Acid-base and lipophilic properties of peptide nucleic acid derivatives / 药物分析学报

The first combined experimental and theoretical study on the ionization and lipophilic properties of peptide nucleic acid(PNA)derivatives,including eleven PNA monomers and two PNA decamers,is described.The acidity constants(pKa)of individual acidic and basic centers of PNA monomers were measured by automated potentiometric pH titrations in water/methanol solution,and these values were found to be in agreement with those obtained by MoKa software.These results indicate that single nucleobases do not change their pKa values when included in PNA monomers and oligomers.In addition,immobilized artificial membrane chromatography was employed to evaluate the lipophilic properties of PNA monomers and oligomers,which showed the PNA derivatives had poor affinity towards membrane phospholipids,and confirmed their scarce cell penetrating ability.Overall,our study not only is of po-tential relevance to evaluate the pharmacokinetic properties of PNA,but also constitutes a reliable basis to properly modify PNA to obtain mimics with enhanced cell penetration properties.

Determination of Stability Constants of Ibandronate Complexes with Ca(II), Mg(II) and Sr(II)

An abnormal condition which troubles a living organism is called a disease. Nowadays, the most common problems thepeople are affected by are the heart problems. Several times, they lead to death in most cases due to the lack of correctdiagnosis. The volume of data has been increasing rapidly in the area of health care. Predicting the heart problems is verydifficult for the physicians. It is intractable to find the interesting patterns among enormous volumes of data. To find those,pattern recognition can be used, and to discover the hidden knowledge, data mining can be used. There have been a largenumber of medical data sets available in the market. Among all types of heart diseases, Cardio Vascular Disease is a type.So, many researchers carried out their works in heart disease dataset with 13 attributes, and 15 attributes with various datamining methods. In this study, ranking method was used in preprocessing a stage with total of 17 attributes for strengtheningthe rate of accuracy. The Zero R and J48 algorithms from NN and Multilayer Perceptron & decision tree were appliedrespectively on the dataset. The classifiers’ performance was analyzed by error rate and time complexity with accuracy. Inthis research, Multilayer perceptron classifier showed high accuracy results with 13 attributes. Out of these three classifiers,J48 classifier gave high accuracy, minimum error rate and less time while using 17 attributes. Hence, these approaches canbe very useful to the physicians to take decisions at the proper time. This research work was entirely carried out by WEKA(Waikato Environment Knowledge Analysis) data mining tool.

Determination of Vitamin U in Vitamin U Preparations by a Potentiometric Titration Method / 中国药师

Objective:To improve the determination method of vitamin U in vitamin U preparations. Methods: A potentiometric titration method was established for the determination of vitamin U and the results were compared with those of the manual titration method described in the current quality standard. Results:The determination results of vitamin U by the potentiometric titration method were affected by neither the excipients and the other components contained in the preparations,nor the precipitation produced in the ti-tration process. The recoveries for two types of vitamin U ( methylmethinine sulfonium chloride and s-methy-L-methionine iodide) were 99. 47%(RSD=1. 0%,n=9) and 100. 22%(RSD=1. 4%,n=9), respectively. The determination results of 6 samples from 3 dif-ferent companies detected by the method were basically consistent to those detected by the manual titration method described in the cur-rent quality standards with the relative deviation less than or equal to 0. 5%. Conclusion:The method is simple,accurate and reliable, and can be used for the quantitative determination of vitamin U in various vitamin U preparations.

Determination of Vitamin U in Vitamin U Preparations by a Potentiometric Titration Method / 中国药师

Objective:To improve the determination method of vitamin U in vitamin U preparations. Methods: A potentiometric titration method was established for the determination of vitamin U and the results were compared with those of the manual titration method described in the current quality standard. Results:The determination results of vitamin U by the potentiometric titration method were affected by neither the excipients and the other components contained in the preparations,nor the precipitation produced in the ti-tration process. The recoveries for two types of vitamin U ( methylmethinine sulfonium chloride and s-methy-L-methionine iodide) were 99. 47%(RSD=1. 0%,n=9) and 100. 22%(RSD=1. 4%,n=9), respectively. The determination results of 6 samples from 3 dif-ferent companies detected by the method were basically consistent to those detected by the manual titration method described in the cur-rent quality standards with the relative deviation less than or equal to 0. 5%. Conclusion:The method is simple,accurate and reliable, and can be used for the quantitative determination of vitamin U in various vitamin U preparations.

