On The Replacement of Traditional Stabilizers by Guaiacol in Environmentally Safe Nitrocellulose-based Propellants

2021 ◽  
Author(s):  
Rodrigo L. B. Rodrigues ◽  
Ana Paula da Silva ◽  
Rogério Rosato ◽  
Maurício F. Lemos ◽  
Fernando C. Peixoto ◽  
...  
Keyword(s):  
High Performance ◽  
Ad Hoc ◽  
Hplc Method ◽  
Artificial Ageing ◽  
Scanning Calorimetry ◽  
Vacuum Stability ◽  
Evolved Gas ◽  
Limit Value ◽  
Environmentally Safe ◽  
Lower Heat

Abstract In this work we investigated the possibility of substituting diphenylamine (DPA) by the natural product guaiacol, as a stabilizer for nitrocellulose (NC)-based propellants. Stability evaluation, using heat-flux calorimetry (HFC), revealed lower heat flows associated with our guaiacol-stabilized propellant samples when compared to those of propellants stabilized with the traditional stabilizers. Also, pressure-vacuum stability tests (PVST) showed that our propellant exhibited lower evolved gas volumes. Traditional tests, such as the German Test, and the Bergmann-Junk Test, scored a NO volume, after titration, of 0.87 ml (below the limit-value for acceptance, which is 2.0 ml), and the Storage Test, showed that our samples are stable and do not degrade for more than 3 days when submitted to a constant temperature of 100°C. The homogeneity, stability and compatibility of our samples were evaluated through scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and isothermal thermogravimetry (TG). Ballistic parameters were estimated using a closed vessel along with ad hoc codes, for comparison purposes. Finally, a high-performance liquid chromatography (HPLC) method developed before allowed inferring the stabilizer consumption after artificial ageing of samples. Such method also showed that the material met the correspondent stability criteria (AOP-48). In short, our results clearly indicate that guaiacol is an effective and efficient substitute for DPA as a propellant stabilizer for single base nitrocellulose-based propellants, making them more environmentally friendly.

scholarly journals Transition Metal Complexes of Naproxen: Synthesis, Characterization, Forced Degradation Studies, and Analytical Method Verification

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Md. Sharif Hasan ◽  
Ruhul Kayesh ◽  
Farida Begum ◽  
S. M. Abdur Rahman
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
High Performance ◽  
Parent Drug ◽  
Reversed Phase ◽  
Hplc Method ◽  
Forced Degradation ◽  
Solution Stability ◽  
Scanning Calorimetry

The aim of our current research was to synthesize some transition metal complexes of Naproxen, determine their physical properties, and examine their relative stability under various conditions. Characterizations of these complexes were done by 1H-NMR, Differential Scanning Calorimetry (DSC), FT-IR, HPLC, and scanning electron microscope (SEM). Complexes were subjected to acidic, basic, and aqueous hydrolysis as well as oxidation, reduction, and thermal degradation. Also the reversed phase high-performance liquid chromatography (RP-HPLC) method of Naproxen outlined in USP was verified for the Naproxen-metal complexes, with respect to accuracy, precision, solution stability, robustness, and system suitability. The melting points of the complexes were higher than that of the parent drug molecule suggesting their thermal stability. In forced degradation study, complexes were found more stable than the Naproxen itself in all conditions: acidic, basic, oxidation, and reduction media. All the HPLC verification parameters were found within the acceptable value. Therefore, it can be concluded from the study that the metal complexes of Naproxen can be more stable drug entity and offer better efficacy and longer shelf life than the parent Naproxen.

scholarly journals Preparation, Stabilization and Carbonization of a Novel Polyacrylonitrile-Based Carbon Fiber Precursor

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1150 ◽  
Author(s):  
Huichao Liu ◽  
Shuo Zhang ◽  
Jinglong Yang ◽  
Muwei Ji ◽  
Jiali Yu ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Carbon Fibers ◽  
High Performance ◽  
Great Influence ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Electrospinning Method ◽  
Lower Heat ◽  
Group 2

