of the half-carbonized BMA reaches 98% under 1 sun illumination. These results jointly demonstrate that the BMA can play the dual role of absorbing moisture and light, allowing for rapid atmospheric water harvesting, massive water storage, and efficient desorption under the light.

Rivastigmine nasal spray for the treatment of Alzheimer’s Disease: Olfactory deposition and brain delivery

Alzheimer’s disease (AD) is characterized by a gradual decline in cognitive function and memory impairment, significantly impacting the daily lives of patients. Rivastigmine (RHT), a cholinesterase inhibitor, is used to treat mild to moderate AD via oral administration. However, oral administration is associated with slow absorption rate and severe systemic side effects. RHT nasal spray (RHT-ns), as a nose-to-brain delivery system, is more promising for AD management due to its efficient brain delivery and reduced peripheral exposure. This study constructed RHT-ns for enhancing AD treatment efficacy, and meanwhile the correlation between drug olfactory deposition and drug entering into the brain was explored. A 3D-printed nasal cast was employed to quantify the drug olfactory deposition. Brain delivery of RHT-ns was quantified using fluorescence tracking and Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) analysis, which showed a good correlation to the olfactory deposition. F2 (containing 1% (w/v) viscosity modifier Avicel® RC-591) with high olfactory deposition and drug brain delivery was further investigated for pharmacodynamics study. F2 exhibited superiority in AD treatment over the commercially available oral formulation. In summary, the present study showed the successful development of RHT-ns with improved olfactory deposition and enhanced brain delivery. It might provide new insight into the design and development of nose-to-brain systems for the treatment of AD.

Comparative Pharmacokinetic Study of Rhubarb Anthraquinones in Normal and Nonalcoholic Fatty Liver Disease Rats.

Rhubarb anthraquinones contain five main components, that is, rhein, emodin, aloe-emodin, chrysophanol, and physcion, which demonstrate good therapeutic effects on nonalcoholic fatty liver disease (NAFLD). However, research on its pharmacokinetics in NAFLD remains lacking. This study aimed to investigate the pharmacokinetic differences of rhubarb anthraquinones in normal and NAFLD rats. This study developed an NAFLD rat model by high-fat diet feeding for 6weeks. Normal and NAFLD groups were orally administered different rhubarb anthraquinones doses (37.5, 75, and 150mg/kg). The concentration of the rhein, emodin, aloe-emodin, chrysophanol, and physcion in plasma was determined by high-performance liquid chromatography-ultraviolet. The results revealed significant differences in pharmacokinetic behavior between normal and NAFLD rats. Compared with normal rats, NAFLD rats demonstrated significantly increased maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC0 → ∞) of rhubarb anthraquinones (P<0.05), as well as significantly prolonged time to reach maximum plasma concentration (Tmax), terminal elimination half-life (t1/2), and mean residence time (MRT) of rhubarb anthraquinones (P<0.05). This study indicates significant differences in the pharmacokinetics of rhubarb anthraquinones between the physiological and NAFLD states of rats. Rhubarb anthraquinone demonstrated a longer retention time and slower absorption rate in NAFLD rats and exhibited higher bioavailability and peak concentration. This finding provides important information for guiding the clinical use of rhubarb anthraquinones under pathological conditions.

Portable Disc Granulator Machine

This work presents the design of a portable disc granulator machine to produce granule shape fertilizer from a powdered mixture. The industry demands granular fertilizer made from chemical substances due to the benefits that can be obtained compared to fine powder fertilizer. It has a longer lifespan of up to 9 months and a slow rate of nitrogen absorption from fertilizer because of its granular form. Granular fertilizers are easy to store and do not settle out over time, or salt out in cold weather. Fertilizer plays the role of a plant food element and is crucial to maintaining the health of plants for their growth. The pharmaceutical method is frequently used by farmers to create fertilizer in the form of granules which are wet granulation and dry granulation process. Wet granulation was employed in this project since it involves the addition of liquids like molasses or water. The portable disc granulator machine is designed to turn fertilizer into granule shapes, which are subsequently used as the product's base material. However, the fertilizer must be produced a uniform ±5 mm diameter of granular shape for bio-organic fertilizer. Solidification has been made to improve the fertilizer’s granular shape to create a consistent ±5 mm diameter in the disc that rotates automatically with an angle of 48°. A disc granulator machine should first be filled with bio-organic fertilizer. Then, use brown sugar solution or cornstarch to form a granule shape. The disc will be rotating at a speed of 11 to 15 rpm. To assess the machine's ability to create granules with a diameter of about 5 mm, evaluation, and analysis were performed using a vernier caliper. The result demonstrated that the machine could produce ±5 mm with a tolerance of 1 mm and uniformity will be constant.

