scholarly journals Insulin release from alginate microspheres reinforced with dextran sulfate

2006 ◽  
Vol 12 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Catarina Silva ◽  
António Ribeiro ◽  
Francisco Veiga ◽  
Adriano Sousa
Keyword(s):  
Insulin Release ◽  
Encapsulation Efficiency ◽  
Dextran Sulfate ◽  
Low Ph ◽  
Gastric Ph ◽  
Release Profile ◽  
Internal Gelation ◽  
High Insulin ◽  
Harsh Conditions ◽  
Alginate Matrix

In a previous study, insulin was efficiently encapsulated in alginate microspheres using an emulsification/internal gelation process. However these microspheres showed a high insulin release at gastric pH, exposing the protein to the harsh conditions of the stomach. In this study, our attempt was to improve insulin release profile by reinforcing the alginate matrix with dextran sulfate (DS). The size distribution was not altered by the presence of DS and the encapsulation efficiency increased to 100%. DS was also able to prevent insulin release at pH 1.2, protecting the insulin from an acidic environment. This effect was explained by an interaction between the permanent negatively charged groups of DS and insulin at low pH. When reinforced alginate microspheres were transferred to neutral pH, dissolution occurred within a few minutes. Increase of the adjuvant concentration did not improve the insulin release profile.

Novel porous starch/ alginate hydrogel for controlled insulin release with dual response of pH and amylase

2021 ◽  
Author(s):  
Yaqiong Chen ◽  
Hongdong Song ◽  
Kai Huang ◽  
Xiao Guan
Keyword(s):  
Insulin Release ◽  
Oral Insulin ◽  
Alginate Hydrogel ◽  
Important Principle ◽  
Dual Response ◽  
Harsh Conditions

An important principle in the development of oral insulin is to protect insulin from the harsh conditions of the stomach and release it in a controlled manner in the intestine....

scholarly journals Nanopolyphenols: a review of their encapsulation and anti-diabetic effects

2020 ◽  
Vol 2 (8) ◽  
Author(s):  
Theresa F. Rambaran
Keyword(s):  
Functional Food ◽  
Encapsulation Efficiency ◽  
Water Solubility ◽  
Drug Loading ◽  
Therapeutic Agents ◽  
Low Ph ◽  
Free Form ◽  
Pharmaceutical Development ◽  
Curcumin Nanoparticles ◽  
Treatment Of Diabetes

AbstractPolyphenols are believed to possess numerous health benefits and can be grouped as phenolic acids, flavonoids or non-flavonoids. Research involving the synthesis of nanopolyphenols has attracted interest in the areas of functional food, nutraceutical and pharmaceutical development. This is in an effort to overcome current challenges which limit the application of polyphenols such as their rapid elimination, low water-solubility, instability at low pH, and their particle size. In the synthesis of nanopolyphenols, the type of nanocarrier used, the nanoencapsulation technique employed and the type of polymers that constitute the drug delivery system are crucial. For this review, all mentioned factors which can influence the therapeutic efficacy of nanopolyphenols were assessed. Their efficacy as anti-diabetic agents was also evaluated in 33 publications. Among these were phenolic acid (1), flavonoids (13), non-flavonoids (17) and polyphenol-rich extracts (2). The most researched polyphenols were quercetin and curcumin. Nanoparticles were the main nanocarrier and the size of the nanopolyphenols ranged from 15 to 333 nm with encapsulation efficiency and drug loading capacities of 56–97.7% and 4.2–53.2%, respectively. The quantity of nanomaterial administered orally ranged from 1 to 300 mg/kg/day with study durations of 1–70 days. Most studies compared the effect of the nanopolyphenol to its free-form and, in all but three cases, significantly greater effects of the former were reported. Assessment of the polyphenol to understand its properties and the subsequent synthesis of its nanoencapsulated form using suitable nanocarriers, polymers and encapsulation techniques can result in effective therapeutic agents for the treatment of diabetes.

scholarly journals Fusion and Infection of Influenza and Sendai Viruses as Modulated by Dextran Sulfate: A Comparative Study

2001 ◽  
Vol 21 (3) ◽  
pp. 293-304 ◽  
Author(s):  
João Ramalho-Santos ◽  
Maria C. Pedroso de Lima
Keyword(s):  
Molecular Weight ◽  
Dextran Sulfate ◽  
Sendai Virus ◽  
Mdck Cells ◽  
Inhibitory Effect ◽  
Low Ph ◽  
Influenza Viruses ◽  
Target Cells ◽  
Fusion Activity ◽  
Viral Envelopes

