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Weng J, Durand A, Desobry S. Chitosan-Based Particulate Carriers: Structure, Production and Corresponding Controlled Release. Pharmaceutics 2023; 15:pharmaceutics15051455. [PMID: 37242694 DOI: 10.3390/pharmaceutics15051455] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 04/30/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
The state of the art in the use of chitosan (CS) for preparing particulate carriers for drug delivery applications is reviewed. After evidencing the scientific and commercial potentials of CS, the links between targeted controlled activity, the preparation process and the kinetics of release are detailed, focusing on two types of particulate carriers: matrix particles and capsules. More precisely, the relationship between the size/structure of CS-based particles as multifunctional delivery systems and drug release kinetics (models) is emphasized. The preparation method and conditions greatly influence particle structure and size, which affect release properties. Various techniques available for characterizing particle structural properties and size distribution are reviewed. CS particulate carriers with different structures can achieve various release patterns, including zero-order, multi-pulsed, and pulse-triggered. Mathematical models have an unavoidable role in understanding release mechanisms and their interrelationships. Moreover, models help identify the key structural characteristics, thus saving experimental time. Furthermore, by investigating the close relation between preparation process parameters and particulate structural characteristics as well as their effect on release properties, a novel "on-demand" strategy for the design of drug delivery devices may be developed. This reverse strategy involves designing the production process and the related particles' structure based on the targeted release pattern.
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Affiliation(s)
- Jiaqi Weng
- Université de Lorraine, LIBio, F-54000 Nancy, France
- Université de Lorraine, CNRS, LCPM, F-54000 Nancy, France
| | - Alain Durand
- Université de Lorraine, CNRS, LCPM, F-54000 Nancy, France
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2
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Çiçek Kırkayak N, Kondolot Solak E. Controlled release of theophylline from ethyl cellulose coated PVA/NaCMC-theophylline microspheres. INT J POLYM MATER PO 2022. [DOI: 10.1080/00914037.2022.2063288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
| | - Ebru Kondolot Solak
- Department of Advanced Technologies, Gazi University, Ankara, Turkey
- Department of Chemistry and Chemical Processing Technologies, Technical Sciences Vocational School, Gazi University, Ankara, Turkey
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3
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Lee JS, Oh H, Sung D, Lee JH, Choi WI. High Solubilization and Controlled Release of Paclitaxel Using Thermosponge Nanoparticles for Effective Cancer Therapy. Pharmaceutics 2021; 13:1150. [PMID: 34452111 PMCID: PMC8398058 DOI: 10.3390/pharmaceutics13081150] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/19/2021] [Accepted: 07/23/2021] [Indexed: 12/12/2022] Open
Abstract
Cancer, which is a leading cause of death, contributes significantly to reducing life expectancy worldwide. Even though paclitaxel (PTX) is known as one of the main anticancer drugs, it has several limitations, including low solubility in aqueous solutions, a limited dosage range, an insufficient release amount, and patient resistance. To overcome these limitations, we suggest the development of PTX-loaded thermosponge nanoparticles (PTX@TNP), which result in improved anticancer effects, via a simple nanoprecipitation method, which allows the preparation of PTX@TNPs with hydrophobic interactions without any chemical conjugation. Further, to improve the drug content and yield of the prepared complex, the co-organic solvent ratio was optimized. Thus, it was observed that the drug release rate increased as the drug capacity of PTX@TNPs increased. Furthermore, increasing PTX loading led to considerable anticancer activity against multidrug resistance (MDR)-related colorectal cancer cells (HCT 15), implying a synergistic anticancer effect. These results suggest that the solubilization of high drug amounts and the controlled release of poorly water-soluble PTX using TNPs could significantly improve its anticancer therapy, particularly in the treatment of MDR-p-glycoprotein-overexpressing cancers.
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Affiliation(s)
- Jin Sil Lee
- Center for Convergence Bioceramic Materials, Convergence R&D Division, Korea Institute of Ceramic Engineering and Technology, 202, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju 28160, Korea; (J.S.L.); (H.O.); (D.S.); (J.H.L.)
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Cheomdan-gwagiro 123, Buk-gu, Gwangju 61005, Korea
| | - Hyeryeon Oh
- Center for Convergence Bioceramic Materials, Convergence R&D Division, Korea Institute of Ceramic Engineering and Technology, 202, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju 28160, Korea; (J.S.L.); (H.O.); (D.S.); (J.H.L.)