Research and prospect of inclusion complexes of dexibuprofen -cyclodextrin

Dexibuprofen is an over-the-counter drug often used to relieve pain and reduce fever. However, dexibuprofen is less soluble in the gastrointestinal tract, resulting in a slower rate of absorption. In order to enhance the bioavailability, researchers have devised inclusion complexes including dexibuprofen and cyclodextrin. -cyclodextrin is a cyclic molecule characterized by its annular configuration and possesses a distinctive void structure that enables the entrapment of other molecules via an enveloping mechanism, ultimately leading to the formation of a robust inclusion complex. The incorporation of dexibuprofen into an inclusion complex resulted in enhanced stability, higher aqueous solubility, and improved oral bioavailability. Furthermore, the incorporation of the inclusion complex can potentially mitigate the gastric mucosa irritation caused by dexibuprofen and minimize the gastrointestinal tract's unfavorable effects via the inclusion combination. The inclusion complex of dexibuprofen and -cyclodextrin is a form of drug with improved solubility and bioavailability that has broad application prospects to provide more effective pain relief and fever treatment. This study focuses on the investigation of the preparation and identification of dexibuprofen clathrate through a comprehensive analysis of existing literature. The primary objective is to determine the most effective inclusion technique for dexibuprofen based on considerations of yield and clathrate rate. Additionally, the research article examined the methodology for the formulation of clathrate into dispersible tablets, along with an initial investigation into the pharmacokinetics of these tablets in rat models.

Enigma of Intramuscular Triamcinolone Acetonide (Kenalog®) Efficacy.

Triamcinolone acetonide is a glucocorticosteroid used in standard clinical practice for its anti-inflammatory properties. Although it can be given via different routes of administration, the intramuscular route is unique compared with other corticosteroids-its effects remain potent over a longer period of time. We summarize the existing literature on the pharmacokinetic and pharmacodynamic mechanisms of intramuscular triamcinolone acetonide (Kenalog®). The fascinating nature of the purported efficacy of triamcinolone acetonide may be attributed to differing binding mechanisms, low solubility in blood, a low renal clearance rate, and various metabolites and other yet defined effects on skin. The enigma of the purported efficacy of triamcinolone acetonide may lie in the fact that it has a unique nature of having a long-term effect on dermatologic disease using a seemingly low dose compared with other routes of administration and other corticosteroids. Possible reasons for this may be binding differences at the intramuscular site, low solubility due to acetonide esters, a slow rate of absorption from the injected site, and a low renal clearance rate. There is still much to be learned about its mechanism of action, which may be of clinical and therapeutic significance.

Bench-scale CO2 capture using water-lean solvent of 2-(ethylamino) ethanol, 1-methyl-2-pyrrolidinone, and water

