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1.
Article in English | MEDLINE | ID: mdl-38781815

ABSTRACT

In this work, a new ultra-performance liquid chromatography method based on photodiode array detection (UPLC-PDA) was first developed for the quantitative analysis of the quaternary mixture of ascorbic acid (AA), paracetamol (PAR), caffeine (CAF) and chlorpheniramine maleate (CPA) in a commercial dosage form. The developed UPLC-PDA method offered a new possibility for the co-determination of four active ingredients in a drug combination with short run time and simple sample preparation. The successful chromatographic separation of the four drugs was performed using a Waters Acquity UPLC BEH C18 column (1.7 µm 2.1 × 100 mm) (Mildford, USA) and a mobile phase consisting of water (12 %), acetonitrile (13 %) and 0.1 M H3PO4 (75 %) at a flow rate of 0.25 mL/min. The validation of the proposed UPLC-PDA approach was verified by analyzing synthetic mixtures, inter- and intra-day experiments, and commercial powder samples and provided satisfactory results.


Subject(s)
Acetaminophen , Caffeine , Chlorpheniramine , Chromatography, High Pressure Liquid/methods , Reproducibility of Results , Caffeine/analysis , Caffeine/chemistry , Acetaminophen/analysis , Acetaminophen/chemistry , Linear Models , Chlorpheniramine/analysis , Chlorpheniramine/chemistry , Limit of Detection , Ascorbic Acid/analysis , Ascorbic Acid/chemistry , Drug Combinations
2.
Mol Pharm ; 21(6): 2828-2837, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38723178

ABSTRACT

Nefecon, a targeted-release capsule formulation of budesonide approved for the reduction of proteinuria in adults with primary immunoglobulin A nephropathy, targets overproduction of galactose-deficient immunoglobulin A type 1 in the Peyer's patches at the gut mucosal level. To investigate whether the commercial formulation of Nefecon capsules reliably releases budesonide to the distal ileum, a human study was conducted with test capsules reproducing the delayed-release function of Nefecon capsules. Caffeine was included in the test capsules as a marker for capsule opening in the gut since it appears rapidly in saliva after release from orally administered dosage forms. Magnetic resonance imaging with black iron oxide was used to determine the capsule's position in the gut at the time caffeine was first measured in saliva and additionally to directly visualize dispersion of the capsule contents in the gut. In vitro dissolution results confirmed that the test capsules had the same delayed-release characteristics as Nefecon capsules. In 10 of 12 human volunteers, the capsule was demonstrated to open in the distal ileum; in the other two subjects, it opened just past the ileocecal junction. These results compared favorably with the high degree of variability seen in other published imaging studies of delayed-release formulations targeting the gut. The test capsules were shown to reliably deliver their contents to the distal ileum, the region with the highest concentration of Peyer's patches.


Subject(s)
Budesonide , Capsules , Drug Delivery Systems , Ileum , Humans , Ileum/metabolism , Ileum/drug effects , Adult , Drug Delivery Systems/methods , Male , Budesonide/administration & dosage , Budesonide/pharmacokinetics , Budesonide/chemistry , Female , Capsules/chemistry , Delayed-Action Preparations/administration & dosage , Delayed-Action Preparations/pharmacokinetics , Magnetic Resonance Imaging/methods , Administration, Oral , Middle Aged , Caffeine/chemistry , Caffeine/administration & dosage , Peyer's Patches/metabolism , Peyer's Patches/drug effects , Young Adult
3.
J Phys Chem B ; 128(19): 4670-4684, 2024 May 16.
Article in English | MEDLINE | ID: mdl-38717304

ABSTRACT

Ryanodine receptor type 1 (RyR1) is a Ca2+-release channel central to skeletal muscle excitation-contraction (EC) coupling. RyR1's cryo-EM structures reveal a zinc-finger motif positioned within the cytoplasmic C-terminal domain (CTD). Yet, owing to limitations in cryo-EM resolution, RyR1 structures lack precision in detailing the metal coordination structure, prompting the need for an accurate model. In this study, we employed molecular dynamics (MD) simulations and the density functional theory (DFT) method to refine the binding characteristics of Zn2+ in the zinc-finger site of the RyR1 channel. Our findings also highlight substantial conformational changes in simulations conducted in the absence of Zn2+. Notably, we observed a loss of contact at the interface between protein domains proximal to the zinc-finger site, indicating a crucial role of Zn2+ in maintaining structural integrity and interdomain interactions within RyR1. Furthermore, this study provides valuable insights into the modulation of ATP, Ca2+, and caffeine binding, shedding light on the intricate relationship between Zn2+ coordination and the dynamic behavior of RyR1. Our integrative approach combining MD simulations and DFT calculations enhances our understanding of the molecular mechanisms governing ligand binding in RyR1.


