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1.
A multiple-unit-type oral floating dosage form (FDF) of 5-fluorouracil (5-FU) was developed to prolong gastric residence time, target stomach cancer, and increase drug bioavailability. The floating bead formulations were prepared by dispersing 5-FU together with calcium carbonate into a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as alginate undergoes ionotropic gelation by calcium ions and carbon dioxide develops from the reaction of carbonate salts with acid. The evolving gas permeated through the alginate matrix, leaving gas bubbles or pores, which provided the beads buoyancy. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, image, surface topography, buoyancy, and in vitro release. The formulations were optimized for different weight ratios of gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated instantaneous, complete, and excellent floating ability over a period of 24 hours. The optimized formulation was subjected to in vivo antitumor studies to check the therapeutic efficacy of the floating dosage forms containing 5-FU against benzo(a)pyrene-induced stomach tumors in albino female mice (Balb/C strain). The multiple-bead FDF was found to reduce the tumor incidence in mice by 74%, while the conventional tablet dosage form reduced this incidence by only 25%. Results indicate that FDF performed significantly better than the simple tablet dosage form. Published: June 22, 2007  相似文献   

2.
3D printing evolved as a promising technique to improve individualization of drug therapy. In particular, when printing sustained release solid dosage forms, as for instance implants, inserts, and also tablets, estimation of the drug release profile in vivo is necessary. In most cases, corresponding analyses cannot be performed at hospital or community pharmacies. Therefore, the present study aimed to develop a sustained release drug delivery system produced via 3D printing, which allows dose adaption and estimation of drug release at the same time. Filaments as feedstock for the printer were produced via hot-melt extrusion and consisted of Eudragit® RL as sustained release polymer, 30% theophylline as model active pharmaceutical ingredient, and stearic acid as solid plasticizer. Assuming that the surface/mass ratio was constant, network structures of different densities were printed as novel solid dosage form. Their weight (263 to 668 mg), thereby their dose, and surface area, determined using X-ray microcomputed tomography, showed a linear correlation with the fill density. The specific surface area of the network hardly varied with changing fill density. Dissolution studies showed a slower drug release for dosage forms with a denser network. Higuchi’s model was used for prediction of drug release and showed limited applicability due to different release kinetics for different fill densities. However, using linear interpolation for the prediction resulted in good RMSEP values between 1.4 and 3.7%. These findings might be useful to enable customized production of sustained release solid dosage forms via 3D printing in hospital and community pharmacies in the future.  相似文献   

3.
The purpose of the current study was to mask the taste of cetirizine HCl and to incorporate the granules produced in oral disintegrating tablets (ODT). The bitter, active substance was coated by fluidized bed coating using Eudragit® RL30-D at levels between 15% and 40% w/w. The ODTs were developed by varying the ratio of superdisintegrants such as sodium croscarmellose, crospovidone grades and low substituted hydroxypropyl cellulose (L-HPC). A direct compression process was used to compress the ODTs under various compaction forces to optimize tablet robustness. The properties of the compressed tablets including porosity, hardness, friability and dissolution profiles were further investigated. The in vitro and in vivo evaluation of the tablet disintegration times showed almost identical rapid disintegration below 10 s at the optimal levels of each superdisintegrant. Finally, the taste and sensory evaluation in human volunteers demonstrated excellence in masking the bitter active and tablet palatability.  相似文献   

