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We propose a strategy to accelerate tissue plasminogen activator (tPA)-mediated thrombolysis using a microswarm under ultrasound imaging. The microswarm is formed in blood using an oscillating magnetic field and navigated with switchable locomotion modes. The aspect ratio of the microswarm can be reversibly tuned by modulating the input field, enabling the capability to adapt to different clot regions. Simulations show that three-dimensional flow is induced around the microswarm, which enhances the mass transfer and shear stress near the clot-fluid interface. Guided by ultrasound imaging, the microswarm can be navigated towards clot regions and deformed to adapt to blood clots with different widths. Affected by the enhanced fluid convection and shear stress, experimental results show that the microswarm-assisted lysis rate enhances up to 3.13-fold compared to that using tPA drug only. Moreover, the comparison between microswarm-assisted thrombolysis in phosphate buffered saline (PBS) and blood environments validates our modeling and simulation results. Our method provides a strategy to increase the efficiency of tPA-mediated thrombolysis by applying an ultrasound-localized microrobotic swarm, indicating that swarming micro/nanorobots have the potential as effective tools towards imaging-guided therapy.

We prepared single-walled carbon nanotube (SWNT) suspensions in phosphate buffer solutions containing 1% of a coconut-based natural detergent (COCO) or 1% of sodium dodecyl sulfate (SDS). The suspensions exhibited strong photoluminescence (PL) in the near-infrared region, suggesting that the SWNTs, such as those with (9, 4) and (7, 6) chiralities, were monodispersed. Upon diluting the suspensions with a detergent-free phosphate buffer solution, the PL intensity of the SDS-containing SWNT suspension was significantly lower than that of the COCO-containing SWNT suspension. The COCO-containing SWNT suspension was more stable than the SDS-containing SWNT suspension. The SWNT concentration of the suspensions prepared via bath-type sonication was lower than that of the suspensions prepared via probe-type sonication. However, near-infrared (NIR) PL intensity of the SWNT suspensions prepared via bath-type sonication was much higher than that of the SWNT suspensions prepared via probe-type sonication regardless of the detergent. This suggested that the fraction of monodispersed SWNTs of the suspensions prepared via bath-type sonication was larger than that of the suspensions prepared via probe-type sonication, although the SWNT concentration was low. Our results indicated that COCO favored the fabrication of SWNT suspensions with stable and strong NIR PL, which are useful for various biological applications.

OBJECTIVES: The present study aimed to develop and validate a discriminative dissolution method for tetrahydrocurcumin (THC), a Biopharmaceutical Classification System class II drug, by a simple ultraviolet (UV) spectrophotometric analysis. The final dissolution medium composition was selected based on the solubility and stability criteria of the drug. MATERIALS AND METHODS: As a prerequisite for this, the solubility of the drug was assessed in media of different pH (1.2-7.4), and surfactant concentrations of 0.5-1.5% (w/v) sodium lauryl sulfate (SLS) in water, and pH 7.4 phosphate buffer. The dissolved drug concentration in each medium was quantified by UV analysis at 280 nm wavelength. RESULTS: The drug solubility was found to be high at a pH of 1.2 and 7.4. The media with surfactant enhanced solubility of the drug by approximately 17-fold and exhibited better sink conditions. The discriminative power of the developed dissolution medium (i.e., 1% w/v SLS in pH 7.4) was determined by performing in vitro dissolution studies of the prepared THC tablets and comparing their release profiles using fit factors (f1 and f2). The results of the fit factor comparisons made between the dissolution profiles of THC tablets proved the discriminative ability of the medium. The validation of the developed dissolution method was performed by international guidelines and the method showed specificity, linearity, accuracy, and precision within the acceptable range. CONCLUSION: The proposed dissolution method was found to be adequate for the routine quality control analysis of THC, as there is no specified dissolution method for the drug in the pharmacopoeia.

