scholarly journals Neutral pH Formulation for 6-[18F]fluoro-ʟ-DOPA With High Radiochemical Stability

2021 ◽  
Author(s):  
Sang Ju Lee ◽  
Seung Jun Oh
Keyword(s):  
Ascorbic Acid ◽  
High Stability ◽  
Radiochemical Purity ◽  
Enantiomeric Purity ◽  
Neutral Ph ◽  
Korean Ministry ◽  
Acidic Conditions ◽  
Pre Treatment ◽  
New Formulation ◽  
Time Point

Abstract 6-[18F]Fluoro-L-DOPA(FDOPA) has always been generally produced under strong acidic conditions, i.e. as an injectable solution of pH 2~3, due to its low stability at a higher or neutral pH. This necessitates the pre-treatment neutralization of this agent with an injectable NaHCO3 solution. We have developed a neutral pH formulation for [18F]FDOPA using ethanol (EtOH) and phosphate buffer to overcome the radioactive and enantiomeric stability problems at a higher pH. Upon [18F]FDOPA generation by nucleophilic substitution methods, we investigated its radiochemical and enantiomeric purity in accordance with the various pH after 6 hours. After EtOH and three kinds of buffer were added, we further examined this purity at pH 6 ~ 7 after 6 hours. The ascorbic acid did not stabilize the radiochemical purity at the higher pH. A 5% EtOH and PBS buffer matrix produced the best stability for radiochemical and enantiomeric purity at pH 6.5 at the 6 hour time point. This combination maintained a > 95% radiochemical and enantiomeric purity at 6 hours after EOS (end of synthesis). Our new formulation for [18F]FDOPA thus showed a high stability at neutral pH and satisfied QC requirements which was listed in European Pharmacopeia. It has also been approved by the Korean Ministry of Food and Drug Safety.

scholarly journals Yoghurt Fortified Formulation of Lakum Fruit (Cayratia trifolia (L.) Domin) Extract as an Antioxidant

2018 ◽  
Vol 23 (3) ◽  
pp. 91 ◽  
Author(s):  
Weni Puspita ◽  
Nurkhasanah Nurkhasanah ◽  
Ika Dyah Kumalasari
Keyword(s):  
Antioxidant Activity ◽  
High Stability ◽  
National Standard ◽  
Total Acid ◽  
Fruit Extract ◽  
Physical Chemical ◽  
Cayratia Trifolia ◽  
Acidic Conditions ◽  
Anthocyanin Stability ◽  
Microbiological Properties

Lakum (Cayratia trifolia (L.) Domin) contains a lot of anthocyanin. Anthocyanin in Lakum fruit has a high stability if stored at low temperatures, acidic conditions, and without light. The acidic product such as yogurt can provide an optimum condition for anthocyanin stability and antioxidant activity. The purpose of this study was to optimize yogurt formulation fortified by lakum fruit extract as an antioxidant according to the requirements of the Indonesian National Standard (SNI). Lakum fruit extract was formulated in yogurt with various concentrations at 0%, 5%, 7.5% and 10%. Evaluations were carried out including tests of physical, chemical and microbiological properties and anthocyanin test and antioxidant of yogurt. The results showed that the yogurt formula fortified lakum fruit extract at 7.5% concentration resulted highest anthocyanin stability and antioxidant activity that fulfilled SNI requirements and the preferred level of respondents' preference with anthocyanin levels of 53.35±1.04 mg/L, antioxidant activity 69.15±0.24%, t90 7.97 days, total of lactic acid bacteria (LAB) 48.2x107 colony/gram, fat 3.72±0.03%, pH 3.87±0.03, total acid 0.83±0.06%, viscosity 639.07±2.06 cP, protein of 4.90±0.11%, hedonic test, 6.88 (like), and organoleptic purple (5), the distinctive aroma of lakum fruit (4.95), sour taste (4.85), fine texture (4.9) and slightly liquid viscosity (4.85).

Reduction of Vanadium(V) byl-Ascorbic Acid at Low and Neutral pH:  Kinetic, Mechanistic, and Spectroscopic Characterization

2006 ◽  
Vol 45 (4) ◽  
pp. 1471-1479 ◽  
Author(s):  
Patricia C. Wilkins ◽  
Michael D. Johnson ◽  
Alvin A. Holder ◽  
Debbie C. Crans
Keyword(s):  
Ascorbic Acid ◽  
Spectroscopic Characterization ◽  
Neutral Ph

scholarly journals The Effects of Salts on the Stability of the Collagen Helix Under Acidic Conditions

