Alta variabilidad en la determinación del Factor IX en muestras de plasma adicionadas con nonacog beta pegol entre distintos pares de reactivos/sistemas de detección / High variability in the determination of Factor IX in plasma samples spiked with nonacog beta pegol between different reagents/detection system pairs / Alta variabilidade na determinação do Fator IX em amostras de plasma enriquecidas com nonacog beta pegol entre diferentes pares de reagentes/ sistema de detecção

Resumen La hemofilia B es un trastorno hemorrágico hereditario, ligado al cromosoma X, que se caracteriza por el déficit del factor IX (FIX) de la coagulación. Para mejorar la calidad de vida de los pacientes y la adherencia al tratamiento se han desarrollado concentrados de factores recombinantes modificados para extender su vida media, denominados factores de vida media extendida (EHL: extended half life concentrates). El nonacog beta pegol (N9-GP) es una molécula de FIX humano recombinante glicopegilada que tiene una vida media de 93 h con una sola dosis y ha mostrado un porcentaje de recuperación mayor que otras moléculas. Para diagnosticar y monitorear el tratamiento del paciente hemofílico se determina la actividad del FIX con el ensayo coagulable en una etapa (OSA: one stage assay) y/o en el ensayo cromogénico. El objetivo de este trabajo, realizado en tres centros, fue medir la recuperación de N9-GP con 10 reactivos de APTT diferentes en tres plataformas, en muestras deficientes en FIX adicionadas in vitro con N9-GP, en cuatro niveles de concentración diferentes. Los resultados muestran una heterogeneidad en la actividad de N9-GP medidos por OSA con los diferentes reactivos de APTT cuando se realizaron las calibraciones con el estándar específico de cada coagulómetro. Se obtuvo un porcentaje de recuperación mayor de 92% con Cephascreen, Actin FSL y APTTest elágico en las tres plataformas evaluadas. Estos reactivos serían los únicos apropiados cuando se usa el OSA calibrado con plasma comercial para monitorear el tratamiento de los pacientes que reciben N9-GP.

Abstract Hemophilia B (HB) is an X-linked hereditary bleeding disorder characterised by coagulation factor IX (FIX) deficiency. To improve the quality of life of patients and adherence to treatment, recombinant factor concentrates glicomodified to extend their half-life have been developed. These are called extended half-life factors (EHL: extended half-life concentrates). Nonacog beta pegol (N9-GP) is a glycopegylated recombinant human FIX molecule that has a half-life of 93 h with a single dose and has shown a higher recovery percentage than other molecules. For diagnosis and monitoring the treatment of hemophiliac patients, FIX activity is determined with the One Stage Clotting Assay (OSA) and/or the chromogenic assay. The objective of this work, carried out in three centres, was to measure the recovery of N9-GP with 10 different APTT reagents on three platforms, in FIX deficient samples spiked in vitro with N9-GP, at four different concentration levels. The results show a heterogeneity in the activity of N9-GP measured by OSA with the different APTT reagents when the calibrations were performed with the specific standard of each coagulometer. A recovery percentage greater than 92% was obtained with Cephascreen, Actin FSL and APTTest ellagic in the three platforms evaluated. These reagents would be the only ones appropriate when using the commercial plasma-calibrated OSA to monitor the treatment of patients treated with N9-GP.

