Complexes of Chromium with β-Glycerophosphate: Their Nature and Properties

Chromium Atom ◽

By ion echange analysis, dialysis and electrophoresis of double labelled (32P and 51Cr) chromic β-glycerophosphate complexes, the stability of the bond β-glycerophosphate-chromium under different conditions of olation and oxolation has been studied. The glycerophosphate can form complexes with 1 or 2 moles per chromium atom. Below pH 6.0 the complexes present cationic characteristics, while between pH 6.0 and pH 8.0 they behave as anions. The oxolation provokes a release of β-glycerophosphate from the complex. The physicochemical characteristics of these complexes are reflected in their behaviour “in vivo” when injected into mice.

Effect of Mixing Ratio of Oppositely Charged Block Copolymers on Polyion Complex Micelles for In Vivo Application

Polymers ◽

10.3390/polym13010005 ◽

2020 ◽

Vol 13 (1) ◽

pp. 5

Author(s):

Noriko Nakamura ◽

Yuki Mochida ◽

Kazuko Toh ◽

Shigeto Fukushima ◽

Horacio Cabral ◽

...

Keyword(s):

Charge Ratio ◽

Structural Variations ◽

Polyion Complex ◽

Functional Capabilities ◽

The Stability ◽

Biological Performance ◽

Complex Micelles ◽

Oppositely Charged

Self-assembled supramolecular structures based on polyion complex (PIC) formation between oppositely charged polymers are attracting much attention for developing drug delivery systems able to endure harsh in vivo environments. As controlling polymer complexation provides an opportunity for engineering the assemblies, an improved understanding of the PIC formation will allow constructing assemblies with enhanced structural and functional capabilities. Here, we focused on the influence of the mixing charge ratio between block aniomers and catiomers on the physicochemical characteristics and in vivo biological performance of the resulting PIC micelles (PIC/m). Our results showed that by changing the mixing charge ratio, the structural state of the core was altered despite the sizes of PIC/m remaining almost the same. These structural variations greatly affected the stability of the PIC/m in the bloodstream after intravenous injection and determined their biodistribution.

FORMULATION AND OPTIMIZATION OF NIFEDIPINE LOADED NANOCARRIERS

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2021v13i5.42050 ◽

2021 ◽

pp. 311-317

Author(s):

ASHWINI JADHAV ◽

BINOY VARGHESE CHERIYAN

Keyword(s):

Particle Size ◽

Zeta Potential ◽

Physical Stability ◽

Entrapment Efficiency ◽

Tween 80 ◽

Good Choice ◽

Objective: The main aim of this study to formulate a nifedipine-loaded nanocarrier for improving solubility and bioavailability. Methods: To improve the solubility of drug, nifedipine-loaded nanocarrier (lipotomes) were prepared by using the film lipid hydration technique. lipotomes were prepared by using tween 80, which is used for increasing solubility and cetyl alcohol for lipophilic environment. Drug excipients interaction determined by FTIR. lipotomes were characterized for particle size, Entrapment efficiency and zeta potential. lipotomes were optimized by using Design-Expert 12 software. Optimized formula further lyophilized by using different cyroproyectant to improve the stability and oral administration of the drug. Results: FTIR shows there was no interaction between formulation ingredients. Mean particle size, entrapment efficiency, zeta potential was determined and found to be 308.1 nm, 96.7%, 20.1mV, respectively. Surface morphology of lipotomes was observed by a scanning electron microscope (SEM). Optimized lipotomes was lyophilized with Mannitol (8% w/v) was the ideal cryoprotectant to retain the physicochemical characteristics of the OLT formulation after lyophilization. Conclusion: Nifedipine loaded nanocarrier was successfully prepared, using film hydration method. Which have good particle size, EE% and zeta potential. After lyophilization no significant changes was observed in particle size with good physical stability, so it could be a good choice for conventional drug delivery system by doing further investigation as in vitro and in vivo study

Insights into Terminal Sterilization Processes of Nanoparticles for Biomedical Applications

Molecules ◽

10.3390/molecules26072068 ◽

2021 ◽

Vol 26 (7) ◽

pp. 2068

Author(s):

Sergio A. Bernal-Chávez ◽

María Luisa Del Prado-Audelo ◽

Isaac H. Caballero-Florán ◽

David M. Giraldo-Gomez ◽

Gabriela Figueroa-Gonzalez ◽

...