Subject(s)
Molecular Dynamics Simulation , Ryanodine Receptor Calcium Release Channel , Zinc , Ryanodine Receptor Calcium Release Channel/chemistry , Ryanodine Receptor Calcium Release Channel/metabolism , Zinc/chemistry , Zinc/metabolism , Ligands , Calcium/chemistry , Calcium/metabolism , Density Functional Theory , Binding Sites , Protein Binding , Zinc Fingers , Caffeine/chemistry , Caffeine/metabolism , Adenosine Triphosphate/chemistry , Adenosine Triphosphate/metabolism , Humans
4.
Chemosphere ; 358: 142222, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38714249

ABSTRACT

In this study, neural networks and support vector regression (SVR) were employed to predict the degradation over three pharmaceutically active compounds (PhACs): Ibuprofen (IBP), diclofenac (DCF), and caffeine (CAF) within a stirred reactor featuring a flotation cell with two non-concentric ultraviolet lamps. A total of 438 datapoints were collected from published works and distributed into 70% training and 30% test datasets while cross-validation was utilized to assess the training reliability. The models incorporated 15 input variables concerning reaction kinetics, molecular properties, hydrodynamic information, presence of radiation, and catalytic properties. It was observed that the Support Vector Regression (SVR) presented a poor performance as the ε hyperparameter ignored large error over low concentration levels. Meanwhile, the Artificial Neural Networks (ANN) model was able to provide rough estimations on the expected degradation of the pollutants without requiring information regarding reaction rate constants. The multi-objective optimization analysis suggested a leading role due to ozone kinetic for a rapid degradation of the contaminants and most of the results required intensification with hydrogen peroxide and Fenton process. Although both models were affected by accuracy limitations, this work provided a lightweight model to evaluate different Advanced Oxidation Processes (AOPs) by providing general information regarding the process operational conditions as well as know molecular and catalytic properties.


Subject(s)
Diclofenac , Hydrogen Peroxide , Ibuprofen , Machine Learning , Neural Networks, Computer , Diclofenac/chemistry , Hydrogen Peroxide/chemistry , Ibuprofen/chemistry , Kinetics , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/analysis , Caffeine/chemistry , Oxidation-Reduction , Pharmaceutical Preparations/chemistry , Pharmaceutical Preparations/analysis , Ozone/chemistry , Support Vector Machine , Cost-Benefit Analysis , Ultraviolet Rays , Catalysis , Photolysis
5.
Eur J Pharm Sci ; 198: 106788, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38705421

ABSTRACT

Physiologically based pharmacokinetic (PBPK) models can help to understand the effects of gastric emptying on pharmacokinetics and in particular also provide a platform for understanding mechanisms of food effects, as well as extrapolation between different postprandial conditions, whether standardized clinical or patient-oriented, non-clinical conditions. By integrating biorelevant dissolution data from the GastroDuo dissolution model into a previously described mechanistic model of fed-state gastric emptying, we simulated the effects of a high-calorie high-fat meal on the pharmacokinetics of sildenafil, febuxostat, acetylsalicylic acid, theobromine and caffeine. The model was able to simulate the variability in Cmax and tmax caused by the presence of the stomach road. The main influences investigated to affect the gastric emptying process were drug solubility (theobromine and caffeine), tablet dissolution rate (acetylsalicylic acid) and sensitivity to gastric motility (sildenafil and febuxostat). Finally, we showed how PBPK models can be used to extrapolate pharmacokinetics between different prandial states using theobromine as an example with results from a clinical study being presented.


