A rapid-acting, long-acting insulin formulation based on a phospholipid complex loaded PHBHHx nanoparticles

The application of poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) for sustained and controlled delivery of hydrophilic insulin was made possible by preparing insulin phospholipid complex loaded biodegradable PHBHHx nanoparticles (INS-PLC-NPs). The INS-PLC-NPs produced by a solvent evaporation method showed a spherical shape with a mean particle size, zeta potential and entrapment efficiency of 186.2 nm, −38.4 mv and 89.73%, respectively. In vitro studies demonstrated that only 20% of insulin was released within 31 days with a burst release of 5.42% in the first 8 h. The hypoglycaemic effect in STZ induced diabetic rats lasted for more than 3 days after the subcutaneous injection of INS-PLC-NPs, which significantly prolonged the therapeutic effect compared with the administration of insulin solution. The pharmacological bioavailability (PA) of INS-PLC-NPs relative to insulin solution was over 350%, indicating that the bioavailability of insulin was significantly enhanced by INS-PLC-NPs. Therefore, the INS-PLC-NPs system is promising to serve as a long lasting insulin release formulation, by which the patient compliance can be enhanced significantly. This study also showed that phospholipid complex loaded biodegradable nanoparticles (PLC-NPs) have a great potential to be used as a sustained delivery system for hydrophilic proteins to be encapsulated in hydrophobic polymers.     

Liquid chromatography-mass spectrometry assay of a thiadiazole derivative in mice: application to pharmacokinetic studies

Modern atmospheric pressure ionization (API) ion-trap mass spectrometry in connection with fast chromatographic separations using a short narrow-bore C8 column was developed to determine 5-phenyl-3-thioureido-1,2,4-thiadiazole (301029), a novel virus inhibitor in serum. Both 301029 and an internal standard (I.S.) were separated from serum samples by acetonitrile deproteinization and extraction without time-consuming reconstitution. The chromatographic separation was achieved on a C8 reversed-phase narrow-bore column using acetonitrile-water-acetic acid (90:10:0.01, v/v/v) as a mobile phase. The mass spectrometric analysis was performed by atmospheric pressure chemical ionization (APCI) mode with positive ion detection. Single ion monitoring (SIM) scan mode of m/z 237 and 158 was used to quantitatively determine 301029 and I.S., respectively. The low limit of quantitation was 25 ng/ml. The assay exhibited a linear range of 25-2500 ng/ml. Recovery from serum proved to be 100-113%. The precision (C.V.) and accuracy (RE) of the method were 2-12% and 94-112%, respectively. The present method was applied to determine the pharmacokinetic parameters of 301029 following oral administration of the agent to mice at 5 g/kg. The results revealed that the elimination half-life of 301029 was 413 min and the area under serum concentration-time curve was 354 microg/ml/min.     

Validation of a modified commercial assay for the detection of rubella-specific IgG in oral fluid for use in population studies

Matching serum and oral fluid (saliva) samples were collected from 369 subjects in Tunisia in 2002, from a city in the north and a rural district in the south. Rubella-specific IgG was detected in sera by commercial ELISA (Dade Behring) and in matching oral fluids by two methods, a previously described IgG-capture ELISA (GACELISA) [J. Clin. Microbiol. 37 (1999) 391] and the Dade Behring ELISA with the assay protocol modified for use with oral fluids. Total IgG concentration of oral fluids was also measured. Rubella-specific IgG was detected in 289 (78.3%) sera overall. Differences in the age distribution of the study population in the north and south led to a higher prevalence being found in the north (86.2%) than in the south (71.8%). This difference was reflected in the oral fluid rubella-specific IgG results. With GACELISA, rubella-specific IgG was detected in 79.4% of oral fluids from the north and 69.7% from the south and with the modified Dade Behring assay, in 81.4% of oral fluids from the north and in 64.9% from the south. The sensitivity and specificity of GACELISA in comparison to results from the matching sera were 92.4 and 93.2%, respectively. The sensitivity and specificity of the modified Dade Behring ELISA were 89.8 and 92.0%, respectively. Total IgG concentration in oral fluid showed a weak correlation (r=0.19) with the modified Dade Behring results and with samples where total IgG was >7.5 mg/l, the sensitivity and specificity were 94.4 and 90.0%, respectively. Twenty-nine oral fluids, which gave false negative rubella-specific IgG results with the modified Dade Behring ELISA, had a lower mean total IgG concentration than 256 oral fluids which gave concordant positive results (7.0mg/l versus 15.8 mg/l, P<0.001). The study validated the modified Dade Behring ELISA, providing an alternative to the GACELISA for assessing levels of rubella immunity for population studies using oral fluid samples.     

