Evaluation of Intravenous Phenobarbital Pharmacokinetics in Critically Ill Patients With Brain Injury

Phenobarbital is still one of the drugs of choice in managing patients with brain injury in the intensive care unit (ICU). However, the impact of acute physiological changes on phenobarbital pharmacokinetic parameters is not well studied. This study aimed to evaluate the pharmacokinetic parameters of parenteral phenobarbital in critically ill patients with brain injury. Patients with severe traumatic or non-traumatic brain injury at high risk of seizure were included and followed for seven days. All patients initially received phenobarbital as a loading dose of 15 mg/kg over 30-minutes infusion, followed by 2 mg/kg/day divided into three doses. Blood samples were obtained on the first and fourth day of study at 1, 2, 5, 8, and 10 hours after the end of the infusion. Serum concentrations of phenobarbital were measured by high-pressure liquid chromatography (HPLC) with an ultraviolet (UV) detector. Pharmacokinetic parameters, including the volume of distribution (Vd), half-life (t1/2), and the drug clearance (CL), were provided by MonolixSuite 2019R1 software using stochastic approximation expectation-maximization (SAEM) algorithm and compared with previously reported parameters in healthy volunteers. Data from seventeen patients were analyzed. The mean value±standard deviation of pharmacokinetic parameters was calculated as follows: Vd: 0.81±0.15 L/kg; t1/2: 6.16±2.66 days; CL: 4.23±1.51 ml/kg/h. CL and Vd were significantly lower and higher than the normal population with the value of 5.6 ml/kg/h (P=0.002) and 0.7 L/kg (P=0.01), respectively. Pharmacokinetic behavior of phenobarbital may change significantly in critically ill brain-injured patients. This study affirms the value of early phenobarbital therapeutic drug monitoring (TDM) to achieve therapeutic goals.

Analysis of Ethyl p-Methoxycinnamate from Kaempferia galanga L. Extract by High Performance Liquid Chromatography

Ethyl para-methoxycinamate (EPMS) is a major compound of Kaempferia galanga L that has anti-inflammatory effect. The purpose of this study was to determine of EPMS in Kaempferiae galanga L rhizome extract by High Performance Liquid Chromatography (HPLC) and evaluated the performance of the analysis. This study included determination of system suitability, accuracy, precision, linearity and range, limit of detection (LOD) and Limit of quantitation (LOQ) and selectivity. The results of system suitability test HPLC System for EPMS analysis were as follows isocratic elution system of a mobile phase mixture of methanol: water (70:30) containing 0.1% TFA, uv detector at a wavelength of 308 nm using column C18 (150 × 4, 6mm, 5μm) flow rate 1 ml / min. From the analysis, it was found that the average EPMS content was 78.74%. Then method had linear concentration range from 5-360 ppm, with R ² = 0.9999. The LOD and LOQ were 7.0722 ppm and 21.4311 ppm respectively. The accuracy of this method that represented by % recovery was 98.02% - 101.26%. The precision of this method that expressed by Relative Standard Deviation (RSD) was 1.57%. The selectivity of this method that showed by resolution value was 2.6. Based on the results of the system suitability test and analysis performance evaluation,all parameters met the requirements.

Fabrication of graphene–ZnO heterostructure-based flexible and thin platform-based UV detector

This work presents the performance evaluation of Graphene/ZnO Schottky junctions grown on flexible indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates. The fabricated structures include chemical vapour deposition grown graphene layer on ITO-coated PET substrates. Polymethyl methacrylate assisted transfer method has been employed for the successful transfer of graphene from Cu substrate to PET. The smaller D-band intensity (1350 cm−1) compared to G-band (1580 cm−1) indicates good quality of carbon lattice with less number of defects. High-quality ZnO has been deposited through RF sputtering. The deposited ZnO with grain size 50–95 nm exhibited dislocation densities of 1.31270 × 10–3 nm−2 and compressive nature with negative strain of − 1.43156 GPa. Further, the electrical and optical characterization of the devices has been done through device I–V characterization and UV detection analysis. The UV detection capability of the device has been carried out with the aid of a UV-lamp of 365 nm wavelength. The fabricated graphene/ZnO photodetector showed good response to UV illumination. The device performance analysis has been done through a comparison of the device responsivity and detectivity with the existing detectors. The detectivity and responsivity of the fabricated detectors were 7.106 × 109 mHz1/2 W−1 and 0.49 A W−1, respectively.