We have directly compared the effect of two types of dextran sulfate with distinct molecular weights (500 kDa and 5 kDa) on the fusion activity and infectivity of both Sendai and influenza viruses, two lipid-enveloped viruses that differ in their routes of entry into target cells. To correlate membrane merging and infectivity MDCK cells were used as targets for the viruses in both approaches. In either case pronounced inhibition of virus–cell interactions by dextran sulfate was only observed at low pH, even though Sendai virus fuses maximally at pH 7.4. Although membrane merging could not be fully abolished, the inhibitory effect was always greater when the higher molecular weight dextran sulfate was used. The presence of this residual fusion activity, that could not be reduced even with high concentrations of agent, suggests that a limited number of binding sites for dextran sulfate may exist on the viral envelopes. The compounds also inhibited fusion of bound virions, and all results could be reproduced using erythrocyte ghosts as target membranes in the fusion assay, instead of MDCK cells. In agreement with these observations only the infectivity of influenza virus (which requires a low pH-dependent step to enter target cells) was affected by dextran sulfate, again the higher molecular weight compound showing a more pronounced inhibitory effect.

scholarly journals INVESTIGATING BETANIN STABILITY, RELEASE PROFILE AND ANTIOXIDANT ACTIVITY OF ETHYL CELLULOSE MICROPARTICLE CONTAINING BEETROOT (BETA VULGARIS, LINN) EXTRACT

2021 ◽  
pp. 133-138
Author(s):  
ANITA SUKMAWATI ◽  
SETYO NURWAINI ◽  
UMI BUDI RAHAYU ◽  
APRILIANA P. C. WIDAWAN ◽  
ANITA SAFITRI ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Beta Vulgaris ◽  
Active Substance ◽  
Ethyl Cellulose ◽  
Encapsulation Efficiency ◽  
Polymer Concentration ◽  
Physical Characteristics ◽  
Release Profile ◽  
The Stability ◽  
Active Substances

Objective: The objective of this research is to evaluate the ability of ethyl cellulose (EC) microparticle to protect the beetroot (Beta vulgaris, Linn) active substance. In addition, this research also investigates the effect of polymer concentration during microparticle preparation toward physical characteristics of microparticle, release profile of betanin as well as antioxidant activity of microparticle. Methods: The microparticle was produced using the emulsification method using various concentrations of EC in the organic phase and beetroot extract as the active substances. The physical characterization was carried out including the imaging of microparticle using scanning electron microscope (SEM), zeta potential and encapsulation efficiency (EE). The stability test for an active substance in microparticle was carried out at temperature 40 °C for 28 d. The release profile was evaluated using the dissolution method and the antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH).Results: The result showed that the EC concentration strongly influenced the physical characteristics and EE of beetroot extract in microparticle. The microparticles also had good protection for betanin during storage. The release of active substance from microparticle following Higuchi kinetic. The highest antioxidant activity was found in the microparticle using EC 20%. Conclusion: The EC microparticle is the potential to protect the degradation of antioxidant substance from natural product. However, the physical properties, EE, the ability to prevent degradation of active substance, release rate and antioxidant activity, are strongly influenced by the EC polymer concentration during microparticle preparation.

Preparation and evaluation of an oral mucoadhesive gel containing nystatin-loaded alginate microparticles

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
S. Mohammadi Samani ◽  
S. Karimaddini ◽  
Z. Sobhani ◽  
F. Ahmadi
Keyword(s):  
Calcium Chloride ◽  
Encapsulation Efficiency ◽  
Bitter Taste ◽  
Drug Loading ◽  
Dosage Forms ◽  
Release Profile ◽  
Burst Release ◽  
Carbopol Gel ◽  
Alginate Concentration ◽  
Preparation And Evaluation

Abstract Nystatin is an antifungal agent used for prophylaxis and treatment of candidiasis, especially oral mycosis. Efficacy of nystatin conventional dosage forms is limited by the short residence time and bitter taste of the drug. This research aims at designing an optimized formulation of oral mucoadhesive gel of nystatin-loaded alginate microparticles, which can be retained in the mouth. Sodium alginate solution containing nystatin was added to the solution of calcium chloride under stirring. Microparticles containing nystatin were incorporated into the Carbopol gel. Size, loading, and release profile and mucoadhesion were investigated. The most suitable microparticles with particle size of < 250 μm were prepared with alginate concentration of 1%(w/v), calcium chloride of 1%(w/v), drug:polymer concentration 1%, and ratio of alginate solution:calcium chloride of 1:10. This formulation showed 49.1% drug loading and 98.2% encapsulation efficiency. Carbopol 934 gel provided optimal mucoadhesive properties. Release profile proved a burst release, which can be attributed to the surface associated drug, followed by a slower sustained release phase for all microparticles. The developed system with ability to adhere to the oral mucosa has great appeal for treatment of localized infections and can mask bitter taste of the drug and be retained in the mouth for long periods.

