Endpoint Determination Research Articles

Automatic determination of optimal endpoint of 1st carbonatation – factory trials

The objective of this paper is to determine the applicability of automatic control of the optimal point in 1st carbonatation of juice purification in a beet sugar factory. To realize the automated determination, a pilot carbonatation tank was constructed and installed in the bypass of the industrial production. Automatic stepwise carbonatation was applied to the circulation juice of the 1st carbonatation. pH value measurement started at a pH value of the circulation juice of approximately 12, and carbonatation gas was injected until the pH reached 10.7 in 0.1–0.2 pH units per step by means of an automatic control system. After every pH step, juice was left to settle for 4min. At the end of this clarification time, turbidity measurement was done. In total carbonatation, sedimentation and turbidity measurement take approximately 45–50min. When the period was completed, the tank was discharged and automatically washed out by extraction feed water. Data obtained at the end of the period were recorded and displayed on a personal computer. The computer software prepared for this system compares all the turbidity values, chooses the lowest one and designates the corresponding pH value at that turbidity as the optimal pH.

近赤外分光法を用いた流動層乾燥プロセスにおける乾燥終点の自動判定

パイロットスケールの流動層乾燥プロセスにおいて結晶粉中の水分量をリアルタイムでモニタリングできるようにした．このプロセスは，ラクチュロースの三水和物結晶粉から無水物結晶粉へ変換するプロセスである．2種類の近赤外分光法（Near-Infrared Spectroscopy; NIRS）について，水分量の推定精度を検討した．3つの波長のみを用いる簡易型のフィルター型分光方式NIRSでは十分な予測精度を得るにはさらなる工夫が必要である．一方，フーリエ変換型分光方式のNIRS（Fourier transform, FT-NIRS）を用いる方法は，高い精度で水分量を推定できた．特に，水分量1.00%以下に限定すると極めて高い精度で水分量を推定できることがわかった．この技術によって，結晶粉中の水分量をリアルタイムにモニタリングすることができるようになり，流動層乾燥プロセスにおける乾燥終点の自動判定が可能になった．

Mechanistic approach in powder blending PAT: Bi-layer mixing and asymptotic end point prediction

We derive a simple first order kinetics model for the powder mixing in a bin blender and adapt it to fit the NIR spectra obtained during the real-time mixing. The model is tested on a full drug product formulation mixing consisting of API and multiple excipients. It allows to extract a quantitative mixing rate for individual ingredients, which may be used in the drug development and production scale-up design. We further propose an algorithm for a calibration-free blending end-point determination from the NIR data, which allows for a robust and easily transferable blending process control.

At-line determination of pharmaceuticals small molecule's blending end point using chemometric modeling combined with Fourier transform near infrared spectroscopy

This article summarizes the development and validation of a Fourier transform near infrared spectroscopy (FT-NIR) method for the rapid at-line prediction of active pharmaceutical ingredient (API) in a powder blend to optimize small molecule formulations. The method was used to determine the blend uniformity end-point for a pharmaceutical solid dosage formulation containing a range of API concentrations. A set of calibration spectra from samples with concentrations ranging from 1% to 15% of API (w/w) were collected at-line from 4000 to 12,500cm−1. The ability of the FT-NIR method to predict API concentration in the blend samples was validated against a reference high performance liquid chromatography (HPLC) method. The prediction efficiency of four different types of multivariate data modeling methods such as partial least-squares 1 (PLS1), partial least-squares 2 (PLS2), principal component regression (PCR) and artificial neural network (ANN), were compared using relevant multivariate figures of merit. The prediction ability of the regression models were cross validated against results generated with the reference HPLC method. PLS1 and ANN showed excellent and superior prediction abilities when compared to PLS2 and PCR. Based upon these results and because of its decreased complexity compared to ANN, PLS1 was selected as the best chemometric method to predict blend uniformity at-line. The FT-NIR measurement and the associated chemometric analysis were implemented in the production environment for rapid at-line determination of the end-point of the small molecule blending operation.

Focus on materials, semiconductors, vacuum, and cryogenics

Focus on materials, semiconductors, vacuum, and cryogenics

Diagnostic Biomarkers in Women With Suspected Preeclampsia in a Prospective Multicenter Study.