4.
The purpose of this study is to characterize the properties of Eudragit® FS-based granules prepared using melt extrusion process for colonic drug delivery. 5-Aminosalicylic acid (5-ASA), theophylline, and diclofenac sodium were used as the model compounds. Drug and polymer blends were melt-extruded into thin rods using a single screw extruder. Drugs were found to be dispersed as crystalline particles in the granules. A hammer mill was used to reduce the extrudate into 16–40 mesh granules, which were mixed with lactose and filled into hard gelatin capsules. Three-stage dissolution testing performed using USP paddle method was used to simulate drug release in gastrointestinal tract. In this study, melt extrusion has been demonstrated to be a suitable process to prepare granules for colonic delivery of 5-amino salicylic acid. At 30% drug loading, less than 25% 5-ASA was released from melt-extruded granules of 20–30 mesh in the first two stages (0.1 N hydrochloric acid solution and phosphate buffer pH 6.8) of the dissolution testing. All 5-ASA was released within 4 h when dissolution medium was switched to phosphate buffer pH 7.4. Drug loading, granule size, and microenvironment pH induced by the solubilized drug were identified as the key factors controlling drug release. Granules prepared with melt extrusion demonstrated lower porosity, smaller pore size, and higher physical strength than those prepared with conventional compression process. Eudragit® FS was found to be stable even when processed at 200°C.  相似文献   

5.
The objective of this work was the preparation of osmotic tablets using polymer blends of cellulose acetate butyrate (CAB) or ethylcellulose with ammonio methacrylate copolymer (Eudragit® RL). The advantage of these coatings in comparison to the traditionally used cellulose acetate is their solubility in safer organic solvents like ethanol. Polymer films were characterized with respect to their water uptake, dry mass loss, and mechanical properties. The effect of the polymer blend ratio on drug release and on the rupture force of the coating was investigated. In addition, the effect of drug solubility and content, pH and agitation rate of the release medium, and coating level and plasticizer content on the release were studied. With increased Eudragit® RL content in the coating blends, higher medium uptake of the film was observed, resulting in shorter lag times and faster drug release from the osmotic tablets. Replacing ethylcellulose with cellulose acetate butyrate as a coating material led to shorter lag times and faster drug release due to increased film permeability. In addition, CAB-based films had a higher strength and flexibility. The drug release was osmotically controlled and decreased with increasing coating level. It increased with increased drug solubility, plasticizer content, change of buffer species (acetate > phosphate), and decreased coating level. Agitation rate and drug content had no effect on the drug release. A 20% w/w coating level was sufficient for the tablet to tolerate forces of more than five times of the gastric destructive force reported in literature.  相似文献   

6.
The present study aims to develop floating drug delivery system by sublimation of ammonium carbonate (AMC). The core tablets contain a model drug, hydrochlorothiazide, and various levels (i.e., 0–50% w/w) of AMC. The tablets were then coated with different amounts of the polyacrylate polymers (i.e., Eudragit® RL100, Eudragit® RS100, and the mixture of Eudragit® RL100 and Eudragit® RS100 at 1:1 ratio). The coated tablets were kept at ambient temperature (25°C) or cured at 70°C for 12 h before further investigation. The floating and drug release behaviors of the tablets were performed in simulated gastric fluid USP without pepsin at 37°C. The results showed that high amount of AMC induced the floating of the tablets. The coated tablets containing 40 and 50% AMC floated longer than 8 h with a time-to-float of about 3 min. The sublimation of AMC from the core tablets decreased the density of system, causing floating of the tablets. The tablets coated with Eudragit® RL100 floated at a faster rate than those of Eudragit® RS100. Even the coating level of polymer did not influence the time-to-float and floating time of coated tablets containing the same amount of AMC, the drug release from the tablets coated with higher coating level of polymer showed slower drug release. The results suggested that the sublimation technique using AMC is promising for the development of floating drug delivery system.  相似文献   

