scholarly journals Stability Analyses of Guanitoxin Isolated from Sphaerospermopsis torques-reginae by Mass Spectrometry

2021 ◽  
Author(s):  
Kelly Fernandes ◽  
Felipe Augusto Dörr ◽  
Ernani Pinto
Keyword(s):  
Mass Spectrometry ◽  
Chemical Structure ◽  
Room Temperature ◽  
Storage Conditions ◽  
Extraction Yield ◽  
Cyanobacterial Blooms ◽  
Main Degradation Product ◽  
The Stability ◽  
Hydrolysis Of ◽  
Freshwater Monitoring

Guanitoxin (GNT) is a natural organophosphate produced by some species of freshwater cyanobacteria, which inhibits the active site of acetylcholinesterase, preventing the hydrolysis of cholinesterases and consequently causing serious disturbances in the neuromuscular system. Despite having a chemical structure like synthetic organophosphates, there is still no analytical standard available for environmental and freshwater monitoring. Therefore, this study investigated the stability of GNT under different storage conditions, pH, and temperature. The toxin is produced by the cyanobacterium Sphaerospermopsis torques-reginae and monitored by liquid chromatography coupled to mass spectrometry (LC-MS) and LC-MS/MS for the identification and verification of its stability. The main degradation product formed is the hydroxy-amino-guanidinic derivative of the toxin. The results also indicate that GNT is stable in acidic medium (pH = 3.0), but can gradually degrade at room temperature (> 23 ºC) over a period of 96 h. Lyophilized biomass of S. torques-reginae containing GNT remained stable when stored in a refrigerator below 4 ºC. In addition, the extraction yield is higher when prepared from fresh S. torques-reginae cells than from lyophilized material. Thus, the results shown here contribute with valuable information for studies that aim at the isolation, identification, and monitoring of GNT in samples of raw water and cyanobacterial blooms.

Stability of extemporaneously prepared rosuvastatin oral suspension

2017 ◽  
Vol 74 (19) ◽  
pp. 1579-1583 ◽  
Author(s):  
Abdel Naser Zaid ◽  
Rania Shtayah ◽  
Ayman Qadumi ◽  
Mashour Ghanem ◽  
Rawan Qedan ◽  
...  
Keyword(s):  
Relative Humidity ◽  
High Performance ◽  
Room Temperature ◽  
Microbial Contamination ◽  
Active Pharmaceutical Ingredient ◽  
Storage Conditions ◽  
Dissolution Profile ◽  
Stability Studies ◽  
Organoleptic Properties ◽  
The Stability

Abstract Purpose The stability of an extemporaneously prepared rosuvastatin suspension stored over 30 days under various storage conditions was evaluated. Methods Rosuvastatin suspension was extemporaneously prepared using commercial rosuvastatin tablets as the source of active pharmaceutical ingredient. The organoleptic properties, dissolution profile, and stability of the formulation were investigated. For the stability studies, samples of the suspension were stored under 2 storage conditions, room temperature (25 °C and 60% relative humidity) and accelerated stability chambers (40 °C and 75% relative humidity). Viscosity, pH, organoleptic properties, and microbial contamination were evaluated according to the approved specifications. High-performance liquid chromatography was used for the analysis and quantification of rosuvastatin in selected samples. Microbiological investigations were also conducted. Results The prepared suspension showed acceptable organoleptic properties. It showed complete release of rosuvastatin within 15 minutes. The pH of the suspension was 9.8, which remained unchanged during the stability studies. The microbiological investigations demonstrated that the preparation was free of any microbial contamination. In addition, the suspension showed stability within at least the period of use of a 100-mL rosuvastatin bottle. Conclusion Extemporaneously prepared rosuvastatin 20-mg/mL suspension was stable for 30 days when stored at room temperature.

scholarly journals Changes of salivary biomarkers under different storage conditions: effects of temperature and length of storage

2018 ◽  
Vol 29 (1) ◽  
pp. 94-111 ◽  
Author(s):  
Tomás Barranco ◽  
Asta Tvarijonaviciute ◽  
Damián Escribano ◽  
Fernando Tecles ◽  
José J Cerón ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Room Temperature ◽  
Storage Conditions ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Long Term Storage ◽  
Reducing Ability ◽  
Trolox Equivalent ◽  
The Stability ◽  
Term Storage

