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1.
RH Fahmy 《AAPS PharmSciTech》2012,13(3):990-1004
Multiparticulate floating drug delivery systems have proven potential as controlled-release gastroretentive drug delivery systems that avoid the "all or none" gastric emptying nature of single-unit floating dosage forms. An objective of the presence investigation was to develop calcium silicate (CaSi)/calcium alginate (Ca-Alg)/hydroxypropyl methylcellulose (HPMC) mucoadhesive-floating beads that provide time- and site-specific drug release of alfuzosin hydrochloride (Alf). Beads were prepared by simultaneous internal and external gelation method utilizing 3(2) factorial design as an experimental design; with two main factors evaluated for their influence on the prepared beads; the concentration of CaSi as floating aid (X (1)) and the percentage of HPMC as viscosity enhancer and mucoadhesive polymer (X (2)), each of them was tested in three levels. Developed formulations were evaluated for yield, entrapment efficiency, particle size, surface topography, and buoyancy. Differential scanning calorimetry, Fourier transform infrared spectroscopy, in vitro drug release, as well as in vitro mucoadhesion using rat stomach mucosal membrane were also conducted. Percentage yield and entrapment efficiency ranged from 57.03% to 78.51% and from 49.78% to 83.26%, respectively. Statistical analysis using ANOVA proved that increasing the concentration of either CaSi or HPMC significantly increased the beads yield. Both CaSi and HPMC concentrations were found to significantly affect Alf release from the beads. Additionally, higher CaSi concentration significantly increased the beads diameter while HPMC concentration showed significant positive effect on the beads mucoadhesive properties. CaSi/Ca-Alg/HPMC beads represent simple floating-mucoadhesive gastroretentive system that could be useful in chronopharmacotherapy of benign prostatic hyperplasia. 相似文献
2.
Characterization of calcium alginate and chitosan-treated calcium alginate gel beads entrapping allyl isothiocyanate 总被引:1,自引:0,他引:1
Won-Tae Kim Hee Chung Il-Shik Shin Kit L. Yam Donghwa Chung 《Carbohydrate polymers》2008,71(4):566-573
Calcium alginate (CA), chitosan-coated calcium alginate (CCA-I), and chitosan–calcium alginate complex (CCA-II) gel beads, in which an oil-in-water emulsion containing allyl isothiocyanate (AITC) was entrapped, were prepared and characterized for efficient oral delivery of AITC. The AITC entrapment efficiency was 81% for CA gel beads, whereas about 30% lower values were determined for the chitosan-treated gel beads. Swelling studies showed that all the gel beads suddenly shrunk in simulated gastric fluid (pH 1.2). In simulated intestinal fluid (pH 7.4), CA and CCA-I gel beads rapidly disintegrated, whereas CCA-II gel beads highly swelled without degradation probably due to the strong chitosan–alginate complexation. Release studies revealed that most entrapped AITC was released during the shrinkage, degradation, or swelling of the gel beads, and the chitosan treatments, especially the chitosan–alginate complexation, were effective in suppressing the release. CCA-II gel beads showed the highest bead stability and AITC retention under simulated gastrointestinal pH conditions. 相似文献
3.
The objective of this study was to develop a multiunit sustained release dosage form of diltiazem using a natural polymer
from a completely aqueous environment. Diltiazem was complexed with resin and the resinate-loaded carboxymethyl xanthan (RCMX)
beads were prepared by interacting sodium carboxymethyl xanthan (SCMX), a derivatized xanthan gum, with Al+3 ions. The beads were evaluated for drug entrapment efficiency (DEE) and release characteristics in enzyme free simulated
gastric fluid (SGF, HCl solution, pH 1.2) and simulated intestinal fluid (SIF, USP phosphate buffer solution, pH 6.8). Increase
in gelation time from 5 to 20 min and AlCl3 concentration from 1 to 3% decreased the DEE respectively from 95 to 79% and 88.5 to 84.6%. However, increase in gum concentration
from 1.5 to 2.5% increased the DEE from 86.5 to 90.7%. The variation in DEE was related to displacement of drug from the resinate
by the gel forming Al+3 ions. While 75–82% drug was released in 2 h in SGF from various beads, 75 to 98% drug was released in 5 hour in SIF indicating
the dependence of drug release on pH of dissolution media. Although the beads maintained their initial integrity throughout
the dissolution process in both media, as evident from scanning electron microscopic studies, the faster release in SGF was
accounted for higher swelling of the beads in SGF than in SIF. When release data (up to 60%) was fitted in power law expression,
the drug release was found to be controlled by diffusion with simultaneous relaxation phenomena. 相似文献
4.
