scholarly journals Ordered mesoporous silicates as matrices for controlled release of drugs

2010 ◽  
Vol 60 (4) ◽  
pp. 373-385 ◽  
Author(s):  
Tina Ukmar ◽  
Odon Planinšek
Keyword(s):  
Controlled Release ◽  
Uv Light ◽  
Release Kinetics ◽  
Stimuli Responsive ◽  
Mesoporous Silicates ◽  
Ordered Mesoporous ◽  
Poorly Soluble ◽  
Model Drug ◽  
Kinetics Of

Ordered mesoporous silicates as matrices for controlled release of drugs Interest in and thereby also development of ordered mesoporous silicates as drug delivery devices have grown immensely over the past few years. On hand selected cases from the literature, the power of such systems as delivery devices has been established. Specifically, it is shown how it is possible to enhance the release kinetics of poorly soluble drugs by embedding them in mesoporous silicates. Further critical factors governing the structure and release of the model drug itraconazole incorporated in an SBA-15 matrix are briefly reviewed. The possibility of functionalizing the surface of mesoporous matrices also under harsher conditions offers a broad platform for the design of stimuli-responsive drug release, including pH responsive systems and systems which respond to the presence of specific ions, reducing agents, magnetic field or UV light, whose efficiency and biocompatibility has been established in vitro.

scholarly journals Development of a reservoir type prolonged release system with felodipine via simplex methodology

2015 ◽  
Vol 89 (1) ◽  
pp. 128-136
Author(s):  
Rareș Iuliu Iovanov ◽  
Ioan Tomuță ◽  
Sorin Emilian Leucuța
Keyword(s):  
Simplex Method ◽  
Release Kinetics ◽  
Prolonged Release ◽  
Lauryl Sulfate ◽  
Pore Former ◽  
Release System ◽  
Reservoir Type ◽  
Model Drug ◽  
Kinetics Of

Background and aims. Felodipine is a dihydropyridine calcium antagonist that presents good characteristics to be formulated as prolonged release preparations. The aim of the study was the formulation and in vitro characterization of a reservoir type prolonged release system with felodipine, over a 12 hours period using the Simplex method.Methods. The first step of the Simplex method was to study the influence of the granules coating method on the felodipine release. Furthermore the influence of the coating polymer type, the percent of the coating polymer and the percent of pore forming agent in the coating on the felodipine release were studied. Afterwards these two steps of the experimental design the percent of Surelease applied on the felodipine loaded granules and the percent of pore former in the polymeric coating formulation variables were studied. The in vitro dissolution of model drug was performed in phosphate buffer solution (pH 6.5) with 1% sodium lauryl sulfate. The released drug quantification was done using an HPLC method. The release kinetics of felodipine from the final granules was assessed using different mathematical models.Results. A 12 hours release was achieved using granules with the size between 315 – 500 µm coated with 45% Surelease with different pore former ratios in the coating via the top-spray method.Conclusion. We have prepared prolonged release coated granules with felodipine using a fluid bed system based on the Simplex method. The API from the studied final formulations was released over a 12 hours period and the release kinetics of the model drug substance from the optimized preparations fitted best the Higuchi and Peppas kinetic models. 

Controlled Release of Bone Growth Factors from Injectable, Biodegradable Polymer Scaffolds for Bone Tissue Engineering

2000 ◽  
Vol 662 ◽  
Author(s):  
Elizabeth L. Hedberg ◽  
Antonios G. Mikos
Keyword(s):  
Growth Factors ◽  
Controlled Release ◽  
Bone Growth ◽  
Bone Ingrowth ◽  
Release Kinetics ◽  
Salt Content ◽  
Burst Effect ◽  
Plga Microparticles ◽  
Model Drug

AbstractThe objective of this research is to fabricate injectable, polymeric composites that will act as scaffolds for bone ingrowth as well as carriers for the controlled release of bone growth factors. To that end, the injectable polyester poly(propylene fumarate) (PPF) was loaded with poly(DLlactic-co-glycolic acid) (PLGA) microparticles carrying the model drug FITC-dextran. This preparation was then crosslinked with N-vinyl pyrrolidinone in the presence of benzoyl peroxide as initiator and sodium chloride (NaCl) as leachable porogen. The encapsulation of growth factors in microparticles is necessary to minimize their denaturation during scaffold crosslinking. PLGA microparticles (0.04 g microparticles/g PPF) were incorporated into PPF composites having variable NaCl weight percents (50 and 70 wt% NaCl) and the effect on FITC-dextran release kinetics was determined in vitro for cylinders of diameter 6.5 mm and height 13.0 mm. The FITC-dextran loaded microparticles alone exhibited a large initial burst effect, while the composite materials displayed a smaller burst effect and a longer linear region of release. At day 3, 54.6±2.1%, 5.1±0.9%, and 12.5±0.3% of loaded FITC-dextran was released into pH 7.4 phosphate buffered saline from the microparticles, the 50 wt% NaCl, and the 70 wt% NaCl composites, respectively. By day 28, 90.9±6.9%, 12.7±1.7%, and 34.4±0.4% of loaded FITC-dextran was released. Our results demonstrate that PLGA microparticles can be incorporated into PPF composites and that the release kinetics of FITC-dextran can be systematically manipulated through alteration of the composite initial salt content.