A Ribavirin Potentiometric Sensor Based on MolecularlyImprinted Polymers Doped with Graphene Oxide Film / 分析化学

Molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using ribavirin as the template molecule and methacrylic acid as the functional monomer.The sensitive film of ribavirin electrode was constructed by molecularly imprinted polymer doped with graphene oxide as the ionophore, poly(vinylchloride) (PVC) as matrix and dioctyl sebacate for plasticizer.The results showed that the best performance of the electrode was obtained when the sensitive film compositions were 100.8 mg of MIP, 14.7 mg of GO, 450.8 mg of PVC and 901.6 mg of dioctyl sebacate, and the inner filling solution composition was 0.1 mol/L NaCl + 0.05 mol/L NaAc-0.05 mol/L HAc + 1.0×10.-5 mol/L ribavirin solution.The electrode showed a near-Nernstian slope of 45.565 mV/decade for ribavirin over the range of 1.0×10.6-1.0×10.-4 mol/L and a detection limit of 1.0×10.-7 mol/L.The electrode could be used in the pH range of 3 to 5 with response time of less than 3 min.The developed electrode exhibited high selectivity for ribavirin and was successfully applied to the determination of ribavirin in feed and injection with recoveries of 90%-110% and RSD of 3.0%-7.9%.

Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration / 药物分析学报

As a mono-sodium salt form of alendronic acid, alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups. The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and pH value based on acid-base potentiometric titration reaction. The distribution curves of alendronate sodium were drawn according to the determined pKa values. There were 4 dissociation constants (pKa1=2.43, pKa2=7.55, pKa3=10.80, pKa4=11.99, respectively) of alendronate sodium, and 12 existing forms, of which 4 could be ignored, existing in different pH environments.

Determine the Grafting Ratio of CS-DCA by Linear Potentiometric Titration / 浙江中医药大学学报

Objective]To establish a new method for grafting ratio(GR) analysis of deoxycholic acid grafted chitosan(CS-DCA). [Methods]In this study, linear potentiometric titration(LPT) and 2,4,6-trinitrobenzenesulfonicacid(TNBS) were introduced to measure the GR of CS-DCA, using the 1H-nuclear magnetic resonance(1H-NMR) as reference, the results obtained by the two methods were analyzed to find a method to substitute H-NMR. [Results]There was no significant difference of the data determined by 1H-NMR and LPT(P>0.05), however, it didn't apply to 1H-NMR and TNBS(P<0.05), the results indicated that LPT had equivalent accuracy of 1H-NMR. Using 1H-NMR method as the standard reference, the relative error was no more than 3.8% for the method of LPT, and the maximum relative error for the method of TNBS was up to 12.8%, it meant that LPT had higher precision. [Conclusion]LPT is an economical, rapid and accurate method for the GR analysis of CS-DCA.

Design and Construction of an Embedded Telemetry System for Potentiometric Sensors / 分析化学

A new embedded telemetry system for potentiometric sensors was developed. The system consisted of a transmitter unit, a receiver unit and a personal computer ( PC) . The transmitter unit included a current amplifier, a∑-Δanalog-to-digital converter ( ADC) , a microcontroller unit ( MCU) and a radio module. The receiver unit was composed of a radio module, a microcontroller unit and a serial-to-USB converter module. The receiver unit was connected to an upper computer via a universal serial bus ( USB ) . The embedded software written in C language controlled the signal acquisition and transmission. The computer software written in LabVIEW language was used for data storage and display. The range of the acquisition voltages was from-1. 17 V to +1. 17 V. In order to verify the accuracy and reliability of this system, a control experiment had been done with this system and a digital multimeter. Moreover, a response test of acidity changes had been done with the self-made H+ selective electrode. The results showed that the accuracy of this system could be up to 0. 1 mV and it had strong anti-noise ability. The square of the linear correlation coefficient of the response of the changes in pH values was 0 . 998 . The curve of the results measured by this system was consistent with that measured by the commercial electrochemical analyzer. The system was built with standard hardware components and the size of the transmitter unit was only 29 mm×14 mm×11 mm. It can be easily used for remote and real-time detection for the potentiometric sensor.

Standardization of Ethanol Potassium Hydroxide Volumetric Solution by Potentiometric Titration / 中国药师

Objective: To improve the standardization method for ethanol potassium hydroxide volumetric solution. Methods: A new potentiometric titration method was established and compared with the indicator method described in Chinese Pharmacopeia (2010 edition) . Results:There was no significant difference between the results of the potentiometric method and the indicator method( P>0. 05). Furthermore, the potentiometric titration had significant jump range, good precision and high reliability. Conclusion:The po-tentiometric method can be used in the standardization of ethanol potassium hydroxide volumetric solution.