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

Three different complexes, TMeQ[6]-TBT, Q[7]-TBT, and Q[8]-TBT are constructed by three different cucurbiturils and synthesized by guest melamine-cored Schiff bases (TBT) through outer-surface interaction and host–guest interactions. TBT forms a TMeQ[6]-TBT complex with TMeQ[6] through outer-surface interaction, while Q[7]-TBT and Q[8]-TBT form complexes with Q[7,8] through host–guest interactions. Among them, Q[7]-TBT is selected as a UV detector for the detection of silver ions (Ag+). This work makes full use of the characteristics of each cucurbituril and melamine-cored Schiff base to construct a series of complexes and these are applied to metal detection.

DEVELOPMENT AND VALIDATION OF ESOMEPRAZOLE RESIDUE IN DOMESTIC WATER BY USING REVERSE PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

As more concern arises day by day for the environmental pollution due to pharmaceutical products and their toxic nature, analytical methods require characterizing drug substances and drug product composition during all phases of environmental habitats, mainly in water habitats. A simple, sensitive, and accurate analysis has been developed to estimate esomeprazole in pharmaceutical effluents, which are released from the pharmaceutical industries into the aquatic environment, by using RP-HPLC with UV detection. The developed method is highly reproducible and sensitive to determine the esomeprazole at less than 10 ppm level. A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the estimation of esomeprazole in effluents or pharmaceutical industry washouts. The separation was achieved on the C18 Gemini NX column (150 mm × 4.6 mm id., 5.0 μm). Detection was carried out using a UV detector at 302 nm. The total chromatographic analysis time per sample was about 10.0 min with esomeprazole eluting at a retention time of about 5.0 min. The method was validated for accuracy, precision, specificity, linearity and sensitivity.

RP-HPLC Method Development and Validation for the Estimation of Lumefantrine in Bulk Drug

Lumefantrine is an antimalarial agent used to treat acute uncomplicated malaria. It is administered in combination with artemether for improved efficacy. This combination therapy exerts its effects against the erythrocytic stages of Plasmodium spp. and may be used to treat infections caused by P. falciparum and unidentified Plasmodium species, including infections acquired in chloroquine-resistant areas. A reversed-phase high performance liquid chromatography (RP-HPLC) method was developed and validated for the estimation of lumefantrine in bulk drug. The separation was achieved on Thermo C18 analytical column (250 mm × 4.6 mm i.d., 5.0 μm) using 10mM KH2PO4: acetonitrile (pH adjust 3.0 with OPA) in the ratio 20:80 v/v as mobile phase and at a flow rate of 1.0 ml/min. Detection was carried out using a UV detector at 240nm. The total chromatographic analysis time per sample was about 6.0 min with lumefantrine eluting at retention time of about 3.225 ± 0.001min. The method was validated for accuracy, precision, specificity, linearity and sensitivity. Validation studies demonstrated that this HPLC method is simple, specific, rapid, reliable and reproducible. The standard curve was linear over the concentration range of 5-25 μg/ml with r2 close to one (0.999). The limit of detection (LOD) and limit of quantitation (LOQ) obtained for lumefantrine were 0.25 μg/ml and 0.75μg/ml respectively. The high recovery and low relative standard deviation confirm the suitability of the proposed method for the determination of lumefantrine in bulk drugs.