The quality of polyacrylonitrile (PAN) precursor has a great influence on the properties of the resultant carbon fibers. In this paper, a novel comonomer containing the sulfonic group, 2-acrtlamido-2-methylpropane acid (AMPS), was introduced to prepare P(AN-co-AMPS) copolymers using itaconic acid (IA) as the control. The nanofibers of PAN, P(AN-co-IA), and P(AN-co-AMPS) were prepared using the electrospinning method. The effect of AMPS comonomer on the carbon nanofibers was studied using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Raman spectrum. The structural evolutions of PAN-based nanofibers were quantitatively tracked by FTIR and XRD during the thermal oxidative stabilization (TOS) process. The results suggested that P(AN-co-AMPS) nanofibers had the lower heat release rate (ΔH/ΔT = 26.9 J g−1 °C−1), the less activation energy of cyclization (Ea1 = 26.6 kcal/mol and Ea2 = 27.5 kcal/mol), and the higher extent of stabilization (Es and SI) during TOS process, which demonstrated that the AMPS comonomer improved the efficiency of the TOS process. The P(AN-co-AMPS) nanofibers had the better thermal stable structures. Moreover, the carbon nanofibers derived from P(AN-co-AMPS) precursor nanofibers had the better graphite-like structures (XG = 46.889). Therefore, the AMPS is a promising candidate comonomer to produce high performance carbon fibers.

scholarly journals Compatibility Study of 1,1-Diamino-2,2-Dinitroethene (FOX-7) with Some Energetic Materials

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yuan-ping Zhang ◽  
Cong-hua Hou ◽  
Xin-lei Jia ◽  
Ying-xin Tan ◽  
Jing-yu Wang
Keyword(s):  
Energetic Materials ◽  
High Performance ◽  
Binary Systems ◽  
Compatibility Study ◽  
Scanning Calorimetry ◽  
Vacuum Stability ◽  
Dsc Measurements ◽  
Vacuum Stability Test ◽  
Low Sensitivity ◽  
Thermal Technique

1,1-diamino-2,2-dinitroethene (FOX-7) is a novel explosive with low sensitivity and high performance. The compatibility of FOX-7 with nine common energetic materials including hexanitrohexazaisowurtzitane (CL-20), cyclotetramethylenetetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), 3,4-dinitrofurazanfuroxan (DNTF), 3-nitro-1,2,4-triazol-5-one (NTO), hexanitrostilbene (HNS-II), 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), 2,4,6-triamino-1,3,5-trinitrobenzene (TATB), and 2,4,6-trinitrotoluene (TNT) were tested by differential scanning calorimetry (DSC) and the vacuum stability test (VST) as the thermal technique and X-ray diffractometry (XRD) as a nonthermal technique. DSC measurements showed that the binary systems of FOX-7/CL-20, FOX-7/HMX, FOX-7/NTO, and FOX-7/TNT were compatible in grade of A, the systems of FOX-7 with heat-resistant explosives including HNS-II, LLM-105, and TATB were compatible as well in grade of A-B, and the binary systems of FOX-7/DNTF and FOX-7/RDX had poor compatibility. VST results indicated that FOX-7 was compatible with nine energetic materials. Besides, the compatibility results of the thermal analysis were confirmed by the XRD technique.

scholarly journals Thermal and Isothermal Methods in Development of Sustained Release Dosage Forms of Ketorolac Tromethamine

2008 ◽  
Vol 5 (2) ◽  
pp. 316-322 ◽  
Author(s):  
Dimple Chopra ◽  
Vivek Ranjan Sinha ◽  
Manjeet Singh
Keyword(s):  
Sustained Release ◽  
High Performance ◽  
Hplc Method ◽  
Matrix Tablets ◽  
Oral Dosage ◽  
Ketorolac Tromethamine ◽  
Scanning Calorimetry ◽  
Drug Content ◽  
Ich Guidelines ◽  
Preformulation Studies

Differential scanning calorimetry (DSC) is a rapid and convenient and conclusive method of screening drug-polymer blend during preformulation studies as it allows polymer incompatibility to be established instantaneously. Various batches of matrix tablets of ketorolac tromethamine (KTM) with a series of compatible polymers were prepared. Batches of tablets which gave desired sustained release profile were subjected to stability testing according to ICH guidelines. The analysis for drug content was done using high performance liquid chromatography (HPLC) method. The results revealed that there was no statistically significant change in drug content after storage of matrix tablets at elevated temperature of 40°C and 75% relative humidity. From our study we conclude that with careful selection of different polymers and their combinations, a stable sustained release oral dosage form of ketorolac tromethamine can be achieved.

scholarly journals DEVELOPMENT OF SUSTAINED RELEASE ALOGLIPTIN TABLETS USING A MULTIPARTICULATES SYSTEM MADE OF BENTONITE

2021 ◽  
pp. 68-73
Author(s):  
RASHAD M. KAOUD ◽  
ALHAMZA HOSHI KHALAF ◽  
JAMAL ALYOUSSEF ALKRAD
Keyword(s):  
Sustained Release ◽  
High Performance ◽  
Hydroxypropyl Methylcellulose ◽  
Hplc Method ◽  
Fickian Diffusion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Xrd Pattern ◽  
Sustained Release Tablets ◽  
Release Data