Resumo A hemofilia B é uma doença hemorrágica hereditária ligada ao cromossomo X caracterizada pela deficiência do fator de coagulação IX (FIX). Para melhorar a qualidade de vida dos pacientes e a adesão ao tratamento, foram desenvolvidos concentrados de fatores recombinantes modificados para prolongar sua meia-vida, chamados de fatores de meia-vida estendida (EHL: extended half life concentrates). Nonacog beta pegol (N9-GP) é uma molécula de FIX humano recombinante glicopeguilada que tem meia-vida de 93 h com uma dose única e mostrou uma porcentagem de recuperação maior do que outras moléculas. Para diagnosticar e monitorar o tratamento de pacientes hemofílicos, a atividade do FIX é determinada com o ensaio coagulável em um estágio (OSA: One Stage Assay) e/ou o ensaio cromogênico. O objetivo deste trabalho, realizado em três centros, foi medir a recuperação de N9-GP com 10 reagentes de APTT diferentes em três plataformas, em amostras deficiente de fator IX adicionadas in vitro com N9-GP, em quatro níveis de concentração diferentes. Os resultados mostram uma heterogeneidade na atividade de N9-GP medidos por OSA com os diferentes reagentes de APTT quando as calibragens foram realizadas com o padrão específico de cada coagulômetro. Uma porcentagem de recuperação superior a 92% foi obtida com Cephascreen, Actin FSL e APTTest elágico nas três plataformas avaliadas. Esses reagentes seriam os únicos apropriados ao usar o OSA calibrado com plasma comercial para monitorar o tratamento de pacientes tratados com N9-GP.

Expression of recombinant human interleukin-29-Fc fusion protein in HEK293F cells and analysis of its anti-tumor activity in vitro / 中国生物制品学杂志

@#Objective To express recombinant human interleukin-29-Fc(rhIL-29-Fc) fusion protein in human embryonic kidney 293-F(HEK293F) cells and analyze its anti-tumor activity in vitro.Methods The recombinant expression plasmid UCOE-IL-29-Fc was constructed and transiently transfected into HEK-293F cells.After expression and purification,rhIL-29-Fc fusion protein was obtained and identified by SDS-PAGE and Western blot;Female Japanese white rabbits were immunized with rhIL-29 and rhIL-29-Fc protein subcutaneously in the left ear respectively,2 rabbits in each group,0.5 mg per rabbit.Blood samples were collected from the vein of right ear,and the serum was separated.The half-life was measured by ELISA and the anti-proliferation effect of rhIL-29-Fc protein on human colon cancer HT-29,human colon cancer HCT-116,human Burkkit lymphoma Daudi,human non-small cell lung cancer NCI-H1975,human small cell lung cancer NCI-H209,human esophageal cancer EC109 and human pancreatic cancer PANC-1 cells in vitro was detected by CCK-8 assay,and the inhibitory concentration 50(IC_(50)) was calculated.Results The recombinant expression plasmid UCOE-IL-29-Fc was constructed correctly as identified by double digestion and sequencing.After transient transfection into HEK-293 cells for 6 d,the culture supernatant was harvested.The relative molecular mass of the purified rhIL-29-Fc fusion protein was consistent with the expectation.The protein showed a specific binding reaction with mouse anti-human IL-29 monoclonal antibody with a concentration of 1.5 mg/ml and a purity of 93%.RhIL-29-Fc protein had a half-life of 25 h and showed different inhibitory effects on the proliferation of 7 kinds of tumor cells,and the IC_(50) on different cells was also different.Conclusion The rhIL-29-Fc fusion protein was successfully expressed in HEK-293F cells,and the half-life of the fusion protein was 20 h longer than that of rhIL-29.According to the different anti-tumor proliferation activity in vitro and IC_(50) results on 7 kinds of tumor cells,it was found that the anti-tumor activity of rhIL-29-Fc fusion protein was higher than that of rhIL-29.This study laid a foundation of the development of IL-29 protein in the treatment of tumors.

Pharmacokinetics and blood-brain barrier penetration of a novel salidroside derivative pOBz in rats / 中国药理学通报

Aim To develop a ultra-high performance liquid chromatography electrospray-ionization tandem mass spectrometry ( UPLC-MS/MS ) method for the simultaneous determination of salidroside derivative pOBz in rat plasma and brain tissue, and to study the pharmacokinetic profile and penetration of the blood-brain barrier in rats after a single dose intravenous administration of pOBz. Methods SD rats were administered pOBz at a dose of 50 mg • kg

Experimental study on the relationship between foam pressure difference and foam stability / 生物医学工程学杂志