Introduction: In this report, we aimed to examine the stability of various analytes in saliva under different storage conditions. Materials and methods: Alpha-amylase (AMY), cholinesterase (CHE), lipase (Lip), total esterase (TEA), creatine kinase (CK), aspartate aminotransferase (AST), lactate dehydrogenase (LD), lactate (Lact), adenosine deaminase (ADA), Trolox equivalent antioxidant capacity (TEAC), ferric reducing ability (FRAS), cupric reducing antioxidant capacity (CUPRAC), uric acid (UA), catalase (CAT), advanced oxidation protein products (AOPP) and hydrogen peroxide (H2O2) were colorimetrically measured in saliva obtained by passive drool from 12 healthy voluntary donors at baseline and after 3, 6, 24, 72 hours, 7 and 14 days at room temperature (RT) and 4 ºC, and after 14 days, 1, 3 and 6 months at – 20 ºC and – 80 ºC. Results: At RT, changes appeared at 6 hours for TEA and H2O2; 24 hours for Lip, CK, ADA and CUPRAC; and 72 hours for LD, Lact, FRAS, UA and AOPP. At 4 ºC changes were observed after 6 hours for TEA and H2O2; 24 hours for Lip and CUPRAC; 72 hours for CK; and 7 days for LD, FRAS and UA. At – 20 ºC changes appeared after 14 days for AST, Lip, CK and LD; and 3 months for TEA and H2O2. At – 80 ºC observed changes were after 3 months for TEA and H2O2. Conclusions: In short-term storage, the analytes were more stable at 4 ºC than at room temperature, whereas in long-term storage they were more stable at - 80 ºC than at – 20 ºC.

Stability studies of Hollow Microspheres at Refrigerated, Normal and Accelerated Conditions

2021 ◽  
pp. 5351-5354
Author(s):  
Surbhi Rohilla ◽  
Dinesh Chandra Bhatt
Keyword(s):  
Drug Release ◽  
Chemical Structure ◽  
Room Temperature ◽  
Hollow Microsphere ◽  
Hollow Microspheres ◽  
Ftir Analysis ◽  
Stability Studies ◽  
Drug Content ◽  
Pharmaceutical Properties ◽  
The Stability

In the present investigation an attempt was made to focus on the stability aspects of itraconazole hollow microsphere at refrigerated condition, room temperature and at accelerated condition. In stability studies, more emphasis given on the effect of different temperature conditions on appearance, % drug content, % buoyancy and % drug release of formulation over a period of 6 months. Apart from above studies, SEM and FTIR analysis was done to determine any change in morphology or chemical structure. The results showed non-significant changes in pharmaceutical properties. From result findings, it can be concluded that the itraconazole hollow microspheres are stable formulation to sustain the drug in upper GIT for prolonged period of time.

scholarly journals Peptidoglycan Cross-Linking Activity of L,D-Transpeptidases from Clostridium difficile and Inactivation of These Enzymes by β-Lactams

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Laetitia Sütterlin ◽  
Zainab Edoo ◽  
Jean-Emmanuel Hugonnet ◽  
Jean-Luc Mainardi ◽  
Michel Arthur
Keyword(s):  
Mass Spectrometry ◽  
Clostridium Difficile ◽  
Cross Linking ◽  
Content Type ◽  
Catalytic Activities ◽  
Cross Links ◽  
Covalent Adducts ◽  
The Stability ◽  
Hydrolysis Of ◽  
Insight Into

ABSTRACT In most bacteria, the essential targets of β-lactam antibiotics are the d , d -transpeptidases that catalyze the last step of peptidoglycan polymerization by forming 4→3 cross-links. The peptidoglycan of Clostridium difficile is unusual since it mainly contains 3→3 cross-links generated by l , d -transpeptidases. To gain insight into the characteristics of C. difficile peptidoglycan cross-linking enzymes, we purified the three putative C. difficile l , d -transpeptidase paralogues Ldt Cd1 , Ldt Cd2 , and Ldt Cd3 , which were previously identified by sequence analysis. The catalytic activities of the three proteins were assayed with a disaccharide-tetrapeptide purified from the C. difficile cell wall. Ldt Cd2 and Ldt Cd3 catalyzed the formation of 3→3 cross-links ( l , d -transpeptidase activity), the hydrolysis of the C-terminal d -Ala residue of the disaccharide-tetrapeptide substrate ( l , d -carboxypeptidase activity), and the exchange of the C-terminal d -Ala for d -Met. Ldt Cd1 displayed only l , d -carboxypeptidase activity. Mass spectrometry analyses indicated that Ldt Cd1 and Ldt Cd2 were acylated by β-lactams belonging to the carbapenem (imipenem, meropenem, and ertapenem), cephalosporin (ceftriaxone), and penicillin (ampicillin) classes. Acylation of Ldt Cd3 by these β-lactams was not detected. The acylation efficacy of Ldt Cd1 and Ldt Cd2 was higher for the carbapenems (480 to 6,600 M −1 s −1 ) than for ampicillin and ceftriaxone (3.9 to 82 M −1 s −1 ). In contrast, the efficacy of the hydrolysis of β-lactams by Ldt Cd1 and Ldt Cd2 was higher for ampicillin and ceftriaxone than for imipenem. These observations indicate that Ldt Cd1 and Ldt Cd2 are inactivated only by β-lactams of the carbapenem class due to a combination of rapid acylation and the stability of the resulting covalent adducts.