Water-lean amine are promising solvent for CO2 capture to significantly reduce regeneration energy. However, existing water-lean solvent hasn’t been put into commercial application due to high reaction heat, slow CO2 absorption rate, and high amine volatility of amine. In this paper, amines with one secondary amino (—NH), one hydroxyl (—OH), and carbon chain length between 3 and 6 (C3-C6) in structure were preferred for water-lean solvent in the light of amine structure–activity relationship. 2-(ethylamino) ethanol (EMEA) dissolving into 1-methyl-2-pyrrolidinone (NMP) and water were favorable water-lean solvent for CO2 capture, and EMEA/NMP was tested in a bench-scale platform. EMEA/NMP solvents have equivalent CO2 removal efficiencies, and 40–69% lower regeneration energy compared to blended amines and MEA solvents. The lower regeneration energy of EMEA/NMP results from lower water vapor ratio, lower reaction heat, and lower heat capacity. Viscosity of EMEA/NMP at rich loading is 6.92–11.11 mPa·s at 40℃. Increased stripper temperature increases CO2 removal efficiency by decreasing lean loading in EMEA/NMP solvents. CO2 desorption dominates mass transfer in stripper at low temperature while water evaporation dominates at high temperature. The lowest regeneration energy obtained with 5.0 M EMEA/NMP at liquid/gas ratio of 10.5 L/m3 and stripper temperature of 80℃ was 0.99 kWh/kg CO2 (equivalent to 3.6 GJ/tCO2), which is 69% lower than that of 5 M MEA. EMEA/NMP has an increasing amine emission from 109 to 1891 mg/m3 as absorber temperature increases from 34℃ to 54℃. Advanced processes would be employed for volatile amine emission control in future study.

Effects of Intradermal Administration Volume Using a Hollow Microneedle on the Pharmacokinetics of Fluorescein Isothiocyanate Dextran (M.W. 4,000).

Hollow microneedles (hMNs) have been gaining attention as a tool to enable the intradermal (i.d.) administration of pharmaceutical products. However, few reports have examined the effect of administration volume on distribution in the skin and pharmacokinetics parameters after i.d. injection. In the present study, a model middle molecular weight compound, fluorescein isothiocyanate dextran (M.W. 4,000, FD-4), was selected, and blood concentration-time profiles after i.d. and subcutaneous (s.c.) injections with different administration volumes were compared. FD-4 solution was injected i.d. using a hMN or injected s.c. with a 27 G needle. Pharmacokinetics and dermatokinetics of FD-4 were analyzed using a compartment model. The skin distribution of iodine, as an X ray tracer, was used to evaluate drug disposition. With the administered drug assumed to be absorbed from the broad injection site into blood vessels in the upper and lower dermis by rapid (krapid) and slow (kslow) first-order absorption rate constants, respectively, better agreement of observed and theoretical values was obtained. Furthermore, the fraction, F, of the administered dose absorbed with krapid decreased with the increase in injection volume after i.d. injection, although the pharmacokinetics parameters were almost the same regardless of administration volume after s.c. injection. The drug distribution in the skin may be related to the obtained pharmacokinetics parameters suggested that the number of needles in the MN system and the total administration volume should be considered in designing hMN systems. The present results provide useful information that may support effective drug delivery with hMNs.

Efficient SO2 capture at ultra-low concentration using a hybrid absorbent of deep eutectic solvent and ethylene glycol

Deep eutectic solvents (DESs) are considered as the highly effective absorbents for sulfur dioxide (SO2) capture. However, the high viscosity of DESs and the resulting slow absorption rate as well as low absorption capacity at low SO2 concentration seriously hinder their industrial application. In this study, DES of N-methyldiethanolamine (MDEA) and imidazole (Im) is simply blended with ethylene glycol (EG) forming a hybrid absorbent, namely MDEA/Im-EG, which exhibits extremely high SO2 capture capacity at low concentration. In particular, SO2 capture capacity in MDEA/Im-EG (molar ratio = 1:1) reaches 0.446 g SO2/g absorbent at 293.2 K with SO2 concentration of 2000 ppm. Moreover, the corresponding desorption enthalpy is only −40.67 kJ/mol. To well understand the results, thermodynamic analysis of SO2 capture is performed and the SO2 capture mechanism is speculated by nuclear magnetic resonance and Fourier transform infrared spectroscopy.

