Preparation and Characterization of Freeze-dried Liposomes Loaded with Amphotericin B

2019 ◽  
Vol 14 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Tran Thi Hai Yen ◽  
Le Nho Dan ◽  
Le Hoang Duc ◽  
Bui Thanh Tung ◽  
Pham Thi Minh Hue
Keyword(s):  
Amphotericin B ◽  
Freeze Drying ◽  
Entrapment Efficiency ◽  
Freezing Process ◽  
Scanning Calorimetry ◽  
Citrate Buffer ◽  
Lipid Film ◽  
Freeze Dried ◽  
Liposomal Suspension

Background: Amphotericin B (AmB) is a drug of choice in the therapy of systemic fungal infection because of its board-spectrum antifungal activity. However, its conventional formulation has many side effects such as acute and chronic nephrotoxicity. Liposomes have been developed to reduce the drug’s toxicity. However, they had to meet strict stability criteria. In general, liposomes can be freeze-dried to inhibit liposomes infusion, phospholipids degradation during storage. Liposomal size usually increases after freeze-drying because of being influenced by many factors in freezing, lyophilizing and rehydration processes. Therefore, cryoprotectants are used to stabilize liposomal vesicles during freeze-drying process. </P><P> Objective: In the present study, we developed AmB liposomal suspension and lyophilized liposomes loaded with AmB, evaluated the effect of different cryoprotectants on the characterization of freeze-dried AmB liposomes. </P><P> Methods: In this study, AmB liposomes were prepared from hydrogenated soy phosphatidylcholine, distearoylphosphatidylglycerol and cholesterol by thin lipid film hydration method using different hydrate mediums likely: Glucose solution, citrate buffer, phosphate buffer. High-pressure homogenization and extrusion methods were used to reducing vesicles size. Dynamic light scattering was used to characterize liposomal size, and size distribution. HPLC method was used to assay drug and determine entrapment efficiency. Liposomal suspension was lyophilized with different cryoprotectants: Sucrose, mannitol, lactose, trehalose and glycerol. Differential scanning calorimetry was used to study lyophilized cake. </P><P> Results: We found that liposomal suspension with hydration medium10 mM citrate buffer pH 5.5 had a small average size (<100nm) and narrow distribution (PDI <0.2). Sucrose and trehalose stabilized vesicles size during freezing process, and lyophilized liposomes with sucrose and trehalose had an elegant appearance, yellow, compact cake. DSC study showed that sucrose and trehalose in lyophilized cake were amorphous. The cake was rehydrated within 10 seconds to form liposomal suspension, in which vesicles size was less than 140 nm. </P><P> Conclusion: We have developed successfully AmB liposomal suspension and lyophilized liposomes loaded with AmB. Sucrose and trehalose can be used as cryoprotectants in the freeze-drying and reconstitution process.

scholarly journals Preparation and physicochemical characterization of Eudragit® RL100 Nanosuspension with potential for Ocular Delivery of Sulfacetamide

2010 ◽  
Vol 13 (4) ◽  
pp. 510 ◽  
Author(s):  
Bivash Mandal ◽  
Kenneth S Alexander ◽  
Alan T Riga
Keyword(s):  
Zeta Potential ◽  
Bacterial Infections ◽  
Room Temperature ◽  
In Vitro Release ◽  
Physicochemical Characterization ◽  
Entrapment Efficiency ◽  
Scanning Calorimetry ◽  
Freeze Dried ◽  
Drug Entrapment Efficiency