scholarly journals Stability of the Combination of Ceftazidime and Cephazolin in Icodextrin or PH Neutral Peritoneal Dialysis Solution

2014 ◽  
Vol 34 (2) ◽  
pp. 212-218 ◽  
Author(s):  
Rahul P. Patel ◽  
Madhur D. Shastri ◽  
Mohammad Bakkari ◽  
Troy Wanandy ◽  
Matthew D. Jose
Keyword(s):  
Peritoneal Dialysis ◽  
Body Temperature ◽  
High Performance ◽  
Room Temperature ◽  
Storage Conditions ◽  
Initial Concentration ◽  
Dialysis Solution ◽  
Different Temperatures ◽  
Colour Changes ◽  
The Stability

IntroductionThe objective of this study was to investigate the stability of ceftazidime and cephazolin in a 7.5% icodextrin or pH neutral peritoneal dialysis (PD) solution.MethodsCeftazidime and cephazolin were injected into either a 7.5% icodextrin or pH neutral PD bag to obtain the concentration of 125 mg/L of each antibiotic. A total of nine 7.5% icodextrin or pH neutral PD bags containing ceftazidime and cephazolin were prepared and stored at 1 of 3 different temperatures: 4°C in a domestic refrigerator; 25°C at room temperature; or 37°C (body temperature) in an incubator. An aliquot was withdrawn immediately before (0 hour) or after 12, 24, 48, 96, 120, 144, 168 and 336 hours of storage. Each sample was analyzed in duplicate for the concentration of ceftazidime and cephazolin using a stability-indicating high-performance liquid chromatography technique. Ceftazidime and cephazolin were considered stable if they retained more than 90% of their initial concentration. Samples were also assessed for pH, colour changes and evidence of precipitation immediately after preparation and on each day of analysis.ResultsCeftazidime and cephazolin in both types of PD solution retained more than 90% of their initial concentration for 168 and 336 hours respectively when stored at 4°C. Both of the antibiotics lost more than 10% of the initial concentration after 24 hours of storage at 25 or 37°C. There was no evidence of precipitation at any time under the tested storage conditions. Change in the pH and color was observed at 25 and 37°C, but not at 4°C.ConclusionPremixed ceftazidime and cephazolin in a 7.5% icodextrin or pH neutral PD solution is stable for at least 168 hours when refrigerated. This allows the preparation of PD bags in advance, avoiding the necessity for daily preparation. Both the antibiotics are stable for at least 24 hours at 25 and 37°C, permitting storage at room temperature and pre-warming of PD bags to body temperature prior to its administration.

Stability of Tacrolimus Injection in Total Parenteral Nutrition Solution

1996 ◽  
Vol 12 (2) ◽  
pp. 58-61
Author(s):  
Yi-Min Ku ◽  
David I Min ◽  
Vijay Kumar ◽  
Saleem A Noormohamed
Keyword(s):  
Amino Acids ◽  
Parenteral Nutrition ◽  
Continuous Infusion ◽  
Total Parenteral Nutrition ◽  
Room Temperature ◽  
Color Change ◽  
Storage Conditions ◽  
Black Background ◽  
Lighting Conditions ◽  
The Stability

Objective: To examine the stability of tacrolimus in a total parenteral nutrition (TPN) solution over 24 hours at room temperature. Study Method: Admixtures of tacrolimus 0.1 mg/mL in TPN, containing amino acids 4.25%, dextrose 25%, and electrolytes, were prepared and visually inspected under normal lighting conditions against a white and black background for color change, turbidity, cloudiness, and precipitation. The concentration of tacrolimus in the admixtures was determined by HPLC at 0, 1, 2, 4, 8, 12, and 24 hours after preparation. Results: The concentration of tacrolimus did not change over the 24-hour study period. No color change, precipitation, or cloudiness was observed in any of the solutions under the storage conditions. Conclusions: Tacrolimus is chemically stable in TPN for 24 hours at room temperature, and therefore can be administered to patients as a 24-hour continuous infusion with TPN.