We present the results of studying and selectiing optimal conditions for the determination of caffeine, catechins and gallic acid in black tea by the method of micellar electrokinetic chromatography. The choice of analytes is determined by the fact that they form the main consumer qualities of tea and, due to their antioxidant properties, have a positive effect on human health. Optimization of the electrophoretic detemination of seven catechins, caffeine and gallic acid in black tea was carried out using the method of ex­ periment design. Optimized conditions — 25 mM phosphate buffer solution with pH 7.4, containing 30 mM SDS and 5% ethyl alcohol — provided a satisfactory resolution of all electrophoretogram peaks, the analysis time was 25 minutes, and the current in the system did not exceed 120 pA. After the assessment of the metrological characteristics of the proposed method the standard deviation of the determina­tion of analytes did not exceed 15%. The samples of black tea from Ceylon, Chinese, Assamese, Indian, Kenyan and Krasnodar regions of growth were analyzed, and an array of data on the contents of the analytes under study was formed. Discriminant analysis was used to develop a model and obtain classifica­tion functions for six tea groups from different regions of the world. Proceeding from the obtained classifi­cation functions, a scatter diagram of canonical values was constructed, which showed that the samples of Krasnodar and Chinese tea were localized from all the studied groups. Indian, Assamese and Ceylon teas formed a single area with close to the Chinese tea group. The correctness of the model was checked and revealed the total predictive force about 92%. It is shown that the content of catechins, gallic acid and caf­feine are suitable markers for the classification of black tea samples from different regions of origin.

Bioabsorbable arterial grafts can potentially improve patency and neovessel formation; however, their application in clinical settings has not been realized. In this study, we developed bioabsorbable gradient sheets based on silk fibroin (SF) and polyvinyl alcohol (PVA) with a core-shell nanofibrous structure. This gradient sheet was expected to promote vascular remodeling while we maintained its physical properties and a gradual degrading process from the luminal surface. ESP was conducted at various flow rates for SF and PVA to achieve the multilayer gradient structure. Furthermore, the elasticity of the gradient sheet could be increased by increasing the PVA flow rate; however, this reduced the tensile strength of the core-shell fibers. Notably, the physical properties of the gradient sheet did not degrade even after 7 days of immersion in a phosphate buffer saline solution, which indicates that the structure could maintain its structural integrity while resisting arterial pressure. In vitro experiments revealed that the number of endothelial cells attached to the SF/PVA sheet was notably higher than that on the cell-culture dish. The gradient sheets were implanted in rat abdominal aortas and explanted after 14 days to confirm acute-phase patency and vascular remodeling. The gradient sheets constructed with SF composed of polyurethane and PVA improved the ease of handling of the material, and these sheets resulted in a favorable vascular remodeling outcome. Our results strongly suggest that the SF/PVA-based gradient sheets described in this study can serve as a novel design for bioabsorbable arterial grafts upon further modifications.

The objective of this experiment was to develop and validate a simple, robust, and accurate QbD based Reverse-Phase High-Performance Liquid Chromatography method for Simultaneous estimation of Amlodipine besylate and Lisinopril dihydrate in bulk and Pharmaceutical Dosage form. A box-Behnken design was employed for optimizing the mobile phase, flow rate and pH of buffer, the optimized chromatographic conditions were Phosphate buffer: Methanol (25: 75 v/v), pH of buffer: 6.5 and flow rate: 1mL/min. Furthermore formulation injected and observed that the additives do not interfere with the peak of Amlodipine besylate and Lisinopril dehydrate. Both drugs are well resolved and Retention times were found to be 2.332 min and 3.584 min respectively. Linearity was observed in the concentration range of 10 μg to 50 μg/mL (r2=0.999). The accuracy range was 99.75 to 100.04%. Intra-day and Inter-day precision was found to be less than 2% RSD. The proposed method was useful for the best analysis of Amlodipine besylate and Lisinopril dihydrate in Bulk, pharmaceutical dosage forms and was successfully applied to routine analysis.

Two different simple, accurate, and precise UV spectrophotometric methods have been developed for the estimation of erlotinib hydrochloride in bulk and tablet forms by the zero-order (method I) and the zero-order AUC (method II). The drug was dissolved in a phosphate buffer solution (pH 7.4), and at 228.20 nm the zero-order (method I) and at 224.20–230.20 nm the zero-order AUC (method II) were developed. For both methods, erlotinib has linearity in the concentration range 10–70 μg/mL, with a correlation coefficient R2 > 0.99. Both methods showed good reproducibility and recovery with %RSD less than 2 and an accuracy of 98.54–101.39 and 98.08–99.83%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.16, 3.51, and 21.41, 64.90 μg/mL, respectively, for both methods.