Purpose: Polymeric nanosuspension was prepared from an inert polymer resin (Eudragit® RL100) with the aim of improving the availability of sulfacetamide at the intraocular level to combat bacterial infections. Methods: Nanosuspensions were prepared by the solvent displacement method using acetone and Pluronic® F108 solution. Drug to polymer ratio was selected as formulation variable. Characterization of the nanosupension was performed by measuring particle size, zeta potential, Fourier Transform infrared spectra (FTIR), Differential Scanning Calorimetry (DSC), Powder X-Ray Diffraction (PXRD), drug entrapment efficiency and in vitro release. In addition, freeze drying, redispersibility and short term stability study at room temperature and at 40C were performed. Results: Spherical, uniform particles (size below 500 nm) with positive zeta potential were obtained. No significant chemical interactions between drug and polymer were observed in the solid state characterization of the freeze dried nanosuspension (FDN). Drug entrapment efficiency of the selected batch was increased by changing the pH of the external phase and addition of polymethyl methacrylate in the formulation. The prepared nanosuspension exhibited good stability after storage at room temperature and at 40C. Sucrose and Mannitol were used as cryoprotectants and exhibited good water redispersibility of the FDN. Conclusion: The results indicate that the formulation of sulfacetamide in Eudragit® RL100 nanosuspension could be utilized as potential delivery system for treating ocular bacterial infections.

Preparation and Characterization of Chitosan-Based Scaffolds for Biomedical Applications

2006 ◽  
Vol 514-516 ◽  
pp. 1005-1009 ◽  
Author(s):  
José V. Araújo ◽  
J.A. Lopes da Silva ◽  
Margarida M. Almeida ◽  
Maria Elisabete V. Costa
Keyword(s):  
Biomedical Applications ◽  
Freeze Drying ◽  
Average Pore Size ◽  
Composite Scaffolds ◽  
Average Pore ◽  
Chitosan Matrix ◽  
Freeze Dried ◽  
Porous Chitosan ◽  
Interconnected Structure

Porous chitosan/brushite composite scaffolds were prepared by a freeze-drying technique, starting from brushite suspensions in chitosan solutions. The obtained scaffolds showed a regular macroporous and interconnected structure with brushite particles uniformly distributed in the chitosan matrix. The variation of the brushite concentration affected the microstructure of the final freeze-dried scaffold, in particular, its porosity and its average pore size. The yield strengths of the composite scaffolds could also be improved by the increase of the brushite content.

scholarly journals Preparation of Co-Amorphous Systems by Freeze-Drying

Pharmaceutics ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 941
Author(s):  
Melvin Wostry ◽  
Hanna Plappert ◽  
Holger Grohganz
Keyword(s):  
Amino Acid ◽  
Freeze Drying ◽  
Sodium Dodecyl ◽  
Solid Content ◽  
Water Soluble ◽  
Tween 20 ◽  
Scanning Calorimetry ◽  
Total Solid Content ◽  
Amorphous Systems ◽  
Freeze Dried

Freeze-drying was evaluated as a production technique for co-amorphous systems of a poorly water-soluble drug. Naproxen was freeze-dried together with arginine and lysine as co-former. To increase the solubility of naproxen in the starting solution, the applicability of five surfactants was investigated, namely sodium dodecyl sulfate, pluronic F-127, polyoxyethylene (40) stearate, tween 20 and TPGS 1000. The influence of the surfactant type, surfactant concentration and total solid content to be freeze-dried on the solid state of the sample was investigated. X-ray powder diffraction and differential scanning calorimetry showed that the majority of systems formed co-amorphous one-phase systems. However, at higher surfactant concentrations, and depending on the surfactant type, surfactant reflections were observed in the XRPD analysis upon production. Crystallization of both naproxen and amino acid occurred from some combinations under storage. In conclusion, freeze-drying was shown to be a feasible technique for the production of a selection of co-amorphous drug–amino acid formulations.

scholarly journals Structural stability of biofilms produced from silkworm cocoon fibers

2021 ◽  
pp. 54-54
Author(s):  
Souza Felício ◽  
Henrique Santana
Keyword(s):  
Conformational Changes ◽  
Casting Process ◽  
Scanning Calorimetry ◽  
Molecular Conformations ◽  
Freeze Dried ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Silkworm Cocoon ◽  
Band Characteristic