1968 ◽  
Vol 21 (4) ◽  
pp. 821 ◽  
Author(s):  
Anne FW oodlock ◽  
BS Harrap
Keyword(s):  
Thermal Stability ◽  
Carboxyl Groups ◽  
Neutral Ph ◽  
Acid Ph ◽  
Helix Stability ◽  
Acidic Conditions ◽  
Anions And Cations ◽  
The Stability ◽  
Thermal Stability Of ◽  
Positively Charged

In the acid pH region, the relative effects of various salts on the thermal stability of the collagen helix are quite different from their effects at neutral pH. The magnitude of the decrease in thermal stability brought about by the salts studied depends mainly on the nature and concentration of the anion and very little on the nature of the cation, whereas at neutral pH the nature of both anions and cations affects the collagen helix stability, the effects of the two ions being roughly additive. The magnitude of the effect of salts at acid pH is much greater than that at neutral pH whereas for a non-ionized denaturant, urea, the magnitudes at both neutral and acid pH are similar. The data are discussed in terms of possible interactions between salts and the positively charged protein with particular consideration of the effects of salts on the pKa of protein carboxyl groups.

scholarly journals L-Alanyl-Glutamine dipeptide pretreatment attenuates ischemia-reperfusion injury in rat testis

2011 ◽  
Vol 26 (suppl 1) ◽  
pp. 21-25 ◽  
Author(s):  
João Paulo de Vasconcelos Leitão ◽  
Jefferson Menezes Viana Santos ◽  
Raquel Cavalcante de Vasconcelos ◽  
José Huygens Parente Garcia ◽  
Paulo Roberto Leitão de Vasconcelos ◽  
...  
Keyword(s):  
Spermatic Cord ◽  
Testicular Torsion ◽  
Ischemia Reperfusion Injury ◽  
Reduced Glutathione ◽  
Ischemia Reperfusion ◽  
Time Points ◽  
Rat Testis ◽  
Pre Treatment ◽  
The Right ◽  
Time Point

PURPOSE: To investigate the effect of alanyl-glutamine dipeptide (L-Ala-Gln) pre-treatment on ischemia-reperfusion (I/R) injury after unilateral testicular torsion-detorsion in a comparative controlled experiment. METHODS: Forty-eight rats (150-200 g) randomly distributed into 4 groups (n=12), and distributed in 2 subgroups (n=6) each, were treated with saline 2.0 ml (G-1, G-3) or L-Ala-Gln 20%, 0.75g/kg dissolved in saline (total volume 2.0 ml) administered in the left saphenous vein 30 minutes before ischemia. Anesthetized rats were subjected to I/R induced by torsion (720°) of the right spermatic cord lasting 1h (G-1, G-2) or 3 hours (G-3, G4). Anesthesia was again applied at the end of ischemia time (T-0) for testis detorsion and 6 hours later (T-6) for orchiectomy. All operations were performed on the right testes through transverse scrotal incisions. Right orchiectomy was carried out at the end of ischemia (T-0), and 6 hours later (T-6) to evaluate the concentrations of malondialdehyde (MDA) and reduced glutathione (GSH) in the testis. RESULTS: Pretreatment with L-Ala-Gln reduced MDA contents in rat testis at the end of ischemia lasting 3 hours. There was significant increase of GSH levels in T-6 time-point after 1 hour of ischemia. GSH levels also increased in T-0 and T-6 time-points in rats subjected to ischemia for 3 hours. CONCLUSION: L-Ala-Gln administered before torsion/detorsion of the spermatic cord decreases lipid peroxidation during ischemia and protects the testis from oxidative stress by upregulating GSH levels during reperfusion.

scholarly journals Physico-Chemical Properties of Sugar Beet Pectin-Sodium Caseinate Conjugates via Different Interaction Mechanisms

Foods ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 192
Author(s):  
Juyang Zhang ◽  
Bettina Wolf
Keyword(s):  
Sugar Beet ◽  
Thermal Processing ◽  
Chemical Properties ◽  
Sodium Caseinate ◽  
Neutral Ph ◽  
Aggregate Properties ◽  
Physico Chemical ◽  
Acid Tolerant ◽  
Acidic Conditions ◽  
Processing Stability

Polysaccharides and proteins are frequently conjugated through electrostatic attraction, enzymatic cross-linking, and heat treatment (Maillard reaction) to obtain food structuring ingredients, mostly for their application as emulsifiers. The conjugate partners and their interaction type affect performance at acidic or neutral pH and during thermal processing, thus requiring careful selection. Here, the aggregate properties (particle size, conjugate charge, shear viscosity) of three types of sugar beet pectin (SBP)-sodium caseinate (SC) 1:1 conjugates, at acidic and neutral pH (4.5; 7), as well as their thermal processing stability (80 °C), were investigated. The enzymatically cross-linked SBP:SC was more acid tolerant than the electrostatically interacting conjugates. Maillard cross-linked conjugates aggregated at pH 4.5, suggesting poor emulsifier performance in acidic conditions. At pH 7, the three conjugate types showed similar aggregate properties. The results are discussed in terms of structural re-arrangement.