Stability of Ondansetron Stored in Polypropylene Syringes

1994 ◽  
Vol 28 (6) ◽  
pp. 712-714 ◽  
Author(s):  
Daniel T. Casto
Keyword(s):  
Room Temperature ◽  
Storage Condition ◽  
Storage Conditions ◽  
Observation Time ◽  
Time Range ◽  
Ondansetron Hydrochloride ◽  
Drug Loss ◽  
Clinically Significant ◽  
The Stability ◽  
Sampling Times

OBJECTIVE: To evaluate the stability of ondansetron hydrochloride undiluted and mixed in dextrose 5% injection or NaCl 0.9% injection during storage in polypropylene syringes when frozen, refrigerated, or at room temperature. DESIGN: Batch quantities of ondansetron 0.25, 0.5, 1.0, and 2.0 mg/mL were prepared and individual doses of 10.5 mg were drawn into polypropylene syringes that were stored at −20 °C for up to 3 months, at 4 °C for up to two weeks, or at 22–25 °C for two days, and various combinations of these conditions. At defined sampling times aliquots were withdrawn from syringes, the solution visually inspected, pH measured, and ondansetron concentration determined by HPLC. Drug loss of ≥10 percent of the original content of the solution was considered clinically significant. RESULTS: The ondansetron concentration in each solution, regardless of storage conditions, remained above 90 percent of the original concentration at each observation time (range 92–107 percent). No changes in color or clarity of any of the solutions were observed, and only slight fluctuations in pH (≤0.05) were noted. CONCLUSIONS: Ondansetron 2 mg/mL undiluted, or at concentrations of 0.25, 0.5, or 1 mg/mL, mixed in dextrose 5% injection or NaCl 0.9% injection was determined to be stable when stored in polypropylene syringes for each storage condition at all time points studied, including the maximum for each: three months at −20 °C, followed by 14 days at 4 °C, and by 48 hours at 22–25 °C.

scholarly journals Investigation of quality indicators and studying the stability of “Propolis-AK” gel for the treatment of acne disease

2019 ◽  
pp. 64-75
Author(s):  
А. I. Tykhonov ◽  
T. G. Yarnykh ◽  
S. G. Bobro ◽  
O. S. Shpychak
Keyword(s):  
Quality Control ◽  
Shelf Life ◽  
Quality Indicators ◽  
Room Temperature ◽  
Storage Period ◽  
Storage Conditions ◽  
Social Adaptation ◽  
Control Methods ◽  
Aluminum Tubes ◽  
The Stability

In modern conditions, the incidence of acne, which is a polymorphic multifactorial disease of the sebaceous glands of the skin, has a tendency to significant growth. Localization of lesions on the face in almost all patients indicates the fact that acne has an effect on their psycho-emotional sphere and social adaptation, which makes this problem urgent and indicates the feasibility of creating new effective domestic medicines for treating this pathology. The aim of the work was to conduct research on the investigation of quality indicators and studying the stability of «Propolis-AK» gel of anti-inflammatory and antimicrobial action for the treatment of acne disease. The objects of research were model test-samples of «Propolis-AK» gel, for which were developed methodic for analyzing the qualitative composition and quantitative content of the active substances – propolis phenolic hydrophobic drug (PPHD) and azelaic acid (AA) in this dosage form, comprehensively allowing to evaluate the quality and criteria for the stability of the gel during the entire storage period for the following indicators: description, identification, homogeneity, tightness of the container, pH, package contents, microbiological purity, quantification. In addition, the requirements for packaging, labeling, transportation, storage conditions and shelf life were included in the draft of quality control methods. According to the results of the study of organoleptic and physical-chemical parameters of the developed «Propolis-AK» gel during storage at two temperature conditions (8‒15 °C and 15‒25 °C), it was found that the test samples of the gel under study remained fairly stable according to the studied indicators for 2 years and 3 months, which allows us to recommend a shelf life of 2 years at room temperature in aluminum tubes for the studied gel. According to the results of research, a specification for «Propolis-AK» gel for external use was developed as a component of the draft of quality control methods for the studied medicine. Studies have been conducted to establish the main indicators and methods of quality control of the developed «Propolis-AK» gel for the treatment of acne disease. According to the results of the tests, a “Specification” was developed, which was included in the draft of quality control methods and experimentally proved the stability of «Propolis-AK» gel prepared in pharmaceutical and industrial conditions for a prescribed shelf life of 24 months when stored in aluminum tubes with an internal lacquer coating in a cool place (8‒15 °C) and at room temperature (15‒25 °C).

