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1.
The influences of aqueous polymeric subcoats and pellet composition on the release properties of a highly water-soluble drug, chlorpheniramine maleate (CPM), from enteric coated pellets were investigated. Three different aqueous polymeric subcoats, Eudragit® RD 100, Eudragit® RS 30D, and Opadry® AMB, were applied to 10% w/w CPM-loaded pellets that were then enteric coated with Eudragit® L 30D-55. Observed drug release from the coated pellets in acidic media correlated with water vapor transmission rates derived for the subcoat films. The influence of pellet composition on retarding the release of CPM from enteric coated pellets in 0.1 N HCl was investigated. The rate of drug release was greatest for pellets prepared with lactose, microcrystalline cellulose, or dibasic calcium phosphate compared with pellets formulated with citric acid and microcrystalline cellulose. Citric acid reduced the pellet micro-environmental pH, decreasing the amount of drug leakage in 0.1 N HCL during the first 2 hr of dissolution. Polymer flocculation was observed when CPM was added to the Eudragit L 30D-55 dispersion. An adsorption isotherm was generated for mixtures of CPM and the polymer and the data were found to fit the Freundlich model for adsorption. Adsorption of CPM to the polymer decreased with the addition of citric acid to the drug-polymer mixtures.  相似文献   

2.
This study was performed in order to develop a sustained-release pellet formulation containing venlafaxine hydrochloride (VEN), an extremely water-soluble drug, prepared by combination of wax matrices and double-layer coatings. The influence of both double-layer polymeric coats and wax matrices on the release of VEN from sustained-release pellets was investigated. The pellets were prepared by wet mass extrusion spheronization methods and then coated with a fluidized bed coater. For the pellets coated with Eudragit® NE30D alone, a coating level of nearly 40% was required to pass the dissolution test compared with commercial product, and it was accompanied by an unacceptable lag time. The application of an alcohol-soluble polymeric subcoat, Opadry® I, was added before the Eudragit® NE30D coating process, which resulted in a marked delay in drug release. However, a faster release was observed for the formulation coated with a high subcoat level (10%) at the end of the dissolution test. A further delay in drug release was observed when a wax matrix, octadecanol, was added to the core pellet formulation. The kinetics of drug release changed from the Higuchi model to a zero order model and the predominant mechanism controlling drug release changed from diffusion to dissolution upon increasing the amount of octadecanol within the matrix pellets. In addition, the drug release was markedly influenced by the drug to matrix ratio. In conclusion, the 40% drug-loaded core pellets with double-layer coatings (8% Opadry® I and 12% Eudragit® NE30D) and 20% octadecanol matrix produced the desired profile for once-daily sustained release compared with the commercial product, and these pellets remained stable during storage.  相似文献   

3.
Background: An extended release pellet formulation (ACES®) of the weakly basic drug propiverine was developed with spheronized citric acid crystals as starter cores. Method: Coated pellets, consisting of several layers of functional coatings, were manufactured by fluid bed coating. Different coating levels were examined with regard to their effect on drug release. Release profiles from the formulations with or without pH modifier and the free base as well as the hydrochloride salt of the active ingredient were compared. Results: The coated citric acid starter cores led to a controlled release of the drug and the pH modifier, resulting from modulation of the microenvironmental pH throughout the dissolution period of 17 hours. If microcrystalline cellulose pellets are used as starter cores drug release is strongly pH-dependent. Significant differences in the drug release profiles were observed between the formulations containing the free drug base and those with the hydrochloride salt as a result of an altered microenvironmental pH. Conclusion: The presented extended release pellet formulation is able to maintain a low pH within the pellet core and thus a sufficiently high drug solubility. By maintaining a low pH inside the pellets, a controlled drug release can be achieved.  相似文献   