To evaluate 47 biomarkers (selected from the current medical literature), in isolation or in combination with placental growth factor (PlGF), to determine the need for delivery within 14 days, in women presenting with suspected preterm preeclampsia. In a prospective, multicenter observational study, 47 biomarkers were measured in 423 women presenting with suspected preterm preeclampsia (in two prespecified groups: group 1 at less than 35 weeks of gestation and group 2 presenting between 35 0/7 and 36 6/7 weeks of gestation) to evaluate their ability to determine the primary endpoint: preeclampsia requiring delivery within 14 days. Using factor analysis and stepwise logistic regression, we sought one or more additional biomarkers for optimal determination of the primary endpoint. In women presenting at less than 35 weeks of gestation (n=286), the best performing combination of PlGF, podocalyxin, endoglin, procalcitonin (receiver operating curve [ROC] area 0.90, 95% confidence interval [CI] 0.86-0.93) was not statistically better than PlGF alone (ROC 0.87, 95% CI 0.83-0.92; P=.43) for preeclampsia requiring delivery within 14 days. Two other single markers had test performance that was not significantly different to PlGF (soluble fms-like tyrosine kinase-1 [sFlt-1] ROC 0.83, 95% CI 0.78-0.88; endoglin ROC 0.83, 95% CI 0.79-0.88). Similar findings were found in women presenting between 35 0/7 and 36 6/7 weeks of gestation (n=137): ROC for PlGF alone 0.75 (95% CI 0.67-0.83); ROC for PlGF, cystatin, pregnancy-associated plasma protein A in combination 0.81 (95% CI 0.74-0.88; P=.40). This study supports the growing body of evidence that a single angiogenesis-related biomarker (PlGF, sFlt-1, or endoglin) alone represents a useful diagnostic test for women presenting with suspected preterm preeclampsia.

Efficient production of nanoparticle-loaded orodispersible films by process integration in a stirred media mill

Orodispersible films possess a great potential as a versatile platform for nanoparticle-loaded oral dosage forms. In this case, poorly water-soluble organic materials were ground in a stirred media mill and embedded into a polymer matrix. The aim of this study was the shortening of this manufacturing process by the integration of several process steps into a stirred media mill without facing disadvantages regarding the film quality. Furthermore, this process integration is time conserving due to the high stress intensities provided in the mill and applicable for high solids contents and high suspension viscosities.Two organic materials, the model compound Anthraquinone and the active pharmaceutical ingredient Naproxen were investigated in this study. Besides the impact of the film processing on the crystallinity of the particles in the orodispersible film, a particle load of up to 50% was investigated with the new developed processing route. Additionally, a disintegration test was developed, combining an appropriate amount of saliva substitute and a clear endpoint determination. In summary, high nanoparticle loads in orodispersible films with good particle size preservation after film redispersion in water as well as a manufacturing of the film casting mass within a few minutes in a stirred media mill was achieved.

Challenges in translating endpoints from trials to observational cohort studies in oncology.

Clinical trials are considered the gold standard for examining drug efficacy and for approval of new drugs. Medical databases and population surveillance registries are valuable resources for post-approval observational research, which are increasingly used in studies of benefits and risk of new cancer drugs. Here, we address the challenges in translating endpoints from oncology trials to observational studies. Registry-based cohort studies can investigate real-world safety issues – including previously unrecognized concerns – by examining rare endpoints or multiple endpoints at once. In contrast to clinical trials, observational cohort studies typically do not exclude real-world patients from clinical practice, such as old and frail patients with comorbidity. The observational cohort study complements the clinical trial by examining the effectiveness of interventions applied in clinical practice and by providing evidence on long-term clinical outcomes, which are often not feasible to study in a clinical trial. Various endpoints can be included in clinical trials, such as hard endpoints, soft endpoints, surrogate endpoints, and patient-reported endpoints. Each endpoint has it strengths and limitations for use in research studies. Endpoints used in oncology trials are often not applicable in observational cohort studies which are limited by the setting of standard clinical practice and by non-standardized endpoint determination. Observational studies can be more helpful moving research forward if they restrict focus to appropriate and valid endpoints.