This work investigates the development, optimization and in vitro evaluation of liquid paraffin-entrapped multiple-unit alginate-based floating system containing cloxacillin by emulsion-gelation method for gastro retentive delivery. The effect of process variables like drug to polymer ratio by weight, and liquid paraffin to water ratio by volume on various physicochemical properties in case of liquid paraffin-entrapped calcium alginate beads containing cloxacillin applicable to drug entrapment efficiency, density and drug release was optimized using 32 factorial design and analyzed using response surface methodology. The observed (actual values) responses were coincided well with the predicted values, given by the optimization technique. The optimized beads showed drug entrapment efficiency of 64.63 ± 0.78%, density of 0.90 ± 0.05 g/cm3, and drug release of 56.72 ± 0.85% in simulated gastric fluid (pH 1.2) after 8 h with floating lag time of 8.45 min and floated well over 12 h in simulated gastric fluid (pH 1.2). The average size of all dried beads ranged from 1.73 ± 0.04 to 1.97 ± 0.08 mm. The beads were characterized by SEM and FTIR for surface morphology and excipients-drug interaction analysis, respectively. All these beads showed prolonged sustained release of cloxacillin over 8 h in simulated gastric fluid (pH 1.2). The cloxacillin release profile from liquid paraffin beads followed Korsmeyer-Peppas model over a period of 8 h with anomalous (non-Fickian) diffusion mechanism for drug release. 相似文献
5.
Response surface methodology was used to optimize bead preparation conditions, including CaCl2 concentration (X1), hydroxypropylmethylcellulose concentration (X2), and bead-hardening time (X3), for the sustained-release of catechin from the calcium pectinate gel beads reinforced with liposomes and hydroxypropylmethylcellulose into simulated gastric fluid (SGF) and intestinal fluid (SIF). The optimized values of X1, X2, and X3 were found to be 5.82%, 0.08%, and 10.29 min, respectively. The beads prepared according to the optimized conditions released only about half of the entrapped catechin into SGF while most of the entrapped catechin was released into SIF after 24 h incubation. 相似文献
6.
The aim of the present research work was to develop release modulated beads of losartan potassium complexed with anion exchange
resin, Duolite AP143 (cholestyramine). Chitosan was selected as a hydrophilic polymer for the formation of beads which could
sustain the release of the drug up to 12 h, along with drug resin complex (DRC). Chitosan beads were prepared using an in-liquid
curing method by ionotropic cross-linking or interpolymer linkage with sodium tripolyphosphate (TPP). The formulation of the
beads was optimized for entrapment efficiency and drug release using 32 full factorial design. The independent variables selected were DRC/chitosan and percent of TPP. The optimization model was
validated for its performance characteristics. Studies revealed that as the concentration of chitosan and TPP was increased,
entrapment efficiency and the drug release were found to increase and decrease, respectively. The swelling capacity of chitosan–TPP
beads decreased with increasing concentration of TPP. The effect of chitosan concentration and percentage of TPP solution
used for cross-linking on entrapment efficiency and drug release rate was extensively investigated. Optimized beads were subjected
to in vivo studies in Wistar albino rats to determine the mean arterial blood pressure and compared with marketed formulation. The pharmacodynamic
study demonstrates steady blood pressure control for optimized formulation as compared to fluctuated blood pressure for the
marketed formulation. 相似文献
7.
Different hydroxypropyl methylcellulose (HPMC)/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed aiming to evaluate the influence of both components ratio in the control release of a water-soluble drug (theophylline). In order to characterise the matrix tablets, swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralised water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid). The HPMC/ADCP ratio has turned out to be the determinant in the matrix behaviour: the HPMC characteristic swelling behaviour was modulated, in some cases, by the ADCP characteristic acidic dissolution. When the HPMC/ADCP ratio was ≥0.69, buoyancy, continuous swelling and low theophylline dissolution rate from the matrices (H1, H2 and H3) were observed in all dissolution media. Consequently, these formulations could be adequate as gastro-retentive drug delivery systems. Additionally, HPMC/ADCP ratio ≤0.11 (H5 and H6) induces a pH-dependent drug release which could be applied to design control drug release enteric formulations (with a suitable enteric coating). Finally, a HPMC/ADCP ratio between 0.11 and 0.69 (H4) yield a gastrointestinal controlled drug release, due to its time-dependent buoyancy (7 h) and a total drug delivery in 17 h in simulated colonic fluid.Key words: anhydrous dibasic calcium phosphate, hydroxypropyl methylcellulose, matrix tablets, oral controlled release, theophylline 相似文献
8.