Keyword(s):

Biomedical Applications ◽

Microbial Contamination ◽

Average Particle Size ◽

Average Particle ◽

Comprehensive Overview ◽

Sterile Filtration ◽

Nonionizing Radiation ◽

Nanoparticles possess a huge potential to be employed in numerous biomedical purposes; their applications may include drug delivery systems, gene therapy, and tissue engineering. However, the in vivo use in biomedical applications requires that nanoparticles exhibit sterility. Thus, diverse sterilization techniques have been developed to remove or destroy microbial contamination. The main sterilization methods include sterile filtration, autoclaving, ionizing radiation, and nonionizing radiation. Nonetheless, the sterilization processes can alter the stability, zeta potential, average particle size, and polydispersity index of diverse types of nanoparticles, depending on their composition. Thus, these methods may produce unwanted effects on the nanoparticles’ characteristics, affecting their safety and efficacy. Moreover, each sterilization method possesses advantages and drawbacks; thus, the suitable method’s choice depends on diverse factors such as the formulation’s characteristics, batch volume, available methods, and desired application. In this article, we describe the current sterilization methods of nanoparticles. Moreover, we discuss the advantages and drawbacks of these methods, pointing out the changes in nanoparticles’ biological and physicochemical characteristics after sterilization. Our main objective was to offer a comprehensive overview of terminal sterilization processes of nanoparticles for biomedical applications.

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067741 ◽

1970 ◽

Vol 28 ◽

pp. 150-151

Author(s):

Robert J. Carroll ◽

Marvin P. Thompson ◽

Harold M. Farrell

Keyword(s):

Size Distribution ◽

G Protein ◽

Milk Proteins ◽

Mammary Tissue ◽

Colloidal System ◽

Casein Micelles ◽

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

Nuklearmedizin ◽

10.1055/s-0037-1620623 ◽

1977 ◽

Vol 16 (04) ◽

pp. 157-162 ◽

Cited By ~ 1

Author(s):

C. Schümichen ◽

B. Mackenbrock ◽

G. Hoffmann

Keyword(s):

Normal Saline ◽

Half Life ◽

Compound A ◽

Short Half Life ◽

Low Concentrations ◽

The Stability ◽

Kinetics Of ◽

In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

Applicability of Instability Index for In vitro Protein Stability Prediction

Protein and Peptide Letters ◽

10.2174/0929866526666190228144219 ◽

2019 ◽

Vol 26 (5) ◽

pp. 339-347 ◽

Cited By ~ 4

Author(s):

Dilani G. Gamage ◽

Ajith Gunaratne ◽

Gopal R. Periyannan ◽

Timothy G. Russell

Keyword(s):

Protein Stability ◽

Caulobacter Crescentus ◽

Effect Of Temperature ◽

Instability Index ◽

Dipeptide Composition ◽

Experimental Conditions ◽

The Stability ◽

Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

Stability and ocular biodistribution of topically administered PLGA nanoparticles

Scientific Reports ◽

10.1038/s41598-021-90792-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sean Swetledge ◽

Renee Carter ◽

Rhett Stout ◽

Carlos E. Astete ◽

Jangwook P. Jung ◽

...

Keyword(s):

Uv Light ◽

Light Exposure ◽

Polymeric Nanoparticles ◽

Plga Nanoparticles ◽

Eye Disease ◽

Control Group ◽

Eye Tissues ◽

Nanoparticle Morphology ◽

AbstractPolymeric nanoparticles have been investigated as potential delivery systems for therapeutic compounds to address many ailments including eye disease. The stability and spatiotemporal distribution of polymeric nanoparticles in the eye are important regarding the practical applicability and efficacy of the delivery system in treating eye disease. We selected poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with lutein, a carotenoid antioxidant associated with eye health, as our model ophthalmic nanodelivery system and evaluated its stability when suspended in various conditions involving temperature and light exposure. We also assessed the ocular biodistribution of the fluorescently labeled nanoparticle vehicle when administered topically. Lutein-loaded nanoparticles were stable in suspension when stored at 4 °C with only 26% lutein release and no significant lutein decay or changes in nanoparticle morphology. When stored at 25 °C and 37 °C, these NPs showed signs of bulk degradation, had significant lutein decay compared to 4 °C, and released over 40% lutein after 5 weeks in suspension. Lutein-loaded nanoparticles were also more resistant to photodegradation compared to free lutein when exposed to ultraviolet (UV) light, decaying approximately 5 times slower. When applied topically in vivo, Cy5-labled nanoparticles showed high uptake in exterior eye tissues including the cornea, episcleral tissue, and sclera. The choroid was the only inner eye tissue that was significantly higher than the control group. Decreased fluorescence in all exterior eye tissues and the choroid at 1 h compared to 30 min indicated rapid elimination of nanoparticles from the eye.

