Machine learning with active pharmaceutical ingredient/polymer interaction mechanism:Prediction for complex phase behaviors of pharmaceuticals and formulations

The high throughput prediction of the thermodynamic phase behavior of active pharmaceutical ingredients(APIs)with pharmaceutically relevant excipients remains a major scientific challenge in the screening of pharmaceutical formulations.In this work,a developed machine-learning model efficiently predicts the solubility of APIs in polymers by learning the phase equilibrium principle and using a few molecular descriptors.Under the few-shot learning framework,thermodynamic theory(perturbed-chain statistical associating fluid theory)was used for data augmentation,and computational chemistry was applied for molecular descriptors'screening.The results showed that the developed machine-learning model can predict the API-polymer phase diagram accurately,broaden the solubility data of APIs in polymers,and reproduce the relationship between API solubility and the interaction mechanisms between API and polymer successfully,which provided efficient guidance for the development of pharmaceutical formulations.

Photocatalytic activation of sulfite by N-doped porous biochar/MnFe_(2)O_(4) interface-driven catalyst for efficient degradation of tetracycline

A novel photo-catalytic system composed of N-doped biochars(NBCs),MnFe_(2)O_(4) and sulfite activation under ultraviolet(NBCs/MnFe_(2)O_(4)/sulfite/UV)was constructed to realize the efficient eliminate of tetracycline(TC).As the carrier of MnFe_(2)O_(4),NBCs were synthesized from alfalfa,which has large specific surface area,graphite like structure and hierarchical porous structure.The adsorption isotherm indicated that NBCs/MnFe_(2)O_(4)-2:1 had the best adsorption performance for TC(347.56 mg g^(-1)).Through synergistic adsorption and photocatalysis,the removal rate of TC reached 84%,which was significantly higher than that of MnFe_(2)O_(4).Electrochemical impedance spectroscopy(EIS)and Photoluminescence(PL)characterization results showed that the introduction of NBCs improved the separation efficiency of photogenerated electron and hole pairs and enhanced the photocatalytic performance.Moreover,the adsorption,degradation mechanism and degradation path of TC by the catalyst were systematically analyzed by coupling HPLC–MS measurement with the theoretical calculation.Considering the advantages of excellent degradation performance,low cost,easy separation and environmental friendliness of NBCs/MnFe_(2)O_(4),this work was expected to provide a new path for the practical application of biochar.

Effects of heavy metal ions Cu^(2+)/Pb^(2+)/Zn^(2+)on kinetic rate constants of struvite crystallization

Struvite(MAP)crystallization technology is widely used to treat ammonia nitrogen in waste effluents of its simple operation and good removal efficiency.However,the presence of heavy metal ions in the waste effluents causes problems such as slow crystallization rate and small crystal size,limiting the recovery rate and economic value of the MAP.The present study was conducted to investigate the effects of concentrations of three heavy metal ions(Cu^(2+),Zn^(2+),and Pb^(2+))on the crystal morphology,crystal size,average growth rate,and crystallization kinetics of MAP.A relationship was established between the kinetic rate constant Ktcalculated by the chemical gradient model and the concentrations of heavy metal ions.The results showed that low concentrations of heavy metal ions in the solution created pits on the MAP surface,and high level of heavy metal ions generated flocs on the MAP surface,which were composed of metal hydroxides,thus inhibiting crystal growth.The crystal size,average growth rate,MAP crystallization rate,and kinetic rate constant Ktdecreased with the increase in heavy metal ion concentration.Moreover,the Ktdemonstrated a linear relationship with the heavy metal concentration ln(C/C~*),which provided a reference for the optimization of the MAP crystallization process in the presence of heavy metal ions.

Recent advances of pharmaceutical crystallization theories

As a technology of separation and purification,crystallization plays a vital role in diverse industries such as inorganic salt,pharmaceutical,and food industries,which has a huge impact on purity,crystal polymorph,crystal morphology,and particle size distribution of final products.In the past few decades,with the rapid advancement of experimental approaches and molecular simulation methods,considerable advances in the interpretation of crystallization mechanisms have been obtained,promoting the investigation and understanding of crystallization theories greatly.In this review,the advances of pharmaceutical crystallization theories in recent years from the perspectives of nucleation and crystal growth are summarized and discussed.Two thermodynamic models that are helpful in the study of the crystallization mechanisms will be introduced.In this section,the perturbed-chain statistical associating fluid theory(PC-SAFT)and a chemical-potential-gradient model will be introduced,which have been successfully applied in pharmaceutical solubility prediction,the research of dissolution mechanism as well as dissolution kinetics analysis.These two models are expected to be applied to the study of pharmaceutical crystallization process and mechanism.Furthermore,molecular simulation based on the interaction between particles can provide structural information,thermodynamics,and dynamics properties of complex systems at the molecular level,like intermolecular interaction and surface adsorption energies.Application and some shortcomings of molecular simulation,especially molecular dynamics simulation,in the field of pharmaceutical crystallization will be expounded.