4.
Abstract

The goal of this study was to investigate the effect of compaction of a coated pelletized dosage form on drug release. Three sizes of microcrystalline cellulose and hydrous lactose pellets containing 4% chlorpheniramine maleate (CPM) were manufactured using a rotogranulator (Glatt GPCG-1). Pellets having mesh cuts of: 590–840 μm (20/30 mesh); 420–590 μm (30/40 mesh); and 250–420 μm (40/60 mesh) were then coated with an aqueous ethylcellulose pseudolatex dispersion plasticized with 24% dibutyl sebacate (DBS). Percent weight gains were 25, 30 and 35% for the 20/30, 30/40 and 40/60 mesh pellets, respectively. Coated pellets were blended with 39.3% by weight excipients, then mixtures lubricated and compacted using a Korsch PH106 instrumented rotary press set at 5 kN and 20 rpm (0.30 s contact time). Magnesium stearate was used as the lubricant at a 0.7% level. Excipients used were microcrystalline cellulose, spray dried lactose, pregelatinized starch, dicalcium phosphate, spray dried sorbitol, polyethylene glycol 8000 powder and compressible sugar. Results indicated this coating to be suitable for the controlled release of CPM from small pellets (250–840 μm). However, films did not have the appropriate mechanical properties to withstand compaction stress without rupturing, regardless of the pellets particle size and excipients used. After compaction, depending on pellet size, between 65–100% CPM was released after one hour as opposed to 10–30% for the non-compacted material. The controlled release properties of the pellets were therefore lost during the process.  相似文献   

5.
The goal of this study was to investigate the effect of compaction of a coated pelletized dosage form on drug release. Three sizes of microcrystalline cellulose and hydrous lactose pellets containing 4% chlorpheniramine maleate (CPM) were manufactured using a rotogranulator (Glatt GPCG-1). Pellets having mesh cuts of: 590-840 μm (20/30 mesh); 420-590 μm (30/40 mesh); and 250-420 μm (40/60 mesh) were then coated with an aqueous ethylcellulose pseudolatex dispersion plasticized with 24% dibutyl sebacate (DBS). Percent weight gains were 25, 30 and 35% for the 20/30, 30/40 and 40/60 mesh pellets, respectively. Coated pellets were blended with 39.3% by weight excipients, then mixtures lubricated and compacted using a Korsch PH106 instrumented rotary press set at 5 kN and 20 rpm (0.30 s contact time). Magnesium stearate was used as the lubricant at a 0.7% level. Excipients used were microcrystalline cellulose, spray dried lactose, pregelatinized starch, dicalcium phosphate, spray dried sorbitol, polyethylene glycol 8000 powder and compressible sugar. Results indicated this coating to be suitable for the controlled release of CPM from small pellets (250-840 μm). However, films did not have the appropriate mechanical properties to withstand compaction stress without rupturing, regardless of the pellets particle size and excipients used. After compaction, depending on pellet size, between 65-100% CPM was released after one hour as opposed to 10-30% for the non-compacted material. The controlled release properties of the pellets were therefore lost during the process.  相似文献   

6.
Abstract

The influence of various additives, namely, PEG, mannitol, and HPMCP 50 incorporated with Eudragit® L30D on drug release from pellets was investigated. Cores of a water soluble drug were prepared by the powder layering technique using the CF Granulator (CF 360) and coating was accomplished utilizing the Glatt GPCG3 machine. Drug release from pellets coated with Eudragit® L30D was found to be influenced by the type and the level of the additive incorporated with the copolymer. At pH 1.5, PEG, regardless of the molecular weight, did not have any significant effect on drug release. At pH 5.5, however, PEG significantly decreased drug release from coated pellets, and the decrease was more pronounced as the molecular weight of PEG was increased. Release of the drug from pellets coated with Eudragit® L30D containing mannitol was found to be dependent on mannitol concentration at pH 1.5, 3.5 and 4.5 but independent of mannitol concentration at pH 5.5. The release of drug through Eudragit® L30D:HPMCP 50 films was found to be dependent on the ratio of the polymers.  相似文献   

7.
The preparation of multiparticulate tablets by direct compression of functionally coated pellets is technologically challenging. The objective was to investigate the influence of different grades of microcrystalline cellulose (Ceolus? UF-711, PH-102, PH-200 and KG-802) as fillers on the properties of blends and tablets containing enteric pellets. Celphere? spheres were drug-layered and then functionally coated with Eudragit(?) L 30 D-55/FS 30D dispersion. Tablets loaded with 50% pellets were prepared using pure or binary blends of microcrystalline cellulose fillers. The influence of the filler on the blend flow, segregation tendency, tablet hardness and enteric release properties were studied using a mixture design, and the optimum filler composition was determined. Rapidly disintegrating tablets, which yielded a drug release of less than 10% after 2 hours in acidic medium, could be successfully prepared. The blend composition had a significant effect on the flowability, but less on the tablet hardness which was influenced by the selection of lubricant. Blends containing celluloses with low bulk densities exhibited a reduced tendency to segregate. Pellet distribution uniformity was further improved when using Ceolus? UF-711 blended with a high-density grade. As a conclusion, multiparticulate tablets containing enteric pellets with preserved delayed-release properties were successfully prepared using Ceolus? microcrystalline celluloses as tableting excipients. The optimized filler blend for the direct compression of 50% enteric pellets into tablets contained Ceolus? UF-711 as main component in combination with Ceolus? PH-200.  相似文献   