Assessment of the environmental quality of coastal sediments by using a combination of in vitro bioassays

The environmental quality of marine sediments collected in the area of influence of the Po and Danube Rivers was assessed by using a battery of bioassays based on the use of PLHC-1 cells, zebrafish-Pxr-transfected COS-7 cells, and sea bass ovarian subcellular fractions. This allowed the determination of multiple endpoints, namely, cytotoxicity, oxidative stress, induction of CYP1A, activation of zebrafish Pxr and inhibition of ovarian aromatase. Organic extracts of sediments influenced by the Danube River and collected near harbors and urban discharges showed significant cytotoxicity, CYP1A induction and inhibition of aromatase activity. An analogous response of CYP1A induction and zfPxr activation was observed, which suggests the existence of common ligands of AhR and PXR in the sediment extracts. The study highlights the usefulness of the selected bioassays to identify those sediments that could pose a risk to aquatic organisms and that require further action in order to improve their environmental quality.

Colour maps of acid–base titrations with colour indicators: how to choose the appropriate indicator and how to estimate the systematic titration errors

To recognise the end point of acid–base titrations, colour indicators are still frequently used. Colour indicators can cause systematic errors, and the theoretical evaluation of these errors is given in many textbooks. Random errors caused by the transition range of an indicator can also be estimated with the help of pH-logc i diagrams. However, very often, undergraduate students have problems to correctly interpret the colours of the different species of an indicator (its acidic and alkaline forms) and colour changes during titration. Frequent questions are of the type: “Is it still blue, or is it already red?” The aim of the present text is to show how carefully a suitable colour indicator has to be chosen, and what colour changes happen at the inflection point of a titration. Typical acid–base titrations like the alkalimetry of hydrochloric acid, sulphuric acid, oxalic acid, and the acidimetry of borax at two concentration levels using eleven common colour indicators are compared with potentiometric end point determination. Photographs were taken of solutions containing the indicators during the course of titration, i.e., at different pH values. These photographs were used to prepare a colour map for each indicator. Such colour maps are very helpful to find the most suitable indicator for a certain reaction, and also to estimate the maximum accuracy.

Monitoring of the hydrolysis process of bear bile powder using near infrared spectroscopy and chemometrics

A near infrared (NIR) spectroscopy-based method was developed for monitoring the hydrolysis process of bear bile powder. During the hydrolysis process, samples were collected and measured using both NIR spectrometer and high performance liquid chromatography. The quantitative calibration models were established with the collected NIR spectra and the reference concentrations of tauroursodeoxycholic acid (TUDCA), taurochenodeoxycholic acid (TCDCA), ursodeoxycholic acid (UDCA), and chenodeoxycholic acid (CDCA) using partial least squares regression algorithm. After the models were established and validated, the samples of new batches can be determined rapidly, and the hydrolysis process of bear bile powder can be monitored quantitatively. Additionally, a movingblockof standarddeviation (MBSD) method was also developed for the endpoint determination of the hydrolysis process. The proposed methods have reduced the laborious workload of process sample analysis significantly, and the fast analytical results have contributed to the understanding and controlling of the bear bile powder hydrolysis process.

Development of a two stage batch fluid bed drying process to minimise impact of entrainment on product quality and drying endpoint determination

Control over batch fluid bed drying processes is important to assure product of uniform moisture content as the level of residual moisture can impact further processing and final product performance and stability. Entrainment during batch fluidised bed drying can potentially result in non-uniformity of the product moisture content and impact reliability of the process endpoint. A two stage inlet air flow batch drying process was defined to minimise the impact of entrainment on product uniformity. The two stage batch fluid bed drying process reduced the level of entrainment observed. This enables the implementation of a relatively straightforward differential temperature technique based on a temperature sensor only to reliably indicate drying endpoint.