Stability of Grape Seed Oil and its Antioxidant Tocotrienols

2014 ◽  
Vol 1030-1032 ◽  
pp. 370-373 ◽  
Author(s):  
Jaromír Lachman ◽  
Alena Hejtmánková ◽  
Zora Kotíková ◽  
Martin Dědina ◽  
Radomíra Střalková ◽  
...  
Keyword(s):  
Peroxide Value ◽  
Room Temperature ◽  
Seed Oil ◽  
Grape Seed ◽  
Storage Conditions ◽  
Oxidation Products ◽  
Light Conditions ◽  
Grape Seed Oil ◽  
The Stability ◽  
Primary Oxidation

For the experiment three different storage conditions were chosen: storage at room temperature of 22 °C in the light and in the dark and in the dark in a refrigerator at 4 °C. Parameters monitored were: peroxide value and changes in the content of α-, γ-and δ-tocotrienols and α - and γ-tocopherols during storage for 210 days (30 weeks). The peroxide value is an indicator of the content of primary oxidation products of oils. From analytical analyses results that the greatest destruction of grape oil occurs during storage at room temperature and access of light, where a peroxide value increased up to 484 meq. O2/kg oil). The least intrusive method of storage was in terms of temperature refrigerator (4 °C) in the dark, when during 30 days of storage peroxide value had risen only to 71.9 meq. O2/kg oil. Between these values ​​were values stored at room temperature in the dark (after 30 weeks storage 196 meq. O2/kg oil). From these parameters is clearly showed that to the stability of oil contribute significantly both factors - temperature and light conditions. The same trend was also found in tocotrienols. At room temperature and access of light was complete decomposition of α-tocotrienol in the 9th week of storage, γ-tocotrienol at 30 weeks of storage and δ-tocotrienol in the 18th week of storage. The most stable seems γ-tocotrienol > δ-tocotrienol > α-tocotrienol. When stored in the refrigerator in the dark, there was practically no decomposition of α-, γ-and δ-tocotrienols whose contents remained completely unchanged.

scholarly journals Stability and Reproducibility of a Single-Sample Urinary C-Peptide/Creatinine Ratio and Its Correlation with 24-h Urinary C-Peptide

2009 ◽  
Vol 55 (11) ◽  
pp. 2035-2039 ◽  
Author(s):  
Tim J McDonald ◽  
Bridget A Knight ◽  
Beverley M Shields ◽  
Pamela Bowman ◽  
Maurice B Salzmann ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Room Temperature ◽  
Storage Conditions ◽  
Urine Samples ◽  
Creatinine Ratio ◽  
Creatinine Concentration ◽  
C Peptide ◽  
Endogenous Insulin ◽  
Highly Correlated ◽  
The Stability

Abstract Introduction: C-peptide measurement in blood or 24-h urine samples provides useful information regarding endogenous insulin secretion, but problems related to the rapid degradation of C-peptide in blood and difficulty of 24-h urine collection have limited widespread routine clinical use of this test. We assessed the feasibility of measuring urinary C-peptide (UCP) with correction for creatinine concentration in single urine samples. Methods: We analyzed UCP using a routine electrochemiluminescence immunoassay in samples from 21 healthy volunteers. We investigated the stability of UCP with different preservatives and storage conditions and compared the reproducibility of urinary C-peptide/creatinine ratio (UCPCR) in first- and second-void fasting urines, then assessed correlations with 24-h collections. Results: UCPCR was unchanged at room temperature for 24 h and at 4 °C for 72 h even in the absence of preservative. UCPCR collected in boric acid was stable at room temperature for 72 h. UCPCR remained stable after 7 freeze-thaw cycles but decreased with freezer storage time and dropped to 82%–84% of baseline by 90 days at −20 °C. Second-void fasting UCPCRs were lower than first-void (median 0.78 vs 1.31, P = 0.0003) and showed less variation (CV 33% vs 52%), as second-void UCPCRs were not influenced by evening food-related insulin secretion. Second-void fasting UCPCR was highly correlated with 24-h UCP (r = 0.8, P = 0.00006). Conclusions: Second-void fasting UCPCR is a reproducible measure that correlates well with 24-h UCP in normal samples. The 3-day stability of UCPCR at room temperature greatly increases its potential clinical utility.

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