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 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.

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

scholarly journals Synthesis and Evaluation of AlgNa-g-poly(QCL-co-HEMA) Hydrogels as Platform for Chondrocyte Proliferation and Controlled Release of Betamethasone

2021 ◽  
Vol 22 (11) ◽  
pp. 5730
Author(s):  
Jomarien García-Couce ◽  
Marioly Vernhes ◽  
Nancy Bada ◽  
Lissette Agüero ◽  
Oscar Valdés ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Controlled Release ◽  
Biomedical Applications ◽  
Release Kinetics ◽  
Cell Types ◽  
Tissue Engineering Scaffolds ◽  
Almost All ◽  
Scanning Electron

Hydrogels obtained from combining different polymers are an interesting strategy for developing controlled release system platforms and tissue engineering scaffolds. In this study, the applicability of sodium alginate-g-(QCL-co-HEMA) hydrogels for these biomedical applications was evaluated. Hydrogels were synthesized by free-radical polymerization using a different concentration of the components. The hydrogels were characterized by Fourier transform-infrared spectroscopy, scanning electron microscopy, and a swelling degree. Betamethasone release as well as the in vitro cytocompatibility with chondrocytes and fibroblast cells were also evaluated. Scanning electron microscopy confirmed the porous surface morphology of the hydrogels in all cases. The swelling percent was determined at a different pH and was observed to be pH-sensitive. The controlled release behavior of betamethasone from the matrices was investigated in PBS media (pH = 7.4) and the drug was released in a controlled manner for up to 8 h. Human chondrocytes and fibroblasts were cultured on the hydrogels. The MTS assay showed that almost all hydrogels are cytocompatibles and an increase of proliferation in both cell types after one week of incubation was observed by the Live/Dead® assay. These results demonstrate that these hydrogels are attractive materials for pharmaceutical and biomedical applications due to their characteristics, their release kinetics, and biocompatibility.

scholarly journals Formulation and development of metformin-loaded microspheres using Khaya senegalensis (Meliaceae) gum as co-polymer

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Chukwuebuka H. Ozoude ◽  
Chukwuemeka P. Azubuike ◽  
Modupe O. Ologunagba ◽  
Sejoro S. Tonuewa ◽  
Cecilia I. Igwilo
Keyword(s):  
Controlled Release ◽  
Sodium Alginate ◽  
Release Kinetics ◽  
Drug Carrier ◽  
In Vitro Release ◽  
Entrapment Efficiency ◽  
Metformin Hydrochloride ◽  
Scanning Calorimetry ◽  
Khaya Senegalensis

Abstract Background Khaya gum is a bark exudate from Khaya senegalensis (Maliaecae) that has drug carrier potential. This study aimed to formulate and comparatively evaluate metformin-loaded microspheres using blends of khaya gum and sodium alginate. Khaya gum was extracted and subjected to preformulation studies using established protocols while three formulations (FA; FB and FC) of metformin (1% w/v)-loaded microspheres were prepared by the ionic gelation method using 5% zinc chloride solution as the cross-linker. The formulations contained 2% w/v blends of khaya gum and sodium alginate in the ratios of 2:3, 9:11, and 1:1, respectively. The microspheres were evaluated by scanning electron microscopy, Fourier transform-infrared spectroscopy, differential scanning calorimetry, entrapment efficiency, swelling index, and in vitro release studies. Results Yield of 28.48%, pH of 4.00 ± 0.05, moisture content (14.59% ± 0.50), and fair flow properties (Carr’s index 23.68 ± 1.91 and Hausner’s ratio 1.31 ± 0.03) of the khaya gum were obtained. FTIR analyses showed no significant interaction between pure metformin hydrochloride with excipients. Discrete spherical microspheres with sizes ranging from 1200 to 1420 μm were obtained. Drug entrapment efficiency of the microspheres ranged from 65.6 to 81.5%. The release of the drug from microspheres was sustained for the 9 h of the study as the cumulative release was 62% (FA), 73% (FB), and 80% (FC). The release kinetics followed Korsmeyer-Peppas model with super case-II transport mechanism. Conclusion Blends of Khaya senegalensis gum and sodium alginate are promising polymer combination for the preparation of controlled-release formulations. The blend of the khaya gum and sodium alginate produced microspheres with controlled release properties. However, the formulation containing 2:3 ratio of khaya gum and sodium alginate respectively produced microspheres with comparable controlled release profiles to the commercial brand metformin tablet.