On the use of pharmacokinetic models

Extensive use of models in pharmacology, in physiology and in radiotherapy raises some questions on the nature and utility of models in general and of compartmental models in particular. In this paper I will define in a simple and logical way a set of useful pharmacokinetic parameters and show how their estimation depends on the assumed model. A special problem arises when some parameters are not identifiable; in that case I will show how it is possible to determine a range for them. Two examples are used to illustrate how to compute the value of the identifiable parameters and the range of the non-identifiable ones, when the available experimental data are not sufficient to identify a model.     

The use of a streamlined bacterial mutagenicity assay, the MINISCREEN

A streamlined bacterial mutagenicity assay, the MINISCREEN,was developed to enable the rapid screening of a large numberof chemical compounds on a purely qualitative basis. Experimentswith a series of known carcinogens/ mutagens and non-carcinogens/mutagensshowed a good correlation with conventional bacterial mutagenicityassays (Ames tests), and the subsequent testing of over 300candidate agricultural chemicals and over 100 industrial chemicalshas proven its value as a screening method.     

Improved assay method for the determination of pyronaridine in plasma and whole blood by high-performance liquid chromatography for application to clinical pharmacokinetic studies

An improved high-performance liquid chromatography method using a diisopropyl-C14 reversed-phase column (Zorbax Bonus-RP column) and a liquid-liquid extraction technique with UV detection is presented for the analysis of pyronaridine in human whole blood and plasma. Tribasic phosphate buffer (50 mM, pH 10.3) and diethyl ether were used for liquid-liquid extraction. The mobile phase consists of acetonitrile-0.08 M potassium dihydrogen phosphate buffer (13:87, v/v) with the pH 2.8 adjusted by orthophosphoric acid. Amodiaquine was found to be a suitable internal standard for the method. The quantification limit with UV detection at 275 nm was 3 ng on-column for both plasma and blood samples. The method was applied to plasma and blood specimens from a rabbit after a single intramuscular dose of pyronaridine tetraphosphate (20 mg/kg as base). From this in vivo study, evidence was found that pyronaridine is concentrated in blood cells, with a blood:plasma ratio ranging from 4.9 to 17.8. We conclude that blood is the preferred matrix for clinical pharmacokinetic studies.     

Immunological studies on Alternaria sensitivity use of crossed radioimmunoelectrophoresis, precipitins and enzyme-linked immunosorbent assay

Characterization of the immunological response to Alternaria in sensitive subjects is not complete. We used crossed radioimmunoelectrophoresis (CRIE) to identify antigens in Alternaria extracts reacting with IgE antibody in five patients with Alternaria-sensitive asthma, four with Alternaria-induced rhinitis, three non-allergic asthmatics, and three normal controls. All five Alternaria-asthma patients and three of four Alternaria-rhinitis patients showed IgE binding to a single antigen peak in the CRIE. One patient exhibited specific radio-staining to a second peak, and two other patients had IgE binding to a third antigen. These results suggest an analogy of Alternaria antigens with that found in ragweed pollen extracts, i.e. that IgE antibody is directed against more than one antigen. Using the enzyme-linked immunosorbent assay (ELISA), we found a significant difference (P < 0·05, unpaired Student's t-test) in igG binding between Alternaria-sensitive asthmatics and normal controls. There was no apparent difference in IgG binding between untreated Alternaria-sensitive asthmatics and those receiving high-dose immunotherapy.     

胰岛素泵联合门冬胰岛素治疗2型糖尿病重型颅脑损伤的临床观察

目的探讨胰岛素泵联合门冬胰岛素（CSII）治疗2型糖尿病（T2DM）重型颅脑损伤的临床疗效。方法选择T2DM重型颅脑损伤（GCS评分小于8分）的患者87例,在颅脑损伤综合治疗的基础上,分为胰岛素泵联合门冬胰岛素组（CSII组,n=42）和常规人胰岛素多次皮下注射组（MSII组,n=45）,观察两组治疗后血糖控制情况、血糖达标时间、每日胰岛素用量、低血糖发生率、重型颅脑损伤的有效率和住院时间。结果两组治疗后空腹血糖及平均随机血糖均较治疗前明显降低,且CSII组较MSII组降低更明显（P〈0.05）;CSII组较MSII组在血糖达标时间、每日胰岛素用量、低血糖发生率、重型颅脑损伤的有效率、住院时间上差异显著（P〈0.05）。结论胰岛素泵联合门冬胰岛素治疗T2DM重型颅脑损伤,能有效地控制血糖,缩短血糖达标时间和住院时间,减少每日胰岛素用量,减少低血糖发生,而且能显著提高重型颅脑损伤的治疗效果。     