Integrated computer-aided formulation design:A case study of andrographolide/cyclodextrin ternary formulation

Current formulation development strongly relies on trial-and-error experiments in the laboratory by pharmaceutical scientists,which is time-consuming,high cost and waste materials.This research aims to integrate various computational tools,including machine learning,molecular dynamic simulation and physiologically based absorption modeling(PBAM),to enhance andrographolide(AG)/cyclodextrins(CDs)formulation design.The light GBM prediction model we built before was utilized to predict AG/CDs inclusion's binding free energy.AG/γ-CD inclusion complexes showed the strongest binding affinity,which was experimentally validated by the phase solubility study.The molecular dynamic simulation was used to investigate the inclusion mechanism between AG andγ-CD,which was experimentally characterized by DSC,FTIR and NMR techniques.PBAM was applied to simulate the in vivo behavior of the formulations,which were validated by cell and animal experiments.Cell experiments revealed that the presence of D-α-Tocopherol polyethylene glycol succinate(TPGS)significantly increased the intracellular uptake of AG in MDCKMDR1 cells and the absorptive transport of AG in MDCK-MDR1 monolayers.The relative bioavailability of the AG-CD-TPGS ternary system in rats was increased to 2.6-fold and 1.59-fold compared with crude AG and commercial dropping pills,respectively.In conclusion,this is the first time to integrate various computational tools to develop a new AG-CD-TPGS ternary formulation with significant improvement of aqueous solubility,dissolution rate and bioavailability.The integrated computational tool is a novel and robust methodology to facilitate pharmaceutical formulation design.

Hollow MnO_2/GNPs serving as a multiresponsive nanocarrier for controlled drug release

In this work,hollow manganese dioxide/gold nanoparticle(MnO2/GNPs)hybrid drug nanocarriers were prepared by coupling the gold nanoparticles(GNPs)with hollow structure manganese dioxide(MnO2).Among them,GNPs have been used as near-infrared(NIR)-responsive element for photothermal effect under NIR laser irradiation.The glutathione(GSH)-responsive and p H-responsive performances of drug release were derived from hollow MnO2.Particularly,Doxorubicin hydrochloride(DOX)can be loaded into hollow MnO2/GNPs with the drug loading efficiency up to 82.0%.Moreover,the photothermal effect and GSH-/pH-responsive properties of hollow MnO2/GNPs were investigated.The hollow MnO2/GNPs possessed satisfactory drug release efficiency(ca.87.4%of loaded drug released in 12 h)and have high photothermal conversion efficiency,multiresponsive properties,and degradability.Finally,the kinetics of drug release was discussed in detail.Thus,our finding highlights that the multiresponsive nanocarriers are of great potential in the field of drug controlled release.

A novel interfacial thermodynamic model for predicting solubility of nanoparticles coated by stabilizers

To improve the stability of nanoparticles in aqueous solution,polymer or surfactant,etc.are often added in solutions during the preparation process of nanoparticles,which can induce new interfaces that influence the solubility of nanoparticles.In this work,a novel interfacial thermodynamic model for describing the Gibbs energy of the nanoparticles coated by stabilizers was proposed to predict the solubility of nanoparticles.Within the developed model,the activity coefficient of nano metal system was determined by Davies model and that of nano drug system by Perturbed-Chain Statistical Associating Fluid Theory(PC-SAFT).The Gibbs energy of the interface was established as a function of molecular parameters via the application for nano metal system.Furthermore,the model was further used to predict the solubility of nano drugs itraconazole,fenofibrate,and griseofulvin.It was found that the Gibbs energy of the interface plays an important role especially when the radius of nano metal is less than 40 nm,and the developed model can predict the solubility of nano drug with high accuracy in comparison with the experimental data as well as predict the changing trend of solubility of nano drugs that increases as the particle size decreases.Meanwhile,the stabilization mechanism of stabilizers on nano drugs was studied which provided theoretical guidance for the selection of polymer or surfactant stabilizer.These findings showed that the developed model can provide a reliable prediction of the solubility of nanoparticles and help to comprehend the stabilization mechanism of the stabilizers on nano drugs with different particle sizes,which is expected to provide important information for the design of nano drugs formulations.