scholarly journals Drug Release Kinetics of Electrospun PHB Meshes

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1924 ◽  
Author(s):  
Vojtech Kundrat ◽  
Nicole Cernekova ◽  
Adriana Kovalcik ◽  
Vojtech Enev ◽  
Ivana Marova
Keyword(s):  
Release Kinetics ◽  
Entrapment Efficiency ◽  
Toxic Substances ◽  
Antimicrobial Efficiency ◽  
Vis Spectroscopy ◽  
Model Drug ◽  
Phosphate Buffered Saline ◽  
Kinetics Of

Microbial poly(3-hydroxybutyrate) (PHB) has several advantages including its biocompatibility and ability to degrade in vivo and in vitro without toxic substances. This paper investigates the feasibility of electrospun PHB meshes serving as drug delivery systems. The morphology of the electrospun samples was modified by varying the concentration of PHB in solution and the solvent composition. Scanning electron microscopy of the electrospun PHB scaffolds revealed the formation of different morphologies including porous, filamentous/beaded and fiber structures. Levofloxacin was used as the model drug for incorporation into PHB electrospun meshes. The entrapment efficiency was found to be dependent on the viscosity of the PHB solution used for electrospinning and ranged from 14.4–81.8%. The incorporation of levofloxacin in electrospun meshes was confirmed by Fourier-transform infrared spectroscopy and UV-VIS spectroscopy. The effect of the morphology of the electrospun meshes on the levofloxacin release profile was screened in vitro in phosphate-buffered saline solution. Depending upon the morphology, the electrospun meshes released about 14–20% of levofloxacin during the first 24 h. The percentage of drug released after 13 days increased up to 32.4% and was similar for all tested morphologies. The antimicrobial efficiency of all tested samples independent of the morphology, was confirmed by agar diffusion testing.

scholarly journals Preparation and in vitro release kinetics of nitrendipine-loaded PLLA–PEG–PLLA microparticles by supercritical solution impregnation process

RSC Advances ◽  
2019 ◽  
Vol 9 (28) ◽  
pp. 16167-16175 ◽  
Author(s):  
Shiping Zhan ◽  
Jingchang Wang ◽  
Weijing Wang ◽  
Liyun Cui ◽  
Qicheng Zhao
Keyword(s):  
Release Kinetics ◽  
Drug Carrier ◽  
In Vitro Release ◽  
Impregnation Process ◽  
Supercritical Solution ◽  
Model Drug ◽  
Polymer Microparticles ◽  
Kinetics Of ◽  
Vitro Release

In this work, drug-loaded polymer microparticles were prepared by a supercritical solution impregnation (SSI) process with nitrendipine as the model drug and PLLA–PEG–PLLA as the drug carrier.

scholarly journals Formulations and evaluation of Cyclodextrin complexed Ceadroxil loaded nanosponges

2017 ◽  
Vol 9 (3) ◽  
pp. 84 ◽  
Author(s):  
Pawan Dubey ◽  
Hemant Kumar Sharma ◽  
Sunil Shah ◽  
Chandra Kishore Tyagi ◽  
Amol R. Chandekar ◽  
...  
Keyword(s):  
Lactone Ring ◽  
Release Kinetics ◽  
Major Drawback ◽  
Zeta Potentials ◽  
Poorly Soluble ◽  
Dosing Intervals ◽  
And Control ◽  
Kinetics Of ◽  
Derivatives Of