Modulating insulin-release profile from pH/thermosensitive polymeric beads through polymer molecular weight

1999 ◽  
Vol 59 (3) ◽  
pp. 287-298 ◽  
Author(s):  
Chaaya Ramkissoon-Ganorkar ◽  
Feng Liu ◽  
Miroslav Baudyš ◽  
Sung Wan Kim
Keyword(s):  
Molecular Weight ◽  
Insulin Release ◽  
Release Profile ◽  
Polymer Molecular Weight ◽  
Polymeric Beads

Predictive modeling of insulin release profile from cross-linked chitosan microspheres

2013 ◽  
Vol 60 ◽  
pp. 249-253 ◽  
Author(s):  
S. Jose ◽  
J.F. Fangueiro ◽  
J. Smitha ◽  
T.A. Cinu ◽  
A.J. Chacko ◽  
...  
Keyword(s):  
Insulin Release ◽  
Predictive Modeling ◽  
Release Profile ◽  
Chitosan Microspheres

scholarly journals Establishment and Characterization of Stable Zein/Glycosylated Lactoferrin Nanoparticles to Enhance the Storage Stability and in vitro Bioaccessibility of 7,8-Dihydroxyflavone

2022 ◽  
Vol 8 ◽  
Author(s):  
Yufeng Chen ◽  
Xiaojing Gao ◽  
Shucheng Liu ◽  
Qiuxing Cai ◽  
Lijun Wu ◽  
...  
Keyword(s):  
Encapsulation Efficiency ◽  
Storage Stability ◽  
Hydrophobic Interactions ◽  
Amorphous State ◽  
Spherical Shape ◽  
Low Ph ◽  
In Vitro Bioaccessibility ◽  
Ph Conditions

In this work, the lactoferrin (LF) was glycosylated by dextran (molecular weight 10, 40, and 70 kDa, LF 10K, LF 40K, and LF 70K) via Maillard reaction as a stabilizer to establish zein/glycosylated LF nanoparticles and encapsulate 7,8-dihydroxyflavone (7,8-DHF). Three zein/glycosylated LF nanoparticles (79.27–87.24 nm) with low turbidity (&lt;0.220) and polydispersity index (PDI) (&lt;0.230) were successfully established by hydrophobic interactions and hydrogen bonding. Compared with zein/LF nanoparticles, zein/glycosylated LF nanoparticles further increased stability to ionic strength (0–500 mM NaCl) at low pH conditions. Zein/glycosylated LF nanoparticles had nanoscale spherical shape and glycosylated LF changed surface morphology of zein nanoparticles. Besides, encapsulated 7,8-DHF exhibited an amorphous state inside zein/glycosylated LF nanoparticles. Most importantly, zein/glycosylated LF nanoparticles had good water redispersibility, high encapsulation efficiency (above 98.50%), favorable storage stability, and bioaccessibility for 7,8-DHF, particularly LF 40K. Collectively, the above research provides a theoretical reference for the application of zein-based delivery systems.

scholarly journals ELECTROSPUN CHITOSAN/PVA NANOFIBERS FOR DRUG DELIVERY

2018 ◽  
Vol 54 (4B) ◽  
pp. 185 ◽  
Author(s):  
Doan Van Hong Thien
Keyword(s):  
Drug Delivery ◽  
Electron Microscope ◽  
Encapsulation Efficiency ◽  
Release Profile ◽  
Poly Vinyl Alcohol ◽  
Electrospinning Technique ◽  
Molecular Weights ◽  
Electrospinning Method ◽  
Surface Morphologies ◽  
Scanning Electron

Electrospinning technique is a versatile method to fabricate continuous fibers with diameters ranging from a few micrometers to a few nanometers. In this study, chitosan/ poly (vinyl alcohol) (PVA) nanofibers were fabricated by an electrospinning method. The effects of chitosan molecular weights and ratio of chitosan/PVA were studied. The characteristics and surface morphologies of nanofibers were observed by the Scanning Electron Microscope (SEM). The diameters of nanofibers were in the range of 100 nm to 250 nm. The chitosan/PVA nanofibers with different molecular weights were applied for curcumin delivery. Curcumin was loaded in the chitosan/PVA nanofibers. Then, release profile of curcumin was investigated. In the results, the encapsulation efficiency and the release rate demonstrate that chitosan/PVA nanofibers would be potential carriers for curcumin and promise to create a prospective drug delivery in the field of medicine.

The Effect of Formulation Variables on the Encapsulation Efficiency and SO2-Release Behavior of Microparticles Containing Sulphite

2010 ◽  
Vol 152-153 ◽  
pp. 512-515
Author(s):  
Ya Ge Xing ◽  
Juan Yun ◽  
Xi Hong Li ◽  
Qing Lian Xu ◽  
Wei Li Li
Keyword(s):  
Phase Separation ◽  
Relative Humidity ◽  
Encapsulation Efficiency ◽  
Separation Process ◽  
Release Profile ◽  
Water Soluble ◽  
Release Behavior ◽  
Phase Separation Process ◽  
Process Factors ◽  
Formulation Variables

The water-soluble sulphite was encapsulated using ethylcellulose phase separation. The effect of different process factors in the phase separation process on the encapsulation efficiency and the release profile of SO2 from the microparticles were evaluated. The results showed that the SO2 release from the microparticles containing sulphite was affected by the relative humidity in the microenvironment.

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