Objective: This study was designed to evaluate the use of bentonite in the formulation of sustained-release tablets containing alogliptin benzoate after granulation. Methods: Bentonite was used for preparing tablets after granulation. The prepared tablets were tested for their pharmacopeial requirements. Further, a high-performance liquid chromatography (HPLC) method was developed to assess the release pattern of alogliptin from the tablets. Besides, differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (XRD) were used for evaluating the compatibility the drugs and bentonite. Finally, the release from the tablets was tested using the paddle apparatus. Results: The FTIR and DSC did not show any interaction between the drug and the excipient in contrast to the powder-XRD pattern, which showed a shift for montmorillonite crystal peak. This shift was interpreted by increasing in the spacing of the crystalline structure of montmorillonite. However, the results of pharmacopeial tests showed that the prepared tablets comply with the compendial requirements, In addition, the release profiles of these tablets with aid of hydroxypropyl methylcellulose (HPMC) as a binder revealed a sustained release of alogliptin. Furthermore, the fitting of release data showed that the release from these tablets followed Fickian diffusion that alogliptin released by diffusion from bentonite gel matrix. Conclusion: Bentonite was successfully used for producing sustained-release tablets of alogliptin. However, maintaining the crystal structure of montmorillonite was essential for building the gel structure of bentonite and releasing the drug in a controlled manner.

Evaluation of Gloriosa superba for Yield Attributing Characters and Quantification of Colchicine Originated from Different Agro Climatic Zones of Tamil Nadu and Andhra Pradesh

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Arun Kumar P. ◽  
Elangaimannan R.
Keyword(s):  
Seed Yield ◽  
Tamil Nadu ◽  
High Performance ◽  
Andhra Pradesh ◽  
Crop Improvement ◽  
Mean Value ◽  
Hplc Method ◽  
Gloriosa Superba ◽  
Climatic Zones ◽  
Colchicine Alkaloid

The study was conducted to evolve Gloriosa superba for yield characters and alkalodi content for selecting elite genotypes for comercial exploitatio n. The genotypes were sowm in Variyankaval village, Udayarpalayam taluk of Ariyalur district, Tamil Nadu. The highest mean value for fresh and dry seed yield was observed in Chittor local. The genotype Mulanur local has recorded the highest mean value for number of pods per plant and number of seeds per pod and Arupukotai local excelled the general mean for the traits seeds per pod, fresh and dry seed yield and also for tuber characters. An investigation was carried out to quantify the colchicine (alkaloid) present in tubers by High Performance Liquid Chromatography (HPLC) method. The genotypes collected from Arupukotai recorded the highest colchicine content (0.760 mg/g) followed by Chittoor (0.578 mg/g) and Mulanur (0.496 mg/g) and there by these three genotypes were utilized for further crop improvement.

Developing a High-performance Liquid Chromatography Method for Simultaneous Determination of Loratadine and its Metabolite Desloratadine in Human Plasma

2020 ◽  
Vol 20 (13) ◽  
pp. 1053-1059
Author(s):  
Mahmoud M. Sebaiy ◽  
Noha I. Ziedan
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Human Plasma ◽  
High Performance ◽  
Allergic Diseases ◽  
Reversed Phase ◽  
Hplc Method ◽  
H1 Receptor ◽  
Chromatography Method

Background: Allergic diseases are considered as the major burden on public health with increased prevalence globally. Histamine H1-receptor antagonists are the foremost commonly used drugs in the treatment of allergic disorders. The target drug in this study, loratadine, belongs to this class of drugs and its biometabolite desloratadine which is also a non-sedating H1 receptor antagonist with anti-histaminic activity being 2.5 to 4 times greater than loratadine. This study aimed to develop and validate a novel isocratic Reversed-phase High-Performance Liquid Chromatography (RP-HPLC) method for rapid and simultaneous separation and determination of loratadine and its metabolite, desloratadine in human plasma. Methods: The drug extraction method from plasma was based on protein precipitation technique. The separation was carried out on a Thermo Scientific BDS Hypersil C18 column (5μm, 250 x 4.60 mm) in a mobile phase of MeOH: 0.025M KH2PO4 adjusted to pH 3.50 using orthophosphoric acid (85: 15, v/v) at an ambient temperature. The flow rate was maintained at 1 mL/min and maximum absorption was measured using the PDA detector at 248 nm. Results: The retention times of loratadine and desloratadine in plasma samples were recorded to be 4.10 and 5.08 minutes, respectively, indicating a short analysis time. Limits of detection were found to be 1.80 and 1.97 ng/mL for loratadine and desloratadine, respectively, showing a high degree of sensitivity of the method. The method was then validated according to FDA guidelines for the determination of the two analytes in human plasma. Conclusion: The results obtained indicate that the proposed method is rapid, sensitive in the nanogram range, accurate, selective, robust and reproducible compared to other reported methods.