A new method was established for simultaneous estimation of Canagliflozin by RP-HPLC method. The chromatographic conditions were successfully developed for the separation of Canagliflozin by using INERTSIL column, C18 (150x4.6)5µm column, flow rate was 1ml/min, mobile phase ratio was Water: Acetonitrile (70:30), detection wavelength was 264nm. The instrument used was Hitachi HPLC Auto Sampler, Separation module 1575. The analytical method was validated according to ICH guidelines (ICH, Q2 (R1)). The linearity study for Canagliflozin was found in concentration range of 1μg-5μg and 100μg-500μg and correlation coefficient (r2) was found to be 0.999 and 0.999, %mean recovery was found to be 100% and 100.5%, %RSD for repeatability was 0.2 and 0.4, %RSD for intermediate precision was 0.5 and 0.1 respectively.

Aim and Study Design: Aims: The current research paper describes the RP-HPLC Method for estimation of Olmesartan Medoxomil, Telmisartan, and Hydrochlorothiazide and implements the role of QbD for Data Analysis Study design: Mentioned study is simple, rapid, economical, accurate, and robust RP-HPLC Method for Olmesartan Medoxomil, Telmisartan, and Hydrochlorothiazide and implementing QbD Approach for Data Analysis. Place and Duration of Study: The present study was carried out at Smt. S. M. Shah Pharmacy College, Mahemdabad, Gujarat, India from October 2019 to February 2020. Methodology: The separation was done on Hypersil ODS C18 column with dimensions (250mm x 4.6ID, Particle size: 5 microns) and Methanol: 0.02M potassium dihydrogen phosphate buffer (60:40%v/v) pH 3 used as mobile phase. The flow rate was 1.2ml/min; detection at 254nm. QbD approach was applied for data analysis. The method was validated according to ICH guidelines. Results: The RP-HPLC method was developed and validated for Linearity and Range through the QbD approach. Factorial Design was developed through Design Expert Software for estimation of Telmisartan, Olmesartan Medoxomil, and Hydrochlorothiazide. 27 experiments were constructed and its effect was seen on Resolution, Tailing factor, and Retention Time. Conclusion: It was clear that the proposed method was suitable for the QbD approach and identification and validation approaches. This process helps in the proper understanding of the parameters and less amount of time for the development cycle of the analytical method.

The possibility of preparing bone substitutes in clinic is demonstrated in this study. With the addition of a small amount of water, the relative density of the calcium sulfate specimen prepared at room temperature became higher than 92%. This value is close to the density of the specimen prepared through conventional sintering at 1100 °C for 1 h. The biaxial strength of the specimen disc can reach 120 MPa. Densification is assisted by the hydration of calcium sulfate hemihydrate to dihydrate wherein coarse hemihydrate particles transformed to fine dihydrate dendrites. Strength is conferred by the entanglement of dendrites and microstructure refinement. The densified calcium sulfate disc remains degradable; its degradation rate in a phosphate buffer saline solution is ~1.6 wt%/day, and the rate remains steady for 28 days.

A magnetic nanoparticle (MNP)-based lateral flow immunochromatography assay (LFIA) was established to detect fluoroquinolones (FQs) in milk. This method is an improvement of traditional Au nanoparticle (AuNP)-based LFIA. Compared with AuNP-labeled antibody, the combination between MNPs and antibody is stronger and more stable, and the preparation process is convenient. In this study, the color intensity of MNPs-LFIA test strip was analyzed, which laid a research foundation for magnetic quantitative analysis and high sensitivity analysis of LFIA. The limits of detection (LODs) for 10 FQs in phosphate buffer (PB) solution ranged from 1 to 5 ng/mL, and in milk ranged from 2 to 20 ng/mL. The recovery in spiked milk sample ranged from 16.47 to 83.67%. The log functions of analyte concentration and T/C value were fitted into a linear equation. The specificity of the MNPs-LFIA is satisfactory, without cross-reaction with antibiotics from other chemical classes. The results of this method are consistent with those of ultra-performance liquid chromatography-mass spectrometry, indicating the MNPs-LFIA method is reliable and accurate. As far as we know, this is the first time that MNPs-LIFA has been applied to the detection of FQs in milk.