Formulation and Evaluation of Mucoadhesive Floating Microspheres of Repaglinide

2021 ◽  
pp. 5673-5679
Author(s):  
S. Sivaprasad ◽  
V. Alagarsamy ◽  
M. Prathibha Bharathi ◽  
P.V. Murali Krishna ◽  
K. Sandeeep Kanna
Keyword(s):  
Controlled Release ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Extended Period ◽  
Entrapment Efficiency ◽  
Sustain Release ◽  
S 100 ◽  
Eudragit S 100 ◽  
Good Flow

The main objective of the present study was to design a controlled release dosage form for an oral anti diabetic drug i.e. repaglinide employing polymers like eudragit s- 100. One of the other objective of this present study was to increase the biological half-life the drug by formulating into microspheres. The microspheres of repaglinide were prepared by solvent evaporation method by using eudragit s-100 and ethyl cellulose as polymers with different concentrations. Formulations (F1-F10) were prepared and evaluated for various micrometric properties and it was observed that though all the formulations were exhibited good flow properties, The F5 formulation exhibits higher in- vitro buoyancy time and entrapment efficiency which is considered for in- vitro and mucoadhesive studies. The FTIR results reveal that there was no interaction between the drug and the excipients. The in- vitro release profiles of F1-F5 indicated that all formulations showed controlled release over an extended period, with acceptable release kinetics. Among the all formulations F5 were considered as a promising candidate for sustain release of repaglinide.

scholarly journals DESIGN AND EVALUATION OF CONTROLLED-RELEASE OCULAR INSERTS OF BRIMONIDINE-TARTRATE AND TIMOLOL MALEATE

2016 ◽  
Vol 9 (1) ◽  
pp. 79 ◽  
Author(s):  
Preethi G. B. ◽  
Prashanth Kunal
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Sodium Alginate ◽  
Calcium Chloride ◽  
Release Kinetics ◽  
Water Soluble ◽  
Moisture Loss ◽  
Timolol Maleate ◽  
Brimonidine Tartrate

<p><strong>Objective: </strong>The current work was attempted to formulate and evaluate a controlled-release matrix-type ocular inserts containing a combination of brimonidine tartrate and timolol maleate, with a view to sustain the drug release in the cul-de-sac of the eye.<strong></strong></p><p><strong>Methods: </strong>Initially, the infrared studies were done to determine the drug–polymer interactions. Sodium alginate-loaded ocuserts were prepared by solvent casting technique. Varying the concentrations of polymer—sodium alginate, plasticizer—glycerine, and cross-linking agent—calcium chloride by keeping the drug concentration constant, made a total of nine formulations. These formulations were evaluated for its appearance, drug content, weight uniformity, thickness uniformity, percentage moisture loss, percentage moisture absorption, and <em>in vitro </em>release profile of the ocuserts. Finally, accelerated stability studies and the release kinetics were performed on the optimised formulation.<strong></strong></p><p><strong>Results: </strong>It was perceived that polymer, plasticizer, and calcium chloride had a significant influence on the drug release. The data obtained from the formulations showed that formulation—F9 was the optimised formulation, which exhibited better drug release. The release data of the optimised formulation tested on the kinetic models revealed that it exhibited first-order release kinetics. <strong></strong></p><p><strong>Conclusion: </strong>It can be concluded that a natural bioadhesive hydrophilic polymer such as sodium alginate can be used as a film former to load water soluble and hydrophilic drugs like brimonidine tartrate and timolol maleate. Among all formulations, F9 with 400 mg sodium alginate, 2% calcium chloride and 60 mg glycerin were found to be the most suitable insert in terms of appearance, ease of handling, thickness, <em>in vitro</em> drug release and stability.</p>