Foam stability affects the efficacy and incidence of side effects of foam sclerotherapy. Exploring the relationship between foam pressure difference and foam stability can provide ideas and basis for obtaining more stable foam. In the experiment, sodium cod liver oleate foam was selected, and poloxamer 188 (concentration of 0%, 4%, 8%, 12%) was added to realize the change of foam pressure. By using the self-written program to process the foam pictures, the foam pressure difference and the relationship between the foam stability indicators (water separation rate curve, half-life) and the foam pressure difference were obtained. The results showed that at first the foam pressure increased with the increase of the concentration, and then it decreased with the increase of the concentration and reached a peak at the concentration of 4%. The foam pressure difference decreases continuously with the increase of decay time. When the additive concentration is low, the foam average pressure difference increases. And if the additive concentration is too high, the foam average pressure difference decreases. The smaller the foam pressure difference is, the better the foam stability is. This paper lays a foundation for the research on the stability of foam hardener.

A short half-life of cccDNA offer or ignite hope for hepatitis B cure under nucleos(t)ide analogues treatment / 中华肝脏病杂志

Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is the template for HBV replication. Currently, there is a lack of therapeutic drugs that directly target cccDNA. Therefore, blocking cccDNA supplements as fast as possible and reducing the existing cccDNA is the key to achieving a complete cure of chronic hepatitis B. Previous studies have suggested that cccDNA had a long half-life, but a recent study showed that it only took a few months to update cycle of cccDNA pool, and its number was much less than previously predicted. In the future, with the advent of new antiviral drugs that can completely inhibit HBV replication, it is expected that the cccDNA pool will be completely cleared due to its supplement complete blockade, so as to achieve virological cure of chronic hepatitis B.

Ozonation of quinoa seeds (Chenopodium quinoa Willd. ): saturation and decomposition kinetics of ozone and physiological quality of seeds / Ozonização de sementes de quinoa (Chenopodium quinoa Willd. ): saturação e cinética de decomposição do ozônio e qualidade fisiológica das sementes

Ozonation has been evaluated as an alternative method for seed treatment. In this context, the goal of this study was to evaluate the saturation process and kinetics of decomposition of ozone in a porous medium composed of quinoa BRS Syetetuba and possible changes in seed quality. Ozone concentration and saturation time in the porous medium and half-life were determined by adopting an inlet ozone concentration of 885 ppm and a flow rate of 5.0 L min-1 at 25 °C. The ozonation periods adopted were 0, 30, 60, 90, and 120 min. Regarding the physiological quality of the seeds, the germination percentage, germination speed index, electrical conductivity, and length of the shoot, root, and normal seedlings were analyzed. At the inlet ozone concentration of 885 ppm and a flow rate of 5.0 L min-1, the saturation concentration and saturation time in the porous medium composed of quinoa were 522.5 ppm and 12.0 min, respectively. The half-life of ozone in the porous medium was 6.08 min at 25 °C. Under these conditions, ozonation did not affect the physiological quality of quinoa BRS Syetetuba seeds for up to 120 min.(AU)

A ozonização tem sido avaliada como método alternativo para tratamento de sementes. Nesse contexto, objetivou-se avaliar o processo de saturação e a cinética de decomposição do ozônio em meio poroso composto de quinoa, cv. BRS Syetetuba, e possíveis alterações na qualidade das sementes. Determinaramse a concentração e o tempo de saturação do ozônio no meio poroso e a meia-vida, adotando-se concentração de entrada de 885 ppm, vazão de 5,0 L min-1, a 25 ºC. Os períodos de ozonização adotados foram 0, 30, 60, 90 e 120 min. Quanto à qualidade fisiológica das sementes, analisaram-se o percentual de germinação, índice de velocidade de germinação, condutividade elétrica e comprimentos da parte aérea, do sistema radicular e das plântulas normais. Para concentração de entrada do ozônio de 885 ppm e vazão de 5,0 L min-1, a concentração e o tempo de saturação do ozônio no meio poroso composto de quinoa foi de 522,5 ppm e 12,0 min, respectivamente. A meia-vida do ozônio em meio poroso foi de 6,08 min, a 25 ºC. Nas condições a adotadas, a ozonização não afeta a qualidade fisiológica das sementes de quinoa, cv. BRS Syetetuba, por até 120 min.(AU)