<p>Cefadroxil (CFD) is a broad spectrum antibiotic that acts against an extensive variety of bacteria, including Gram-positive and Gram-negative bacteria. The major drawback of orally administered drug like cefadroxil is its shorter half life of 1.2 hrs. The goal of the study is to prolong the drug release, producing a desired blood serum level, reduction in drug toxicity and improving the patient compliance by prolonging the dosing intervals. Cyclodextrin-based nanosponges (NS) are a novel class of cross-linked derivatives of cyclodextrins. They have been used to increase the solubility of poorly soluble actives, to protect the labile groups and control the release. This study aimed at formulating complexes of CFDwith three types of β-cyclodextrin NS obtained with different cross-linking ratio (viz. 1:2, 1:4 and 1:8 on molar basis with the cross-linker) to protect the lactone ring from hydrolysis and to prolong the release kinetics of CFD. Crystalline (F<sub>1:2</sub>, F<sub>1:4</sub> and F<sub>1:8</sub>) and paracrystalline NS formulations were prepared. XRPD, DSC and FTIR studies confirmed the interactions of CFDwith NS. XRPD showed that the crystallinity of CFD decreased after loading. CFD was loaded as much as 21%, 37% and 13% w/w in F<sub>1:2 </sub>, F<sub>1:4</sub> and F<sub>1:8</sub>, respectively while the paracrystalline NS formulations gave a loading of about 10% w/w or lower. The particle sizes of the loaded NS formulations were between 450 and 600 nm with low polydispersity indices. The zeta potentials were sufficiently high (-20 to -25 mV) to obtain a stable colloidal nanosuspension. The in vitro studies indicated a slow and prolonged CFD release over a period of 24 h. The NS formulations protected the lactone ring of CFD after their incubation in physiological conditions at 37°C for 24 h with a 80% w/w of intact lactone ring when compared to only around 20% w/w of plain CFD.</p>

Crosslinked Chitosan/PVA Film, Suturated with 5- Fluorouracil for The Prevention of Proliferative Vitreoretinopathy

2016 ◽  
Vol 6 (2) ◽  
Author(s):  
Baiyrkhanova A. ◽  
Ismailova A. ◽  
Botabekova T. ◽  
Enin E. ◽  
Semenova Y.
Keyword(s):  
Proliferative Vitreoretinopathy ◽  
Release Kinetics ◽  
Drug Loading ◽  
In Vitro Release ◽  
Chemical Compositions ◽  
Ophthalmic Administration ◽  
Model Drug ◽  
Kinetics Of

5-Fluorouracil (5-FU)-loaded chitosan (Ch) film for chemotherapy were prepared applying a superhydrophobic surfacebased encapsulation technology. The aim of this study was to develop polymeric film with glutaraldehyde (GA) of controlled drug delivery systems for 5 – fluorouracil (FU) as a model drug for the treatment of proliferative vitreoretinopathy. Polymer film of chitosan and polyvinyl alcohol (PVA in 75:25 ratios were prepared and treated with GA. FTIR spectra of 5-FU, Ch/5-FU and Ch/PVA film loaded 5-FU were studied. Physical characteristics such as thickness and swelling coefficient of the film were performed. The thermal of the Ch/PVA film was studied with thermogravimethric analysis. The drug loading efficiency, film size and chemical compositions of the film loaded drug were confirmed by UV–vis spectrophotometer and Fourier transform infrared spectroscopy. In vitro release kinetics of drug from the polymeric films was investigated to determine the drug release properties. In vivo study of PVR was showed the efficacy and no toxicity of this formulation. Further uses of the film loaded 5 - fluorouracil may provide an efficiency deliverable for ophthalmic administration.

scholarly journals Preparation and Evaluation of In Vitro Release Kinetics of Theophylline Loaded Matrix Tablet Based on Eudragit NE 30 D and Eudragit RS 30 D

1970 ◽  
Vol 8 (2) ◽  
pp. 153-159
Author(s):  
Mohammad Borhan Uddin ◽  
Jakir Ahmed Chowdhury ◽  
Kazi Rashidul Azam ◽  
Reza-ul Jalil ◽  
Md Selim Reza
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Release Kinetics ◽  
Matrix Tablet ◽  
Matrix System ◽  
Polymeric Systems ◽  
Eudragit Rs ◽  
Kinetics Of ◽  
Preparation And Evaluation

In the present study efficiency of Eudragit NE 30 D and RS 30 D as matrix forming materials was investigated. It was found that theophylline loaded granules prepared with these two polymers could not sustain drug release for a significant period of time. However, compression of these granules into tablets retarded drug release for up to 7 hours. Release was similar with both of the polymers. Effects of fillers and rate modifiers on drug release have been assessed. Incorporation of lactose and starch caused substantial release of theophylline from both the polymeric systems. Avicel PH 101 intensified the retardation effect of both NE 30 D and RS 30 D on theophylline release. Hydrophobic excipients also show retardation of release from both NE 30 D and RS 30 D. Key words: Eudragit RS 30 D; Eudragit NE 30 D; Theophylline; Matrix system; Controlled release DOI: 10.3329/dujps.v8i2.6030 Dhaka Univ. J. Pharm. Sci. 8(2): 153-159, 2009 (December)

scholarly journals Functionalized Mesoporous Silica Nanoparticles as Delivery Systems for Doxorubicin: Drug Loading and Release