Subject(s)
Computer Simulation , Gastric Emptying , Models, Biological , Postprandial Period , Solubility , Gastric Emptying/physiology , Postprandial Period/physiology , Humans , Febuxostat/pharmacokinetics , Febuxostat/chemistry , Theobromine/pharmacokinetics , Theobromine/chemistry , Caffeine/pharmacokinetics , Caffeine/chemistry , Caffeine/administration & dosage , Sildenafil Citrate/pharmacokinetics , Sildenafil Citrate/chemistry , Drug Liberation , Aspirin/pharmacokinetics , Aspirin/chemistry , Aspirin/administration & dosage
6.
Food Chem ; 448: 139138, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38569407

ABSTRACT

Tea cream formed in hot and strong tea infusion while cooling deteriorates quality and health benefits of tea. However, the interactions among temporal contributors during dynamic formation of tea cream are still elusive. Here, by deletional recombination experiments and molecular dynamics simulation, it was found that proteins, caffeine (CAF), and phenolics played a dominant role throughout the cream formation, and the contribution of amino acids was highlighted in the early stage. Furthermore, CAF was prominent due to its extensive binding capacity and the filling complex voids property, and caffeine-theaflavins (TFs) complexation may be the core skeleton of the growing particles in black tea infusion. In addition to TFs, the unidentified phenolic oxidation-derived products (PODP) were confirmed to contribute greatly to the cream formation.


Subject(s)
Caffeine , Camellia sinensis , Catechin , Molecular Dynamics Simulation , Tea , Tea/chemistry , Caffeine/chemistry , Caffeine/metabolism , Camellia sinensis/chemistry , Camellia sinensis/metabolism , Camellia sinensis/growth & development , Catechin/chemistry , Catechin/metabolism , Biflavonoids/chemistry , Biflavonoids/metabolism , Phenols/chemistry , Phenols/metabolism , Food Handling , Hot Temperature
7.
An Acad Bras Cienc ; 96(1): e20230067, 2024.
Article in English | MEDLINE | ID: mdl-38656055

ABSTRACT

Platinum nanoparticles supported by carbon nanotubes were obtained by a simple chemical route and used for preparation of electrochemical sensor towards caffeine determination. Carbon nanotubes were used before and after an acid treatment, yielding two different materials. Morphological and structural characterization of these materials showed platinum nanoparticles (size around 12 nm) distributed randomly along carbon nanotubes. Modified electrodes were directly prepared through a dispersion of these materials. Voltammetric studies in the presence of caffeine revealed an electrocatalytic effect of platinum oxides, electrochemically produced from the chemical oxidation of the platinum nanoparticles. This behavior was explored in the development a selective method for caffeine determination based on platinum oxide reduction at a lower potential value (+0.45 V vs. Ag/AgCl). Using the best set of experimental conditions, it was shown a linear relationship for the caffeine concentration ranging from 5.0 to 25 µmol L-1 with a sensitivity of 449 nA L µmol-1. Limits of detection and quantification of 0.54 and 1.80 µmol L-1 were calculated, respectively. Recovery values for real samples of caffeine pharmaceutical formulations between 98.6% and 101.0% (n = 3) were obtained using the proposed procedure. Statistical calculations showed good concordance (95% confidence level) between the added and recovery values.


Subject(s)
Caffeine , Electrochemical Techniques , Metal Nanoparticles , Nanotubes, Carbon , Platinum , Nanotubes, Carbon/chemistry , Caffeine/analysis , Caffeine/chemistry , Platinum/chemistry , Metal Nanoparticles/chemistry , Electrochemical Techniques/methods , Electrodes , Limit of Detection , Reproducibility of Results , Oxidation-Reduction
8.
Eur J Clin Pharmacol ; 80(7): 1079-1087, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38546840

ABSTRACT

PURPOSE: To investigate the physicochemical compatibility of caffeine citrate and caffeine base injections with 43 secondary intravenous (IV) drugs used in Neonatal Intensive Care Unit (NICU) settings. METHODS: Caffeine citrate (20 mg/mL or 10 mg/mL) or caffeine base injection (10 mg/mL) were mixed in a volume ratio of 1:1 with the secondary drug solution to simulate Y-site co-administration procedures in NICUs. Physical compatibility was evaluated based on visual observation for 2 h, against a black and white background and under polarised light, for changes in colour, precipitation, haze and evolution of gas. Chemical compatibility was determined from caffeine concentration measurements, using a validated high-performance liquid chromatography assay. RESULTS: Six of the 43 secondary drugs tested (aciclovir, amphotericin (liposomal), furosemide, hydrocortisone, ibuprofen and ibuprofen lysine) were physically incompatible with caffeine citrate undiluted injection (20 mg/mL), at their high-end, clinically relevant concentrations for NICU settings. However, when tested at lower concentrations, hydrocortisone (1 mg/mL) was physicochemically compatible, whereas furosemide (0.2 mg/mL) was physically incompatible with caffeine citrate. The six drugs which showed physical incompatibility with caffeine citrate 20 mg/mL injection were also physically incompatible with caffeine citrate 10 mg/mL solution. All 43 secondary drugs tested were physicochemically compatible with caffeine base injection. CONCLUSIONS: Most secondary test drugs, except aciclovir, amphotericin (liposomal), furosemide, hydrocortisone, ibuprofen and ibuprofen lysine, were physicochemically compatible with caffeine citrate injection. Caffeine base injection was physicochemically compatible with all 43 test drugs tested.