Determination of escitalopram oxalate and its related substances by HPLC / 中国药学杂志

OBJECTIVE: To establish an HPLC method and potentiometric titration method for the determination of escitalopram oxalate and its related substances for quality control.

Development of methodologies for dimethylaminoethanol glycolate assay in association with sunscreens in dermocosmetic formulation

DMAE glycolate (DG) and sunscreens have been used associated in anti-aging dermocosmetic formulations. Despite extensive use of these substances, methods for quantification of DG as raw material and in cosmetic formulations, especially when associated, are not described in the literature. RP-HPLC and non-aqueous titration methods, with determination potentiometric end-point (PT), were developed and validated for rapid assay of DG as raw material and in a topic emulsion in association with sunscreens. Both methods are simple, selective, linear, accurate and precise. The PT method was chosen for stability study of DG in the formulation developed. The proposed formulation presented good stability performance as regards aspect, pH, apparent viscosity, and SPF, with less than 5% of DG degradation compared to initial conditions.

Glicolato de DMAE (DG) e protetores solares têm sido utilizados associados em formulações dermocosméticas antiidade. Apesar da ampla utilização dessas substâncias, métodos de quantificação para DG matéria-prima e em formulações cosméticas, especialmente quando associados, não estão descritos na literatura. Neste trabalho foram desenvolvidas e validadas metodologias por CLAE-FR e titulação em meio não-aquoso, com determinação do ponto final por potenciométrica (TP), para a rápida análise de DG matéria-prima e em emulsão tópica em associação com fotoprotetores. Ambos os métodos são simples, seletivos, lineares, exatos e precisos. O método TP foi escolhido para o estudo da estabilidade do DG na formulação desenvolvida. A formulação proposta apresentou um bom desempenho no que se refere a estabilidade, aspecto, pH, viscosidade aparente e SPF, com menos de 5% degradação do DG comparado as condições iniciais.

Micro Potentiometric Label-free Immunosensor for Glycated Hemoglobin / 分析化学

A miniaturized potentiometric label-free immunosensor based on the standard complementary metal-oxide-semiconduction transistor(CMOS) process and micro fabrication technique was developed to monitoring diabetes, which could detect the concentrations of glycated hemoglobin (HbA1c) and hemoglobin. This immunosensor includes a micro field-effect transistor based sensor chip integrated with signal readout circuit and a disposable probe electrode. The micro sensor chip was designed by our lab and fabricated by Chartered Semiconductor, Singapore. The disposable probe electrode, which was integrated with sensitive electrodes array and micro reaction pool, was deposited on polyester plastic based on micro fabrication techniques. Antibody of HbA1c and hemoglobin were immobilized on the electrode based on self assemble monolayer and gold nanoparticles. The characteristics of the electrode during modification were studied by cyclic voltammetry and electrochemical impedance technique. The response characteristic of the immunosensor was detected. HbA1c from 4 to 24 mg/L and hemoglobin from 60 to 180 mg/L can be detected by this immunosensor.

Optimization of the Determination Method of Terbinafine Hydrochloride by Non-aqueous Potentiometric Titration / 中国药房

OBJECTIVE: To improve the determination method of terbinafine hydrochloride by non-aqueous potentiometric titration.METHODS: Potentiometric titration was adopted to determine the content of terbinafine hydrochloride using glacial acetic acid as solvent,acetic anhydride instead of mercury acetate.Results of improved determination method were compared with that of primary method.RESULTS: One abrupt change was obtained in the titration curve.The repeatability precision RSD was lower than 0.15%.Results of improved determination method were compared with that of primary method with maximum deviation of 0.1%.CONCLUSION: Improved method not only discards mercuric salt but also obtain obvious abrupt change of titration curve.It is simple and rapid for the determination of terbinafine hydrochloride.

Comparison of the Contents of Free Total Organic Acids in Pinellia ternata and Its Processed Products / 中国中医药信息杂志

Objective To determine and compare the contents of free total organic acids in Pinellia ternata and its processed products.Methods Back potentiometric titration was employed to determine the contents of free total organic acids in Pinellia ternata and its processed products.Results The contents of free total organic acids in three batches of Pinellia ternata and its processed products were determined.The contents of free total organic acids in prepared rhizoma pinelliae was higher than that of the crude drug.The recovery was 95.20% and RSD was 1.81%.Conclusion This method were simple,accurate and can be used to estimate the quality of Pinellia ternata and its processed products(prepared with potash alum and juice of rhizima zingiber or with just potash alum).