Hee-Jung Park Chang-Moon Lee Yong-Bok Lee Ki-Young Lee 《Biotechnology and Bioprocess Engineering》2006,11(6):526-529
The aim of this study was to prepare cyclosporin A-loaded liposome (CyA-Lip) as an oral delivery carrier, with their encapsulation
into microspheres based on alginate or extracellular polysaccharide (EPS) p-m 10356. The main advantage of liposomes in the
microspheres (LIMs) is to improve the restricted drug release property from liposomes and their stability in the stomach environment.
Alginate microspheres containing CyA-Lip were prepared with a spray nozzle; CyA-Liploaded EPS microspheres were also prepared
using a w/o emulsion method. The shape of the LIMs was spherical and uniform, and the particle size of the alginate-LIMs ranged
from 5 to 10 μm, and that of the EPS-LIMs was about 100 μm. In a release test, release rate of CyA in simulated intestinal
fluid (SIF) from the LIMs was significantly enhanced compared to that in simulated gastric fluid (SGF). In addition, the CyA
release rates were slower from formulations containing the liposomes compared to the microspheres without the liposome. Therefore,
alginate-and EPS-LIMs have the potential for the controlled release of CyA and as an oral delivery system. 相似文献
9.
Stomach-Specific Controlled Release Gellan Beads of Acid-Soluble Drug Prepared by Ionotropic Gelation Method 总被引:1,自引:0,他引:1
The purpose of the present work was the development and evaluation of stomach-specific controlled release mucoadhesive drug
delivery system prepared by ionotropic gelation of gellan beads, containing acid-soluble drug amoxicillin trihydrate, using
32 factorial design with concentration of gellan gum and quantity of drug as variables. The study showed that beads prepared
in alkaline cross-linking medium have higher entrapment efficiency than the acidic cross-linking medium. The entrapment efficiency
was in the range of 32% to 46% w/w in acidic medium, which increased up to 60% to 90% w/w in alkaline medium. Batches with lowest, medium, and highest drug entrapment were subjected to chitosan coating to form a
polyelectrolyte complex film. As polymer concentration increases, entrapment efficiency and particle size increases. Scanning
electron microscopy revealed spherical but rough surface due to leaching of drug in acidic cross-linking solution, dense spherical
structure in alkaline cross-linking solution, and rough surface of chitosan-coated beads with minor wrinkles. The in vitro drug release up to 7 h in a controlled manner following the Peppas model (r = 0.9998). In vitro and in vivo mucoadhesivity study showed that beads have good mucoadhesivity and more than 85% beads remained adhered to stomach mucosa
of albino rat even after 7 h. In vitro growth inhibition study showed complete eradication of Helicobacter pylori. These results indicate that stomach-specific controlled release mucoadhesive system of amoxicillin gellan beads may be useful
in H. pylori treatment. 相似文献
10.
Context: Avanafil (AVA) is used in the treatment of erectile dysfunction, but is reported for its poor aqueous solubility. Solid lipid nanoparticles (SLNs) are lipid carriers that can greatly enhance drug solubility and bioavailability.Objective: This work was aimed to formulate and optimize AVA SLNs with subsequent loading into hydrogel films for AVA transdermal delivery.Materials and methods: AVA SLNs were prepared utilizing homogenization followed by ultra-sonication technique. The prepared SLNs were characterized for particle size, charge, surface morphology and drug content. The optimized SLNs formulation was incorporated into transdermal films prepared using HPMC and chitosan. Hydrogel films were evaluated for ex-vivo rat skin permeation using automated Franz diffusion cells. The permeation parameters and the release mechanism were evaluated. The transdermal permeation of the prepared AVA SLNs through the skin layers was studied using confocal laser scanning microscope.Results: Lipid concentration and % of oil in lipid had a pronounced effect on particle size while, entrapment efficiency was significantly affected by lipid concentration and % of cholesterol. The optimized AVA SLNs showed particle size and entrapment efficiency of 86?nm and 85.01%, respectively. TEM images revealed spherecity of the particles. High permeation parameters were observed from HPMC films loaded with AVA SLNs. The release data were in favor of Higuchi diffusion model. The prepared AVA SLNs were able to penetrate deeper in skin layers.Conclusion: HPMC transdermal film-loaded AVA SLNs is an effective and alternative to per-oral drug administration. 相似文献
11.