Residues Decomposition in Crop Rotations under No-till System

Abstract The effectiveness soil cover in no-till is relating to quantity and quality of the phytomass produced by crops in rotation and, its persistence over the soil depends on residues decomposition. The objective of this study was to evaluate the phytomass production, decomposition rate and the half-life of crops in rotation at the Subtropical region, Brazil. The study was carried out at the Agronomic Institute of the Paraná (IAPAR), in Ponta Grossa, Parana State, Brazil. The experimental design was randomized blocks, with six treatments and four replicates. Winter cash crops and cover crops, single and in consortium, were evaluated in the year 2014 (wheat, black oats + hairy vetch + rye, black oats + ryegrass and black oats + blue lupine), in 2015 (canola, black oats, and black oats + hairy vetch + forage turnip) and in 2016 (barley, triticale, and triticale + black oats + rye). The phytomass was evaluating by collect three subsamples of 0.25 m2 per plot. For decomposition rate and the half-life of the crop residues, litter bags (LBs) methodology was used. A mathematical model (Q=Q0exp-kt) was used to represent the crop residues decomposition and the half-life of crop residues were obtained by the equation t1/2 = (ln2)/k. Poaceae consortia, single Poaceae and canola presented higher phytomass production when compared to Poaceae-Fabaceae consortia. The half-life for Poaceae-Fabaceae corsortia was shorter than single Poaceae.

Study on the factors affecting the degradation of niclosamide in the soil / 中国血吸虫病防治杂志

ObjectiveTo investigate the factors affecting the degradation of niclosamide in the soil, so as to provide the evidence for the assessment of the environmental safety in the field snail control with niclosamide. MethodsA high performance liquid chromatography was established for the determination of niclosamide in the field. Then, the degradation of niclosamide was investigated in soils with different moistures (10%, 30%, 50%, 70% and 90%), temperatures [(15 ± 1), (25 ± 1), (35 ± 1) °C], initial concentrations (1, 5, 10 mg/kg) and in sterilized and non-sterilized soils. In addition, the degradation of niclosamide was fitted with the first-order kinetics equation, and the degradation half-life was calculated. Results The niclosamide residues gradually decreased over time in soils with different moistures, and a higher rate of degradation was seen in soils with a higher moisture. The degradation half-life of niclosamide reduced from 4.258 d in the soil with a 10% moisture to 2.412 d in the soil with a 90% moisture. The niclosamide residues gradually decreased over time in soils with different temperatures, and a higher rate of degradation was seen in soils with a higher temperature. The degradation half-life of niclosamide reduced from 4.398 d in the soil with a temperature of (15 ± 1) °C to 2.828 d in the soil with a temperature of (35 ± 1) °C. The degradation half-lives of niclosamide were 3.212, 3.333 d and 3.448 d in soils containing niclosamide at initial concentrations of 1, 5 mg/kg and 10 mg/kg, and > 30 d and 3.273 d in sterilized and non-sterilized soils. Multiple linear regression analysis revealed that soil microorganisms (P = 0.010), moisture (P = 0.000) and temperature (P = 0.002) affected the half-life of niclosamide degradation. Conclusions The degradation of niclosamide in soils fits the first-order kinetics equation, and presence of microorganisms, a high temperature and high moisture may accelerate the degradation of niclosamide in the soil.

Effective strategies for improving the stability of peptides in vivo / 药学学报

Peptides have been extensively used in the fields of gene/drug delivery and disease targeting therapy. However, natural peptides are sensitive to protease digestion with short circulatory half-lives in vivo. Many studies on structural modifications of peptides have been reported to improve the delivery or therapeutic effect. In this review we focus on the recent literature on peptide stability in accordance with different structural modifications and summarize the methods and influential factors that are involved in the improvement of stability and half-life in vivo. This review will provide the scientific basis and theoretical references for further investigations and applications in vivo.

