Robotic microplate voltammetry for real-time hydrogel drug release testing

Validation of electrochemical device setup for detection of dual antibiotic drug release from hydrogel

Due to antimicrobial resistance that occurs throughout the world, antibiotic-releasing hydrogel with at least two drugs that synergistically treat stubborn bacteria is preferable for infection prevention. Hydrogel can serve as a drug reservoir to gradually release drugs in a therapeutic window to effectively treat microorganisms with minimal side effects. The study and development of drug releasing hydrogels requires a reliable, straightforward, cost-effective, fast, and low labor-intensive drug detection technique. In this study, we validate the electrochemical technique and device setup for real-time determination of dual antibacterial drugs released from a hydrogel. Concentrations of two representative antibacterial drugs, tetracycline (TC) and chloramphenicol (CAP), were determined using square wave voltammetry (SWV) mode that yields the lower limit of detection at 2.5 µM for both drugs. Measurement accuracy and repeatability were verified by 36 known drug combination concentrations. Capability in long-term measurement was confirmed by the measurement stability which was found to last for at least 72 h. Stirring was revealed as one of the significant factors for accurate real-time detection. Real-time measurement was ultimately performed to demonstrate the determination of multiple drug releases from a drug releasing hydrogel and validated by high-performance liquid chromatography (HPLC). All the results support that the electrochemical technique with the proposed device design and setup can be used to accurately and simultaneously determine dual drugs that are released from a hydrogel in real-time.

Development of a low-cost semi-automated robotic orthophosphate system for batch analysis

Monitoring the level of nutrients in soil and their availability for crops can be time-consuming or require expensive instrumentation. This work describes a low-cost (<€500) portable, semi-automated colourimetric orthophosphate (PO₄^3-) analyser supplemented with 3D printed parts. Colour development was based on the phosphomolybdenum blue formation coupled with spectrophotometric detection using a low-cost LED-photodiode assembly. The batch analysis technique required only minimal autonomous additions of reagents to the reaction vessel. In addition, the reaction time was reduced with vigorous automated stirring of the small quantity of reactants. Continuous monitoring of the absorbance throughout the reaction also decreased contact time, eliminating the prerequisite of a blank and warm-up time, customarily associated with colourimetric measurements. The semi-automated Robotic Orthophosphate System (saROS) has a linear dynamic range between 10-750 μg L^-1 P-PO₄^3-, and a limit of detection of 3 μg L^-1 P-PO₄^3- with good repeatability (RSD of 2.4%). In addition to portability and low cost, the prototype is an accurate and reproducible device for measuring phosphorus in aquatic ecosystems and soil extracts.

Towards a 'wide' role for venture capital in OECD countries' industry 4.0

This paper focuses on the current theoretical views of venture capital that predetermines a "narrow" treatment. In the light of the existing "narrow" treatment, venture investors seek private commercial interests in financial support for Industry 4.0, ignoring other interests that fall beyond the limits of the current "narrow" treatment of venture capital. A "wide" treatment of venture capital 4.0 proposed in this paper allows for improving venture investors' market strategies. Implementing this treatment, they will strive for providing a whole range of advantages for society. Due to this novel approach, venture capital 4.0 might become a tool of corporate social responsibility. To substantiate this novel approach, this paper considers data for 2020 that reflect the influence of venture capital 4.0 on the economy in the period of its stability for 33 countries of the OECD, including developed and developing countries. Econometric modelling based on the official statistics data proves that Industry 4.0 venture capital will help achieve such growth goals as innovative development, global competitiveness, and increasing digital competitiveness. The limitations of this research are due to the impossibility of achieving such goals as sustainable development, economic growth, and implementation of human potential; what's more, the specifics of developing countries have not been studied sufficiently. The conclusions are oriented mainly at developed countries and could merely partially be applied to developing countries. During further research, it is expedient to explore - more thoroughly - the experience of the influence of Industry 4.0 venture capital on emerging economies.