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. 

scholarly journals Optimizing the Role of Polymer Blend in the Preparation of Acyclovir Controlled-Release Tablets: An Approach for Better Patient Compliance

2018 ◽  
Author(s):  
Barkat Khan ◽  
Faheem Haider ◽  
Kifayat Shah ◽  
Bushra Uzair ◽  
Kaijian Hou ◽  
...  
Keyword(s):  
Controlled Release ◽  
Drug Release ◽  
Release Kinetics ◽  
Immediate Release ◽  
Matrix Tablets ◽  
Release Mechanism ◽  
In Vitro Drug Release ◽  
Solubility Study ◽  
Release Data

This study was carried out to formulate and evaluate controlled release (CR) matrix tablets of Acyclovir using combination of hydrophilic and hydrophobic polymers. Acyclovir is a guanine derivative and is its half-life is short hence administered five times a day using immediate release tablets. Six formulations (F1-F6) were developed using Ethocel and Carbopol in equal combinations at drug-polymer (D:P) ratio of 10:5, 10:6, 10:7, 10:8, 10:9 and 10:10. Solubility study was performed using six different solvents. The compatibility studies were carried out using FTIR and DSC. According to USP, Quality Control and dimensional tests (hardness, friability, disintegration and thickness) were executed. In-vitro drug release studies of Acyclovir was carried out in dissolution apparatus using using 0.1 N HCl medium at constant temperature of 37 ± 0.5 ºC. In order to analyze the drug release kinetics, five different mathematical models were applied to the release data. The results showed that there was no incompatibility between drug and polymers. Physical QC tests were found within limits of USP. The release was retarded upto 24 hrs and non-fickian in-vitro drug release mechanism was found. A formulation developed using blend of polymers, showed excellent retention and desired release profiles thus providing absolute control for 24 hrs.

Modulation of growth factor incorporation into ECM of human osteoblast-like cells in vitro by 17 beta-estradiol

1994 ◽  
Vol 267 (6) ◽  
pp. E990-E1001 ◽  
Author(s):  
M. Slater ◽  
J. Patava ◽  
K. Kingham ◽  
R. S. Mason
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Bone Growth ◽  
Transforming Growth Factor ◽  
Bone Matrix ◽  
Tgf Beta ◽  
Subsequent Formation ◽  
Igf I

Human fetal osteoblast-like cells formed a regular multilayered structure in vitro with an extensive collagen-based extracellular matrix. With colloidal gold immunocytochemistry, labels for alkaline phosphatase and osteocalcin were distributed in a relatively diffuse pattern, in contrast to the bone growth factors, insulin-like growth factors I and II (IGF-I and IGF-II), transforming growth factor-beta 1 (TGF-beta 1), and basic fibroblast growth factor, which were colocalized in the collagenous matrix of the multilayer. The inclusion of 17 beta-estradiol (10(-11) to 10(-9) M) in the culture medium increased multilayer depths, increased labeling for IGF-I, IGF-II, and TGF-beta 1, and resulted in earlier detection of TGF-beta 1 label. In contrast, the increase in multilayer depth resulting from treatment with human platelets, an exogenous source of growth factors, was not accompanied by an increase in matrix IGF-I, IGF-II, or TGF-beta 1 label, suggesting a particular effect of estradiol to facilitate this process. Because growth factors in bone matrix may act as coupling agents when released during resorption, reduced growth factor incorporation in the presence of reduced sex steroid concentrations may lead to uncoupling of resorption and subsequent formation.

Sign in / Sign up

Export Citation Format

Share Document