Lesion-Wise Comparison of Pre-Therapy and Post-Therapy Effective Half-Life of Iodine-131 in Pediatric and Young Adult Patients with Differentiated Thyroid Cancer Undergoing Radioiodine Therapy / 대한핵의학회잡지

PURPOSE: The effective half-life of radioiodine is an important parameter for dosimetry in differentiated thyroid cancer patients, particularly in children. We determined the pre-therapy and post-therapy effective half-life in different types of lesions, i.e., remnant, node, or lung metastases.METHODS: Of 84 patients recruited, 27 were < 18 years (group 1) and the remaining 57 were between 18 and 21 years (group 2). A total of 114 studies were conducted and 253 lesions were analyzed. Serial whole-body scans were acquired at 24, 48, and ≥ 72 h after administration of iodine-131. Region of interests was drawn over lesions to determine counts in the lesion. Time versus counts graphs were plotted and mono-exponentially fitted to determine effective half-life.RESULTS: The post-therapy effective half-life was found to be lesser than pre-therapy effective half-life in all types of lesions and in all groups. Median effective half-life was found maximum in intact lobe, minimum in the lung, and intermediate in remnant and nodes. In the assessment of all lesions together, pre- and post-therapy median and interquartile range (IQR) effective half-life were 59.8 (37–112) h and 48.6 (35.2–70.8) h (p < 0.0001) in group 1, 73.9 (46.2–112.7) h and 60 (57.4–85.9) h (p < 0.0001) in group 2, and 68.6 (41.53–112.36) h and 54.7 (36–80.6) h (p < 0.0001) in combined group, respectively. Importantly, the pre- and post-therapy median effective half-life serially dropped after each successive cycles of iodine-131.CONCLUSIONS: There was a significant difference in pre-therapy and post-therapy effective half-life in all types of lesions. These results may have implications in calculating the correct therapeutic dose in children and in young adults.

Pharmacokinetics and bioavailability of glucosamine after administration of glucosamine hydrochloride or glucosamine sulfate / 中国药理学通报

Aim: To determine the pharmacokinetics and bioavailability of glucosamine after administration of glucosamine hydrochloride (GH) and glucosamine sulfate (GS). Methods: GH or GS was given ig and iv to rats, respectively. An LC-MS/MS method was developed to measure the concentrations of glucosamine in plasma. DAS 3. 0 was employed to obtain the pharmacokinetical parameters as well as bioavailability. Results: There was no marked difference in T1/2, Vz and absolute availability between GH and GS. However, the relative bioavailability of GH was higher than that of GS. In addition, Tmax of GS was shorter than that of GH. Conclusion: There are some differences between the glucosamine pharmacokinetics of GH and GS.

Remaining straw and release of nutrients from oat managed in integrated crop-livestock / Palhada remanescente e liberação de nutrientes da aveia preta manejada em sistema de integração lavoura-pecuária

This study aimed to evaluate the decomposition and nutrient release from residues of the culture of oats and fallow in crop-livestock integration system. The experimental design was a randomized complete block design with two replications, as parcels being formed by four managements (fallow, oats without grazing, oats grazed once and twice), and the subplots for evaluation periods along the soybean crop in succession (0, 10, 20, 30, 50, 100 and 120 days after sowing). The residual amounts of dry matter and the contents of Carbon (C), Nitrogen (N), Phosphorus (P) and Potassium (K) were determined. Oats without grazing and fallow with natural reappearance of turnip + ryegrass were the treatments that presented the highest amount of dry matter remaining, reaching 5,219 and 6,781 kg ha-1, respectively. The amount of nutrients, N, P and K released from the residues, were similar independent from the management adopted, with exponential reduction proportional to the reduction of the remaining dry matter. K was the nutrient released faster from the residues and should be considered at the time of fertilization calculation of the culture to be implanted. The integrated crop-livestock system in which takes place one and two grazing oats, even reducing soil cover, enables high nutrient cycling.