7.
Ritonavir is an anti-viral compound that has also been employed extensively as a CYP3A4 and P-glycoprotein (Pgp) inhibitor to boost the pharmacokinetic performance of compounds that undergo first pass metabolism. For use in combination products, there is a desire to minimize the mass contribution of the ritonavir system to reduce patient pill burden in these combination products. In this study, KinetiSol® processing was utilized to produce an amorphous solid dispersion of ritonavir at two times the drug load of the commercially available form of ritonavir, and the composition was subsequently developed into a tablet dosage form. The amorphous intermediate was demonstrated to be amorphous by X-ray powder diffraction and 13C solid-state nuclear magnetic resonance and an intimately mixed single-phase system by modulated differential scanning calorimetry and 1H T1/1H T solid-state nuclear magnetic resonance relaxation. In vitro transmembrane flux analysis showed similar permeation rates for the KinetiSol-made tablet and the reference tablet dosage form, Norvir®. In vivo pharmacokinetic comparison between the two dosage forms resulted in equivalent exposure with approximately 20% Cmax reduction for the KinetiSol tablet. These performance gains were realized with a concurrent reduction in dosage form mass of 45%.  相似文献   

8.
For a drug with low bioavailability, a matrix tablet with liquid permeation enhancer (Labrasol®) was formulated. Factorial design was used to evaluate the effect of three formulation factors: drug percentage, polymer type (Methocel® K100M or Eudragit® L 100-55), and tablet binder percentage (Plasdone® S-630) on tablet characteristics. Tablets were prepared by direct compression and characterized. Compressibility index values ranged between 15.90% and 29.87% and tablet hardness values from 7.8 to 29.78 Kp. Eudragit®-containing formulations had better compressibility index values with higher tablet hardness. Time for 75% of drug release (T 75) was calculated, and formulations containing Eudragit® L 100-55 had faster release rates than tablet formulations with Methocel® K100M. Formulations with Methocel® K100M fit well in the Higuchi model as indicated by their R 2 values (>0.98). Among all the formulation factors studied, polymer type displayed the highest and statistically significant effect on compressibility index, tablet hardness, and dissolution rate. Statistical design helped in better understanding the effect of formulation factors on tablet characteristics important for designing formulations with desired characteristics.  相似文献   

9.
The objective of the present study was to investigate the effect of the pellet core materials isomalt, sugar, and microcrystalline cellulose on the in vitro drug release kinetics of coated sustained-release pellets as well as to evaluate the influence of different ratios of polymethacrylate copolymers exhibiting different permeability characteristics on the drug release rate. For characterization of the drug release process of pellets, the effect of osmolality was studied using glucose as an osmotically active agent in the dissolution medium. The pellet cores were layered with diclofenac sodium as model drug and coated with different ratios of Eudragit® RS30D and Eudragit® RL30D (ERS and ERL; 0:1 and 0.5:0.5 and 1:0 ratio) in a fluid bed apparatus. Physical characteristics such as mechanical strength, shape, and size proved that the inert cores were adequate for further processing. The in vitro dissolution tests were performed using a USP Apparatus I (basket method). The results demonstrated that, besides the ratio of the coating polymers (ERS/ERL), the release mechanism was also influenced by the type of starter core used. Sugar- and isomalt-type pellet cores demonstrated similar drug release profiles.  相似文献   

10.
The aim of this study was to formulate and characterize Eudragit® L100 and Eudragit® L100-poly(lactic-co-glycolic acid) (PLGA) nanoparticles containing diclofenac sodium. Diclofenac generates severe adverse effects with risks of toxicity. Thus, nanoparticles were prepared to reduce these drawbacks in the present study. These nanoparticles were evaluated for surface morphology, particle size and size distribution, percentage drug entrapment, and in vitro drug release in pH 6.8. The prepared nanoparticles were almost spherical in shape, as determined by atomic force microscopy. The nanoparticles with varied size (241–274 nm) and 25.8–62% of entrapment efficiency were obtained. The nanoparticles formulations produced the release profiles with an initial burst effect in which diclofenac sodium release ranged between 38% and 47% within 4 h. The extent of drug release from Eudragit® L100 nanoparticles was up to 92% at 12 h. However, Eudragit®/PLGA nanoparticles showed an initial burst release followed by a slower sustained release. The cumulative release at 72 h was 56%, 69%, and 81% for Eudragit®/PLGA (20:80), Eudragit®/PLGA (30:70) and Eudragit®/PLGA (50:50) nanoparticles, respectively. The release profiles and encapsulation efficiencies depended on the amount of Eudragit in the blend. These data demonstrated the efficacy of these nanoparticles in sustaining the diclofenac sodium release profile.  相似文献   