8.
In this study, a new co-processed excipient composed of microcrystalline cellulose (MCC), sorbitol, chitosan and Eudragit® E, easily obtained by wet massing, to increase the dissolution rate of active ingredients of low water solubility from pellets prepared by extrusion–spheronization is evaluated. Indomethacin, nifedipine, furosemide, ibuprofen, prednisolone and hydrochlorothiazide are used as model drugs of different solubility. All pellet formulations evaluated showed adequate morphological, flow and mechanical properties. Pellets prepared with the co-processed excipient show a higher drug dissolution rate than those prepared with MCC and even higher than the pure drug powder. The fast drug dissolution and the complete disintegration (<3?min) of the pellets can be explained by the great porosity of the formulations, the high solubility of the sorbitol, the disintegrant capacity of the chitosan and the distribution of the Eudragit® E polymer particles in-between the other components of the co-processed mixture. In conclusion, this new co-processed excipient is very suitable to increase the dissolution rate of poorly soluble drugs from pellets prepared by extrusion–spheronization. Moreover, the drug release rate can be estimated from the Ln of the drug solubility in acidic medium.  相似文献   

9.
Abstract

Phenylpropanolamine hydrochloride (PPA) pellets were prepared in a fluidized-bed rotary granulator. Microcrystalline cellulose and distilled water were used as pelletization enhancer and binder, respectively. The pellets were coated with methacry-late ester copolymer (Eudragit® RS 100) solution containing a 1:1 ratio mixture of triethyl citrate and castor oil as plasticizers. The addition of approximately 30% microcrystalline cellulose and 2% croscarmellose sodium to the 50% coated pellets produced fast disintegrating tablets. Dissolution profiles of both pellets and their respective matrix tablets were comparable and conformed to the USP dissolution requirement for PPA extended-release capsules.  相似文献   

10.
The objective of this study was to develop doxofylline-loaded sustained-release pellets coated with Eudragit® NE30D alone (F1) or blend of Eudragit® RL30D/RS30D (F2) and further evaluate their in vitro release and in vivo absorption in beagle dogs. Doxofylline-loaded cores with a drug loading of 70% (w/w) were prepared by layering drug-MCC powder onto seed cores in a centrifugal granulator and then coating them with different kinds of polymethacrylates in a bottom-spray fluidized bed coater. Dissolution behaviour of these formulations was studied in vitro under various pH conditions (from pH 1.2 to pH 7.4) to evaluate the effect of pH on drug release profiles. It was found that F2 produced a better release profile than F1 did and two different release mechanisms were assumed for F1 and F2, respectively. The relative bioavailability of the sustained-release pellets was studied in six beagle dogs after oral administration in a fast state using a commercially available immediate release tablet as a reference. Coated with Eudragit® NE30D and a blend of Eudragit® RL30D/RS30D (1:12), at 5% and 8% coating level, respectively, the pellets acquired perfect sustained-release properties and good relative bioavailability, with small fluctuation of drug concentration in plasma. But combined use of mixed Eudragit® RL30D/RS30D polymers with proper features as coating materials produced a longer Tmax, a lower Cmax and a little higher bioavailability compared to F1 (coated with Eudragit® NE30D alone). The Cmax, Tmax and relative bioavailability of F1 and F2 coated pellets were 15.16 μg/ml, 4.17 h, 97.69% and 11.41 μg/ml, 5 h, 101.59%, respectively. Also a good linear correlation between in vivo absorption and in vitro release was established for F1 and F2, so from the dissolution test, formulations in vivo absorption can be properly predicted.  相似文献   