2021 ◽  
Vol 11 (13) ◽  
pp. 6121
Author(s):  
Candace M. Day ◽  
Martin J. Sweetman ◽  
Yunmei Song ◽  
Sally E. Plush ◽  
Sanjay Garg
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Release Kinetics ◽  
Drug Loading ◽  
In Vitro Release ◽  
Delivery Systems ◽  
Stimuli Responsive ◽  
Kinetics Of

Functionalized nanoparticles have played a major role in the field of targeted therapy, owing to their ability to control the release and for the selective delivery of entrapped materials to tumours. In this work, we described the loading capacity and in vitro release kinetics of mesoporous silica nanoparticles (MSNs), functionalized with Poly-L-Histidine and Tamoxifen. The model drug Doxorubicin (DOX) was successfully encapsulated into MSN-based systems, using the technique of solvent immersion. A post-surface grafting loading method was investigated on functionalized systems, with DOX loading content determined using HPLC. Dialysis bag diffusion was employed to investigate the release kinetics of DOX-loaded-systems at pH 7.4 and 5. The amount of DOX released from native MSNs systems over a 72 h period at pH 5 was approximately 40%; and at pH 7.4 ≈ 30%. A moderate pH dependent release behaviour was observed with both our functionalized systems: DOX@MSN-PLH and DOX@MSN-PLH-TAM; with approximately 5% of DOX released from DOX@MSN-PLH-TAM at pH 7.4 and about 9% released at pH 7.4 over 72 h. The maximal cumulated release of DOX molecules from DOX@MSN-PLH after 72 h was ≈ 18% at pH 7.4 and ≈ 23% at pH 5, respectively. The outcome of this work offers a promising contribution towards building future stimuli-responsive nano-drug delivery systems.

Controlled Release of Metformin Hydrochloride I. In vitro Release from Physical Mixture Containing Xanthan Gum as Hydrophilic Rate Retarding Polymer

1970 ◽  
Vol 4 (1) ◽  
Author(s):  
Mashkura Ashrafi ◽  
Jakir Ahmed Chowdhury ◽  
Md Selim Reza
Keyword(s):  
Controlled Release ◽  
Xanthan Gum ◽  
In Vitro Release ◽  
Correlation Coefficients ◽  
High Ratio ◽  
Water Soluble ◽  
Metformin Hydrochloride ◽  
Model Drug ◽  
Very High

Capsules of different formulations were prepared by using a hydrophilic polymer, xanthan gum and a filler Ludipress. Metformin hydrochloride, which is an anti-diabetic agent, was used as a model drug here with the aim to formulate sustained release capsules. In the first 6 formulations, metformin hydrochloride and xanthan gum were used in different ratio. Later, Ludipress was added to the formulations in a percentage of 8% to 41%. The total procedure was carried out by physical mixing of the ingredients and filling in capsule shells of size ‘1’. As metformin hydrochloride is a highly water soluble drug, the dissolution test was done in 250 ml distilled water in a thermal shaker (Memmert) with a shaking speed of 50 rpm at 370C &plusmn 0.50C for 6 hours. After the dissolution, the data were treated with different kinetic models. The results found from the graphs and data show that the formulations follow the Higuchian release pattern as they showed correlation coefficients greater than 0.99 and the sustaining effect of the formulations was very high when the xanthan gum was used in a very high ratio with the drug. It was also investigated that the Ludipress extended the sustaining effect of the formulation to some extent. But after a certain period, Ludipress did not show any significant effect as the pores made by the xanthan gum network were already blocked. It is found here that when the metformin hydrochloride and the xanthan gum ratio was 1:1, showed a high percentage of drug release, i.e. 91.80% of drug was released after 6 hours. But With a xanthan gum and metformin hydrochloride ratio of 6:1, a very slow release of the drug was obtained. Only 66.68% of the drug was released after 6 hours. The percent loading in this case was 14%. Again, when Ludipress was used in high ratio, it was found to retard the release rate more prominently. Key words: Metformin Hydrochloride, Xanthan Gum, Controlled release capsule Dhaka Univ. J. Pharm. Sci. Vol.4(1) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

Sign in / Sign up

Export Citation Format

Share Document