Improvement of Content Determination of Rocuronium Bromide by Potentiometric Titration / 中国药房

OBJECTIVE:To establish a mercury-free perchloric acid potentiometric titration method for the content determination of rocuronium bromide.METHODS:Mettler DG113-SC was used as the composite electrode.The potentiometric titration was performed with glacial acetic acid and acetic anhydride as solvents and perchloric acid(0.1 mol?L-1) as titration.The method was compared with that stated in European Pharmacopeia.RESULTS:The linear range of rocuronium bromide was 0.150 1～0.401 3 g(r=0.999 9) with an average recovery within 99.90%～99.98%.The detection limit was 1.71 mg.There was no difference between results detected by two methods.CONCLUSION:The method is simple,sensitive and accurate for the content determination of rocuronium bromide.

Toxicokinetics Study of Lead Acetate in Domestic Rabbits / 环境与健康杂志

Objective To research the toxicokinetics model of lead acetate in the domestic rabbits.Methods Injecting lead acetate into the vein of the domestic rabbit at the dose of 3 mg/kg,then the blood was collected at the 10th,20th,30th,60th,90th,120th,180th,240th and 360th min.The concentrations of the blood lead were measured by differential potentiometric stripping analysis,the data were analyzed by DAS2.0 software.Results The linear was at the range of 10 to 50 ?g/ml,the major toxicokinetics parameters were:t1/2? = 8.60 min,t1/2? = 67.69 min,t1/2? = 729.84 min,V1= 77 033.08 L/kg,CL = 709.27 L/(min?kg),AUC(0-t) = 3 106.59 ng/(L?min).According to the smallest principle of AIC,the lead concentration in vivo conformed to the three compartmental models in domestic rabbit after injecting lead acetate at 3 mg/kg.Conclusion The lead concentration conforms to the three compartmental models in the domestic rabbit after intravascular injection of lead acetate,and it is eliminated according to the first order processes.

Determination of Hydroxide in Depilatory Cosmetics With Potentiometric Titration Method / 环境与健康杂志

Objective To develope a method for determination of hydroxide in depilatory cosmetics and to provide the basis for the establishment of national standard method for determination of hydroxide in depilatory cosmetics. Methods Potentiometric titration method was used in this assay. Results This method revealed good precision(RSD

Determination of Chloride in Water by Automatic Potentiometric Titrimeter / 环境与健康杂志

0.05). The titrimetric determination of standard solution containing different levels of chloride showed recovery rates of 98.0%～103.7%, relative standard deviation was 0.16%. Conclusion Automatic potentiometric titration was easy to grasp, rapid and accurate, which was a new analytical method worthy to be applied extensively.

Determination of alkaloids in Dendrobium nobile Lindl. by automatic potentiometric titration / 中成药

AIM: Determination of total alkaloids in Dendrobium nobile Lindl.METHODS: Dried materials were subjected to exhaustive extraction with ethanol: water (9:1,v/v) under reflux.Following filtration and condensation,the residue was dissolved in 3% hydrochloric acid and filtered.The solution was refined using a strongly acidic cation exchange resin column through sequential elution.After elution of deionized H2O,the eluent with 50% of alcoholic plus 5% of ammonia was collected until alkaloids were completely desorbed and evaporated under reduced pressure.The test sample was obtained.The test sample was dissolved in glacial acetic acid and titrated with perchloric acid titrand(0.1 mol/L) with automatic titrator.The herb should contain alkaloids,calculated as dendrobium(per 1ml of perchloric acid titrand is equivalent to 26.3 mg dendrobium).RESULTS: The results of three batches of material were 0.85% ,0.63% ,1.03% respectively.CONCLUSION: The method is convenient,fast,effective and reliable.Automatic potentiometric titration can be used for determination of alkaloids in Dendrobium nobile Lindl.

Determination of Trace Silver in Drinking Water by Differential Potentiometric Stripping Analysis / 环境与健康杂志

Objective To establish a rapid method having great capability for enrichment and anti-interference, higher sensitivity and good precision for determination of trace silver in drinking water. Methods The conditions of determination such as the definition of peak potentials, the selection of auxiliary electrolytes, the selection of kind and amount of oxidants and anti-interference test were carried out by MP-1 potentiometer using glass-carbon electrode. Results The lowest detection limit, average recorery rate and average relative standard deviation were 0.004 ug/ml, 100.3% and 2.73% respectively. Conclusion This method was suitable for determination of trace silver in drinking water.