11.
Tamsulosin hydrochloride (TSH) controlled-release capsule (pellets) was successfully prepared using a novel, simple, and flexible multiunit drug delivery system, which consisted of two different coated pellets. The TSH-loaded core pellets consisting of microcrystalline cellulose (MCC), lactose, Carbopol® 974P, and the active agent, were prepared by extrusion/spheronization method. Eudragit® NE30D and Eudragit® L30D-55 were used as the coating materials to prepare sustained-release (SR) pellets and enteric-release (ER) pellets. The coated pellets were prepared using two different equipments: centrifugal coater and fluidized-bed coater. By adjusting the ratio of SR and ER pellets, more than one blend ratios, which meet the in vitro release criterion were obtained. A similarity factor (f2) was employed to choose the optimum proportion compared with the commercial product (Harnal® capsule). The morphology of the pellet surfaces was examined by scanning electron microscopy (SEM) before and after dissolution. The release profiles were significantly affected by changing the proportions of SR and ER. The optimum ratio is SR:ER?=?2:1 using a centrifugal coater (f2?=?61.93) and SR:ER?=?3:1 using a fluidized coater (f2?=?66.42). This result suggests that blending these two-part pellets (SR and ER) can provide an alternative to preparing a controlled-release dosage form, instead of blending of the coating polymer.  相似文献   

12.
The objective of this study was to obtain detailed information on the mechanism of drug release from mixed-film of pectin-chitosan/Eudragit® RS. Pellets (710–840 μm in diameter) containing 60% theophylline and 40% microcrystalline cellulose were prepared by extrusion-spheronization method. Eudragit® L100-55 enteric coating capsules included film-coated pellets of theophylline in theoretical coating weight gains of 10, 15, and 20%, with pectin-chitosan complex contents of 5, 10, 15, and 20% for each level of weight gain were prepared and subjected to in vitro drug release. Drug release from this system showed a bimodal release profile characteristic with the drug release enhancement, being triggered (burst release) in the colonic medium. The reason for burst drug release may be due to the enzymatic degradation of pectin via pectinolytic enzymes in the simulated colonic medium. The mechanism of drug release from each formulation was evaluated in the terms of zero-order, first-order, Higuchi and Korsmeyer-Peppas models. It was observed that none of the enteric coating capsules showed any drug release in the simulated gastric medium (phase I). The analysis of release profiles showed that zero-order kinetics was found as the better fitting model for all formulations in the simulated small intestine (phase II) and it could be due to the pectin-chitosan swelling and subsequent formation of aqueous channels. In the colonic medium (phase III), due to degradation of pectin and its leaching from the mixed-film, there was a modification in drug release kinetics from swelling-controlled at phase II to anomalous at phase III. It also was found that both zero-order and Higuchi models contributed in colonic drug release from most of the formulations.  相似文献   

13.
Sustained-release coated pellets containing terbutaline sulfate (TS) 1.8% w/w were prepared. The suitable core formulation that gave round-shape TS pellets was preformulated and was composed of microcrystalline cellulose:lactose 38.61%:57.92%, hydroxypropyl cellulose (HPC-M®) 1.67%, and water 40%, respectively. The core pellets containing active drug were coated with various amounts of ethylcellulose (EC) and a combination of EC/HPC-M polymers. The effects of fluidized bed polymeric film coats on drug release were studied in vitro. The dissolution characteristics were also investigated. The release of the active drug decreased as the amount of EC increased. This may be due to water-insoluble EC film, leading to decreased permeability in water. In the case of the combination of EC/HPC-M, the release of the active drug increased as the amount of HPC-M in the coating solution increased. Since HPC-M is a water-soluble polymer, it may be suggested that formation of pores were increased in the coating layer. Among five coating formulas in this study, formulation 1 (F1) (at 1.1% EC concentration) shows a similar dissolution profile to Bricanyl Durules®; however, lag time for the release occurred. In conclusion, the formulation that gave an insignificant release profile (p <. 01) when compared with commercial product was the capsule containing F1 (at 1.1% EC concentration) mixed with uncoated pellets at a ratio of 7:1, and the release was found to be reproducible.  相似文献   

14.
Abstract

Weakly basic drugs, such as verapamil hydrochloride, that are poorly soluble in neutral/alkaline medium may have poor oral bioavailability due to reduced solubility in the small intestine and colon. Film coated pellets were prepared using two strategies to enhance drug release at high pH values. Firstly, pellets were coated with Eudragit® RS/hydroxypropyl methylcellulose acetate succinate (HMAS) mixtures in proportions of 10:1 and 10:3, respectively. The enteric polymer, HMAS, would dissolve in medium at pH>6 creating pores through the insoluble Eudragit RS membrane to increase drug release. Secondly, an acidic environment was created within the core by the inclusion of fumaric acid at concentrations of 5 and 10% in order to increase drug solubility. Both strategies enhanced drug release into neutral medium in dissolution studies using the pH change method to simulate GIT transit. Dissolution profiles of samples tested in pH 1.2 for 12 hr were compared with those using the pH change method (pH 1.2 for first 1.5 hr, pH raised to 6.8 for remaining 10.5 hr) using the area under the dissolution curve (AUC), the dissolution half-life (t50%), and the amount of drug released in 3 hr (A3 hr) values. Both strategies enhanced drug release into neutral medium although the strategy using HMAS in the film was more effective. The formulation least affected by pH change was a combination of the two strategies, i.e., pellets containing 5% fumaric acid coated with Eudragit RS 12% w/w and HMAS 1.2% w/w.  相似文献   