Protocol for the in vitro rearing of honey bee (Apis mellifera L.) workers

The in vitro rearing of worker honey bees (Apis mellifera L.) has become an increasingly important method in honey bee research in general, and in pesticide risk assessment specifically. Authorities from the European Organization for Economic Co-operation and Development and the United States Environmental Protection Agency are requesting data on pesticide impacts on immature bee survivorship prior to registering new crop protection products. Those using the current in vitro rearing protocols have had variable success with immature bee survival and protocol repeatability. Here, we present an improved method for the in vitro rearing of worker honey bees from larvae to adult emergence. We have achieved consistently high survival (>95%) in our control and solvent-control rearing trials. Changes in the proportion of diet components, royal jelly source, maintenance of the developing bee, and rearing environment are the main contributors for our high rearing success and are discussed herein. Our in vitro rearing protocol can be implemented as the standard protocol to determine the impact of pesticides on immature bees because of the protocol’s high control survivability, ease in end point determination, and high overall repeatability.

OPTICAL AND CONFOCAL MICROSCOPIC STUDIES ON DISSOLUTION OF RICE STRAW PARTICLES IN 1-ETHYL-3- METHYLIMIDAZOLIUM ACETATE

Abundant agriculture residue such as rice straw needs an effective pretreatment method in order to efficiently and economically process it into biofuels and chemicals. In order to develop an economical liquefaction process for pretreatment of rice straw, a 3D particle based-dissolution process model needs to be investigated. As a result, this study was undertaken to develop a dissolution model of ball milled rice straw (RS) particles in 1-Ethyl-3-Methylimidazolium Acetate [Emim][OAc], at 120°, 140° and 160°C using optical and confocal microscopes. These results showed the rectangular particle swelled in-plane during the heat treatment in [Emim][OAc] but the thickness and volume decreased with heating time. As the particle swelling progressed, the particle light intensity ratio increased which was confirmed by confocal and optical microscopy. Both the particle light intensity ratio and volume ratio measurement were used to estimate the particle dissolution end point. Heating at 160oC accelerated particle dissolution and swelling significantly. Decreasing the temperature from 160oC to 120oC extended the dissolving time changing from 10 min to 1 h. This new imaging analysis process model utilizing particle light intensity and volume ratios allows significant improvement in dissolution process modeling for endpoint determination and prediction. The dissolution process also has applications to other types of biomass.

Caenorhabditis elegans, a Biological Model for Research in Toxicology.

Caenorhabditis elegans is a nematode of microscopic size which, due to its biological characteristics, has been used since the 1970s as a model for research in molecular biology, medicine, pharmacology, and toxicology. It was the first animal whose genome was completely sequenced and has played a key role in the understanding of apoptosis and RNA interference. The transparency of its body, short lifespan, ability to self-fertilize and ease of culture are advantages that make it ideal as a model in toxicology. Due to the fact that some of its biochemical pathways are similar to those of humans, it has been employed in research in several fields. C. elegans' use as a biological model in environmental toxicological assessments allows the determination of multiple endpoints. Some of these utilize the effects on the biological functions of the nematode and others use molecular markers. Endpoints such as lethality, growth, reproduction, and locomotion are the most studied, and usually employ the wild type Bristol N2 strain. Other endpoints use reporter genes, such as green fluorescence protein, driven by regulatory sequences from other genes related to different mechanisms of toxicity, such as heat shock, oxidative stress, CYP system, and metallothioneins among others, allowing the study of gene expression in a manner both rapid and easy. These transgenic strains of C. elegans represent a powerful tool to assess toxicity pathways for mixtures and environmental samples, and their numbers are growing in diversity and selectivity. However, other molecular biology techniques, including DNA microarrays and MicroRNAs have been explored to assess the effects of different toxicants and samples. C. elegans has allowed the assessment of neurotoxic effects for heavy metals and pesticides, among those more frequently studied, as the nematode has a very well defined nervous system. More recently, nanoparticles are emergent pollutants whose toxicity can be explored using this nematode. Overall, almost every type of known toxicant has been tested with this animal model. In the near future, the available knowledge on the life cycle of C. elegans should allow more studies on reproduction and transgenerational toxicity for newly developed chemicals and materials, facilitating their introduction in the market. The great diversity of endpoints and possibilities of this animal makes it an easy first-choice for rapid toxicity screening or to detail signaling pathways involved in mechanisms of toxicity.