A drug delivery system with near-infrared emissions response to drug delivery and release is essential as marking or targeting drug delivery system. For this reason, the Er3+-doped ZnAl-LDH with near-infrared emissions was used for the first time for controlled release of the ibuprofen (IBU) that is a non-steroidal antiinflammatory drug. The drug release was controlled in simulated intestinal medium (pH 7.4 phosphate buffer solutions at 37 °C). The release kinetics showed an initial burst release followed by a slow release of IBU. The most important thing is that the intercalation of IBU into the Er3+-doped ZnAl-LDH greatly reduced the near-infrared emissions of the Er3+-doped ZnAl-LDH, whereas the near-infrared emissions were recovered after the IBU was released from the Er3+-doped ZnAl-LDH delivery system. This change of near-infrared emissions would provide a useful technique for in situ monitoring of the delivery and release of IBU. The Er3+-doped ZnAl-LDH with near-infrared emissions is inexpensive, biocompatible, nontoxic, and little damage to biological tissue, which would be potential application as drug delivery system with marking or targeting performance.

This paper is focused on the specifics of amperometric oxygen (O2) measurements in biological media (cultivation media, reaction mixtures, media designed for isolated cellular and subcellular structures) and other complex media using Clark-type electrodes. Specifically, the impact of the qualitative and quantitative composition of liquid media on the readings of Clark electrodes is considered. Using sucrose, sorbitol, NaCl and phosphate buffer as examples, it has been shown that, provided the content of dissolved O2 is constant, an increase in the content of concomitant to O2 substances in the test medium results in an increase of the signal of the Clark electrode located in this medium. On the basis of the obtained and published data, the effect of the qualitative and quantitative composition of media on the readings of Clark electrodes is evaluated. In its turn, the very effect of media composition on Clark electrodes readings can be explained by the fact that in reality Clark electrodes measure the activity of dissolved O2, which usually increases with an increase in the content of concomitant to O2 substances. Since Clark electrodes measure the activity rather than the true O2 content in media and the ratio between the activity and true O2 content is often unknown, the issue regarding the calibration of Clark electrodes has been also considered in this study. It is noted that the methods of adding known amount of O2 to liquid media (the Hill reaction, catalase reaction, or injection of a micro portion of water saturated with pure O2), which were applied in this work to demonstrate the effect of media composition on the Clark electrode readings, can be used to calibrate the Clark electrodes in units of the true O2 content, and, thus, to take into account the influence of the media content on the readings of these O2-sensors when it is necessary. It is suggested that the calibration based on the addition of an O2-saturated micro-portion of water or, if necessary, O2-saturated micro-portion of another suitable liquid to the medium with the Clark electrode is, due to its almost unlimited applicability and other advantages, the most satisfactory way of calibration. The introduction of this calibration method into scientific practice can make quantitative O2-measurements with Clark electrodes more accurate in many difficult cases.

In this study, phosphate-buffered saline solution (PBS) was successfully radiolabeled with technetium-99m. The biodistribution profile and bone accumulation of the [99mTc]Tc-PBS system were evaluated in healthy swiss mice. The radiolabeling of the system was successfully obtained, yielding around 90 % of radiochemical purity. The system stability was tested in the presence of saline medium at 25 oC and mouse plasma at 37 oC, and results revealed that [99mTc]Tc-PBS showed excellent stability over time, in both media. It was observed a biphasic clearance profile, with fast elimination from the bloodstream by renal filtration. The radiolabeled system revealed a high specificity bone accumulation was observed, demonstrating an uptake behavior from 20 to 50 times higher than muscle, used as control. From all results obtained, the system constituted by [99mTc]Tc-PBS can be considered a potential selective agent for bone imaging.