Preface to special issue on frontiers of chemical engineering thermodynamics

“Thermodynamics is the only physical theory of universal content concerning which I am convinced that,within the framework of the applicability of its basic concepts,it will never be overthrown.”—Albert Einstein Chemical Engineering plays an essential role in modern society.It has been used to produce a wide variety of important materials,for example,the plastic drinking-water bottles,the jet fuels for transoceanic flights,and raw materials for assembling CPUs.Chemical Engineering is also on the frontline to manufacture massive masks,gloves,testing kits,and vaccines to fight against COVID-19 globally.

医药化工领域研究现状和发展态势

化学工程的研究对象正不断拓展并与其他诸多学科进行交叉,医药工业在我国已进入蓬勃发展的新时期。医药与化工的融合由来已久,在“医药化工”被写入国家自然科学基金委项目指南后,这一交叉领域的发展进入新阶段。本文基于国家自然科学基金委员会化学科学部第一期科技活动项目—“食品与医药化工学科发展战略研讨会”取得的成果,凝练了医药化工这一交叉学科的科学内涵,总结了医药化工学科的重大技术难题和关键科学问题,并对该领域未来需重点研究的内容给出了建议。

Theoretical insights into influence of additives on sulfamethoxazole crystal growth kinetics and mechanisms

In this work,the influence of the initial chemical potential gradient,stirring speed,and polymer type on sulfamethoxazole(SMX)crystal growth kinetics was systematically investigated through density functional theory(DFT)calculations,experimental measurements and the two-step chemical potential gradient model.To investigate the influence of different conditions on the thermodynamic driving force of SMX crystal growth,SMX solubilities in different polymer solutions were studied.Four model polymers effectively improved SMX solubility.It was further found that polyvinylpyrrolidone(PVP)and hydroxypropyl methyl cellulose(HPMC)played a crucial role in inhibiting SMX crystal growth.However,polyethylene glycol(PEG)promoted SMX crystal growth.The effect of the polymer on the crystal growth mechanisms of SMX was further analyzed by the two-step chemical potential gradient model.In the system containing PEG 6000,crystal growth is dominated by the surface reaction.However,in the system containing PEG 20000,crystal growth is dominated by both the surface reaction and diffusion.In addition,DFT calculations results showed that HPMC and PVP could form strong and stable binding energies with SMX,indicating that PVP and HPMC had the potential ability to inhibit SMX crystal growth.

Progress in thermodynamic simulation and system optimization of pyrolysis and gasification of biomass

Due to the shortage of fossil energy,biomass has a potential to be a very promising alternative source.Unfortunately,a large part of biomass resources worldwide causes serious environmental pollution,low value-added utilization and energy waste due to unsustainable utilization of biomass.Simulation and optimization of the thermochemical utilization of biomass resources is a hot issue in the industry and academia,which can provide the relationship between the utilizations of biomass with sustainable objective and compositions of biomass,operational parameters,etc.This review focused on the theoretical research progress of sustainable utilization of biomass resources from three aspects:basic thermochemical data estimation,process simulation and system optimization of pyrolysis and gasification.And the application of artificial intelligence as a tool in the field of above three aspects was also introduced.Advantages and limitations of current methods,as well as future opportunities and challenges were also discussed.

布洛芬-乙醇-水混合物相分离机制的分子模拟研究

本文通过分子模拟研究了水含量的变化对布洛芬-乙醇-水混合物相分离机制的影响,系统分析了溶剂化结构性质、相互作用能以及分子间作用.模拟发现,当水的摩尔分数大于70%时,布洛芬-乙醇-水混合物形成了两个互不相溶的相:一相为富含布洛芬的相,另一相则为富含乙醇和水的溶剂相.当水的摩尔分数极低时,布洛芬通过氢键作用优先被乙醇溶剂化,并逐渐在其周围形成富含乙醇聚集体的溶剂化层结构.随着水的含量升高,布洛芬与溶剂之间的相互作用被削弱,溶剂的极性增加,乙醇分子与水分子之间形成强的氢键作用,而布洛芬之间通过范德华作用形成聚集体.本工作研究的相分离机制将有助于药物提取分离过程中溶剂的设计和选择.

Modeling of specific structure crystallization coupling with dissolution

In this paper,the research framework for specific structure crystallization modeling has been proposed in which four steps are required in order to investigate the rigorous crystallization modeling by thermodynamics.The first is the activity coefficient model of the solution,the second is Solid-Liquid equilibrium,the third and fourth are the dissolution and crystallization kinetics modeling,respectively.Our investigations show that the mechanisms of complex structure formation and microphase transition can be analyzed by combining the dissolution and crystallization kinetics modeling.Moreover,the formation mechanism of the porous KCl has been analyzed,which may provide a reference for the porous structure formation in the advanced material synthesis.