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Cheomdan-gwagiro 123, Buk-gu, Gwangju 61005, Korea
| | - Daekyung Sung
- Center for Convergence Bioceramic Materials, Convergence R&D Division, Korea Institute of Ceramic Engineering and Technology, 202, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju 28160, Korea; (J.S.L.); (H.O.); (D.S.); (J.H.L.)
| | - Jin Hyung Lee
- Center for Convergence Bioceramic Materials, Convergence R&D Division, Korea Institute of Ceramic Engineering and Technology, 202, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju 28160, Korea; (J.S.L.); (H.O.); (D.S.); (J.H.L.)
| | - Won Il Choi
- Center for Convergence Bioceramic Materials, Convergence R&D Division, Korea Institute of Ceramic Engineering and Technology, 202, Osongsaengmyeong 1-ro, Osong-eup, Heungdeok-gu, Cheongju 28160, Korea; (J.S.L.); (H.O.); (D.S.); (J.H.L.)
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4
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Abbasi S, Sato Y, Kajimoto K, Harashima H. New Design Strategies for Controlling the Rate of Hydrophobic Drug Release from Nanoemulsions in Blood Circulation. Mol Pharm 2020; 17:3773-3782. [DOI: 10.1021/acs.molpharmaceut.0c00542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Saed Abbasi
- Innovation Center of NanoMedicine (iCONM), Kawasaki Institute of Industrial Promotion, Tonomachi 3-25-14, Kawasaki 210-0821, Japan
| | - Yusuke Sato
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo 060 0812, Hokkaido, Japan
| | - Kazuaki Kajimoto
- Health Research Institute, National Institute of Advanced Industrial Science and Technology, 2217-14 Hayashi-cho, Takamatsu 761-0395, Kagawa, Japan
| | - Hideyoshi Harashima
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo 060 0812, Hokkaido, Japan
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5
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Cholesterol modulates the liposome membrane fluidity and permeability for a hydrophilic molecule. Food Chem Toxicol 2018; 113:40-48. [PMID: 29337230 DOI: 10.1016/j.fct.2018.01.017] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/09/2018] [Accepted: 01/11/2018] [Indexed: 01/27/2023]
Abstract
The effect of cholesterol (CHOL) content on the permeability and fluidity of dipalmitoylphosphatidylcholine (DPPC) liposome membrane was investigated. Liposomes encapsulating sulforhodamine B (SRB), a fluorescent dye, were prepared by reverse phase evaporation technique (REV) at various DPPC:CHOL molar ratios (from 100:0 to 100:100). The release kinetics of SRB was studied during 48 h in buffer (pH 7.4) containing NaCl at 37 °C. The DPPC:CHOL formulations were also characterized for their size, polydispersity index and morphology. Increasing CHOL concentration induced an increase in the mean liposomes size accompanying with a shape transition from irregular to nanosized, regular and spherical vesicles. The release kinetics of SRB showed a biphasic pattern; the release data was then analyzed using different mathematical models. On the overall, the SRB release was governed by a non-Fickian diffusion during the first period (0-10 h) while it followed a Fickian diffusion between 10 and 48 h. Changes in DPPC liposome membrane fluidity of various batches (CHOL% 0, 10, 20, 30 and 100) were monitored by using 5- and 16 doxyl stearic acids (DSA) as spin labels. CHOL induced a decrease in the bilayer fluidity. Concisely, CHOL represents a critical component in modulating the release of hydrophilic molecules from lipid vesicles.