Portable and automated analyzer for rapid and high precision in vitro dissolution of drugs

We developed a novel portable and automated dissolution test analyzer for rapid and high precision in vitro dissolution testing of drugs. The analyzer consists of a flow-through-cell drug dissolution system, an automated sequential sampling system, a high-speed capillary electrophoresis (HSCE) system, and a data acquisition system. Combining the high-temporal resolution flow-gating sampling approach with HSCE, which has outstanding advantages of efficient separation and resolution, the analyzer can achieve rapid analysis and exhibits the ability in miniaturization for on-site assessment of different active pharmaceutical ingredients. To integrate the flow-through-cell dissolution system with HSCE, a specially designed flow-gating-injection (FGI) interface was employed. The performance of the analyzer was investigated by analyzing the dissolution of immediate-release drugs including single dose (amoxicillin dispersible tablets) and fixed dose combination (amoxicillin and clavulanate potassium) drug tablets with the high-temporal resolutions of 12 s and 20 s, respectively. The dissolution profiles of different active pharmaceutical ingredients could be simultaneously and automatically monitored with high repeatability and accuracy. The analyzer was successfully utilized for the pharmaceutical quality control and bio-relevant dissolution testing, as well as in vivo-in vitro correlation analysis. Our portable analyzer is miniaturized, convenient and of low-cost, and will provide a valuable tool for dissolution testing in pharmaceutical research and development.

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Portable automated analyzer for rapid and high precision dissolution of drugs.

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Miniaturized, low-cost and battery-powered with high repeatability and accuracy.

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Successful applications in QC, bio-relevant dissolution and IVIVC analysis of drugs.

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Universal applicability for both immediate-release and fixed dose combination drugs.

Predictive Performance Comparison of Computed Linear and Quadratic Multivariate Models for In-Situ UV Fiber Optics Tablet Dissolution Testing

A present investigation aimed for multivariate modeling as a solution to resolve inaccuracy in dissolution testing experienced in the use of in-situ UV fiber optics dissolution systems (FODS) due to signal saturation problems. This problem is specifically encountered with high absorbance of moderate to high dose formulations. A high absorbance not only impede a real-time assessment but can also result in inaccurate dissolution profiles. Full spectra (F) and low absorbance regions (L) were employed to develop linear and quadratic (Q) partial least squares (PLS) and principal component regression (PCR) models. The conventional dissolution of atenolol, ibuprofen, and metformin HCl immediate-release (IR) tablets followed by HPLC analysis was used as a reference method to gauge multivariate models' performance in the 'built-in' Opt-Diss model. The linear multivariate modeling outputs resulted in accurate dissolution profiles, despite the potentially high UV signal saturation at later time points. Conversely, the 'built-in' Opt-Diss model and multivariate quadratic models failed to predict dissolution profiles accurately. The current studies show a good agreement in the predictions across both low absorbance region and full spectra, demonstrating the multivariate models' robust predictability. Overall, linear PLS and PCR models showed statistically similar results, which demonstrated their applicative flexibility for using FODS despite signal saturation and provides a unique alternative to traditional and labor-intensive UV or HPLC dissolution testing.

A 3D-printed robotic system for fully automated multiparameter analysis of drinkable water samples

This work describes a 3D-printed robotic system named RSAWA (robotic system for automatic water analysis) for fully automated water analysis. RSAWA consists of a robotic arm coupled to a syringe pump, temperature and conductivity sensors, a low-cost webcam as colorimetric detector, and a 96-well microplate placed on a 3D-printed platform. The robotic system is controlled by software and it performs all analytical procedures. RSAWA was applied to measure conductivity (CDT), pH, total alkalinity (TA), total hardness (TH), chloride (Cl^-), nitrite (NO₂^-), total dissolved phosphorus (TP), and total iron (TI) in drinkable water samples. A simple circuit was designed for conductivity determinations, while colorimetric pH determinations were carried out using Hue values extracted from digital images and a pH universal indicator. HSV histograms were used to calculate Pearson's correlation coefficients, allowing the construction of accurate titration curves. In addition to achieving sample throughputs of 112 h^-1 for TA and TH determinations and 92 h^-1 for Cl^- determinations, RSAWA produced 99.5% less waste than the corresponding reference methods during titrations. Colorimetric measurements were performed through RGB vector norms calculated from digital images were used as analytical signals. Limits of quantification (μg L^-1) were 6.83, 13.0 and 1.5 mg L^-1 for NO₂^-, TP, and TI determinations, respectively. Sample throughputs (samples h^-1) were 83 for NO₂^- and TP and 72 for TI with a 98.5% reduction in waste generation. Thus, RSAWA is a low-cost, feasible, and environmentally friendly alternative to quickly and accurately determine several chemical and physicochemical parameters in aqueous samples.

