Oxytetracycline and Florfenicol Concentrations in Food-Additive Premixes Authorised for Broiler Chickens: Assessing Degree of Agreement with Manufacturers Labelling

Antimicrobials premixes are the presentation of choice to administer drugs simultaneously to groups of animals in intensive husbandry systems that require treatment for pathologies of bacterial origin. Among the premixes available for use in poultry, florfenicol and oxytetracycline are commonly administered via food or water. However, their actual concentration in premixes must meet on-label statements to ensure plasma concentrations reach effective therapeutic levels. Hence, this work was designed for the purpose of verifying whether the concentration of antimicrobial present in five premixes matched their on-label statement. Three oxytetracycline premixes, and two of florfenicol, were analysed using a Xevo TQ-S micro UPLC-MS/MS, and an ABSciex API4000 HPLC-MS/MS, respectively. Analytical methodologies were implemented and validated, showing an R2 ≥ 0.99 for the calibration curves. Oxytetracycline was detected in these premixes at concentrations exceeding on-label statements by 13.28%, 21.54%, and 29.68%, whereas florfenicol concentrations detected in premixes were 13.06% and 14.75% lower than expected. Consequently, this work shows that the concentration of active ingredients that are present in commercial formulations effectively differ from those stated on premix labels, and it also highlights how unpredictable their range of variability might be. This must be addressed through solid and updated laws that guarantee an effective pharmaceutical product.

Identifikasi dan Purifikasi Vitelogenin Arwana Asia: Banjar, Pinoh (Scleropages macrocephalus), Papua (Scleropages jardinii) dan Super Red (Scleropages legendrei)

Arowana fish (Scleropages sp.) are monomorphic species, those animals that physically could not be distinguished between male and female. The research was aimed to identify and purify Vitellogenin of four variants of Asian Arowana: Banjar, Papua, Pinoh, and Super red. 12 fishes, 3 from each variant were given estradiol stimulation through toad for vitellogenin production purpose. The SDS-PAGE results expressed that there were two types of Asian Arowana vitellogenin characters, single Vtg for Arowana Banjar, Pinoh (Scleropages macrocephalus) and Super Red (Scleropages legendrei) with a molecular weight of 180 kDa and double Vtg in Papuan Arowana (Scleropages jardinii) with molecular weight 180 and 110 kDa. Pure vitellogenin has been collected from 3 varieties, Banjar, Papua, and Super red with a concentration range between 0.1 - 0.67 mg / mL. The actual concentration is believed to be greater than the measured concentration.

Quality testing of veterinary antimicrobial products used for livestock in Vietnam, 2018–2019

Access to quality veterinary antimicrobial products contributes to efficient treatment of diseases in Vietnamese livestock and to reducing antimicrobial resistance (AMR). Poor quality antimicrobial drugs can lead to treatment failure, potentially influencing the inappropriate use of antimicrobials products, including increasing the dose, combining drugs, or changing to a broader spectrum antimicrobial. The objective of the study was to determine the actual concentration of antimicrobial active ingredient (AAI) in commercially available veterinary antimicrobial products as an indicator of their quality. A total of 144 veterinary antimicrobial products were purchased from randomly selected veterinary drug stores in 34 districts in eight provinces. For the qualitative analysis, we observed criteria linked to form, colour, and labelling information according to the Department of Animal Health regulations. For the quantitative analysis, high-performance liquid chromatography was used to determine the actual concentration of AAI in each sample. Of the 144 samples, 131 (91%) met the national standard of quality of being within ±10% of the labelled concentration. Ten antimicrobials (6.9%) contained less than half of the labelled content concentrations. Veterinary antimicrobial product quality control is an important part of addressing AMR. To support the national action plan to lower AMR, a veterinary drug quality control program should be implemented at all stages of the supply chain to assure high quality drugs and effective treatment of sick animals.

Нелинейно-регрессионный алгоритм обработки сигналов полупроводниковых химических сенсоров, обеспечивающий селективное детектирование примесей в искусственном воздухе

New method is developed for proceeding a conductance change response Δσ,μS of a temperature (T) modulated chemical sensor. The method provides reliable substance identification and measurement of its trace concentrations for such impurities in arti-ficial air as ammonia, acetone, hexane, propane, toluene, turpentine etc. Due to this method the response of the ΔσY for a substance Y in actual concentration C range is interpolated with a completely nonlinear regression via discriminant modelling func-tions Fi(z=103/T,Ai, bi,ci,..),i=1-4 or 5. For principal parameters the plots AiY(C) are built which compose the selectivity/gauge portrait of Y in the air. In case when the analogous parameters of unknown substance X fit this portrait the substance is iden-tified as Y. And the common abscissa of corresponding crossing points of AiX with the curves AiY(C) indicates the value of the X concentration in units been used for Y.