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6
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Thakare M, Israel B, Garner S, Ahmed H, Elder D, Capomacchia A. Nonionic surfactant structure on the drug release, formulation and physical properties of ethylcellulose microspheres. Pharm Dev Technol 2016; 22:418-425. [DOI: 10.1080/10837450.2016.1221431] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Mohan Thakare
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA
| | | | - Solomon Garner
- Department RTRN-Data Coordinating Center, Jackson State University, Jackson, MS, USA
| | - Hisham Ahmed
- Pharmaceutical International Inc., Hunt Valley, MD, USA
| | - Deborah Elder
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA
| | - Anthony Capomacchia
- School of Pharmacy, Department of Pharmaceutical Sciences, Lebanese American University, Byblos, Lebanon
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7
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Werzer O, Baumgartner R, Zawodzki M, Roblegg E. Particular film formation of phenytoin at silica surfaces. Mol Pharm 2014; 11:610-6. [PMID: 24417472 PMCID: PMC3915752 DOI: 10.1021/mp4006479] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Given the increasing number of poorly soluble and thus poorly bioavailable active pharmaceutical materials, there is a demand for innovative formulation platforms for such molecules. Thus a focus on enhancing dissolution properties of poorly soluble drugs exists. Within this study, the spin coating of acetone solutions containing 5,5-diphenyl-2,4-imidazolidinedione (phenytoin) in various concentrations is evaluated. The results reveal strong variations of the morphology of deposited phenytoin crystals at silica surfaces. Individual separated particles are obtained on low phenytoin concentrations, and closely packed particular films form when the concentration is increased. As the material is isomorphic, these various morphologies have the same crystalline structure. Dissolution experiments reveal that both the apparent maximum solubility and as the dissolution rate are strongly enhanced compared to bulk powder, suggesting that formulation based on this preparative technique will allow overcoming the low solubility problematic for a variety of drugs.
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Affiliation(s)
- Oliver Werzer
- Institute of Pharmaceutical Sciences, Department of Pharmaceutical Technology, University of Graz , 8010 Graz, Austria
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8
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Obeidat WM, Price JC. Viscosity of polymer solution phase and other factors controlling the dissolution of theophylline microspheres prepared by the emulsion solvent evaporation method. J Microencapsul 2010. [DOI: 10.3109/02652040309178049] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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9
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Nilkumhang S, Alhnan MA, McConnell EL, Basit AW. Drug distribution in enteric microparticles. Int J Pharm 2009; 379:1-8. [DOI: 10.1016/j.ijpharm.2009.05.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 05/28/2009] [Accepted: 05/28/2009] [Indexed: 10/20/2022]
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10
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Chen W, He J, Olson JJ, Robert Lu D. Direct Intracerebral Delivery of Carboplatin from PLGA Microspheres Against Experimental Malignant Glioma in Rats. Drug Deliv 2009; 5:101-10. [DOI: 10.3109/10717549809031385] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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11
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Obeidat WM, Obeidat SM, Alzoubi NM. Investigations on the physical structure and the mechanism of drug release from an enteric matrix microspheres with a near-zero-order release kinetics using SEM and quantitative FTIR. AAPS PharmSciTech 2009; 10:615-23. [PMID: 19444619 PMCID: PMC2690803 DOI: 10.1208/s12249-009-9240-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Accepted: 04/09/2009] [Indexed: 11/30/2022] Open
Abstract
The objectives of this study were to evaluate the physical structure and the release mechanisms of theophylline microspheres made of Eudragit S 100 polymer as an enteric polymer, combined with a nonerodible polymer, Eudragit RL 100. In the preparation process, polymer combinations (1:1) were dissolved in an organic solvent mixture composed of acetone and methanol at a specific ratio containing a theoretical drug loading of approximately 15%. Two microsphere formulations (LS1 and LS2) were prepared at two different total polymer concentrations (10% in LS1 and 12.7% in LS2). Dissolution studies were carried out using US Pharmacopeia Dissolution Apparatus II in an acidic medium for 8 h and in an acidic medium (2 h) followed by a slightly basic-buffered medium for 10 h. Both LS1 and LS2 microsphere formulations produced particles that were spherical in shape and had very narrow size distributions with one size fraction comprising 70-80% of the yield. Scanning electron microscopy and quantitative Fourier transform infrared were used for microsphere physical structure evaluation. Except for the absence of drug crystals, photomicrographs of both LS microspheres after dissolution in pH 1.2 and 7.2 buffer solutions were similar to those before dissolution. Dissolution results indicated the ability of LS microspheres to minimize drug release during the acid stage. However, in the slightly basic medium that followed the acidic stage, the drug release was sustained and controlled in its kinetics and data fitted to Peppas equation indicated a case II transport suggesting that the drug release is mainly through swelling/erosion mechanism.