This research constructed and utilized a screen-printed electrode (SPE) modified with V2O5 nanoparticles (NPs) (V2O5/SPE) employed in order to sensitively and selectively quantify ciprofloxacin with exceptional accuracy in the phosphate buffer solution (PBS) with the use of differential pulse voltammetry (DPV). Moreover, electrochemical properties of this new V2O5/SPE sensor have been examined using diverse characterization procedures. Very good V2O5/SPE electrochemical features offered sensitive ciprofloxacin voltammetric determination with the reduced limit of detection (LOD = 0.01 µM) toward electrocatalytic oxidation of ciprofloxacin in comparison with the bare SPE. Finally, this new disposable sensor exhibited higher sensitivity and thus has been efficiently utilized to determine ciprofloxacin in the real samples.

Purpose: To investigate the dissolution properties of various brands of naproxen in four dissolution media in order to forecast their biological availability. Methods: Dissolution tests were carried out in a dissolution tester with 48 tablets of different naproxen brands in 900 mL of 0.1 M phosphate buffer, pH 7.4. Subsequently, the medium was modified with 600 mL of buffer plus 300 mL of cola drink, grapefruit or milk. Each sample was taken and brought to a concentration approximating that of a reference solution. Absorbance at 332 nm was determined and the dissolution, Q, was calculated (Q values ≥ 80.0 ± 5 % were acceptable). Results: Dissolution in buffer was > 85 %. In cola drink, it was < 80 %, while in grapefruit juice, it was in the range of 7 - 68 %. Using 2-way ANOVA, these media and the three naproxen brands showed significant differences (F = 68.90, p = 0.0000; F = 23.18, p = 0.0000). With Fisher's LSD test, two of these media contributed consistently to dissolution, and the three drug brands showed statistically different dissolution profiles (p ≤ 0.05). Conclusion: Caution must be exercised cola drink, grapefruit juice and milk are used to administered naproxen as the biological availability of the drug may be altered.

The effects of chemical agent (Sodium Azide) on Onion growing in organic and inorganic fertile soil was to be examined during this study. The analysis work was carried out within the green house of the research laboratory technology of the Oke Ogun Science Laboratory Technology, Saki, Oyo State. Onion seeds were soaked inside different beakers containing the mixture of Sodium Azide and water mixed with 10 ml of Phosphate solution for 4 hours. Also, the control was soaked with normal water and 10 ml of Phosphate buffer solution. The treated seeds of onions was planted in plastic containers containing 4.2 g of weighed humus soil within the green house at the Department of research lab Technology of The Oke Ogun polytechnic school, Saki Oyo State. The samples parameter were taken daily for six consecutive months. The result obtained was additionally subjected to statistical analysis by using DMRT techniques. The results showed that the stem length was ranged from 11.39±0.62 and 9.98±0.52 with sample of onion without sodium Azide and inorganic had the highest stem length values and samples of onion with Sodium Azide and inorganic had very cheap stem length. However, the leave length ranged from 29.63±0.12 and 22.45±0.10 with the Onion samples with inorganic and Organic fertilizers which had the highest leave length and sample of onion without Sodium Azide was very low leave length. The results of this study showed that each one the parameters studied within the plant were low with Sodium Azide treatment. The decrease in plant growth, plant heights, root lengths, and Phaonerogam survival, fruit yield per plant and height at maturity with agent concentration. It is hereof suggested that Sodium Azide (NaN3) was expected to produce mutation in onion that area unit extremely liable to harmful pathogens and making them cheap to be useful for farmers.

Environmental monitoring for Listeria monocytogenes in food processing environments is key for ensuring the safety of ready-to-eat foods. For sampling, swabs are often hydrated with a wetting or transport medium that may contain neutralizers and other ingredients. After swabbing the environment, the swabs may then be transported or shipped cold to an off-site laboratory for testing, ideally within 48 h. Extended shipping times may subject the pathogen to increased temperatures in the presence of the wetting medium, organics, and other chemicals from the processing facility that could confound detection. This study evaluated growth and detection of L. monocytogenes on stainless steel exposed to either buffer or sodium hypochlorite before drying. Swabs were rehydrated with Butterfield's phosphate buffer, neutralizing buffer, Letheen broth, or Dey-Engley neutralizing broth before swabbing. Swabs were stored in the presence of no added food, cheese whey, or ice cream under both optimal (4°C) and suboptimal (15°C) temperatures for up to 72 h. Overall, there was no growth of L. monocytogenes at 4°C through 72 h of storage, although enrichment from these swabs was dependent on the presence and type of food matrix. Pathogen growth during storage at 15°C was more variable and depended on both the food matrix and transport media used, with Dey-Engley and Letheen broths allowing for the highest population increases. Overall, more enrichments resulting in L. monocytogenes detections were observed when using Letheen broth and neutralizing buffer than Dey-Engley broth, which resulted in fewer detections at 15°C. Logistic regression and Cochran-Mantel-Haenszel analyses determined that storage temperature, transport media, and food matrix all significantly affected detection of L. monocytogenes, whereas storage time did not have a clear effect on recovery from swabs. HIGHLIGHTS