11.
According to the World Health Organization (WHO), using antibiotics as growth promoters for livestock—particularly swine—is the principal cause of antibiotic resistance. It is therefore clear that finding an alternative to antibiotics becomes an emergency. Hundreds of recent studies have appointed probiotics as potential candidates to replace or to be used in combination with antibiotics. However, bringing probiotics alive to the colon—their site of action—remains a big challenge because of different physiological barriers encountered in proximal gastrointestinal tract (GIT) such as acidic pH and bile salts that may affect the viability of probiotic cultures. To overcome this problem, in previous studies, we developed and characterize a synbiotic formula consisting of beads of a mixture of alginate and inulin. Three potential probiotics strains namely Pediococcus acidilactici UL5 (UL5), Lactobacillus reuteri (LR), and Lactobacillus salivarius (LS) were encapsulated to study their release and the behavior of this synbiotic formula throughout the GIT using in vitro models. The survival and the release of bacteria from beads were studied by specific PMA-qPCR counting. The microscopic aspects of the beads were studied using scanning electron microscopy (SEM). Moreover, the microbial dynamics inside beads were studied by fluorescence microscopy using the live/dead test. Our results have shown that the beads containing 5% inulin were the most stable in the stomach and throughout the small intestine. However, beads were completely degraded in approximately 3 h of incubation in the fermented medium that mimic the colon. These results were confirmed by SEM and fluorescence microscopy images. Therefore, it can be stated that the AI5 formulation well protected the bacteria in the upper part of the digestive tract and allowed their controlled release in the colon.  相似文献   

12.
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   

13.
Bovine serum albumin-loaded beads were prepared by ionotropic gelation of alginate with calcium chloride and chitosan. The effect of sodium alginate concentration and chitosan concentration on the particle size and loading efficacy was studied. The diameter of the beads formed is dependent on the size of the needle used. The optimum condition for preparation alginate–chitosan beads was alginate concentration of 3% and chitosan concentration of 0.25% at pH 5. The resulting bead formulation had a loading efficacy of 98.5% and average size of 1,501 μm, and scanning electron microscopy images showed spherical and smooth particles. Chitosan concentration significantly influenced particle size and encapsulation efficiency of chitosan–alginate beads (p < 0.05). Decreasing the alginate concentration resulted in an increased release of albumin in acidic media. The rapid dissolution of chitosan–alginate matrices in the higher pH resulted in burst release of protein drug.  相似文献   

14.
Synechococcus elongatus cells were immobilized in alginate beads, and the effects of increasing the cross-linker concentration from 2 to 4 % CaCl2 were evaluated, as well as the effects of coating the beads with either glycerol or poly(ethylene glycol) methyl ether methacrylate (PEGMA)—not previously reported for immobilized microalgae—to improve the holding time of the immobilized cells. S. elongatus cells remain metabolically active after coating with glycerol or PEGMA. There is an inverse relation between the glycerol concentration and the chlorophyll a content for the alginate beads cross-linked with 2 % CaCl2. PEGMA diminishes the rate of liberation of cells as its concentration increases, although results suggest the ability of S. elongatus to degrade PEGMA, which increases the growth rate of the liberated cells, because of PEGMA being used as carbon source.  相似文献   