Sustainability of Water Sprinkling Effect of Water-Retaining Ceramic Block

In recent years, heat management by a temperature reduction effect, such as a water sprinkling effect, is strongly desired because of suppression of global warming. In this study, in order to evaluate the sustainability of the water sprinkling effect of pavement blocks, we attempted to clarify the evaporation performance from the inside of the blocks by the viewpoint of wettability. Specifically, the wettabilities were analyzed by measurement of static and dynamic contact angles and of the pavement blocks with different surface porous spaces. Water evaporation properties were measured from the fully water-containing block. As a result of sustainability of water evaporation, the ceramic block, which has a small porous space and a slow water absorption rate, was capable of transport water from the wetting sand to the inside, and had the ability to transport the inside water to the evaporation surface. In order to maintain the water sprinkling effect of the paving block, the water diffusion behavior for maintaining the sustainability of water evaporation on the surface layer is important, and the water inside the block is diffused to the surface. It was found from these results that it is necessary to absorb moisture from the external environment on the block surface.

Quantification of Bisphenol A in Swiss albino mice following topical exposure

Bisphenol A (BPA) is an industrial chemical used in plastics, resin-based food packaging, and thermal papers etc. BPA is reported as an endocrine disruptor and implicated in many disorders including infertility, diabetes, neurological, obesity, and cancer. The populace comes in contact with BPA through oral, inhalation, and dermal routes as it leaches out of the finished products. The present study is aimed to determine the levels of absorption through the skin as well as the penetration rate of BPA into the circulation following dermal exposure in Swiss albino mice. We used ultra-performance liquid chromatography with fluorescence detector to quantify the unconjugated BPA in the serum and skin samples collected at 6 h, 12 h, 24 h, 48 h, 72 h, and 168 h from Swiss albino mice exposed to 250 mg/kg bw BPA through a single dermal application. Mean serum unconjugated BPA Cmax of 745 ng/mL was observed at 24 h. Unconjugated BPA appeared in serum 562 ng/mL within 6 h and was detected till 72 h at concentrations near the LOD (3.9 ng/mL) while those in skin samples unconjugated BPA is detectable at all the time points and displayed a gradual decrease in BPA concentration with progressing duration post dermal exposure. Our study showed a slow absorption rate of BPA through the skin into the circulation and greater bioavailability of unconjugated BPA as it bypasses the first-pass metabolism, resulting in prolonged retention in the system with delayed elimination on dermal exposure.

Vasodilatory effects of glucagon: A possible new approach to enhanced subcutaneous insulin absorption in artificial pancreas devices.

Patients with diabetes mellitus type 1 depend on exogenous insulin to keep their blood glucose concentrations within the desired range. Subcutaneous bihormonal artificial pancreas devices that can measure glucose concentrations continuously and autonomously calculate and deliver insulin and glucagon infusions is a promising new treatment option for these patients. The slow absorption rate of insulin from subcutaneous tissue is perhaps the most important factor preventing the development of a fully automated artificial pancreas using subcutaneous insulin delivery. Subcutaneous insulin absorption is influenced by several factors, among which local subcutaneous blood flow is one of the most prominent. We have discovered that micro-doses of glucagon may cause a substantial increase in local subcutaneous blood flow. This paper discusses how the local vasodilative effects of micro-doses of glucagon might be utilised to improve the performance of subcutaneous bihormonal artificial pancreas devices. We map out the early stages of our hypothesis as a disruptive novel approach, where we propose to use glucagon as a vasodilator to accelerate the absorption of meal boluses of insulin, besides using it conventionally to treat hypoglycaemia.

Novel tertiary amine-based biphasic solvent for energy-efficient CO2 capture with low corrosivity

A tertiary amine-based biphasic solvent, N,N-dimethylethanolamine (DMEA)/piperazine (PZ)/N-butanol (n-BuOH)/H2O, was proposed for energy-efficient CO2 capture. Low energy-consuming deprotonation dominated the CO2 desorption reaction, resulting in a Qrxn as low as 1.17 GJ/t CO2. Combining with the significantly reduced Qsen and Qlatent due to phase separation, an extremely low regeneration energy consumption (1.59 GJ/t CO2) was obtained, which was only 39.8% of 30 wt% MEA, and lower than most of reported biphasic solvents. The addition of n-BuOH not only induced the phase separation, but also reduced the activation energy of the reaction between DMEA and CO2. It worked together with PZ to improve the inherent slow absorption rate of DMEA to a comparable value with 30 wt% MEA. Although a decreased CO2 loading in the total solution was detected because the addition of n-BuOH reduced the equilibrium constant from 3.82 E+2 to 8.98 E+1, this biphasic solvent still achieved high CO2-rich loading (4.23 mol/L), large desorption capacity (3.77 mol/L), and superior desorption efficiency (89.1% at 393.15 K) owing to the good phase separation and desorption properties. In addition, the corrosion rate of CO2-rich phase was only 1.35% of CO2-loaded MEA. This research provided a promising alternative absorbent for CO2 capture.