Background and Aims: It has been observed that the combined treatment of esomeprazole and pirfenidone provides increased efficacy in the treatment of pulmonary fibrosis disease, recently. The aim of this study is to develop a simple, sensitive, and reliable high-performance liquid chromatography method to be used in drug monitoring to increase the effectiveness of esomeprazole and pirfenidone in treatment and to reduce their adverse effects. Methods: Separation was conducted with a C18 reverse-phase column (4.6 mm x 250 mm, 5 mu m) used as a mobile phase prepared with the phosphate buffer (10 mM KH2PO4 and 10 mM K2HPO4) and acetonitrile (60:40, v/v) by an isocratic flow (1 mL/min). Mobile phase pH was adjusted to 3.0. Ultraviolet detection was accomplished at 305 nm. The column oven was held at 35 degrees C to ensure an efficient analytical separation. Results: Analytical recovery of esomeprazole was between 92.43 and 105.36% and for pirfenidone it was found between 89.56 and 104.32%. Accuracy values of esomeprazole and pirfenidone were determined between (-2.90) - 4.22 and (-4.45) - 5.78, respectively. Precision (RSD%) was

Aims: To improve the dissolution of indomethacin through developing liquid indomethacin loaded cubosomes dispersion for oral delivery. Methodology: Glyceryl monooleate based indomethacin loaded cubosomes dispersion were prepared using Taguchi design to study the effect of indomethacin to the disperse phase ratio and poloxamer 407 (PLX%) concentrations on the particle size and entrapment efficiency (%EE). Furthermore, in vitro release in phosphate buffer (pH 6.8), and morphology were investigated. Also, the stability of indomethacin loaded cubosomes dispersions was examined after 6 months storage at 25°C in the dark. Results: The prepared indomethacin cubosomes dispersions were in the nanoscale (184.53±0.7 to 261.33±0.8 nm) with reasonable %EE (49.30±2.6 to 95.55±3.4 %). Moreover, a biphasic release profile was predominant for all formulations, up to 50% of payload released after 2h followed by a second continuous sustained release phase over 24h. The kinetics of indomethacin release was best explained by Higuchi model and the mechanism of drug release from these cubosomes dispersions was by fickian diffusion mechanism. In general, the indomethacin loaded cubosomes dispersions were stable after 6 months storage at 25°C in the dark. Conclusion: Indomethacin loaded cubosomes dispersions proved to be a successful platform to encapsulate and enhance the release of indomethacin with a good stability profile over 6 months.

Digital, Background and Aim: Balantidium coli is a protozoan that can infect humans and non-human primates, being the domestic pigs the animals most affected by this parasite. This study aimed to compare the performance of five coprological methods for diagnosis of Balantidium coli cysts in fecal samples from pigs. Materials and Methods: From September to December 2019, 558 fecal samples were collected from the rectum of backyard pigs in the Bucaramanga metropolitan area, Colombia. The average age of the sampled animals was 3-4 months. Fecal samples collected were tested using the following coprological techniques: Direct examination with Lugol’s iodine solution, buffered saline, centrifugation/flotation and McMaster techniques, and Ziehl–Neelsen method. Results: The results indicate that B. coli cysts were diagnosed most frequently through direct examination with Lugol’s iodine solution (52.7% of the samples) followed by direct examination with a buffered saline solution (37.6%). Moderate concordance (k=0.41; p, Ciencias Veterinarias