Effect of food processing on the antioxidant activity of flavones from Polygonatum odoratum (Mill.) Druce

Open Life Sciences ◽

10.1515/biol-2021-0010 ◽

2021 ◽

Vol 16 (1) ◽

pp. 92-101

Author(s):

Guanghui Xia ◽

Xinhua Li ◽

Zhen Zhang ◽

Yuhang Jiang

Keyword(s):

Antioxidant Activity ◽

High Pressure ◽

Food Processing ◽

Yeast Fermentation ◽

Pressure Treatment ◽

Processing Methods ◽

High Pressure Treatment ◽

Effect Of Food ◽

Abstract Polygonatum odoratum (Mill.) Druce (POD) is a natural plant widely used for food and medicine, thanks to its rich content of a strong antioxidant agent called homoisoflavones. However, food processing methods could affect the stability of POD flavones, resulting in changes to their antioxidant activity. This study attempts to evaluate the antioxidant activity of POD flavones subject to different processing methods and determines which method could preserve the antioxidant activity of POD flavones. Therefore, flavones were extracted from POD samples, which had been treated separately with one of the four processing methods: extrusion, baking, high-pressure treatment, and yeast fermentation. After that, the antioxidant activity of the flavones was subject to in vivo tests in zebrafish embryos. The results show that yeast fermentation had the least disruption to the antioxidant activity of POD flavones, making it the most suitable food processing method for POD. By contrast, extrusion and high-pressure treatment both slightly weakened the antioxidant activity of the flavones and should be avoided in food processing. The research results provide a reference for the development and utilization of POD and the protection of its biological activity.

Clinical Application and Efficacy of Silver Drug in Ophthalmology: A Literature Review and New Formulation of EYE Drops with Drug Silver (I) Complex of Metronidazole with Improved Dosage Form

Biomedicines ◽

10.3390/biomedicines9020210 ◽

2021 ◽

Vol 9 (2) ◽

pp. 210

Author(s):

Arleta Waszczykowska ◽

Dominik Żyro ◽

Justyn Ochocki ◽

Piotr Jurowski

Keyword(s):

Dosage Form ◽

Complex Analysis ◽

Bacterial Resistance ◽

Eye Drops ◽

Ophthalmic Diseases ◽

The Stability ◽

New Formulation ◽

Additional Therapy ◽

Antibacterial Potential

The use of silver preparations in medicine is becoming increasingly popular. The basic aim of this evaluation was to review the literature on the clinical (in vivo) and antibacterial potential of silver preparations in ophthalmic diseases. The second goal was to summarize the results of experimental research on the use of silver preparations in ophthalmology. The third objective was to present a method for stabilizing eye drops containing silver (I) complex. Analysis of the pH stability of the silver (I) complex with metronidazole in the prepared dosage form (eye drops) was carried out. Most silver preparations are clinically used for topical application. Few experimental results indicate the usefulness of intraocular or systemic administration of silver (I) preparations as an alternative or additional therapy in infectious and angiogenic eye diseases. The development of a new formulation increases the stability of the dosage form. New forms of silver (I) products will certainly find application in the treatment of many ophthalmic diseases. One of the most important features of the silver (I) complex is its capacity to break down bacterial resistance. The new eye drops formula can significantly improve comfort of use. Due to their chemical nature, silver (I) compounds are difficult to stabilize, especially in the finished dosage form.

DBC1 (Deleted in Breast Cancer 1) modulates the stability and function of the nuclear receptor Rev-erbα

Biochemical Journal ◽

10.1042/bj20121085 ◽

2013 ◽

Vol 451 (3) ◽

pp. 453-461 ◽

Cited By ~ 26

Author(s):

Claudia C. S. Chini ◽

Carlos Escande ◽

Veronica Nin ◽

Eduardo N. Chini

Keyword(s):

Breast Cancer ◽

Nuclear Receptor ◽

Clock Genes ◽

Mrna Levels ◽

Protein Levels ◽

The Stability ◽

And Function ◽

Interfering Rna ◽

In Cells

The nuclear receptor Rev-erbα has been implicated as a major regulator of the circadian clock and integrates circadian rhythm and metabolism. Rev-erbα controls circadian oscillations of several clock genes and Rev-erbα protein degradation is important for maintenance of the circadian oscillations and also for adipocyte differentiation. Elucidating the mechanisms that regulate Rev-erbα stability is essential for our understanding of these processes. In the present paper, we report that the protein DBC1 (Deleted in Breast Cancer 1) is a novel regulator of Rev-erbα. Rev-erbα and DBC1 interact in cells and in vivo, and DBC1 modulates the Rev-erbα repressor function. Depletion of DBC1 by siRNA (small interfering RNA) in cells or in DBC1-KO (knockout) mice produced a marked decrease in Rev-erbα protein levels, but not in mRNA levels. In contrast, DBC1 overexpression significantly enhanced Rev-erbα protein stability by preventing its ubiquitination and degradation. The regulation of Rev-erbα protein levels and function by DBC1 depends on both the N-terminal and C-terminal domains of DBC1. More importantly, in cells depleted of DBC1, there was a dramatic decrease in circadian oscillations of both Rev-erbα and BMAL1. In summary, our data identify DBC1 as an important regulator of the circadian receptor Rev-erbα and proposes that Rev-erbα could be involved in mediating some of the physiological effects of DBC1.