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Affiliation(s)
- Wasfy M. Obeidat
- />College of Pharmacy, University of Sharjah, P.O. Box 27272, Sharjah, UAE
- />Jordan University of Science and Technology, P.O. Box 3030, Irbid, 22110 Jordan
| | - Safwan M. Obeidat
- />College of Science, Philadelphia University, P.O. Box 1, Amman, 11392 Jordan
| | - Nizar M. Alzoubi
- />College of Pharmacy, Applied Science University, P.O. Box 926296, Amman, 11931 Jordan
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12
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Nilkumhang S, Basit AW. The robustness and flexibility of an emulsion solvent evaporation method to prepare pH-responsive microparticles. Int J Pharm 2009; 377:135-41. [PMID: 19515519 DOI: 10.1016/j.ijpharm.2009.03.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 03/14/2009] [Accepted: 03/20/2009] [Indexed: 10/21/2022]
Abstract
A microparticle preparation method based on an emulsion of ethanol in liquid paraffin stabilised using sorbitan sesquioleate which produces enteric microparticles of excellent morphology, size and pH-sensitive drug release was assessed for its robustness to changes in formulation and processing parameters. Prednisolone and methacrylic acid and methyl methacrylate copolymer (Eudragit S) were the drug and polymer of choice. Emulsion solvent evaporation procedures are notoriously sensitive to changes in methodology and so emulsion stirring speed, drug loading, polymer concentration and surfactant (emulsifier) concentration were varied; microparticle size, encapsulation efficiency, yield and in vitro dissolution behaviour were assessed. The yield and encapsulation efficiency remained high under all stirring speeds, drug loadings and polymer concentrations. This suggests that the process is flexible and efficiency can be maintained. Surfactant concentration was an important parameter; above an optimum concentration resulted in poorly formed particles. All processing parameters affected particle size but this did not alter the acid resistance of the microparticles. At high pH values the smaller microparticles had the most rapid drug release. In conclusion, the microparticle preparation method was resistant to many changes in processing, although surfactant concentration was critical. Manipulation of particle size can be used to modify the drug release profiles without adversely affecting the gastro-resistant properties of these pH-responsive microparticles.
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Affiliation(s)
- Suchada Nilkumhang
- Department of Pharmaceutics, The School of Pharmacy, University of London, 29/39 Brunswick Square, London WC1N 1AX, UK
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13
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Palomo ME, Ballesteros MP, Frutos P. Diclofenac Sodium Microcapsules: In Vitro Testing Considerations. Drug Dev Ind Pharm 2008. [DOI: 10.3109/03639049709149804] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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14
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Obeidat WM, Price JC. Preparation andin vitroevaluation of propylthiouracil microspheres made of Eudragit RL 100 and cellulose acetate butyrate polymers using the emulsion-solvent evaporation method. J Microencapsul 2008; 22:281-9. [PMID: 16019914 DOI: 10.1080/02652040500100907] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The objectives of this investigation are to evaluate the encapsulation efficiency of the anti-thyroid agent 6-n-propyl-2-thiouracil using two polymers of different characteristics (cellulose acetate butyrate polymer, (CAB-551-0.01) and ammonio methacrylate copolymer (Eudragit RL 100) and to study the effect of this encapsulation on the drug release properties. Polymers were used separately and in combination to prepare different microspheres. Also, the effect of polymer solution phase viscosity was studied for each of the polymers and for their combinations. An Ostwald viscometer was used to evaluate the relative viscosities of polymer solution phases and their combinations. Microspheres with 25% theoretical drug loading of 6-n-propyl-2-thiouracil core material were prepared by the emulsion solvent evaporation method. Microspheres prepared from CAB-551-0.01, which has higher relative polymer phase viscosity than Eudragit RL 100, showed significantly lower drug release rates and a noticeable lag time. Polymer combinations of CAB-551-0.01 and Eudragit RL 100 (1:1) showed an interesting synergistic increase in relative polymer solution viscosities at all concentrations. Unlike microspheres prepared from the two polymers separately which follow Higuchi spherical matrix release kinetics, microspheres prepared using a combination (1:1) of the two polymers showed near zero order with faster rates compared to those prepared using CAB-551-0.01 equivalent polymer concentrations. The results of this study suggest that 6-n-propyl-2-thiouracil was successfully and efficiently encapsulated and release rates of matrix microspheres are related to polymer solution phase viscosity, but when polymer combinations were used other factors such as structural effects must be considered.
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Affiliation(s)
- W M Obeidat
- Jordan University of Science and Technology, Irbid, Jordan.