An electrochemical method for detecting the biomarker 4-HPA by allosteric activation of Acinetobacterbaumannii reductase C1 subunit

The C1 (reductase) subunit of 4-hydroxy-phenylacetate (4-HPA) 3-hydroxylase (HPAH) from the soil-based bacterium Acinetobacterbaumannii catalyzes NADH oxidation by molecular oxygen, with hydrogen peroxide as a by-product. 4-HPA is a potent allosteric modulator of C1, but also a known urinary biomarker for intestinal bacterial imbalance and for some cancers and brain defects. We thus envisioned that C1 could be used to facilitate 4-HPA detection. The proposed test protocol is simple and in situ and involves addition of NADH to C1 in solution, with or without 4-HPA, and direct acquisition of the H₂O₂ current with an immersed Prussian Blue–coated screen-printed electrode (PB-SPE) assembly. We confirmed that cathodic H₂O₂ amperometry at PB-SPEs is a reliable electrochemical assay for intrinsic and allosterically modulated redox enzyme activity. We further validated this approach for quantitative NADH electroanalysis and used it to evaluate the activation of NADH oxidation of C1 by 4-HPA and four other phenols. Using 4-HPA, the most potent effector, allosteric activation of C1 was related to effector concentration by a simple saturation function. The use of C1 for cathodic biosensor analysis of 4-HPA is the basis of the development of a simple and affordable clinical routine for assaying 4-HPA in the urine of patients with a related disease risk. Extension of this principle to work with other allosteric redox enzymes and their effectors is feasible.

Electroanalysis Applied to Compatibility and Stability Assays of Drugs: Carvedilol Study Case

Carvedilol (CRV) is a non-selective blocker of α and β adrenergic receptors, which has been extensively used for the treatment of hypertension and congestive heart failure. Owing to its poor biopharmaceutical properties, CRV has been incorporated into different types of drug delivery systems and this necessitates the importance of investigating their compatibility and stability. In this sense, we have investigated the applicability of several electroanalytical tools to assess CRV compatibility with lipid excipients. Voltammetric and electrochemical impedance spectroscopy techniques were used to evaluate the redox behavior of CRV and lipid excipients. Results showed that Plurol^® isostearic, liquid excipient, and stearic acid presented the greatest anode peak potential variation, and these were considered suitable excipients for CRV formulation. CRV showed the highest stability at room temperature and at 50 °C when mixed with stearic acid (7% w/w). The results also provided evidence that electrochemical methods might be feasible to complement standard stability/compatibility studies related to redox reactions.

Drug Release from Polymer Thin Films and Gel Pellets: Insights from Programmed Microplate Electroanalysis

Robotic electroanalysis in 24-well microplates was used to determine Paracetamol (PCT) release from thin films of chitosan and two pH-sensitive synthetic polymers as well as blends of the polymers with each other and with agarose. Square-wave voltammograms were recorded automatically in a potential window of 0.35 V-0.85 V vs. Ag/AgCl/0.1 M KCl and their evaluation revealed time-dependent PCT release into acidic and basic media. Comparison of the release profiles showed that pure chitosan layers released PCT quickly in a single-phase process while liberation from synthetic polymer thin films was slower with a sigmoidal shape at pH 1.2 and pH 8.0 with a maximum release of PCT after approximately 150 and 140 min, respectively. The release profile from thicker agarose films was between those of the thin films. Agarose blended with chitosan or synthetic polymers formed films with biphasic release behavior. Chitosan linearized the initial section of the release profile in chitosan/polymer blends. The automated procedure for release testing offers the advantage of low-cost, labor-effective and error-free data acquisition. The procedure has been validated as a useful microplate assay option for release profile testing.

Automatic Dissolution Testing with High-Temporal Resolution for Both Immediate-Release and Fixed-Combination Drug Tablets

Dissolution testing plays many important roles throughout the pharmaceutical industry, from the research and development of drug products to the control and evaluation of drug quality. However, it is a challenging task to perform both high-efficient separation and high-temporal detection to achieve accurate dissolution profile of each active ingredient dissolved from a drug tablet. In our study, we report a novel non-manual-operation method for performing the automatic dissolution testing of drug tablets, by combining a program-controlled sequential analysis and high-speed capillary electrophoresis for efficient separation of active ingredients. The feasibility of the method for dissolution testing of real drug tablets as well as the performance of the proposed system has been demonstrated. The accuracy of drug dissolution testing is ensured by the excellent repeatability of the sequential analysis, as well as the similarity of the evaluation of dissolution testing. Our study show that the proposed method is capable to achieve simultaneous dissolution testing of multiple ingredients, and the matrix interferences can be avoided. Therefore it is of potential valuable applications in various fields of pharmaceutical research and drug regulation.