Magnetic iron nanoparticles (MNPs) encapsulated in a carbon shells and containing sulfo groups on the surface (Fe@C-SO3H) were synthesized. The aggregative stability of aqueous suspensions of the Fe@C-SO3H nanoparticles was studied in solutions of bovine serum albumin and calcium chloride and in phosphate-buffered saline, which simulate blood plasma. It is shown that the Fe@C-SO3H particles practically do not aggregate in the phosphate buffer saline for a long time (several days). On the contrary, MNPs encapsulated in a protein shells using ultrasonic treatment form aggregates up to 110–120 nm in size under these conditions. Suspensions of the Fe@C-SO3H particles are stable in aqueous solutions of calcium chloride in the range of the solid phase concentration between 0.05 and 0.10 g L−1. The results obtained indicate the possibility of using the functionalized Fe@C-SO3H nanoparticles in vitro experiments in biological media.

The enormous need for support of measurements of the hydrogen index (pH) in various branches of industry and the national economy of Russia make measurement of pH one of the most important methods for monitoring aqueous media. In 2013 work was carried out to introduce into the State Register of Means of Measurement of the Russian Federation a buffer solution and titration standard with a pH value of 7.00, a 2nd order working standard for pH which is one of the nonstandard solutions most in demand for verification and calibration of instruments for measuring pH. The metrological characteristics of the 2nd order working standard for pH have been confirmed in pilot comparisons through COOMET (COOMET project 655/RU/15). The results of a pilot comparison for determination of the pH of a phosphate buffer solution with pH=7.00 are presented here. 8 metrological institutes and 10 metrological organizations took part in the comparisons. The results showed that the overwhelming majority of the participants in the comparisons obtained results for the pH measurements with an uncertainty that did not exceed ±0.03 of the average value, which is an acceptable criterion for pH measurements.

In this work, the development and optimization of a secondary method for pH measurement using a differential potentiometric cell are described. The method was optimized and validated by measurement of three certified primary buffer solutions (CRMs) with nominal pH values of 4.005, 6.865 and 9.180 at 25 °C. The method was applied to assess homogeneity and stability of phosphate buffer solution with nominal pH of 7.000 at 25 °C which will be used as test item in proficiency testing schemes for pH measurement of testing laboratories. The experiments carried out and described in this article proved that this particular design of secondary differential potentiometric cell requires small volume of solutions, is fast, accurate and precise and is suitable for the characterization of secondary buffer solutions and assessment of homogeneity and stability of buffer solutions.

The antimicrobial susceptibility ofHelicobacter pyloriisolated from suspected patient using stool sample at Beijing greatest college of health sciences and technology, Kaduna, demonstration clinic. The analyses were carried out to further understand the intestinal environment condition of the sample sites. As it has been noted that: it is difficult of growingHelicobacter pyloriin a broth, hence, no specific enrichment has been proposed. Note: As everything present in the stomach would be found in the stools, hence there is no doubt thatHelicobacter pylorican be eliminated via this route and successful culturing ofHelicobacter pylorifrom the stool sample had been achieved. [4]. The stool was diluted to a 20% w/v solution of in phosphate buffered saline (PBS) and the suspension was sieved through a 250 um strainer before plating onto the selective media. The sample was passed through a series of dilution techniques and centrifugation before finally plating on to the deoxycholate citrate agar (selective) and incubates at 37oC under the microacrobic atmospheric oxygen concentration of 7 – 12% (O2) for four (4) days. Across the cultured, the cultured plate there was marked abundant of bacterial cells with some colonies having the characteristics ofHelicobacter pyloriwhich later sub-cultured and isolated for antimicrobial test.

A specific, accurate rp-HPLC (reversed-phase high performance liquid chromatographic) method was developed for the quantification of Cabozantinib. The effective separation was achieved through reversed-phased C18 column 4.6 x 250 mm, 5µm using a mobile phase Methanol: phosphate buffer (ph. 3.00) with orthophosphoric acid (OPA) (55:45 % v/v). The flow rate of the mobile phase was found to be 0.8 mL/min. The detection was carried at a wavelength of 244 nm. The retention time of Cabozantinib was found to be 3.702 min. The correlation coefficient was found to be 0.9999. The developed method was accurately validated in the terms of accuracy, linearity range, precision, system suitability, robustness, limit of detection and limit of quantification. The details presented in this test will be useful for industrial application for determining Cabozantinib in active pharmaceutical ingredient and pharmaceutical dosage form.