Early ART Results in Greater Immune Reconstitution Benefits in HIV-Infected Infants: Working with Data Missingness in a Longitudinal Dataset.

BackgroundEarly initiation of anti-retroviral treatment (ART) decreases mortality as compared to deferred treatment, but whether it preserves immune cells from early loss or promotes their recovery remains undefined. Determination of complex immunological endpoints in infants is often marred by missing data due to missed visits and/or inadequate sampling. Specialized methods are required to address missingness and facilitate data analysis.MethodsWe characterized the changes in cellular and humoral immune parameters over the first year of life in 66 HIV-infected infants (0–1 year of age) enrolled in the CHER study starting therapy within 12 weeks of birth (n = 42) or upon disease progression (n = 24). A convenience cohort of 23 uninfected infants aged 0–6 months born to mothers with HIV-1 infection was used as controls. Flow cytometry and ELISA were used to evaluate changes in natural killer (NK) cells, plasmacytoid dendritic cells (pDC), and CD4+ or CD8+ T-cell frequencies. Data missingness was assessed using Little's test. Complete datasets for analysis were created using Multiple Imputation (MI) or Bayesian modeling and multivariate analysis was conducted on the imputed datasets.ResultsHIV-1-infected infants had greater frequency of CD4+ T cells with naïve phenotype, as well as higher serum IL-7 levels than HIV exposed/uninfected infants. The elevated data missingness was completely at random, allowing the use of both MI and Bayesian modeling. Both methods indicate that early ART initiation results in higher CD4+ T cell frequency, lower expression of CD95 in CD8+ T cell, and preservation of naïve T cell subsets. In contrast, innate immune effectors appeared to be similar independently of the timing of ART initiation.ConclusionsEarly ART initiation in infants with perinatal HIV infection reduces immune activation and preserves an early expansion of naïve T-cells with undiminished innate cell numbers, giving greater immune reconstitution than achieved with deferred ART. Both statistical approaches concurred in this finding.

A Modified Walkley-Black Method Based on Spectrophotometric Procedure

ABSTRACTThe Walkley-Black (WB) method, because of its simplicity and rapidity, has been widely used during the past 50 years for determination of soil organic carbon (SOC), but one of the main problems with WB method in operation is determination of titration end point by the observer. In the past several years some studies have been done to reduce the human role in determination of titration end point in WB method. In this study, in addition to the routine method of using an indicator for end point determination, a potentiometric and a spectrophotometric method was also employed for end point determination. The results indicated that these two methods are more accurate than the indicator method. Finally, a modified Walkley-Black (MWB) method employing a spectrophotometric procedure was proposed, which is more reproducible, easier in operation, and more economical.

Assessment of loading conditions with cardiac ultrasound. A comprehensive review.

Optimization of the preloading conditions and concomitant determination of endpoints of fluid administration are the most frequent therapeutic actions in critically ill patients. Besides a clinical appraisal, reproducible data should be acquired at the bedside to estimate the adequacy of fluid resuscitation. The dynamic assessment and determination of fluid responsiveness plays a major role in this respect. Right-sided cardiac variables, such as inferior and superior caval vein diameter variation during mechanical ventilation, are easily obtained with cardiac ultrasound. Moreover, left sided variables, including aortic flow variation, with intermittent swings of intrathoracic pressure during mechanical ventilation, may be achieved non-invasively with Doppler-echocardiography. Both in terms of resuscitation, as well as correct interpretation of various two-dimensional and Doppler variables, it is essential to acquire a clear understanding of the filling status of a patient. Doppler-echocardiography plays herein a pivotal role.

Artesunate–mefloquine versus chloroquine for treatment of uncomplicated Plasmodium knowlesi malaria in Malaysia (ACT KNOW): an open-label, randomised controlled trial