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15
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Literature Alerts. J Microencapsul 2008. [DOI: 10.3109/02652049209021254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Literature Alerts. J Microencapsul 2008. [DOI: 10.3109/02652049209040490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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17
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Sobral MCCM, Sobral AJFN, Guthrie JT, Gil MH. Ketotifen controlled release from cellulose acetate propionate and cellulose acetate butyrate membranes. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:677-82. [PMID: 17619990 DOI: 10.1007/s10856-007-0168-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 02/12/2007] [Indexed: 05/16/2023]
Abstract
Ketotifen was immobilised in cellulose acetate propionate (CAP) membranes and in cellulose acetate butyrate (CAB) membranes. The characteristics of each system were evaluated under a range of experimental conditions. The topography and uniformity of the membranes was assessed using scanning electron microscopy. The release characteristics associated with Ketotifen were monitored spectrophotometrically. The swelling capacity of the membranes was evaluated and attributed to the combined effects of diffusion and of complex dissociation, during swelling. The materials produced were able to provide controlled release of Ketotifen due to their controlled swelling behaviour and adequate release properties. The results showed that the release of Ketotifen from the CAB membranes is higher but the release from the CAP membranes is more uniform.
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18
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Obeidat WM, Obaidat IM. Effect of the dispersion of Eudragit S100 powder on the properties of cellulose acetate butyrate microspheres containing theophylline made by the emulsion-solvent evaporation method. J Microencapsul 2008; 24:263-73. [PMID: 17454437 DOI: 10.1080/02652040701233648] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The dispersion/incorporation of Eudragit S100 powder as a filler in cellulose acetate butyrate (CAB-551-0.01) microsphere containing theophylline was investigated as a means of controlling drug release. Microspheres of CAB-551-0.01 of different polymer solution concentrations/viscosities were prepared (preparations Z(0), Z(A), Z(B) and Z(C)) and evaluated and compared to microspheres of a constant concentration of CAB-551-0.01 containing different amounts of Eudragit S100 powder as a filler (preparations X(A), X(B) and X(C)). The organic solvent acetonitrile used was capable of dissolving the matrix former CAB-551-0.01 only but not Eudragit S100 powder in the emulsion-solvent evaporation method. The CAB-551-0.01 concentration in Z(A), Z(B) and Z(C) was equal to the total polymer concentration (CAB-551-0.01 and Eudragit S100 powder) in X(A), X(B) and X(C), respectively. Scanning electron microscopy (SEM) was used to identify microspheres shape and morphology. In vitro dissolution studies were carried out on the microspheres at 37 degrees C (+/-0.5 degrees C) at two successive different pH media (1.2 +/- 0.2 for 2 h and 6.5 +/- 0.2 for 10 h). Z preparations exhibited low rates of drug release in the acidic and the slightly neutral media. On the other hand, X preparations showed an initial rapid release in the acidic medium followed by a decrease in the release rate at the early stage of dissolution in the slightly neutral pH which could be due to some relaxation and gelation of Eudragit S100 powder to form a gel network before it dissolves completely allowing the remained drug to be released.
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Affiliation(s)
- Wasfy M Obeidat
- Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan.
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19
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Scarfato P, Avallone E, Iannelli P, Aquino RP, Lauro MR, Rossi A, Acierno D. Quercetin microspheres by solvent evaporation: Preparation, characterization and release behavior. J Appl Polym Sci 2008. [DOI: 10.1002/app.28365] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Miyazaki Y, Yakou S, Takayama K. Effect of Amount of Water in Dispersed Phase on Drug Release Characteristics of Dextran Microspheres Prepared by Emulsion-Solvent Evaporation Process. Biol Pharm Bull 2007; 30:543-6. [PMID: 17329853 DOI: 10.1248/bpb.30.543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Microspheres containing theophylline (TH) were prepared from a hydrophobic dextran derivative by emulsion solvent evaporation method. The objective of this study was to evaluate the effects of poor solvent in dispersed phase on the particle properties and drug release characteristics of the microspheres. Mixtures of acetone and water were used as the dispersed phase and liquid paraffin as the continuous phase. The amount of water (poor solvent for polymer) was varied from 0.5 to 2 ml in 15 ml of dispersed phase. Drug release from the microspheres was examined using JPXIV 1st Fluid (pH 1.2) containing 0.02% Tween 20, and their structure was analyzed by scanning electron microscopy (SEM). The drug release behaviors were greatly affected by the amount of water. The percentage released until 8 h were 89% and 23% for 0.5 and 2.0 ml of water, respectively. The release mechanism shifted from Fickian diffusion to zero-order transport as the amount of water increased. According to SEM observations, TH was uniformly distributed over the entire microsphere prepared using 0.5 ml of water, and existed in the center of the microsphere, having a core-shell structure, when prepared using 2 ml of water. The amount of poor solvent in the dispersed phase was found to be a crucial factor determining the internal structure of microspheres and drug release characteristics.