O objetivo do trabalho foi avaliar a decomposição e liberação de nutrientes dos resíduos da cultura da aveia preta e do pousio conduzidos em sistema de integração lavoura-pecuária. O delineamento experimental utilizado foi o de blocos casualizados, em esquema de parcelas subdivididas, com duas repetições, sendo as parcelas constituídas por quatro manejos (pousio, aveia sem pastejo, aveia pastejada uma e duas vezes) e as subparcelas, pelas épocas de avaliação ao longo do cultivo da soja em sucessão (0, 10, 20, 30, 50, 100 e 120 dias após a semeadura). Foram determinadas as quantidades residuais de matéria seca e os teores de Carbono (C), Nitrogênio (N), Fósforo (P) e Potássio (K). A aveia sem pastejo e o pousio com ressemeadura natural de aveia + azevém, foram os manejos que apresentaram as maiores quantidades de matéria seca remanescentes, chegando a 5.219 e 6.781 kg ha-1, respectivamente. A quantidade dos nutrientes, N, P e K liberados dos resíduos, foram semelhantes independente do manejo adotado, com redução exponencial e proporcional à redução da matéria seca remanescente. O K foi o nutriente liberado mais rapidamente dos resíduos e deve ser considerado no momento do cálculo de adubação da cultura a ser implantada. O sistema de integração lavoura-pecuária no qual se realiza um e dois pastejos da aveia, mesmo reduzindo a cobertura do solo, possibilita elevada ciclagem de nutrientes.

A single compartment simulation model of pharmacokinetics

For better understanding about derivation of various parameters related to pharmacokinetics, this model is developed. Animals or human volunteers are not used in this model but the principles used in pharmacokinetic studies in volunteers are incorporated. There is detailed description about setting of the model and derivation of various parameters step by step. An example is followed to illustrate the calculations involved. Possibilities of further extension of model to derive additional parameters and variations are discussed. The experience indicates that the model serves as a good demonstration to undergraduate students and a meaningful experiment for PG-students for learning and as a practical-examination exercise. The purpose of the article is to widen the use of this simple teaching tool at various centers.

Preparation of osthole foaming microemulsion / 中草药

Objective: To prepare osthole foaming microemulsion and study its foaming force. Methods: In this paper, the overall desirability of drug loading rate, half foam life period, and foaming force was taken as index. Based on the result of solubility test and pseudo-ternary phase diagram, the formula for the osthole foaming microemulsion was optimized by D-optimal mixture optimization design test. Results: The optimal ratio of the prescription was as follows: ethyl oleate-Cremophor EL-40-transcutol P-water (8.13: 14.81: 6.58: 71.44); Average particle size was (43.54 ± 3.43) nm (n=3), average polydispersity factor was (0.839 ± 0.092) % (n=3), average potential was (-2.32 ± 0.78) mV (n=3), frothing volume was (8.57 ± 0.28) cm, half foam life period was (6.79 ± 0.32) min. At 37℃, the maximum drug loading of foaming microemulsion was 13.62 mg/g, and the solubility in water was 0.42 mg/mL. Conclusion: Osthole foaming microemulsion was stable, which could greatly increase the solubility of osthole and remarkably enhance the bioavailability of osthole.

Advances of long-acting recombinant protein therapeutics / 生物工程学报

Some of the recombinant protein therapeutics with short half-life requires high frequent dose or injection, which results in poor patient compliance. This challenge has prompted the development of long-acting recombinant proteins in recent years. Four strategies and methods, including chemical modification, protein engineering, fusion proteins and protein glycosylation are used to modify protein molecule and finally obtain improved pharmacokinetics (PK) properties. This article reviews the four strategies of half-life extension and presents a detailed list of long-acting therapeutics on US, EU and China markets.