Preclinical pharmacokinetic, biodistribution, and anti-cancer efficacy studies of a docetaxel-carboxymethylcellulose nanoparticle in mouse models

We have developed a polymer conjugate (Cellax) composed of acetylated carboxymethylcellulose (CMC), docetaxel (DTX), and PEG, designed to enhance the pharmacokinetics (PK) and antitumor efficacy of DTX. Our design placed an emphasis on nanoparticle self-assembly to protect DTX during blood transport, stability of the nanoparticle, and PEGylation to enhance PK. Compared to Taxotere, Cellax exhibited a 38.6 times greater area under the curve (AUC), and significantly lower clearance (2.5%) in PK. Less than 10% of DTX was released from Cellax in the blood circulation, indicating that Cellax were stable during blood transport. Cellax reduced non-specific distribution of DTX to the heart, lung and kidney by 48, 90, and 90%, respectively, at 3 h, compared to Taxotere. The uptake of Cellax at 3 h in the liver and spleen was high (15-45 μg DTX/g) but declined rapidly to <10 μg DTX/g in 24 h, and induced no measurable toxicity at 170 mg DTX/kg. Taxotere, on the other hand, displayed non-specific uptake in all the examined normal tissues and induced significant apoptosis in the lung and kidney at 40 mg DTX/kg. The tumor uptake of Cellax was 5.5-fold more than that by Taxotere and the uptake occurred within 3 h after injection and persisted for 10 days. The conjugate exhibited enhanced efficacy in a panel of primary and metastatic mouse tumor models. These results clearly demonstrated that Cellax improved the pharmacokinetics, biodistribution and efficacy of DTX compared to Taxotere with reduced toxicity.     

The relevance of analogue studies for understanding obsessions and compulsions

Analogue samples are often used to study obsessive–compulsive (OC) symptoms and related phenomena. This approach is based on the hypothesis that results derived from such samples are relevant to understanding OC symptoms in individuals with a diagnosis of obsessive–compulsive disorder (OCD). Two decades ago, Gibbs (1996) reviewed the available literature and found initial support for this hypothesis. Since then there have been many important advances addressing this issue. The purpose of the present review was to synthesize various lines of research examining the assumptions of using analogue samples to draw inferences about people with OCD. We reviewed research on the prevalence of OC symptoms in non-clinical populations, the dimensional (vs. categorical) nature of these symptoms, phenomenology, etiology, and studies on developmental and maintenance factors in clinical and analogue samples. We also considered the relevance of analogue samples in OCD treatment research. The available evidence suggests research with analogue samples is highly relevant for understanding OC symptoms. Guidelines for the appropriate use of analogue designs and samples are suggested.     

Principles, problems, and strategies in the use of antigenic mixtures for the enzyme-linked immunosorbent assay

Competition between proteins and other macromolecules for adsorption sites on plastic was studied with the enzyme-linked immunosorbent assay (ELISA) to determine effects of the use of antigenic mixtures or extracts of organisms on assays of antibodies and antigens by ELISA. A comparison of a number of different polystyrene microplates with bovine albumin and human immunoglobulin G (IgG) as antigens showed two major classes of plates; those which adsorbed albumin poorly and those which adsorbed albumin well. IgG adsorbed well on all plates, but plates which adsorbed albumin best also gave significant background levels of nonspecific binding of conjugate. When mixtures of IgG and bovine serum albumin were used as coating antigens, significant competition was observed; the component present at 1% or less in the mixture was essentially undetectable unless excessive amounts of conjugate were used. The important factor was the ratio of competitor to antigen, not the absolute amount. Other proteins (ovalbumin, rabbit albumin, human albumin, and gelatin) were equally effective competitors for adsorption sites on plastic. Nonionic detergents (Tween 20, and Triton X-100) were strong competitors even at 10:1 competitor-to-antigen ratios. In antigen capture assays, normal serum components blocked attachment of antigen-specific IgG, but this competition could be lessened to a degree by the use of strongly binding polystyrene plates. In indirect ELISA for measurement of serum antibody, the use of antigenic mixtures gave significantly lower antibody titers when the desired antigen was less than 1% of the total protein coated. Therefore, the use of mixed or crude antigens in ELISA presents significant problems concerning the sensitivity and specificity of tests.     