Present study reports design of experiment (DoE) based development and validation of a simple, rapid and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method for estimation of efavirenz (EFZ), a non-nucleotide reverse transcriptase inhibitor (NNRTs), used in the treatment of acquired immunodeficiency syndrome (AIDS). Plackett–Burman design was explored to screen the critical method variables (CMVs) for the RP-HPLC method. A response surface Box–Behnken design was employed to optimize the screened CMVs which affect the analytical responses (ARs) of RP-HPLC method. Using the optimized CMVs the HPLC method was developed and validated according to International Conference on Harmonization (ICH) guidelines. EFZ in marketed formulation was estimated using the validated method. Acetonitrile proportion, pH of the phosphate buffer and mobile phase flow rate were the CMVs and retention time and number of theoretical plates were the ARs for the study. The optimized chromatographic parameters were acetonitrile proportion in mobile phase: 51.17%v/v, pH of phosphate buffer: 4.04 and flow rate: 1.25 mL/min. Use of these optimized parameters resulted in retention time of 11.031 min and 9,498.787 number of theoretical plates as ARs of the HPLC method. The method was further validated in harmony with current ICH guidelines Q2 (R1). The method was capable of the successful estimation of EFZ in marketed formulation. The study depicts successful development and validation of a simple RP-HPLC method of EFZ using DoE approach.

Scanning ion conductance microscopy (SICM) is useful for imaging soft and fragile biological samples in liquids because it probes the samples’ surface topography by detecting ion currents under non-contact and force-free conditions. SICM acquires the surface topographical height by detecting the ion current reduction that occurs when an electrolyte-filled glass nanopipette approaches the sample surface. However, most biological materials have electrically charged surfaces in liquid environments, which sometimes affect the behavior of the ion currents detected by SICM and, especially, make topography measurements difficult. For measuring such charged samples, we propose a novel imaging method that uses a double-barrel nanopipette as an SICM probe. The ion current between the two apertures of the nanopipette desensitizes the surface charge effect on imaging. In this study, metaphase chromosomes of Indian muntjac were imaged by this technique because, owing to their strongly negatively charged surfaces in phosphate-buffered saline, it is difficult to obtain the topography of the chromosomes by the conventional SICM with a single-aperture nanopipette. Using the proposed method with a double-barrel nanopipette, the surfaces of the chromosomes were successfully measured, without any surface charge confounder. Since the detailed imaging of sample topography can be performed in physiological liquid conditions regardless of the sample charge, it is expected to be used for analyzing the high-order structure of chromosomes in relation to their dynamic changes in the cell division.

Carbon paste electrode was prepared for the determination of ascorbic acid in ginger (Zingiber officinale) samples from three ginger growing areas (Chilga, Tepi and Dale Sadi) in Ethiopia. The effect of pH on the oxidation response of ascorbic acid in 0.1 M phosphate buffer was investigated and pH 2 was chosen as an optimum value. The oxidation response of ascorbic acid was predominantly diffusion-controlled reaction with a better determination coefficient R2= 0.9945 on the plot of anodic peak current vs square root of scan rate. A square wave amplitude of 45 mV, step potential of 7.0 mV and frequency of 25 Hz were chosen as optimum values. Linear calibration curve in the range of 0.1 – 8.0 mM of ascorbic acid standard in pH 2 phosphate buffer solution was obtained with a determination coefficient of 0.998. The amount of ascorbic acid detected in ginger samples collected from the three areas, Chilga was 6.85, Tepi was 6.59 and Dale Sadi was 6.54 mg/g of ginger powder. Percentage recovery in the range of 93% and 100% was validated for the applicability of the method for the quantitative determination of ascorbic acid in ginger samples. According to Health Canada dietary reference intakes, the maximum amount of ginger powder recommended intake for adult males in Chilga was 13.1, in Tepi 13.7 and in Dale Sadi 13.8 g/day.