Elimination half-lives of interleukin-6 and cytokine-induced neutrophil chemoattractant-1 synthesized in response to inflammatory stimulation in rats / 한국실험동물학회지

The elimination half-lives of in Interleukin-6 (IL-6) and cytokine-induced neutrophil chemoattractant-1 (CINC-1) in rats after inflammatory stimulation were investigated. Five male Sprague-Dawley rats were used (age, 9 weeks; body weight, 235–375 g). Turpentine oil was intramuscularly injected at a dose of 2 mL/kg body weight to induce acute inflammation. Blood was collected pre-injection and 6, 12, 24, 36, 48, 60, 72, 84, and 96 h after the turpentine oil injection. Serum concentrations of IL-6, CINC-1, and α₂-macroglobulin (α2M) were measured by enzyme-linked immunosorbent assay. Half-lives were calculated as 0.693/elimination rate constant. The serum concentration of α2M peaked at 48 h after turpentine oil injection. Serum concentrations of IL-6 and CINC-1 increased and peaked at 12 and 24 h, respectively. The terminal elimination half-lives of IL-6 and CINC-1 were 15.5 and 29.9 h, respectively. The half-life of CINC-1 was significantly longer than that of IL-6 (P=0.006). These results suggested that these cytokines synthesized in response to inflammatory stimulation were rapidly eliminated in rats. The serum concentrations of these cytokines should be measured at an early stage if these cytokines will be used as surrogate inflammatory markers instead of acute-phase proteins.

Generation of dimeric single-chain antibodies neutralizing the cytolytic activity of vaginolysin

Background: Gardnerella vaginalis is a bacterial vaginosis (BV)-associated vaginal bacterium that produces the toxin vaginolysin (VLY). VLY is a pore-forming toxin that is suggested to be the main virulence factor of G. vaginalis. The high recurrence rate of BV and the emergence of antibiotic-resistant bacterial species demonstrate the need for the development of recombinant antibodies as novel therapeutic agents for disease treatment. Single-chain variable fragments (scFvs) generated against VLY exhibited reduced efficacy to neutralize VLY activity compared to the respective full-length antibodies. To improve the properties of scFvs, monospecific dimeric scFvs were generated by the genetic fusion of two anti-VLY scFv molecules connected by an alpha-helix-forming peptide linker. Results: N-terminal hexahistidine-tagged dimeric scFvs were constructed and produced in Escherichia coli and purified using metal chelate affinity chromatography. Inhibition of VLY-mediated human erythrocyte lysis by dimeric and monomeric scFvs was detected by in vitro hemolytic assay. The circulating half-life of purified scFvs in the blood plasma of mice was determined by ELISA. Dimeric anti-VLY scFvs showed higher neutralizing potency and extended circulating half-life than parental monomeric scFv. Conclusions: The protein obtained by the genetic fusion of two anti-VLY scFvs into a dimeric molecule exhibited improved properties in comparison with monomeric scFv. This new recombinant antibody might implement new possibilities for the prophylaxis and treatment of the diseases caused by the bacteria G. vaginalis.

Investigation on enzymatic degradation stability of peptide drugs LXT101 and its structural modified analogs in pancreatin system / 国际药学研究杂志

Objective To find the efficient modification groups of anti-proteinase hydrolyzation in polypeptide by investigat-ing and comparing the relation between the functional groups and their ability to inhibit proteinase hydrolyzation. Methods Reverse phase-high performance liquid chromatography(RP-HPLC)method was developed to investigate in vitro metabolisms of new drug LXT101 and its structural modified analogs LZN series and LMP series in pancreatin system. All the separations of peptide drugs and their digested fragments were monitored at 225 nm. Results The good linear range was 4.0-400 μg/ml(r>0.9990)for new drug LXT101 and its structural modified analogs,i.e.,LZN series and LMP series. The recoveries of all peptide drugs ranged from 95.0%to 98.7%in pancreatin systems. The relative standard derivations(RSD)of intra-day and inter-day were less than 1.5%and 2.5%,re-spectively. The revealed order of digested half-life of the peptide drugs was LZN series>LMP series>LXT101. Conclusion The study of different sites and different functional groups on the lifetime indicates that the half-lives of peptides are prolonged by introducing the functional groups in the suitable sites of peptide,which feature as proteinase inhibitors,such as carbamoyl(Cbm),acetyl(Ac),para-amino-phenylalanine(Aph)or para-uramido-phenylalanine(Uph),which work as either proton donor or acceptor. Our results can pro-vide some useful and valuable information on structural design of peptide drug with long lifetime and high activity.