15.
Tamsulosin hydrochloride (TSH) controlled-release capsule (pellets) was successfully prepared using a novel, simple, and flexible multiunit drug delivery system, which consisted of two different coated pellets. The TSH-loaded core pellets consisting of microcrystalline cellulose (MCC), lactose, Carbopol(R) 974P, and the active agent, were prepared by extrusion/spheronization method. Eudragit NE30D and Eudragit L30D-55 were used as the coating materials to prepare sustained-release (SR) pellets and enteric-release (ER) pellets. The coated pellets were prepared using two different equipments: centrifugal coater and fluidized-bed coater. By adjusting the ratio of SR and ER pellets, more than one blend ratios, which meet the in vitro release criterion were obtained. A similarity factor (f(2)) was employed to choose the optimum proportion compared with the commercial product (Harnal capsule). The morphology of the pellet surfaces was examined by scanning electron microscopy (SEM) before and after dissolution. The release profiles were significantly affected by changing the proportions of SR and ER. The optimum ratio is SR:ER = 2:1 using a centrifugal coater (f(2) = 61.93) and SR:ER = 3:1 using a fluidized coater (f(2) = 66.42). This result suggests that blending these two-part pellets (SR and ER) can provide an alternative to preparing a controlled-release dosage form, instead of blending of the coating polymer.  相似文献   

16.
Background: Oral absorption of low-molecular-weight heparin (LMWH) is limited by its molecular size and negative charge. It has been shown previously that orally administered polymeric nano- or microparticles containing encapsulated LMWH have led to gastrointestinal absorption of heparin in rabbits. Method: Based on these investigations, pellets containing two LMWHs, enoxaparin (MW 4500 Da) or bemiparin (MW 3600 Da), and Eudragit®RS30D (ERS), were prepared using extrusion/ spheronization technique. Uncoated or coated (ERS) pellets were evaluated in vitro and in vivo on rabbits. Results: Enoxaparin pellets showed fast in vitro release in phosphate buffer (pH 7.4) and prolonged in vivo drug absorption after a single oral dose of 600 anti-Xa IU/ kg of body weight, leading to relative bioavailabilities ranging from 9.7 ± 1.9% to 12.8 ± 2.7% and anti-Xa activity over the curative dose. Bemiparin included in matrix pellets of ERS and coated with ERS exhibited in vitro prolonged release up to 4 hours and in vivo anti-Xa activity below the therapeutic minimum value of 0.1 IU/mL. Conclusion: This study presents LMWH in a pellet dosage form, which compared to nano- or microparticles, may offer a more convenient and industrializable way of manufacture leading to an easier scale-up process.  相似文献   

17.
In the search for antitack additives for Kollicoat EMM 30 D (ethyl acrylate-methyl methacrylate 30% dispersion, Ph. Eur.) film coatings, various possibilities were investigated. The best results were obtained using a combination of simethicone and talc. This mixture was tested on propranolol, theophylline, and verapamil HCl blank pellets in a previously developed Kollicoat EMM 30 D basic formulation. Almost any desired drug release rate can be obtained with all three pellet formulations by varying the two pore formers hypromellose 3mPas and microcrystalline cellulose type 105. A thin application of colloidal silica onto the coated pellets additionally prevents them from sticking together during storage.  相似文献   