Commercial stocks of SARS-CoV-2 RNA may report low concentration values, leading to artificially increased apparent sensitivity of diagnostic assays

In response to the rapidly evolving COVID-19 pandemic, the U.S. Food and Drug Administration (FDA) has rapidly issued 49 emergency use authorizations (EUAs) for SARS-CoV-2 in vitro diagnostic test-kits. A critical metric in the performance evaluation for a diagnostic test kit is the analytical sensitivity, which is measured by the limit of detection (LOD). Commercial RNA stocks with known titers are used to determine LOD. We identified a problem with the titer reported for the commercial stocks when examining the analytical sensitivity of the reverse transcription quantitative PCR (RT-qPCR) protocol that is recommended by the Centers for Disease Control and Prevention (CDC) using plasmid DNA from Integrated DNA Technologies (IDT), synthetic RNA from BEI Resources (BEI), and extracted genomic RNA from BEI. We detected 3/3 positives for reactions containing synthetic RNA at a concentration of 0.1 copies/reaction (based on the supplier’s label concentration). The apparent better-than-single-molecule performance is a statistically highly unlikely event, indicating a potential inaccuracy in the supplier’s quantification of the stock material. Using an ultrasensitive and precise assay, reverse transcription digital PCR (RT-dPCR), we independently quantified concentrations of commercial SARS-CoV-2 plasmid DNA and SARS-CoV-2 RNA stocks. For plasmid DNA, the actual concentration measured by RT-dPCR was 11% of the nominal label concentration. For synthetic RNA, the actual concentration measured by RT-dPCR for one lot was 770% of the label concentration and for a different lot was 57% of the label concentration. For genomic RNA, the concentration measured by RT-dPCR for one lot was 240% of the label concentration and for a different lot it was 300% of the label concentration. This SARS-CoV-2 genomic RNA from BEI Resources has been used in at least 11 approved FDA Emergency Use Authorizations as of April 27, 2020. Such deviations of reported RNA or DNA stock concentrations from true concentrations can result in inaccurate quantification and calculation of LOD. Precise and accurate reporting of DNA and RNA stock concentrations by commercial suppliers will enable accurate quantification of assay performance, which is urgently needed to improve evaluation of different assays by diagnostic developers and regulatory bodies.

A Quantitative Analysis Model Established to Determine the Concentration of Each Source in Mixed Astaxanthin from Different Sources

Astaxanthin from different sources possesses different biological activities and optical isomers. The ingredients of astaxanthin mixtures from different sources on the market have often been mislabeled. Therefore, it is important to determine the sources of astaxanthin and their respective concentrations in a mixture. To solve this problem, a quantitative analysis model was established and further verified. The results showed that the deviation between the calculated concentration and the actual concentration ranged from 0 to 7 µg/mL, and the recovery rate was between 88.90% and 103.56%. This indicates that the quantitative analysis model of astaxanthin was feasible and reliable. This study not only has important applications in the astaxanthin mixture component determination but may also shed light on the quantitative analysis of other sample mixtures with stereoisomers from different sources.

Quantification of Riboflavin and Pyridoxine in a Mixed Solution at a High Concentration by Fluorescence Spectrophotometry

A new method of quantifying the contents of riboflavin (RF) and pyridoxine (PY) in their mixed solution was introduced in this study. A mathematical model was established to calculate the actual concentration of PY (Z) based on the apparent concentrations of PY (Y) and RF (X), which were quantified directly when RF and PY were mixed together. First, a linear relationship was found between Y and Z with a high coefficient, which defines fluorescence quenching efficiency. Second, a curvilinear equation was established between the apparent concentration of X and the fluorescence quenching efficiency (k) of PY. The actual concentration of PY could be obtained by using the two equations. The established mathematical model was verified, and the relative error of the calculated PY value was below 2.5%. The upper limit of fluorescence spectrophotometry quantification was up to 20 μg/mL for both RF and PY. Compared with RP-HPLC, this method is convenient in terms of sample pretreatment, as well as saves organic solvents and time.