Liposomes, which had entrapped bovine serum albumin (BSA), were modified with diglucosamine by two methods. The liposome was prepared by a freeze-thawing method in the presence of the disaccharide, or the disaccharide was added to the liposome prepared in advance without it. To examine the effects of diglucosamine, the morphology, mean particle size, and zeta potential of both liposomes were compared with those of BSA-entrapping liposome prepared without the disaccharide. Diglucosamine caused no remarkable change in shape and no aggregation of the liposome. The presence of the disaccharide was confirmed on the surfaces of modified liposomes, and the entrapment of BSA into the liposomes was increased by the disaccharide. The entrapment behavior was affected by the way the disaccharide was added, and the difference in the way the BSA was entrapped was also indicated. 相似文献
12.
Liposomes, which had entrapped bovine serum albumin (BSA), were modified with diglucosamine by two methods. The liposome was prepared by a freeze-thawing method in the presence of the disaccharide, or the disaccharide was added to the liposome prepared in advance without it. To examine the effects of diglucosamine, the morphology, mean particle size, and zeta potential of both liposomes were compared with those of BSA-entrapping liposome prepared without the disaccharide. Diglucosamine caused no remarkable change in shape and no aggregation of the liposome. The presence of the disaccharide was confirmed on the surfaces of modified liposomes, and the entrapment of BSA into the liposomes was increased by the disaccharide. The entrapment behavior was affected by the way the disaccharide was added, and the difference in the way the BSA was entrapped was also indicated. 相似文献
13.
M. Tavakol E. Vasheghani-Farahani T. Dolatabadi-Farahani S. Hashemi-Najafabadi 《Carbohydrate polymers》2009,77(2):326-330
In the present study, spherical beads were prepared from a water-soluble chitosan (N,O-carboxymethyl chitosan, NOCC) and alginate with ionic gelation method. Then, swollen calcium–alginate–NOCC beads were coated with chitosan. To prepare drug loaded beads, sulfasalazine (SA) was added to the initial aqueous polymer solution. The effect of coating, as well as drying procedure, on the swelling behavior of unloaded beads and SA release of drug loaded ones were evaluated in simulated gastrointestinal tract fluid. The rate of swelling and drug release were decreased for air-dried and coated beads in comparison with freeze-dried and uncoated ones, respectively. No burst release of drug was observed from whole tested beads. Chitosan coated beads released approximately 40% of encapsulated drug in simulated gastric and small intestine tract fluid. Based on these results, the chitosan coated alginate–NOCC hydrogel may be used as potential polymeric carrier for colon-specific delivery of sulfasalazine. 相似文献
14.
Enas M. Elmowafy Gehanne A.S. Awad Samar Mansour Abd El-Hamid A. El-Shamy 《Carbohydrate polymers》2009,75(1):135-142
Floating famotidine loaded mineral oil-entrapped emulsion gel (MOEG) beads were prepared by the emulsion–gelation method. Different polysaccharides (sodium alginate and pectin), oil concentrations (10%, 20% and 30% w/w) and drug:polymer (D:P) ratios (1:1, 2:1 and 3:1) were used and their influence on beads uniformity, drug entrapment efficiency (DEE) and in vitro drug release, was studied. The results clearly indicated that retardation of drug release for 4 h was achieved by the oil hydrophobic diffusional barrier, especially in the presence of the compact network of alginate beads. Calcium alginate beads containing 20% oil and 2:1 D:P ratio, showed an optimum DEE of 88.32%. When evaluated in vivo, this formula displayed superior antiulcer activity (>2) over drug suspension or marketed conventional tablets. 相似文献
15.
The plant growth-promoting bacteria (PGPR) Raoultella planticola Rs-2 was encapsulated with the various blends of alginate, starch, and bentonite for development of controlled-release formulations.
The stability and release characteristics of these different capsule formulations were evaluated. The entrapment efficiency
of Rs-2 in the beads (capsules) was more than 99%. The diameter of dry beads ranged from 0.98 to 1.41 mm. The bacteria release
efficiency, swelling ratio, and biodegradability of the different bead formulations were enhanced by increasing the starch
or alginate contents, but were impeded by higher bentonite content. The release kinetics of viable cells from capsules and
the swelling ratio of capsules were studied in simulated soil media of varying temperature, moisture, pH, and salt content.
The release of loaded Rs-2 cells and swelling of capsules are greatly affected by moisture, temperature, pH and salt content
of the release medium. The release of viable Rs-2 cells from capsules was positively associated with the swelling properties
of the capsules. The release of Rs-2 cells occurred through a Case II diffusion mechanism. In summary, this work indicates
that alginate-starch-bentonite blends are a viable option for the development of efficient controlled-release formulations
of Rs-2 biofertilizer, and which could have a promising application in natural field conditions. 相似文献
16.