Outcomes of transition from premixed and intensive insulin therapies to insulin aspart/degludec co-formulation in type 2 diabetes mellitus: a real-world experience

IntroductionTo evaluate the efficacy and safety of transition from premixed and intensive insulin to twice-daily insulin degludec/aspart (IDegAsp) co-formulation in patients with type 2 diabetes mellitus.Material and methodsIn this 12-week study, patients receiving twice-daily premixed insulin therapy in group 1 (n = 55) were switched to twice-daily IDegAsp. In group 2 (n = 60), patients on intensive insulin therapy were switched to IDegAsp injected twice a day. Inter- and intragroup comparisons were made.ResultsA total of 115 patients were included in the study. There was a significant improvement in glycaemic control, median daily total insulin dose, body mass, body mass index, and hypoglycaemic events in group 1 and group 2 with the switch to IDegAsp (p < 0.05). The decrease in median daily total insulin dose requirement in group 2 was higher than that of group 1 (p = 0.001). There was no difference between groups in terms of other parameters (p > 0.05).ConclusionsThe current analysis indicates that IDegAsp treatment improves outcomes, with the most notable differences observed in daily total insulin requirement, body mass, and hypoglycaemia.     

Validity of tagging SNPs across populations for association studies

Recent advances in high throughput genotyping technologies will allow large-scale association studies to disentangle the genetic basis of human common diseases. Currently, a large-scale genotyping effort is being carried out by the HapMap project and the outcome of this project is expected to help researchers in their efforts to understand how genetic variation influences susceptibility to disease. However, there is some controversy on whether this huge public effort will be of value for those populations not studied in the HapMap project. Here, we present simulation results based on the empirical distribution of linkage disequilibrium (LD) on a large chromosomal region (10 Mb) on human chromosome 20(1,2) for two European and two Asian populations. These results show that statistical power to detect associations does not depend on the population were SNP tagging was performed.     

量子点流式微球技术检测抗胰岛素抗体方法学建立

目的将量子点荧光探针应用于流式微球技术,创建出量子点流式微球技术检测人抗胰岛素抗体的方法并对其偶联率、精密度、线性范围、灵敏度进行初步评价。方法将胰岛素与羧基化微球偶联制备免疫诊断微球,与血清或标准品中人抗胰岛素抗体结合后,加入兔抗人IgG抗体,最后加入生物素化的羊抗兔IgG抗体和链霉亲和素化的量子点,使微球表面呈现荧光,并通过流式细胞仪检测平均荧光强度(mean fluorescent intensity,MFI)并记录。结果羧基化微球偶联胰岛素的性能显著强于空白微球,偶联0.5～3 h为最佳偶联反应时间,偶联成功的免疫诊断微球放置4℃冰箱至少可稳定50 d。微球偶联微球表面所携带荧光MFI与所测抗胰岛素抗体浓度成正比,量子点流式微球技术检测同一标本的灵敏度(3.74 pg/ml)、精密度(8.24%)、线性范围(3.74～5 000 pg/ml)都优于酶联免疫吸附试验所测得灵敏度(24.53 pg/ml)、精密度(12.31%)、线性范围(24.53～2 500 pg/ml)。结论本实验创建的量子点流式微球技术可用于人血清抗胰岛素抗体测定,其检测性能良好。     

Intranasal aerosolized insulin. Mixed-meal studies and long-term use in type I diabetes

We assessed the efficacy of intranasal aerosolized insulin containing laureth-9 as a surfactant in patients with Type I diabetes by fasting studies in 8 patients, mixed-meal studies in 15, and long-term home use in 8. The intranasal insulin (1 U per kilogram of body weight in 1 per cent laureth-9) was rapidly absorbed (in 15 minutes); it lowered the plasma glucose level by 50 per cent in 45 minutes in fasting normal controls and by 50 per cent in 120 minutes in fasting diabetics. The glucose-lowering potency depended on the insulin dose and surfactant concentration. Nasal irritation was proportional to surfactant concentration, with great variability among subjects. After intranasal insulin used before meals (1 U per kilogram in 1 per cent laureth-9), the two-hour postprandial glucose level increased above before-meal levels by 38 mg per deciliter, as compared with 191 mg per deciliter after intranasal placebo in patients with Type I diabetes (P less than 0.05). An outpatient feasibility study examining three months of use of intranasal aerosolized insulin before meals as a supplement to Ultralente insulin revealed that the aerosol was well tolerated, with glycemic control (as indicated by the percentage of glycohemoglobin, home glucose measurements, and hypoglycemic reactions) comparable to that during a subsequent three-month period of conventional subcutaneous insulin treatment. The results suggest that intranasal insulin has potential as an adjunct to subcutaneous insulin in the therapy of Type I diabetes.     