15.
The aim of this study was to develop and validate a discriminating in vitro release test to evaluate rivastigmine transdermal patches. The Exelon® Patch was chosen as a model transdermal product. The studies of in vitro release were designed to determine the impact of the official apparatus chosen (USP apparatus 5 and USP apparatus 6), the rotation speed, and the dissolution medium characteristics on the rivastigmine release profile from transdermal patches. Patches with different drug release profiles were tested in order to evaluate the discriminating power of the in vitro release test developed and validated. Variables such as the apparatus type, the dissolution medium, and the rotation speed have a significant influence on the drug release characteristics from a transdermal patch. The in vitro release methodologies using the USP apparatus 5 at 50 rpm and USP apparatus 6 at 25 rpm using the medium phosphate-buffered saline pH 7.4 were considered discriminative and adequate to characterize the rivastigmine (RV) release from a commercial transdermal patch, Exelon® Patch.  相似文献   

16.
The present study was aimed at formulating tablets comprising of coating susceptible to microbial enzyme degradation for releasing budesonide in the colon. Tablets prepared by using Avicel® pH 102 as diluent and Eudragit® L100-55 as binder were coated to a weight gain of 10% w/w employing aqueous mixtures containing chitosan (CH) and chondroitin sulfate (CS). The interpolymer complex between CH and CS was characterized using Fourier transform infrared (FTIR) and differential scanning calorimetery (DSC) studies. The tablets were evaluated for release of budesonide through in vitro in vivo studies. Formation of bonds between –COO? and –OSO 3 ? groups of CS and –NH 3 + groups of CH was evident in the FTIR spectra of these interpolymer complexed (IPC) films. The DSC thermograms of these films revealed one endothermic transition between 190°C and 205°C, suggesting the formation of new bonds in the IPC. The pH sensitive swelling exhibited by these films was observed to be a function of CH concentration. Tablets coated with aqueous mixtures containing 40:60 or 50:50 ratio of CH/CS totally prevented the release of budesonide in pH 1.2 buffer. The peaks (FTIR) and endothermic transitions (DSC) characteristic of interpolymer complexation were observed to remain unaffected after sequential exposure of the films to pH 1.2 and pH 7.4 buffer IP. This proved the versatility of these IPC films for colon delivery. C max of 1,168.99 and 1,174.2 ng/mL, respectively, at 12 and 8 h post-oral dosing of tablets coated with 40:60 or 50:50 ratio of CH/CS was observed in rats. The aqueous CH/CS (40:60) coating could provide a facile method for delivering budesonide to the colon.  相似文献   

17.
Context: Drotaverine hydrochloride (DRT) is used to treat gastrointestinal spasms accompanied with diarrhoea. Hence, the drug suffers from brief residence in the highly moving intestine during diarrhoea which leads to poor bioavailability and frequent dosing.

Objective: This study aimed to extend DRT residence in the stomach.

Methods: Calcium alginate floating beads were prepared using sodium alginate, isopropylmyristate (oil), and Gelucire® 43/01 (lipid) adopting emulsion gelation technique. The beads were evaluated for their floating ability, DRT entrapment efficiency and in-vitro release. Gelucire® 43/01 /oil-based beads of the selected formula were coated using ethylcellulose and different plasticizers as polyethylene glycol 400 and triethyl citrate to retard the drug release. The coated beads were re-characterized. Finally, the best formulae were investigated for their in-vivo floating ability in dogs besides their delivery to the systemic circulation compared to drug powder in human volunteers.

Results: Incorporation of Gelucire® 43/01 to oil-based beads enhanced the in-vitro performance of the beads. Coated beads prepared using drug:sodium alginate ratio of 1:3 (w/w), 20% (w/v) isopropylmyristate, 20% (w/v) Gelucire® 43/01 showed promising in-vitro performance. The beads floated for 12?h in the dogs’ stomach and produced three-fold increase of the total amount of DRT absorbed within 24?h compared to that of DRT powder.