Tablets of three different grades of hydroxypropyl methyl cellulose (HPMC), having different viscosity, were prepared using the direct-compression technique with no additive or binder. The fluid uptake behavior of these HPMC tablets was studied in three types of bio-media – water, simulated gastric fluid (SGF), and simulated intestinal fluid (SIF). The amount of fluid uptake by the tablets followed a power law relationship with time for all three media. Variants such as pH value, type of salts and salt concentration in the media were found to have little influence on the swelling process for the tablet. On the contrary, viscosity and molecular weight of HPMC were the controlling parameters for the swelling process. Subsequently, Indomethacin was added in certain percentage to the tablets as a model drug. It was to examine and elucidate drug releasing properties of the HPMC tablets. The possible mechanisms involved in the process of drug dispersion are proposed and discussed. 相似文献
17.
目的:制备一种D-甘露糖修饰的黄芩苷阳离子脂质体[Baicalin cationic liposome,BC-Lipo(+)],并考察其对肺癌A549细胞增殖的抑制效果。方法:用乙醇注入法制备BC-Lipo(+),并考察其药剂学性质;以肺癌A549细胞为模型,采用MTT法考察其对肿瘤细胞的抑制效果。结果:透射电镜下可见BC-Lipo(+)呈圆形或类圆形,平均粒径(111.3±2.7)nm,Zeta电位(9.6±0.3)m V,包封率(95.4±0.8)%;体外释药行为符合Ritger-Peppas方程(lnQ=0.3497lnt-1.6611,r=0.9924);A549细胞的增殖抑制率可达(88.3±5.7)%。结论:处方和制备工艺合理,BC-Lipo(+)包封率较高,粒径分布均匀,带一定的正电荷,具有明显的体外缓释特性,抑制肺癌A549细胞增殖效果显著,为深入研究肺靶向BC纳米脂质体制剂奠定了基础。 相似文献
18.
Khalid M. El-Say Fathy I. Abd-Allah Ahmed E. Lila Abd El-Saboor A. Hassan Alaa Eldin A. Kassem 《Journal of liposome research》2016,26(1):57-68
The purpose of this study was to load diacerein (DCR) in niosomes by applying response surface methodology and incorporate these niosomes in gel base for topical delivery. Box–Behnken design was used to investigate the effect of charge-inducing agent (X1), surfactant HLB (X2) and sonication time (X3) on the vesicle size (Y1), entrapment efficiency (Y2) and cumulative drug released (Y3). DCR niosomal formulations were prepared by thin film hydration method. The optimized formula was incorporated in different gel bases. DCR niosomal gels were evaluated for homogeneity, rheological behavior; in vitro release and pharmacodynamic activity by carrageenan-induced hind paw edema method in the rat compared with DCR commercial gel. The results revealed that the mean vesicle sizes of the prepared niosomes ranged from 7.33 to 23.72?µm and the entrapment efficiency ranged from 9.52% to 58.43% with controlled release pattern over 8?h. DCR niosomal gels exhibited pseudoplastic flow with thixotropic behavior. The pharmacodynamic activity of DCR niosomal gel in 3% HPMC showed significant, 37.66%, maximum inhibition of edema size in comparison with 20.83% for the commercial gel (p?0.05). These results recommended the incorporation of DCR niosomes in 3% HPMC for topical application as a potent anti-inflammatory drug for the treatment of osteoarthritis. 相似文献
19.
Thermoalkalophilic esterase enzyme from Bal?ova (Agamemnon) geothermal site were aimed to be immobilized effectively via a simple and cost-effective protocol in silicate coated Calcium alginate (Ca-alginate) beads by entrapment. The optimal immobilization conditions of enzyme in Ca-alginate beads were investigated and obtained with 2% alginate using 0.5mg/ml enzyme and 0.7 M CaCl(2) solution. In order to prevent enzyme from leaking out of the gel beads, Ca-alginate beads were then coated with silicate. Enzyme loading efficiency and immobilization yield for silicate coated beads was determined as 98.1% and 71.27%, respectively and compared with non-coated ones which were 68.5% and 45.80%, respectively. Surface morphologies, structure and elemental analysis of both silicate coated and non-coated alginate beads were also compared using Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM) equipped with Energy-dispersive X-ray spectroscopy (EDX). Moreover, silicate coated alginate beads enhanced reusability of esterase in continuous processes compared to non-coated beads. The hydrolytic properties of free and immobilized enzyme in terms of storage and thermal stability as well as the effects of the temperature and pH were determined. It was observed that operational, thermal and storage stabilities of the esterase were increased with immobilization. 相似文献