A Simulation Study of the Comparative Performance of Partial Area under the Curve (pAUC) and Partial Area under the Effect Curve (pAUEC) Metrics in Crossover Versus Replicated Crossover Bioequivalence Studies for Concerta and Ritalin LA.

Concerta and Ritalin LA are methylphenidate (MPH) drugs with different release mechanisms. Generic bioequivalence (BE) to these conventionally uses pAUC (partial area under the curve) as metrics in addition to Cmax (maximum concentration), AUC0-t (area from time 0 to time t), and AUC0-infinity. The recommended BE design was a standard two-formulation, two-sequence, and two-period crossover; however, the currently recommended design is a replicated crossover to better define subject-by-formulation interaction variance. The current purpose was to compare via simulation, using literature MPH models, the performance of the pAUC metrics in establishing BE via the standard crossover design versus a replicated design, and the relationship of the pAUC metrics to PD (pharmacodynamics) metrics, e.g., SKAMP (Swanson, Kotkin, Agler, M-Flynn, and Pelham rating scale) composite scores pAUEC (partial area under the effect curve). One-thousand, 40-subject studies were simulated with model literature parameters. An indirect response model described the SKAMP composite scores corrected for placebo. Performance of the pAUC metrics was demonstrated by the calculation of 90% confidence intervals (CIs) for each k0fast (fast absorption rate constant) and kaslow (slow absorption rate constant) test/reference (T/R) ratio. The 90% CIs resulting from changes in the k0fast and kaslow ratios, e.g., T/R, showed greater sensitivity to changes in the ratios at quotients below 0.8 than above for both Concerta and Ritalin LA. Ritalin LA pAUC values were insensitive to increases in either ratio once the ratio exceeded 1.0 and the study design. Correlations between least squares means (LSM) for pAUC and the SKAMP pAUEC for the composite scores were near 90%.

Pharmacokinetics and bioavailability of carprofen in sheep.

The aim of this study was to determine the pharmacokinetics and bioavailability of carprofen in sheep following single intravenous (IV), intramuscular (IM), subcutaneous (SC), and oral (PO) administrations of a parenteral formulation at a dose of 4mg/kg. A total of eight sheep were used for the investigation. The study comprised four periods, according to a crossover design with a 21-day washout period between treatments. Plasma concentrations of carprofen were measured using HPLC-UV. Pharmacokinetic parameters were estimated by non-compartmental model analysis. Following IV administration, t1/2ʎz , ClT , and Vdss were 43.36 h, 1.98 ml/h/kg, and 121.36 ml/kg, respectively. The Cmax(obs) was 26.57 mg/ml for the IM, 23.76 mg/ml for the SC, and 15.90 mg/ml for the PO. The bioavailability following IM, SC, and PO administrations was 75.47%, 82.00%, and 62.51%, respectively. Plasma creatine kinase activity increased significantly at 3, 6, and 12 h following IM administration of carprofen. Despite differences in plasma concentrations and bioavailability among administration routes, carprofen at 4mg/kg dose may provide the plasma concentration (>1.5μg/ml) needed for analgesic effect during 144 h in all routes. However, because of the slow absorption rate after SC and PO routes, the IV route may be preferred primarily for the rapid onset in the analgesic and anti-inflammatory effect of carprofen in sheep. Despite the favorable kinetics, the muscle damage caused by IM injection limits use of carprofen via IM route.