Graphene in the Form of Liquid Suspension by Shear Exfoliation of Liquids: Stability Study of Gasoline, Diesel, Kerosene and Water Based Nanofluids Containing Graphene Nanolayers

Author(s):  
Udawattha DS ◽  
Kasthurige SE ◽  
Mahinsasa Narayana
2019 ◽  
Vol 55 (5) ◽  
pp. 314-322
Author(s):  
Oriana Boscolo ◽  
Francesco Perra ◽  
Leandro Salvo ◽  
Fabián Buontempo ◽  
Silvia Lucangioli

Objectives: To develop and to study the physicochemical and microbiological stability of omeprazole liquid oral formulations used as therapeutic agent in many acid-related disorders, for pediatric use. Furthermore, to optimize and validate a stability-indicating high-performance liquid chromatography (HPLC) method for the analysis of omeprazole in the studied formulations. Method: Oral liquid suspensions of omeprazole were prepared at 2 mg/mL using crushed omeprazole pellets (formulation A) and pure omeprazole (formulation B) with a complete vehicle including humectant, suspending, sweetening, antioxidant, and flavoring agents. Samples were stored at 4°C and 25°C. Omeprazole content of each formulation was analyzed in triplicate using micro-HPLC at 0, 3, 7, 14, 30, 60, 90, 120, and 150 days. Other parameters were also determined, such as appearance, pH, resuspendibility, and viscosity. Microbiological studies were conducted according to the United Stated Pharmacopeia (USP) guidelines for non-sterile products. Results: Formulation A stayed physicochemical and microbiologically stable at refrigerated (4°C) conditions during at least 150 days and it only stayed stable during 14 days at 25°C. Formulation B was stayed physicochemical and microbiologically stable at refrigerated (4°C) conditions at least 90 days, but it is not recommended to store at 25°C for more than 1 day. Conclusions: Formulation A and formulation B can be stored for at least 150 and 90 days, respectively, at refrigerated conditions. Formulation A can be stored at room temperature for 14 days. Both formulations are perfectly suitable for pediatric patients who are usually notable to swallow solid oral formulations. The proposed analytical method was suitable for the study of stability of different formulations.


2014 ◽  
Vol 21 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Ilze Barene ◽  
Irena Daberte ◽  
Sanita Siksna

The aim of the study. The objective of this study was to investigate microscopic, physical and chemical properties of bee bread collected in three regions of Latvia in order to compare the quality and to investigate the possibility of producing granules containing bee bread. Material and methods. Microscopic analysis of bee bread samples was performed. Plant herbaria, special literature and internet sources were used for identification of pollen. Thin layer chromatography was used for identification of carotenoids and flavonoids. Granules were prepared by wet granulation method. Lactose, calcium lactate, calcium carbonate, potato starch and purified water were used as excipients. Appearance, loss on drying, pH of aqueous solution and content of carotenes were estimated. Results. Microscopic analysis showed mostly native pollen identified as willow pollen. Beta-carotene identified and 2 carotenoids found by thin layer chromatography. Two zones of flavonoids found on chromatograms at day light and 6 zones at ultra violet light. The comparison of bee bread samples of 3 regions of Latvia showed insignificant differences in appearance and consistency, hydrogen ion concentration 3.93–4.23, loss on drying 7.72–11.07 %; content of carotenes calculated to bcarotene 6.77–9.35 mg%. Stability study of bee bread samples showed greater changes after storage at 40ºC temperature. All compositions of granules showed appropriate appearance and flowability. Quality of granules: loss on drying 5.48–13.5%, content of carotenes calculated to b-carotene 5.77–6.75 mg%. Conclusions. Pollen of willow can be considered as an indicator of the origin of bee bread in Latvia. Bee bread samples of three regions of Latvia have insignificant differences in physical, chemical parameters.


Author(s):  
N.P. Kopylov ◽  
◽  
D.V. Fedotkin ◽  
A.V. Karpov ◽  
E.Yu. Sushkina ◽  
...  
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