Subject(s)
Caffeine , Citrates , Drug Incompatibility , Caffeine/chemistry , Caffeine/administration & dosage , Humans , Citrates/chemistry , Citrates/administration & dosage , Infant, Newborn , Intensive Care, Neonatal , Intensive Care Units, Neonatal , Acyclovir/administration & dosage , Acyclovir/chemistry
9.
Magn Reson Med ; 92(2): 459-468, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38469685

ABSTRACT

PURPOSE: To demonstrate hyperpolarization of 15N-caffeine and report exploratory findings as a potential probe of liver function and perfusion. METHODS: An amorphous formulation of [1,3-15N2]caffeine was developed for hyperpolarization via dissolution dynamic nuclear polarization. Polarizer hardware was augmented to support monitoring of solid-state 15N MR signals during the buildup of hyperpolarization. Liquid state hyperpolarized 15N MR signals were obtained in a preclinical 3T magnet by interfacing an external spectrometer console with home-built RF surface coils. 15N signal decay constants were estimated in H2O and in vivo in liver and brain regions of rats at 3 T. Decays were also measured at 9.4 T to assess the effect of B0, and in the presence of albumin to assess the impact of protein binding. RESULTS: Polarization levels of 3.5% and aqueous T1 relaxation times of nearly 200 s were attained for both N1 and N3 positions at 3 T. Shorter apparent decay constants were observed in vivo, ranging from 25 s to 43 s, with modest extensions possible by exploiting competitive binding of iophenoxate with plasma albumin. Downstream products of caffeine could not be detected on in vivo 15N-MR spectra of the liver region, even with metabolic stimulation by ß $$ \beta $$ -naphthoflavone treatment. Considering the high perfusion rate of brain, persistence of caffeine signal in this region is consistent with potential value as a perfusion imaging agent. CONCLUSION: These results establish the feasibility of hyperpolarization of hyperpolarized 15N-caffeine, but further work is necessary to establish the role of this new agent to probe liver metabolism and perfusion.


Subject(s)
Caffeine , Liver , Nitrogen Isotopes , Caffeine/pharmacology , Caffeine/chemistry , Animals , Rats , Liver/diagnostic imaging , Liver/metabolism , Male , Magnetic Resonance Imaging , Brain/diagnostic imaging , Brain/metabolism , Rats, Sprague-Dawley , Magnetic Resonance Spectroscopy , Liver Function Tests
10.
Sci Rep ; 14(1): 4453, 2024 02 23.
Article in English | MEDLINE | ID: mdl-38396007

ABSTRACT

Consumer demand for natural, chemical-free products has grown. Food industry residues, like coffee pulp, rich in caffeine, chlorogenic acid and phenolic compounds, offer potential for pharmaceutical and cosmetic applications due to their antioxidant, anti-inflammatory, and antibacterial properties. Therefore, the objective of this work was to develop a phytocosmetic only with natural products containing coffee pulp extract as active pharmaceutical ingredient with antioxidant, antimicrobial and healing activity. Eight samples from Coffea arabica and Coffea canephora Pierre were analyzed for caffeine, chlorogenic acid, phenolic compounds, tannins, flavonoids, cytotoxicity, antibacterial activity, and healing potential. The Robusta IAC-extract had the greatest prominence with 192.92 µg/mL of chlorogenic acid, 58.98 ± 2.88 mg GAE/g sample in the FRAP test, 79.53 ± 5.61 mg GAE/g sample in the test of total phenolics, was not cytotoxic, and MIC 3 mg/mL against Staphylococcus aureus. This extract was incorporated into a stable formulation and preferred by 88% of volunteers. At last, a scratch assay exhibited the formulation promoted cell migration after 24 h, therefore, increased scratch retraction. In this way, it was possible to develop a phytocosmetic with the coffee pulp that showed desirable antioxidant, antimicrobial and healing properties.