Biofilms were obtained from cocoons of the silkworm, Bombyx mori, involving the removal of sericin, extraction and solubilization of fibroin fibers, dialysis of fibroin dispersions and preparation of biofilms by the casting process. Biofilm transparency was verified by UV-Vis spectroscopy and thermal stability by thermogravimetric/differential scanning calorimetry (TG/DSC). Soon after preparation, the solidification of the fibroin solution prepared from the cocoons and extracted by the Ajisawa method was monitored until the biofilm stabilized, using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR FT-IR) as a function of time. The results showed that there is a change in the conformation from the silk I structure (?-helix) to silk II (?-sheet). In order to improve the characterization of the biofilms obtained by the Ajisawa method and LiBr solubilization of fibroin fibers, Raman spectroscopy was used to verify stabilization of the different possible molecular conformations for the fibers in these materials, by comparison with the cocoon spectra and those of the solid (freeze-dried hydrogel) precipitated by dialysis for 72 h. By comparing the Raman spectra of the biofilms in terms of the intensities of the broadened band characteristic of amide I, it was possible to assess the conformational changes in both materials based on possible transitions between ?-sheet conformations and flexible ?-helix and ?-turn structures. The results showed a dispersion of these conformations in the biofilms generated and in the solid freeze-dried hydrogel spectrum, and the ?-sheet conformation was found to be predominant. The TG and DSC curves showed that the materials with higher ?-sheet content exhibited higher thermal resistance. Thus, the data obtained further elucidate the properties of these materials which are widely used in various processes.

scholarly journals Synthesis and Characterization of Orotic Acid Loaded Chitosan Inclusion Complex

2020 ◽  
Vol 10 (01) ◽  
pp. 1-4
Author(s):  
ABM Helal Uddin ◽  
Abdelkader Hassani ◽  
Abul K. Azad ◽  
Hamid H. Enezei ◽  
Siti A. Hussain
Keyword(s):  
Electron Microscopy ◽  
Inclusion Complex ◽  
Orotic Acid ◽  
Drug Delivery Systems ◽  
Freeze Drying ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

The current study aims to improve drug release properties of orotic acid loaded with chitosan inclusion complex (OA/CS). The OA/CS inclusion complex was synthesized using the freeze-drying technique. The characterization of inclusion OA/CS was carried out using fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), zeta sizer, and transmission electron microscopy (TEM). Furthermore, the size of OA/CS ranged between 58 nm and 200 nm, and the zeta potential was 30 mV. Thus, this study indicates that OA/CS has a promising future to develop a carrier for drug delivery systems further.

Preparation and characterization of dried cellulose nanofibrils

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jianping Ni ◽  
Chen Gong ◽  
Zhenghua Su ◽  
Chao Tian
Keyword(s):  
Spray Drying ◽  
Freeze Drying ◽  
Cellulose Nanofibrils ◽  
Time Dependent ◽  
X Ray ◽  
Original State ◽  
Final Mass ◽  
Freeze Dried ◽  
Spray Dried

Abstract One of the main manufacturing challenges is to obtain dried cellulose nanofibrils (CNFs) so that they can be cost effectively transported to customers. This work presents a study on using two methods of drying: freeze drying and spray drying; these dried CNFs were then characterized. The dried CNFs from either freeze drying or spray drying could not recover their original state after simple re-dispersion in water. Compared to spray dried CNFs, the microstructure of the freeze dried CNFs remained in a better shape. This was because the packing of nanofibrils as a result of freeze drying was not as tight as that from spray drying. It was demonstrated by the lower final mass residue and crystallinity of the freeze-dried CNFs, which led to better re-dispersion in water. X-ray diffractometry proved the occurrence of aggregation/hornification of the dried CNFs with increased crystallinity. Time-dependent sedimentation confirmed that the dried CNFs were incapable of forming stable water-re-dispersible suspensions.