One-pot cascade catalysis at neutral pH driven by CuO tandem nanozyme for ascorbic acid and alkaline phosphatase detection

2020 ◽  
Vol 321 ◽  
pp. 128511
Author(s):  
Shao-Bin He ◽  
Paramasivam Balasubramanian ◽  
Ai-Ling Hu ◽  
Xiao-Qing Zheng ◽  
Meng-Ting Lin ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Ascorbic Acid ◽  
One Pot ◽  
Neutral Ph ◽  
Acid And Alkaline Phosphatase ◽  
Cascade Catalysis

scholarly journals THE EFFECTS OF APPLYING PARAQUAT, ATRAZINE AND SIMAZINE FOR WEED CONTROL IN RASPBERRIES IN COASTAL BRITISH COLUMBIA

1967 ◽  
Vol 47 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Jack A. Freeman
Keyword(s):  
Ascorbic Acid ◽  
Weed Control ◽  
Ascorbic Acid Content ◽  
Early Spring ◽  
The Other ◽  
Leaf Injury ◽  
Excellent Control ◽  
Winter Annuals ◽  
Pre Treatment ◽  
Coastal British Columbia

Early spring and fall applications of a mixture of paraquat 2.2 kg and simazine 2.2 to 3.4 kg/ha repeated over a 3-year period provided excellent weed control without adversely affecting raspberry yield. Paraquat 2.2 kg/ha applied in April gave good broadleaf weed control for 2 months and fairly good grass control for 3 months. Fall applications suppressed grasses and controlled winter annuals through to spring. Combining paraquat with simazine eliminated the need for pre-treatment hoeing or cultivation and prolonged weed control. Atrazine 3.4 and 5.6 kg/ha applied in the spring resulted in excellent control of grass and broadleaf weeds. But, fall applications were not as effective for weed control as the paraquat and hoe-plus-simazine treatments. Atrazine 5.6 kg/ha caused chlorosis and necrosis of the raspberry leaves and reduced yields. Simazine, on the other hand, caused little or no leaf injury, but it also reduced yields at the 5.6-kg rate. Fruit quality was not affected significantly by any treatment, although atrazine and simazine tended to increase ascorbic acid content.

Developmental Changes in the PH of Enamel Fluid and Its Effects On Matrix-Resident Proteinases

1996 ◽  
Vol 10 (2) ◽  
pp. 159-169 ◽  
Author(s):  
C.E. Smith ◽  
M. Issid ◽  
H.C. Margolis ◽  
E.C. Moreno
Keyword(s):  
Acetic Acid ◽  
Protein Extraction ◽  
Maturation Stage ◽  
Activity Levels ◽  
Freeze Dried ◽  
Mineral Components ◽  
Acidic Conditions ◽  
Pre Treatment

The objectives of this study were to measure pH in developing enamel at progressively older (more mature) stages of amelogenesis in vivo, and then to formulate synthetic enamel fluid mixtures that approximated these pH values for in vitro studies. The ultimate goal was to characterize the molecular weights of proteinases visualized by enzymograms incubated in synthetic enamel fluid using gelatin and casein as substrates. For most experiments. the proteinases were extracted en masse from small freeze-dried enamel strips directly into a non-reducing sample preparation buffer. In some experiments, we pre-treated the enamel strips with acetic acid to determine if this common method for demineralization and protein extraction caused any changes in the activity levels of the enamel proteinases. In other experiments, we first soaked enamel strips in synthetic enamel fluid to determine solubility of the proteinases within an aqueous phase. The results indicated that the pH of developing enamel remained fairly constant near pH 7.23 across the secretory stage, but it was generally more acidic (6.93) and fluctuated in focal areas between mildly acidic (6.2-6.8) and near-neutral (7.2) conditions across the maturation stage. The pH then slowly rose to near 7.35 when the enamel was almost mature (hard). The acidic conditions were generally inhibitory to most enamel proteinases, but there were some caseinase activities in mid-maturation-stage enamel near 23-30 kDa which appeared to be activated by weakly acidic conditions (pH 6.28). Pre-treatment of enamel samples with 0.5 M acetic acid markedly altered the overall profile of enamel proteinases, causing activation of some latent proteinase activities and permanent inhibition of other activities. Most proteinases in whole homogenates were insoluble in synthetic enamel fluid. This suggests that they may be tightly bound, directly or indirectly, to matrix proteins or mineral components in situ.

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