Subject(s)
Antioxidants , Coffea , Humans , Antioxidants/pharmacology , Antioxidants/chemistry , Caffeine/pharmacology , Caffeine/chemistry , Chlorogenic Acid/pharmacology , Chlorogenic Acid/chemistry , Plant Extracts/pharmacology , Plant Extracts/chemistry , Phenols/pharmacology , Anti-Bacterial Agents/pharmacology , Coffea/chemistry
11.
Mol Pharm ; 21(3): 1479-1489, 2024 Mar 04.
Article in English | MEDLINE | ID: mdl-38373877

ABSTRACT

In a competitive coformer exchange reaction, a recent topic of interest in pharmaceutical research, the coformer in a pharmaceutical cocrystal is exchanged with another coformer that is expected to form a cocrystal that is more stable. There will be a competition between coformers to form the most stable product through the formation of hydrogen bonds. This will cause destabilization of the pharmaceutical products during processing or storage. Therefore, it is important to develop a mechanistic understanding of this transformation by monitoring each and every step of the reaction, employing a technique such as 1H nuclear magnetic resonance (NMR). In this study, an in situ monitoring of a coformer exchange reaction is carried out by 1H magic angle spinning (MAS) solid-state NMR (SSNMR) at a spinning frequency of 60 kHz. The changes in caffeine maleic acid cocrystals on addition of glutaric acid and caffeine glutaric cocrystals on addition of maleic acid were monitored. In all of the reactions, it has been observed that caffeine glutaric acid Form I is formed. When glutaric acid was added to 2:1 caffeine maleic acid, the formation of metastable 1:1 caffeine glutaric acid Form I was observed at the start of the experiment, indicating that the centrifugal pressure is enough for the formation. The difference in the end product of the reactions with a similar reaction pathway of 1:1 and 2:1 reactant stoichiometry indicates that a complete replacement of maleic acid has occurred only in the 1:1 stoichiometry of the reactants. The polymorphic transition of caffeine glutaric acid Form II to Form I at higher temperatures was a crucial reason that triggered the exchange of glutaric acid with maleic acid in the reaction of caffeine glutaric acid and maleic acid. Our results are novel since the new reaction pathways in competitive coformer exchange reactions enabled understanding the remarkable role of stoichiometry, polymorphism, temperature, and centrifugal pressure.


Subject(s)
Caffeine , Glutarates , Maleates , Caffeine/chemistry , Magnetic Resonance Spectroscopy
12.
Int J Pharm ; 653: 123859, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38307401

ABSTRACT

This study explores the innovative production of personalized bilayer tablets, integrating two advanced manufacturing techniques: Droplet Deposition Modeling (DDM) and Injection Molding (IM). Unlike traditional methods limited to customizing dense bilayer medicines, our approach uses Additive Manufacturing (AM) to effectively adjust drug release profiles. Focusing on Caffeine and Paracetamol, we found successful processing for both DDM and IM using Caffeine formulation. The high viscosity of Paracetamol formulation posed challenges during DDM processing. Integrating Paracetamol formulation for the over-molding process proved effective, demonstrating IM's versatility in handling complex formulations. Varying infill percentages in DDM tablets led to distinct porosities affecting diverse drug release profiles in DDM-fabricated tablets. In contrast, tablets with high-density structures formed through the over-molding process displayed slower and more uniform release patterns. Combining DDM and IM techniques allows for overcoming the inherent limitations of each technique independently, enabling the production of bilayer tablets with customizable drug release profiles. The study's results offer promising insights into the future of personalized medicine, suggesting new pathways for the development of customized oral dosage forms.