The zoonotic parasite Plasmodium knowlesi has become the most common cause of human malaria in Malaysia and is present throughout much of southeast Asia. No randomised controlled trials have been done to identify the optimum treatment for this emerging infection. We aimed to compare artesunate-mefloquine with chloroquine to define the optimum treatment for uncomplicated P knowlesi malaria in adults and children. We did this open-label, randomised controlled trial at three district hospitals in Sabah, Malaysia. Patients aged 1 year or older with uncomplicated P knowlesi malaria were randomly assigned, via computer-generated block randomisation (block sizes of 20), to receive oral artesunate-mefloquine (target dose 12 mg/kg artesunate and 25 mg/kg mefloquine) or chloroquine (target dose 25 mg/kg). Research nursing staff were aware of group allocation, but allocation was concealed from the microscopists responsible for determination of the primary endpoint, and study participants were not aware of drug allocation. The primary endpoint was parasite clearance at 24 h. Analysis was by modified intention to treat. This study is registered with ClinicalTrials.gov, number NCT01708876. Between Oct 16, 2012, and Dec 13, 2014, we randomly assigned 252 patients to receive either artesunate-mefloquine (n=127) or chloroquine (n=125); 226 (90%) patients comprised the modified intention-to-treat population. 24 h after treatment, we recorded parasite clearance in 97 (84% [95% CI 76-91]) of 115 patients in the artesunate-mefloquine group versus 61 (55% [45-64]) of 111 patients in the chloroquine group (difference in proportion 29% [95% CI 18·0-40·8]; p<0·0001). Parasite clearance was faster in patients given artesunate-mefloquine than in those given chloroquine (18·0 h [range 6·0-48·0] vs 24·0 h [6·0-60·0]; p<0·0001), with faster clearance of ring stages in the artesunate-mefloquine group (mean time to 50% clearance of baseline parasites 8·6 h [95% CI 7·9-9·4] vs 13·8 h [12·1-15·4]; p<0·0001). Risk of anaemia within 28 days was lower in patients in the artesunate-mefloquine group (71 [62%; 95% CI 52·2-70·6]) than in those in the chloroquine group (83 [75%; 65·6-82·5]; p=0·035). Gametocytaemia as detected by PCR for pks25 was present in 44 (86%) of 51 patients in the artesunate-mefloquine group and 41 (84%) of 49 patients in the chloroquine group at baseline, and in three (6%) of 49 patients and two (4%) of 48 patients, respectively, at day 7. Fever clearance was faster in the artesunate-mefloquine group (mean 11·5 h [95% CI 8·3-14·6]) than in the chloroquine group (14·8 h [11·7-17·8]; p=0·034). Bed occupancy was 2426 days per 1000 patients in the artesunate-mefloquine group versus 2828 days per 1000 patients in the chloroquine group (incidence rate ratio 0·858 [95% CI 0·812-0·906]; p<0·0001). One (<1%) patient in the artesunate-mefloquine group had a serious neuropsychiatric event regarded as probably related to study drug. Artesunate-mefloquine is highly efficacious for treatment of uncomplicated P knowlesi malaria. The rapid therapeutic response of the drug offers significant advantages compared with chloroquine monotherapy and supports a unified treatment policy for artemisinin-based combination therapy for all Plasmodium species in co-endemic areas. Malaysian Ministry of Health, Australian National Health and Medical Research Council, and Asia Pacific Malaria Elimination Network.

Pharmaceutics, Drug Delivery and Pharmaceutical Technology: A New Test Unit for Disintegration End-Point Determination of Orodispersible Films

No standard time or pharmacopoeia disintegration test method for orodispersible films (ODFs) exists. The USP disintegration test for tablets and capsules poses significant challenges for end-point determination when used for ODFs. We tested a newly developed disintegration test unit (DTU) against the USP disintegration test. The DTU is an accessory to the USP disintegration apparatus. It holds the ODF in a horizontal position, allowing top-view of the ODF during testing. A Gauge R&R study was conducted to assign relative contributions of the total variability from the operator, sample or the experimental set-up. Precision was compared using commercial ODF products in different media. Agreement between the two measurement methods was analysed. The DTU showed improved repeatability and reproducibility compared to the USP disintegration system with tighter standard deviations regardless of operator or medium. There is good agreement between the two methods, with the USP disintegration test giving generally longer disintegration times possibly due to difficulty in end-point determination. The DTU provided clear end-point determination and is suitable for quality control of ODFs during product developmental stage or manufacturing. This may facilitate the development of a standardized methodology for disintegration time determination of ODFs. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3893-3903, 2015.