A Logical Approach to Development of Natamycin Loaded NLCs: Preformulation Studies, Formulation Development and In Vitro Characterization

2021 ◽  
pp. 6033-6040
Author(s):  
Ishwari Choudhary ◽  
Preeti K. Suresh
Keyword(s):  
Entrapment Efficiency ◽  
Formulation Development ◽  
Visible Spectroscopy ◽  
Scanning Calorimetry ◽  
Solubility Profile ◽  
In Vitro Characterization ◽  
Uv Visible ◽  
Preformulation Studies

This study was aimed at the development of natamycin loaded nano-structured lipid carriers (NLCs) and their characterization for physicochemical properties i.e., Fourier Transform Infrared (FTIR), UV-Visible spectroscopy, meting point, solubility profile and partition coefficient. FTIR and Differential Scanning Calorimetry (DSC) permit the characterization of the drug, excipients and binary mixture and thus assisted in predicting the compatibility of natamycin with other excipients. Lipid screening for formulation of NLCs were performed by their solubility and drug affinity studies. High homogenization and sonication method was employed for the development of natamycin loaded NLCs and it was characterized for vesicle size, zeta potential, % entrapment efficiency, viscosity, pH and percentage drug release up to 12 h.

Effects of Prior Freezing Conditions on the Quality of Blueberries in a Freeze-Drying Process

2017 ◽  
Vol 60 (4) ◽  
pp. 1369-1377 ◽  
Author(s):  
Hien Thi Ngo ◽  
Seishu Tojo ◽  
Takuya Ban ◽  
Tadashi Chosa
Keyword(s):  
Freeze Drying ◽  
Far Infrared ◽  
Aroma Compounds ◽  
Operating Conditions ◽  
Test Material ◽  
Freezing Process ◽  
Sublimation Process ◽  
Freeze Dried ◽  
Infrared Heater ◽  
Ice Crystal Size

Abstract. Freeze-drying has played an increasingly important role in the production of dehydrated foods. This article discusses the operating conditions of the prior freezing process of blueberry fruit to maintain the fruit aroma during the sublimation process. The properties of frozen fruit, such as ice crystal size, seem to depend on the freezing speed, leading to some aroma loss during the sublimation process. The temperature of the deep freezer was set at -20°C, -40°C, -60°C, or -80°C to determine the effects of changing the freezing speed of blueberries during prior freezing. Northern highbush blueberry cultivars Dixi and Elliott harvested in a university orchard (Tokyo, Japan) were used as the test material. The sublimation process of freeze-drying was done using a transparent vacuum desiccator connected to a vacuum pump through a vapor cooling trap under heating conditions provided by a far-infrared heater. Trapped vapors were analyzed with GC-MS to identify and quantify the aroma compounds of the blueberries, such as benzaldehyde. The change in the appearance of the freeze-dried blueberries following prior freezing at various speeds is also described. The amounts of typical volatile compounds, such as acetic acid, 2-hexanol, and 3-hexanol, decreased as the freezing speed increased. Most volatile aroma compounds could be preserved when blueberries were frozen rapidly in a deep freezer. Keywords: Aroma loss, Blueberry, Freeze drying, Freezing speed, Prior freezing.

scholarly journals Formulation and Characterization of gallic acid and quercetin chitosan nanoparticles for sustained release in treating Colorectal Cancer

2021 ◽  
Author(s):  
Poournima Patil ◽  
Suresh Killedar
Keyword(s):  
Colorectal Cancer ◽  
Gallic Acid ◽  
Chitosan Nanoparticles ◽  
Entrapment Efficiency ◽  
Aberrant Crypt Foci ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Scanning Calorimetry

Abstract The current work was addressed to characterize gallic acid from amla fruit and quercetin from peels of pomegranate fruit and formulated into Chitosan (CS) nanoparticles and to evaluate their cytotoxicity towards human colorectal cancer (HCT 116) cell lines for the treatment of DMH induced colorectal cancer in Wistar rats. Identification of the biomolecules was performed by using different chromatographic and spectroscopic techniques, as 1H-NMR, GC-MS, LC-MS and HPTLC. Characterization of CS nanoparticles carried out by using X- ray diffraction (XRD) Differential scanning calorimetry (DSC), Scanning Electron Microscope (SEM), entrapment efficiency and In vitro drug release confirmed successful encapsulation of biomolecules into CS nanoparticles. A significant change in aberrant crypt foci (ACF) in CS nanoparticles compared to polyherbal extract were observed, with decrease in the colonic glutathione, catalase and superoxide dismutase levels and values differed significantly (P < 0.005).

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