Subject(s)
Acetaminophen , Caffeine , Drug Liberation , Caffeine/chemistry , Tablets/chemistry , Printing, Three-Dimensional , Technology, Pharmaceutical/methods
13.
Int J Pharm ; 647: 123520, 2023 Nov 25.
Article in English | MEDLINE | ID: mdl-37858637

ABSTRACT

Hydrotropism is a convenient way to increase the solubility of drugs by up to several orders of magnitude, and even though it has been researched for decades with both experimental and simulation methods, its mechanism is still unknown. Here, we use caffeine/sodium benzoate (CAF-SB) as model system to explore the behaviour of caffeine solubility enhancement in water through NMR spectroscopy and neutron total scattering. 1H NMR shows strong interaction between caffeine and sodium benzoate in water. Neutron total scattering combined with empirical potential structure refinement, a systematic method to study the solution structure, reveals π-stacking between caffeine and the benzoate anion as well as Coulombic interactions with the sodium cation. The strongest hydrogen bond interaction in the system is between benzoate and water, which help dissolve CAF-SB complex and increase the solubility of CAF in water. Besides, the stronger interaction between CAF and water and the distortion of water structure are further mechanisms of the CAF solubility enhancement. It is likely that the variety of mechanisms for hydrotropism shown in this system can be found for other hydrotropes, and NMR spectroscopy and neutron total scattering can be used as complementary techniques to generate a holistic picture of hydrotropic solutions.


Subject(s)
Caffeine , Sodium Benzoate , Caffeine/chemistry , Magnetic Resonance Spectroscopy , Benzoates , Water , Neutrons
14.
Phytother Res ; 37(12): 5558-5598, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37679309

ABSTRACT

Caffeine, which shares consubstantial structural similarity with purine adenosine, has been demonstrated as a nonselective adenosine receptor antagonist for eliciting most of the biological functions at physiologically relevant dosages. Accumulating evidence supports caffeine's beneficial effects against different disorders, such as total cardiovascular diseases and type 2 diabetes. Conversely, paradoxical effects are also linked to caffeine ingestion in humans including hypertension-hypotension and tachycardia-bradycardia. These observations suggest the association of caffeine action with its ingested concentration and/or concurrent interaction with preferential molecular targets to direct explicit events in the human body. Thus, a coherent analysis of the functional targets of caffeine, relevant to normal physiology, and disease pathophysiology, is required to understand the pharmacology of caffeine. This review provides a broad overview of the experimentally validated targets of caffeine, particularly those of therapeutic interest, and the impacts of caffeine on organ-specific physiology and pathophysiology. Overall, the available empirical and epidemiological evidence supports the dose-dependent functional activities of caffeine and advocates for further studies to get insights into the caffeine-induced changes under specific conditions, such as asthma, DNA repair, and cancer, in view of its therapeutic applications.


Subject(s)
Cardiovascular Diseases , Diabetes Mellitus, Type 2 , Hypertension , Humans , Caffeine/pharmacology , Caffeine/chemistry , Hypertension/drug therapy
15.
Int J Mol Sci ; 24(17)2023 Aug 22.
Article in English | MEDLINE | ID: mdl-37685879

ABSTRACT

Numerous basic studies have reported on the neuroprotective properties of several purine derivatives such as caffeine and uric acid (UA). Epidemiological studies have also shown the inverse association of appropriate caffeine intake or serum urate levels with neurodegenerative diseases such as Alzheimer disease (AD) and Parkinson's disease (PD). The well-established neuroprotective mechanisms of caffeine and UA involve adenosine A2A receptor antagonism and antioxidant activity, respectively. Our recent study found that another purine derivative, paraxanthine, has neuroprotective effects similar to those of caffeine and UA. These purine derivatives can promote neuronal cysteine uptake through excitatory amino acid carrier protein 1 (EAAC1) to increase neuronal glutathione (GSH) levels in the brain. This review summarizes the GSH-mediated neuroprotective effects of purine derivatives. Considering the fact that GSH depletion is a manifestation in the brains of AD and PD patients, administration of purine derivatives may be a new therapeutic approach to prevent or delay the onset of these neurodegenerative diseases.


Subject(s)
Alzheimer Disease , Glutathione , Neuroprotection , Neuroprotective Agents , Parkinson Disease , Purines , Humans , Adenosine A2 Receptor Antagonists/chemistry , Adenosine A2 Receptor Antagonists/pharmacology , Adenosine A2 Receptor Antagonists/therapeutic use , Alzheimer Disease/drug therapy , Alzheimer Disease/prevention & control , Brain/metabolism , Cysteine/metabolism , Excitatory Amino Acid Transporter 3/metabolism , Glutathione/metabolism , Neuroprotective Agents/chemistry , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Parkinson Disease/drug therapy , Parkinson Disease/prevention & control , Purines/chemistry , Purines/pharmacology , Purines/therapeutic use , Receptor, Adenosine A2A , Theophylline/chemistry , Theophylline/pharmacology , Theophylline/therapeutic use , Uric Acid/blood , Caffeine/chemistry , Caffeine/pharmacology , Caffeine/therapeutic use
16.
J Food Sci ; 88(10): 4068-4078, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37623917