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Affiliation(s)
- Yasunori Miyazaki
- Department of Pharmacy, Tokyo Women's Medical University Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan.
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21
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Yang JF, Qiu LY, Jin Y, Zhang JX. Thymosin-loaded enteric microspheres for oral administration: Preparation and in vitro release studies. Int J Pharm 2005; 301:41-7. [PMID: 16009514 DOI: 10.1016/j.ijpharm.2005.05.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 04/17/2005] [Accepted: 05/06/2005] [Indexed: 10/25/2022]
Abstract
Thymosin, a water-soluble polypeptide compound, was encapsulated within enteric microspheres of acrylic acid resin II by modified oil in oil (o/o) emulsion solvent evaporation method. The mixture emulsifier composed of lecithin and Span 80 was critical to the formation of sphere-shaped thymosin microparticles. Optimizing process parameters, such as the volume ratio of organic solvent to water, initial drug feed and polymer concentration, resulted in high drug encapsulation efficiency of 89.7% (6% polymer concentration and 0.5% initial drug feed). In vitro release studies suggested that thymosin release from microspheres exhibited pH dependent profiles. For formulation with 6% polymer concentration and 0.5% initial drug feed, 68.7% thymosin was released within 4h in pH 6.8 PBS buffer, while only 6.5% was observed in acid medium.
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Affiliation(s)
- Ju Fei Yang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310031, PR China
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22
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Raman C, Berkland C, Kim K, Pack DW. Modeling small-molecule release from PLG microspheres: effects of polymer degradation and nonuniform drug distribution. J Control Release 2005; 103:149-58. [PMID: 15773062 DOI: 10.1016/j.jconrel.2004.11.012] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Modeling release of small molecules from degradable microspheres is important to the design of controlled-release drug delivery systems. Release of small molecules from poly(d,l-lactide-co-glycolide) (PLG) particles is often controlled by diffusion of the drug through the polymer and by polymer degradation. In this study, a model is developed to independently determine the contributions of each of these factors by fitting the release of piroxicam from monodisperse 50-microm microspheres made with PLG of different initial molecular weights. The dependence of the drug diffusivity on polymer molecular weight was determined from in vitro release of piroxicam from monodisperse 10-microm PLG microspheres, and the polymer degradation rate was experimentally measured using gel permeation chromatography. The model also incorporates the effect of nonuniform drug distribution within the microspheres, which is obtained from confocal fluorescence microscopy. The model results agree well with experiments despite using only one fit parameter.
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Affiliation(s)
- Chandrashekar Raman
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801, United States
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23
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Wang YM, Sato H, Horikoshi I. In vitro and in vivo evaluation of taxol release from poly(lactic-co-glycolic acid) microspheres containing isopropyl myristate and degradation of the microspheres. J Control Release 1997. [DOI: 10.1016/s0168-3659(97)00082-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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24
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Palomo ME, Ballesteros MP, Frutos P. Solvent and plasticizer influences on ethylcellulose-microcapsules. J Microencapsul 1996; 13:307-18. [PMID: 8860686 DOI: 10.3109/02652049609026018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Variations in microencapsulation processes give rise to different products and it seems there are no firm rules. It is thus difficult to know what kind of product will be obtained before the research is carried out. Changes in temperature, rate, time and type of stirring can cause great modifications in the system, most of which are responsible for variations in standard techniques. In our study, we investigate the solvent influence on ethylcellulose (EC) microcapsule formation. We have selected four different solvents: ethanol as an aqueous solvent and acetone, chloroform and toluene as organic solvents. Diclofenac sodium (DFNa), a non-steroidal anti-inflammatory agent, has been used as an encapsulated substance as it is inactivated in the gastric juices. This polymer and microencapsulation process was selected after an exhaustive study with different polymers and processes. Once the solvent influence was determined, ethylphthalate was incorporated in one type of microcapsule in order to study the influence of this plasticizer on drug release by the modification of film-permeability.