Introduction and analysis of FDA issuedguidance on bioequivalence recommendations for specific products related with longhalf-life drugs / 中国药学杂志

OBJECTIVE: To study and analyze FDA issued guidance on Bioequivalence Recommendations for Specific Products related with long Half-life drugs. METHODS: Bioequivalence Recommendations for Specific Products related with long Half-life drugs was analyzed from multiple aspects, including bioequivalence study designs, selection of bioequivalence subjects, dosage, selection of reference products, analytes to measure, bioequivalence waiver on multiple-strength products and implementation of the Biopharmaceutics Classification System. RESULTS: Bioequivalence Recommendations for Specific Products issued by FDA are to further facilitate generic drug product availability and to assist generic pharmaceutical industry with identifying the most appropriate methodology for developing drugs and generating evidence needed to support ANDA approval or reassessment, as an extension and implement to the guideline involved in the aspect of bioequivalence. CONCLSUTION: Bioequivalence Recommendations for Specific Products issued by FDA would provide instructive and practical assists to the equivalence assessment of quality and curative effect for generic products in China, since there is not corresponding bioequivalence guidance on specific long Half-life drugs released by CFDA yet.

Optimization of estimating 131I effective half-life in patients with Graves' disease / 中华核医学与分子影像杂志

Objective To explore optimized method of estimating 131I effective half-life(EHL) in patients with Graves' disease(GD).Methods The EHL was obtained by measuring thyroid radioactive iodine uptake (RAIU) of 126 patients (32 males,94 females,average age (38.47± 11.49) years) with GD at 4,24,48,96,120,144,168,192 and 216 h.Two-sample t test,bivariate correlation analysis and curve estimation were used for statistical analysis.Results The EHL of 126 patients was 0.5-7.5 (4.70±1.46) d.The EHL was 3.0-7.5(5.25±1.01) d and 0.5-6.0(3.24±1.52) d in group A (94 patients,without advanced peak of RAIU) and group B (32 patients,with advanced peak of RAIU),respectively,and the difference between the 2 groups was significant (t =8.499,P＜0.01).The EHL had no significant correlation with RAIU4h/RAIU24h(r=-0.177,P＞0.05) in group A,while it had negative correlation with RAIU4h/RAIU24h in group B (r =-0.724,P＜0.01).In group A,the EHL of patients with RAIU24h/RAIU48h ＞100％ was 3.0-7.5 (5.11 ±0.98) d,the EHL of patients with RAIU24h/RAIU48h ≤ 100％ was 4.0-7.0(5.91±0.94) d (t=3.141,P＜0.01).In group B,when RAIU4h/RAIU24h+RAIU24h/RAIU48h was used as the independent variable in S curve model to estimate the EHL,the result was the best (R2=0.930,F=397.22,both P＜0.01,b0 =-3.038 0,b1 =9.659 4).Conclusions In order to optimally estimate EHL,patients should be grouped according to 131I turnover.In patients with advanced peak of RAIU,the EHL should be calculated by using formula of (RAIU4h/RAIU24h +RAIU24h/RAIU48h).If no advanced peak of RAIU exists,patients should be further divided according to RAIU24h/RAIU48h ＞ 100％ or RAIU24h/RAIU48h ≤100％,and the EHL mean value of each group is taken as the estimated EHL.