Determination of Selected Phthalates in Some Commercial Cosmetic Products by HPLC-UV

2020 ◽  
Vol 23 (10) ◽  
pp. 1010-1022
Author(s):  
Emrah Dural
Keyword(s):  
High Performance ◽  
Phthalate Esters ◽  
High Sensitivity ◽  
Hplc Method ◽  
Cosmetic Products ◽  
Limit Of Quantification ◽  
Nail Polish ◽  
Accuracy And Precision ◽  
Butyl Phthalate

Aim and scope: Due to the serious toxicological risks and their widespread use, quantitative determination of phthalates in cosmetic products have importance for public health. The aim of this study was to develop a validated simple, rapid and reliable high-performance liquid chromatography (HPLC) method for the determination of phthalates which are; dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), di(2- ethylhexyl) phthalate (DEHP), in cosmetic products and to investigate these phthalate (PHT) levels in 48 cosmetic products marketing in Sivas, Turkey. Materials and Methods: Separation was achieved by a reverse-phase ACE-5 C18 column (4.6 x 250 mm, 5.0 μm). As the mobile phase, 5 mM KH2PO4 and acetonitrile were used gradiently at 1.5 ml min-1. All PHT esters were detected at 230 nm and the run time was taking 21 minutes. Results: This method showed the high sensitivity value the limit of quantification (LOQ) values for which are below 0.64 μg mL-1 of all phthalates. Method linearity was ≥0.999 (r2). Accuracy and precision values of all phthalates were calculated between (-6.5) and 6.6 (RE%) and ≤6.2 (RSD%), respectively. Average recovery was between 94.8% and 99.6%. Forty-eight samples used for both babies and adults were successfully analyzed by the developed method. Results have shown that, DMP (340.7 μg mL-1 ±323.7), DEP (1852.1 μg mL-1 ± 2192.0), and DBP (691.3 μg mL-1 ± 1378.5) were used highly in nail polish, fragrance and cream products, respectively. Conclusion: Phthalate esters, which are mostly detected in the content of fragrance, cream and nail polish products and our research in general, are DEP (1852.1 μg mL-1 ± 2192.0), DBP (691.3 μg mL-1 ± 1378.5) and DMP (340.7 μg mL-1 ±323.7), respectively. Phthalates were found in the content of all 48 cosmetic products examined, and the most detected phthalates in general average were DEP (581.7 μg mL-1 + 1405.2) with a rate of 79.2%. The unexpectedly high phthalate content in the examined cosmetic products revealed a great risk of these products on human health. The developed method is a simple, sensitive, reliable and economical alternative for the determination of phthalates in the content of cosmetic products, it can be used to identify phthalate esters in different products after some modifications.

Development and Validation of a Novel Reversed Phase High Performance Liquid Chromatography with Refractive Index Detector Method for Assay of Polyvinyl Alcohol in an Ophthalmic Solution

2020 ◽  
Vol 16 (7) ◽  
pp. 867-871
Author(s):  
Harun Ergen ◽  
Muge Guleli ◽  
Cigdem Sener ◽  
Cem Caliskan ◽  
Sercan Semiz ◽  
...  
Keyword(s):  
Refractive Index ◽  
Liquid Chromatography ◽  
Polyvinyl Alcohol ◽  
High Performance ◽  
Ophthalmic Solution ◽  
Reversed Phase ◽  
Hplc Method ◽  
Solution Stability ◽  
Technical Requirements ◽  
Refractive Index Detector

Introduction: Polyvinyl alcohol (PVA), a polymer, is in demand due to its usage in different applications such as pharmaceutical, biomedical and textile, paper, food industries. Methods: A new sensitive reversed phased high-pressure liquid chromatography (RP-HPLC) method with refractive index detector (RID) was developed for determination of PVA in an ophthalmic solution containing dexpanthenol and PVA as active substances and it was validated according to The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guideline. Results: Chromatographic separation was achieved on a Chiral-AGP (150 mm × 4.0 mm, 5 μm) column kept at 30°C with an isocratic flow at a flow rate of 1.0 ml/min. The detector temperature was 30°C, the retention time of PVA was around 1.0 min and the total run time was 5 minutes. Conclusion: The proposed method showed linearity, accuracy, precision, specificity, robustness, solution stability, and system suitability results within the acceptance criteria.

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