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Affiliation(s)
- M E Palomo
- Departmento de Farmacia y Tecnologia Farmaceutica, Universidad Complutense de Madrid, Madrid, Spain
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25
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Abu-Izza KA, Garcia-Contreras L, Lu DR. Preparation and evaluation of sustained release AZT-loaded microspheres: optimization of the release characteristics using response surface methodology. J Pharm Sci 1996; 85:144-9. [PMID: 8683438 DOI: 10.1021/js950353+] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The purpose of the study was to prepare and optimize a sustained release formulation of zidovudine (AZT). Ethylcellulose microspheres containing AZT were prepared using an emulsification/solvent evaporation technique. The critical formulation variables were emulsifier concentration, drug to polymer ratio, and ethyl acetate concentration in the internal phase of the emulsion. The time to release 85% of the contents of the microspheres (t85) was used as a measure for the release time. A second-year polynomial equation was fitted to the release data to systemically investigate the effect of the formulation variables on the release rate. This equation was then used to predict t85 in the optimum region. The t85 was found to be dependent on the three formulation variables, with strong interactions observed between these variables. The microspheres were characterized in terms of their particle size and surface morphology. The study indicated no overall correlation between the mean diameter of the microspheres and the t85.
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Affiliation(s)
- K A Abu-Izza
- Department of Pharmaceutics, College of Pharmacy, University of Georgia, Athens 30602, USA
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26
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Bhardwaj SB, Shukla AJ, Collins CC. Effect of varying drug loading on particle size distribution and drug release kinetics of verapamil hydrochloride microspheres prepared with cellulose esters. J Microencapsul 1995; 12:71-81. [PMID: 7730959 DOI: 10.3109/02652049509051128] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Microspheres containing two different drug loadings of a calcium channel blocker, verapamil hydrochloride, were prepared with three different cellulose esters namely cellulose acetate (CA), cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) of approximately similar molecular weights using the emulsion-solvent evaporation method. Increasing the drug loading from 33.3 to 50% w/w increased the geometric mean diameter of the microspheres as well as the T50% values, i.e. time required to release 50% of the drug from microspheres prepared with all the three cellulose esters. Drug release from the microspheres was affected by the nature of polymer. Mathematical modelling of drug release data by fitting the data to various equations revealed that the data did not fit the conventional Higuchi's and Baker-Lonsdale's models for drug release from spherical matrices. Instead, the data fitted the log-probability and the Weibull models quite well.
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Affiliation(s)
- S B Bhardwaj
- SmithKline Beecham, Parsippanny, NJ 07054-3884, USA
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27
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Vilivalam VD, Adeyeye CM. Development and evaluation of controlled-release diclofenac microspheres and tabletted microspheres. J Microencapsul 1994; 11:455-70. [PMID: 7931945 DOI: 10.3109/02652049409034263] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Diclofenac wax microspheres were prepared using the congealable dispersephase encapsulation method. Emulsifiers, glyceryl monostearate (GMS) and stearic acid, were added to improve the efficiency of emulsification. Microspheres containing either of the emulsifiers or both showed a high drug content (80-90%) and the particle size distribution was log-normal compared with microspheres without the emulsifiers. Increase in GMS concentration decreased the drug release and, in contrast, stearic acid appeared to channel the drug from the wax matrix. The addition of both emulsifiers at different concentrations modified drug release. Increase in dispersant (PVP) concentration, and decrease in microsphere size accelerated the rate of drug release. Higuchi/Baker Londsdale spherical matrix dissolution kinetics was followed. Disintegrating tableted microspheres were prepared with Avicel and Explotab. With the increase in compression pressure the crushing force and disintegrating time increased, but the thickness decreased, and the dissolution profile did not appear to be affected. Slightly faster release was noticed with tableted microspheres compared with that of uncompressed microspheres. Tablets containing 40 and 60% microsphere loadings had disintegration times of 5.12 +/- 0.63 and 57.73 +/- 3.53 min, respectively. In contrast, tablet formulation containing 80% microsphere load had a significant increase in disintegration time (130.83 +/- 4.26 min). The dissolution from this formulation also showed a lag time of 30 min in contrast with the other two formulations, which showed no lag time. Increased microsphere size from 215 to 630 microns had no effect on tableting properties (such as hardness and thickness); and only very little effect on dissolution. The microspheres appeared deformed but intact irrespective of compression pressures on scanning electron micrographs.
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Affiliation(s)
- V D Vilivalam
- Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282
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