Microwave Assisted Extraction of Berberine and Preparation of Berberine Hydrochloride from Berberis Aristata Variety of Nepal, and Quantification using RP-HPLC and HPTLC Methods

Berberis aristata a Himalayan woody spiny shrub with yellow flowers and red berries commonly called as Daruharidra in Sanskrit and locally in Nepal is called as Chutro or Chitra. The root and stem are the two parts widely used in traditional medicines of India and China. Berberine is the key active ingredient present in stem and root parts. Berberine hydrochloride is the derivative of berberine. The present study aimed to study the microwave assisted extraction of berberine and its conversion into berberine hydrochloride and quantifying by RP-HPLC and HPTLC methods.In the present paper we have mentioned microwave assisted extraction of berberine and preparation of berberine hydrochloride in detail. Berberine extracted from roots of Berberis aristata using microwave assisted extraction in 80% ethanol to obtain 20% pure berberine crude by HPTLC densitometry at 350 nm absorption. The crude berberine was further purified to berberine hydrochloride by adding 10% Hcl in aqueous solution of berberine and allowed to crystallize at 5 0C over 24 hours. The crystals were further purified and recrystallized in ethanol and subjected to RP-HPLC. Reverse phase HPLC was carried out on Shimadzu UV detector at wave length of 265 nm using Acetonitrile-0.1% phosphoric acid solution (50:50) (add 0.1g sodium dodecyl sulfonate per 100ml) as the mobile phase; Phenomenex RP-column (250 mm × 4.6 mm, 5 μm), With flow rate 1.0 mL/minute, 5 µL injection volume, column temperature 25 0C for run time of 35 minutes, and retention time of berberine hydrochloride was 12.008 minutes with purity of 82% and recovery of 90% yield obtained.

Ultrasound-assisted Emulsified Microextraction Followed by High Performance Liquid Chromatography for Permethrin

Ultrasound assisted emulsification microextraction (UAEME) as a new sample preparation method was optimized for the determination of permethrin in urine samples. Also, deep eutectic solvent was used as the extracting solvent instead of organic solvents in this method. In order to determine the optimal values, six main parameters were studied in different levels. Totally, 105 runs were performed using the one-variable-at-a-time method followed by high-performance liquid chromatography with a UV detector. Under the optimum conditions, the calibration curve for permethrin was linear in the concentration range of 5 to 500 μgL‑1 for urine samples. The accuracy and reproducibility of the introduced method were determined using the relative recovery (RR%) and relative standard deviation (RSD%) tests on the fortified urine samples. RR% and RSD% were found to be 96.3–101.7 % and 3.2–7.6 %, respectively. The limit of quantification and also the limit of detection were obtained 5 and 1 μg/L, respectively. In the present study, the DES-UA-EME technique was successfully developed for the extraction of permethrin from urine samples and subsequent quantification by high-performance liquid chromatography.In comparison to the other sample preparation methods, the proposed technique has the advantages of shorter extraction time, simplicity, and applicability in laboratories with less equipment

Simultaneous HPLC Method Development and Validation of Bilastine and Montelukast in Bulk and Formulation

A new, simple, rapid, selective, precise and accurate reverse phase high performance liquid chromatography assay has been developed for simultaneous estimation of Bilastine, and Montelukast in tablet formulations. The separation was achieved by using Phenomenax Kinetex XB C-18 column (150 x 4.6mm, 5 .) using mobile phase Methanol: 0.1% TFA water (80:20). Injection volume was 10µl. The flow rate was 1.0mL.min-1 and the separated drugs were detected using UV detector at the wavelength of 270nm. The retention time of Bilastine and Montelukast was noted to be 1.27, and 4.86 respectively, indicative of rather shorter analysis time. The method was validated as per ICH guidelines. The proposed method was found to be accurate, reproducible, and consistent. It was successfully applied for the analysis of these drugs in marketed formulations and could be effectively used for the routine analysis of formulations containing any one of the above drugs, or a combination, without any alteration in the chromatographic conditions.