18.
Abstract

The objective of this research project was to characterize the drug release profiles, physicochemical properties and drug–polymer interaction of melt-extruded granules consisting of chlorpheniramine maleate (CPM) and Eudragit® FS. Melt extrusion was performed using a single screw extruder at a processing temperature of 65–75?°C. The melt extrudate was milled, blended with lactose monohydrate and then filled into hard gelatin capsules. Each capsule contained 300?mg CPM granules. The release of CPM was determined with the United States Pharmacopeia dissolution apparatus II using a three-stage dissolution medium testing in order to simulate the pH conditions of the gastrointestinal tract. Pore structure, thermal properties and surface morphologies of CPM granules were studied using mercury and helium pycnometer, differential scanning calorimeter and scanning electron microscope. Sustained release of CPM over 10?h was achieved. The release of CPM was a function of drug loading and the size of the milled granules. The complexation between CPM and Eudragit® FS as the result of counterion condensation was observed, and the interaction was characterized using membrane dialysis and H1 NMR techniques. In both 0.1?N HCl and phosphate buffer pH 6.8, CPM was released via a diffusion mechanism and the release rate was controlled by the pore structure of the melt-extruded granules. In phosphate buffer pH 7.4, CPM release was controlled by the low pH micro-environment created by CPM, the pore structure of the granules and the in situ complexation between CPM and Eudragit® FS.  相似文献   

19.
In this study a sustained-release formulation of traditional Chinese medicine compound recipe (TCMCR) was developed by selecting heart-protecting musk pills (HPMP) as the model drug. Heart-protecting musk pellets were prepared with the refined medicinal materials contained in the recipe of HPMP. Two kinds of coated pellets were prepared by using pH-dependent methacrylic acid as film-forming material, which could dissolve under different pH values in accordance with the physiological range of human gastrointestinal tract (GIT). The pellets coated with Eudragit L30D-55, which dissolves at pH value over 5.5, were designed to disintegrate and release drug in the duodenum. The pellets coated with Eudragit L100-Eudragit S100 combinations in the ratio of 1:5, which dissolve at pH value 6.8 or above, were designed to disintegrate and release drug in the jejunum to ileum. The pellets coated with HPMC, which dissolves in water at any pH value, were designed to disintegrate and release drug in the stomach. Finally, the heart-protecting musk sustained-release capsules (HPMSRC) with a pH-dependent gradient-release pattern were prepared by encapsulating the above three kinds of coated pellets at a certain ratio in hard gelatin capsule. The results of dissolution of borneol (one of the active compounds of the TCMCR) in vitro demonstrated that the coating load and the pH value of the dissolution medium had little effect on the release rate of borneol from pellets coated with hydroxypropyl methyl cellulose (HPMC), but had a significant effect on the release rate of borneol from pellets coated with Eudragit L30D-55 or Eudragit L100-Eudragit S100 combinations in the ratio of 1:5. The pellets coated with Eudragit L30D-55 at 30% (w/w) coating load or above had little drug release in 0.1 mol/L HCl for 3 hr and started to release drug at pH value over 5.5. The pellets coated with Eudragit L100-Eudragit S100 combinations in the ratio of 1:5 at 36% (w/w) coating load or higher had little drug release in 0.1 mol/L HCl for 3 hr and in phosphate buffer of pH value 6.6 for 2 hr, and started to release drug at pH value 6.8 or above. The release profiles of lipophilic bornoel and hydrophilic total ginsenoside from HPMSRC, consisting of three kinds of pellets respectively coated at a certain ratio with HPMC, Eudragit L30D-55, and Eudragit L100-Eudragit S100 in the ratio of 1:5, showed a characteristic of pH-dependent gradient release under the simulated gastrointestinal pH conditions and no significant difference between them. The results indicated that various components with extremely different physicochemical properties in the pH-dependent gradient-release delivery system of TCMCR could release synchronously while sustained-releasing. This complies with the organic whole concept of compound compatibility of TCMCR.  相似文献   

20.
An instrumented tablet press was used to study the compression behavior of different acetylsalicylic acid (AAS) formulations. Formulations of AAS crystals and uncoated AAS pellets have compression behavior similar to formulations of AAS pellets coated with acrylic resins (Eudragit RS) and mixed with a 20% of microcrystalline cellulose. Formulations of AAS coated pellets without any excipient exhibited a more plastic compression behavior then the other formulations. Matrix tablets of AAS were produced by compression of formulations of AAS coated pellets without any excipients.

The drug release profile of the pellets before and after compression was also studied. Microcrystalline cellulose concentrations higher than 15% w/w were required to obtain tablets of coated pellets with drug release profiles similar to the coated pellets before compression. It can be concluded from the present work that compression data of coated particles can be useful to study the possible damage of the film coat of the particles during tableting. Futhermore, instrumented tablet press data can be a good complement of in vitro drug release studies.  相似文献   

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