ABSTRACT

Colloidal nanoparticles in tea infusion are the link connecting micromolecular mechanism and macro-aggregation process of tea cream formation. In order to elucidate, the kinetics mechanism of green tea nanoparticles (gTNPs) aggregation, zeta-potentials, total average aggregation (TAA) rates, and critical coagulation concentration (CCC) in the presence of various pH and metal ions were investigated. Additionally, the effect of temperature on gTNPs aggregation was further explored. The results revealed that the TAA rate of gTNPs increased with decreasing pH values, the CCC of gTNPs increased in the order Mg2+  ≈ Ca2+  < Na+  ≈ K+ . The reason was that different positive ions changed the surface electric field strength of gTNPs to a different extent. Furthermore, it was indicated that low temperature could promote gTNPs aggregation in indirect way. Low temperature promoted the binding of epigallocatechin gallate (EGCG) and caffeine, and the combination between gTNPs and EGCG-caffeine complexes weakened the stability of gTNPs resulting from reduction in electrostatic repulsion. PRACTICAL APPLICATION: Tea is a popular beverage all over the world. This research revealed the mechanism of green tea nanoparticles aggregation and laid a theoretical foundation for the regulation of tea cream formation in tea beverage.


Subject(s)
Catechin , Nanoparticles , Tea/chemistry , Caffeine/chemistry , Temperature , Metals , Ions , Nanoparticles/chemistry , Catechin/chemistry , Hydrogen-Ion Concentration
17.
J Dairy Sci ; 106(12): 8249-8261, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37641325

ABSTRACT

The majority of bioactive substances in the human diet come from polyphenols. Here, we use spectroscopy, molecular docking, molecular dynamics simulations, and in vitro digestion to look at the relationship between caffeine (CAF) and bovine lactoferrin (BLF). The correlation analysis of the CAF-BLF fluorescence quenching process revealed that the reaction was spontaneous and that the CAF-BLF fluorescence quenching process may have been static. The predominant intrinsic binding forces were hydrogen bonds and van der Waals forces, which were also supported by molecular docking and molecular dynamics simulations. Through Fourier infrared and circular dichroism spectroscopy experiments, it was found that CAF changed the secondary structure of BLF and might bind to the hydrophobic amino acids of BLF. Compared with BLF, CAF-BLF showed inhibitory effects on digestion in simulated in vitro digestion. It will be helpful to better understand the interaction between CAF and BLF and provide the basis for the development of innovative dairy products.


Subject(s)
Caffeine , Lactoferrin , Caffeine/chemistry , Caffeine/metabolism , Lactoferrin/chemistry , Lactoferrin/metabolism , Molecular Docking Simulation , Cattle , In Vitro Techniques , Digestion , Animals , Humans , Spectroscopy, Fourier Transform Infrared , Circular Dichroism , Molecular Dynamics Simulation , Dairy Products
18.
Biochemistry ; 62(15): 2280-2288, 2023 08 01.
Article in English | MEDLINE | ID: mdl-37433121

ABSTRACT

The classical DNA aptamer for adenosine and ATP was selected twice using ATP as the target in 1995 and 2005, respectively. In 2022, this motif appeared four more times from selections using adenosine, ATP, theophylline, and caffeine as targets, suggesting that this aptamer can also bind methylxanthines. In this work, using thioflavin T fluorescence spectroscopy, this classical DNA aptamer showed Kd values for adenosine, theophylline, and caffeine of 9.5, 101, and 131 µM, respectively, and similar Kd values were obtained using isothermal titration calorimetry. Binding to the methylxanthines was also observed for the newly selected Ade1301 aptamer but not for the Ade1304 aptamer. The RNA aptamer for ATP also had no binding to the methylxanthines. Molecular dynamics simulations were performed using the classical DNA and RNA aptamers based on their NMR structures, and the simulation results were consistent with the experimental observations, explaining the selectivity profiles. This study suggests that a broader range of target analogues need to be tested for aptamers. For the detection of adenosine and ATP, the Ade1304 aptamer is a better choice due to its better selectivity.