Conclusions: Gelucire® 43/01 /isopropylmyristate-based calcium alginate floating beads coated with ethylcellulose using either PEG 400 or TEC as plasticizers proved to be a successful dosage form in extending DRT release.  相似文献   

18.
A novel encapsulation technique for the production of artificial seeds   总被引:3,自引:0,他引:3  
A novel technique for the encapsulation of plant material in calcium alginate hollow beads was tested. The technique involves suspending plant material (i.e. plant cells, tissues, organs, shoot tips, somatic embryos) in a solution containing carboxymethylcellulose and calcium chloride and then dripping it into a stirred sodium alginate solution. In initial experiments with Daucus carota (carrot), it was found that after 14 days of cultivation, 100 % of seeds encapsulated in calcium alginate hollow beads would germinate in the liquid core and that 13% would burst the capsules. Embryogenic calli developed inside hollow beads and formed somatic embryos while calli in conventional calcium alginate beads became detached from the beads early in development, and no somatic embryogenesis occurred. With Solanum tuberosum (potato), development of calli was observed in 50% of hollow beads. Eighty-one percent of shoot tips encapsulated in hollow beads sprouted and grew out of the capsules. Received: 28 October 1999 / Revision received: 11 February 2000 / Accepted: 22 February 2000  相似文献   

19.
Cancer diseases are a common problem of the population caused by age and increased harmful environmental influences. Herein, new therapeutic strategies and compound screenings are necessary. The regular 2D cultivation has to be replaced by three dimensional cell culturing (3D) for better simulation of in vivo conditions. The 3D cultivation with alginate matrix is an appropriate method for encapsulate cells to form cancer constructs. The automated manufacturing of alginate beads might be an ultimate method for large-scaled manufacturing constructs similar to cancer tissue. The aim of this study was the integration of full automated systems for the production, cultivation and screening of 3D cell cultures. We compared the automated methods with the regular manual processes. Furthermore, we investigated the influence of antibiotics on these 3D cell culture systems. The alginate beads were formed by automated and manual procedures. The automated steps were processes by the Biomek® Cell Workstation (celisca, Rostock, Germany). The proliferation and toxicity were manually and automatically evaluated at day 14 and 35 of cultivation. The results visualized an accumulation and expansion of cell aggregates over the period of incubation. However, the proliferation and toxicity were faintly and partly significantly decreased on day 35 compared to day 14. The comparison of the manual and automated methods displayed similar results. We conclude that the manual production process could be replaced by the automation. Using automation, 3D cell cultures can be produced in industrial scale and improve the drug development and screening to treat serious illnesses like cancer.  相似文献   

20.
This study elucidates the physical properties of sono-crystallised micro/nano-sized acetaminophen/paracetamol (PMOL) and monitors its possible transformation from polymorphic form I (monoclinic) to form II (orthorhombic). Hydrophilic Plasdone® S630 copovidone (S630), N-vinyl-2-pyrrolidone and vinyl acetate copolymer, and methacrylate-based cationic copolymer, Eudragit® EPO (EPO), were used as polymeric carriers to prepare drug/polymer binary mixtures. Commercially available PMOL was crystallised under ultra sound sonication to produce micro/nano-sized (0.2–10 microns) crystals in monoclinic form. Homogeneous binary blends of drug-polymer mixtures at various drug concentrations were obtained via a thorough mixing. The analysis conducted via the single X-ray crystallography determined the detailed structure of the crystallised PMOL in its monoclinic form. The solid state and the morphology analyses of the PMOL in the binary blends evaluated via differential scanning calorimetry (DSC), modulated temperature DSC (MTDSC), scanning electron microscopy (SEM) and hot stage microscopy (HSM) revealed the crystalline existence of the drug within the amorphous polymeric matrices. The application of temperature controlled X-ray diffraction (VTXRPD) to study the polymorphism of PMOL showed that the most stable form I (monoclinic) was altered to its less stable form II (orthorhombic) at high temperature (>112°C) in the binary blends regardless of the drug amount. Thus, VTXRD was used as a useful tool to monitor polymorphic transformations of crystalline drug (e.g. PMOL) to assess their thermal stability in terms of pharmaceutical product development and research.  相似文献   

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