Stereoselective analysis of fluvastatin in human plasma for pharmacokinetic studies

Fluvastatin, an inhibitor of cholesterol biosynthesis, is commercialized as a racemic mixture of the (+)-3R,5S and (-)-3S,5R stereoisomers, although inhibition of HMG-CoA reductase mainly resides in the (+)-(3R,5S)-fluvastatin isomer. The aim of the present study was to analyze fluvastatin isomers in human plasma with application to studies on kinetic disposition. Plasma samples of 1 ml were eluted into 3 ml LC-18 Supelclean (Supelco) columns equilibrated with methanol and water. The columns were washed with water and acetonitrile and then eluted with methanol containing 0.2% diethylamine. The (+)-3R,5S and (-)-3S,5R isomers were separated by HPLC on a Chiralcel OD-H chiral phase column and detected by fluorescence (lambda(ex) 305 nm; lambda(em) 390 nm). The quantification limit was 0.75 ng for each isomer/ml plasma and linearity was observed up to 625 ng/ml. The relative standard deviations obtained for intra- and inter-assay precision were lower than 10% and the recovery was higher than 80% for both enantiomers. Application of the method to a stereoselective study on the pharmacokinetics of fluvastatin administered as a single oral dose (Lescol, 20 mg) to a healthy volunteer revealed stereoselectivity, with the highest plasma concentrations being observed for the (-)-3S,5R isomer (Cmax 92.4 vs. 60.3 ng/ml, AUC(0-infinity) 133.3 vs. 97.4 ng h/ml, Cl/f 150.2 vs. 205.2 l h(-1) and Vd/f 4.4 vs. 6.0 l/kg).     

Intravenous quinidine for the treatment of severe falciparum malaria. Clinical and pharmacokinetic studies

Quinidine has proved more effective than quinine against chloroquine-resistant Plasmodium falciparum both in vitro and in patients with uncomplicated disease. To examine the effectiveness and pharmacokinetics of quinidine for this use, we treated 14 patients who had severe falciparum malaria with intravenous quinidine gluconate; a loading dose of 15 mg of the base per kilogram of body weight was followed by 7.5 mg per kilogram every eight hours. Two of the five patients with cerebral malaria died, but parasitemia was eliminated in the 12 survivors. Two patients had recurrent parasitemia on Days 25 and 28. Times required for parasite clearance and elimination of fever (49.4 +/- 17.8 and 69.5 +/- 18.7 hours, respectively) were comparable to those in earlier studies with a loading dose of quinine. Quinidine appears to have a larger volume of distribution than quinine. The elimination half-life was 12.8 hours, the volume of distribution was 1.68 liters per kilogram, total clearance was 1.75 ml per kilogram per minute, and urinary clearance was 0.62 ml per kilogram per minute. Electrocardiographic changes were common but there were no dysrhythmias. In two patients, blood pressure fell during the initial infusion of quinidine. Quinidine gluconate is more widely available than quinine in many countries, and our findings show that it is effective in severe falciparum malaria.     

Severe hypoglycemias in a diabetic man by surreptitious self-injections of an insulin analogue

A 44 years-old diabetic male patient was admitted several times to the emergency department of Albi Hospital (France) for nocturnal hypoglycemias with losses of consciousness. The initial blood analysis, performed on a Cobas(?) analyzer, retrieved low levels of insulinemia. This patient was treated by analogues of insulin and did not present any comorbidities. Moreover, an extensive check-up did not retrieve any evident cause for these hypoglycemias. After a severe hypoglycemic coma that occurred during the last hospitalization when insulinotherapy was interrupted, the staff suggested the possibility of a factice hypoglycemia by surreptitious administration of insulin. Hormonal assays were then performed on a Centaur(?) analyzer, which is able to recognize insulin aspart and glargine. They revealed elevated concentrations of insulin along with low levels of C-peptide. Such a blood profile is consistent with an exogenous administration of insulin or its analogues. On the basis of this biological clue, the patient was questioned again and he finally admitted self-injection of insulin aspart. This case gives us the opportunity to review the diabetic hypoglycemia, to point out the particularities of the blood assays of insulin analogues and to confirm the need of a close collaboration between clinic and laboratory staffs in the difficult cases of factice hypoglycemias.