Subject(s)
Aptamers, Nucleotide , Theophylline , Caffeine/chemistry , Adenosine , Aptamers, Nucleotide/chemistry , Adenosine Triphosphate
19.
J Biol Chem ; 299(9): 105117, 2023 09.
Article in English | MEDLINE | ID: mdl-37524132

ABSTRACT

Human cytochrome P450 3A4 (CYP3A4) is a major drug-metabolizing enzyme that shows extreme substrate promiscuity. Moreover, its large and malleable active site can simultaneously accommodate several substrate molecules of the same or different nature, which may lead to cooperative binding and allosteric behavior. Due to difficulty of crystallization of CYP3A4-substrate complexes, it remains unknown how multiple substrates can arrange in the active site. We determined crystal structures of CYP3A4 bound to three and six molecules of caffeine, a psychoactive alkaloid serving as a substrate and modulator of CYP3A4. In the ternary complex, one caffeine binds to the active site suitably for C8-hydroxylation, most preferable for CYP3A4. In the senary complex, three caffeine molecules stack parallel to the heme with the proximal ligand poised for 3-N-demethylation. However, the caffeine stack forms extensive hydrophobic interactions that could preclude product dissociation and multiple turnovers. In both complexes, caffeine is also bound in the substrate channel and on the outer surface known as a peripheral site. At all sites, aromatic stacking with the caffeine ring(s) is likely a dominant interaction, while direct and water-mediated polar contacts provide additional stabilization for the substrate-bound complexes. Protein-ligand interactions via the active site R212, intrachannel T224, and peripheral F219 were experimentally confirmed, and the latter two residues were identified as important for caffeine association. Collectively, the structural, spectral, and mutagenesis data provide valuable insights on the ligand binding mechanism and help better understand how purine-based pharmaceuticals and other aromatic compounds could interact with CYP3A4 and mediate drug-drug interactions.


Subject(s)
Caffeine , Cytochrome P-450 CYP3A , Humans , Binding Sites , Caffeine/chemistry , Caffeine/metabolism , Catalytic Domain , Cytochrome P-450 CYP3A/chemistry , Cytochrome P-450 CYP3A/genetics , Cytochrome P-450 CYP3A/metabolism , Ligands , Substrate Specificity , Protein Binding , Allosteric Regulation , Crystallography, X-Ray , Crystallization , Demethylation , Heme/metabolism , Hydrophobic and Hydrophilic Interactions , Mutation
20.
Int J Pharm ; 642: 123132, 2023 Jul 25.
Article in English | MEDLINE | ID: mdl-37315638

ABSTRACT

Through 3D printing (3DP), many parameters of solid oral dosage forms can be customised, allowing for truly personalised medicine in a way that traditional pharmaceutical manufacturing would struggle to achieve. One of the many options for customisation involves dose titration, allowing for gradual weaning of a medication at dose intervals smaller than what is available commercially. In this study we demonstrate the high accuracy and precision of 3DP dose titration of caffeine, selected due to its global prevalence as a behavioural drug and well-known titration-dependent adverse reactions in humans. This was achieved using a simple filament base of polyvinyl alcohol, glycerol, and starch, utilising hot melt extrusion coupled with fused deposition modelling 3DP. Tablets containing 25 mg, 50 mg, and 100 mg doses of caffeine were successfully printed with drug content in the accepted range prescribed for conventional tablets (90 - 110%), and excellent precision whereby the weights of all doses showed a relative standard deviation of no more than 3%. Importantly, these results proved 3D printed tablets to be far superior to splitting a commercially available caffeine tablet. Additional assessment of filament and tablet samples were reviewed by differential scanning calorimetry, thermogravimetric analysis, HPLC, and scanning electron microscopy, showing no evidence of degradation of caffeine or the raw materials, with smooth and consistent filament extrusion. Upon dissolution, all tablets achieved greater than 70% release between 50 and 60 min, showing a predictable rapid release profile regardless of dose. The outcomes of this study highlight the benefits that dose titration with 3DP can offer, especially to more commonly prescribed medications that can have even more harmful withdrawal-induced adverse reactions.


Subject(s)
Caffeine , Polyvinyl Alcohol , Humans , Caffeine/chemistry , Tablets/chemistry , Polyvinyl Alcohol/chemistry , Hot Melt Extrusion Technology , Printing, Three-Dimensional , Drug Liberation , Technology, Pharmaceutical/methods
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