1,720,976 research outputs found
In vitro evaluation of pectin-HPMC compression coated 5-aminosalicylic acid tablets for colonic delivery
No full textIn this study, we report pectin-HPMC compression coated core tablets of 5-aminosalicylic acid (5-ASA) for colonic delivery. Each 100 mg core tablet contained 5-ASA and was compression coated at 20 kN or 30 kN using 100% pectin, 80% pectin-20% HPMC, or 60% pectin-40% HPMC, at two different coat weights as 400 or 500 mg. Drug dissolution/system erosion/degradation studies were carried out in pH 1.2 and 6.8 buffers using a pectinolytic enzyme. The system was designed based on the gastrointestinal transit time concept, under the assumption of colon arrival times of 6 h. It was found that pectin alone was not sufficient to protect the core tablets and HPMC addition was required to control the solubility of pectin. The optimum HPMC concentration was 20% and such system would protect the cores up to 6 h that corresponded to 25-35% erosion and after that under the influence of pectinase the system would degrade faster and delivering 5-ASA to the colon. The pectin-HPMC envelope was found to be a promising drug delivery system for those drugs to be delivered to the colon
Hexagonal boron nitride as a tablet lubricant and a comparison with conventional lubricants
No full textThe objective of this study was to investigate the lubrication properties of hexagonal boron nitride (HBN) as a new tablet lubricant and compare it with conventional lubricants such as magnesium stearate (MGST), stearic acid (STAC), and glyceryl behenate (COMP). Tablets were manufactured on an instrumented single-station tablet press to monitor lower punch ejection force (LPEF) containing varied lubricants in different ratio (0.5, 1, 2%). Tablet crushing strength, disintegration time and thickness were measured. Tensile strength of compacted tablets were measured by applying a diametrical load across the edge of tablets to determine mechanical strength. The deformation mechanism of tablets was studied during compression from the Heckel plots with or without lubricants. MGST was found to be the most effective lubricant based on LPEF-lubrication concentration profile and LPEF of HBN was found very close to that of MGST. HBN was better than both STAC and COMP. A good lubrication was obtained at 0.5% for MGST and HBN (189 and 195N, respectively). Where COMP and STAC showed 20 and 35% more LPEF compare to that of MGST (239 and 288N, respectively). Even at the concentration of 2% COMP and STAC did not decrease LPEF as much as 0.5% of MGST and HBN. Like all conventional lubricants the higher the concentration of HBN the lower the mechanical properties of tablets because of its hydrophobic character. However, this deterioration was not as pronounced as MGST. HBN had no significant effect on tablet properties. Based on the Heckel plots, it was observed that after the addition of 1% lubricant granules showed less plastic deformation. (c) 2007 Elsevier B.V. All rights reserved
Development and In Vitro Evaluation of a Novel Pulsatile Drug Delivery System Containing Dexketoprofen Trometamol
No full textPurpose A pulsatile drug delivery system containing dexketoprofen trometamol was designed by combining immediate release and colon-targeted mini tablets into a capsule. Methods Both immediate release and colon-targeted mini tablets were prepared by wet granulation. Furthermore, colon-targeted mini tablets were coated with Eudragit L 100, Eudragit S 100, Eudragit RS 30D, and ethylcellulose (Surelease (R)) using Wurster and pan coating methods. Results The optimum drug release of the system developed in the study was found to be mini tablets coated with 30% Eudragit S 100 on a 20% Surelease (R) subcoating for the purpose of colon targeting. Conclusion In the finished product, the immediate release part released the drug within the first hour, and less than 5% release was observed from the colon-targeted tablets in a 0.1 N HCl in 2 h. Then, less than 20% release occurred in the colon-targeted tablets up to 6 h in pH 6.8 phosphate buffer solution. The cumulative release rate reached 100% for up to 12 h. To our knowledge, it was the first time dexketoprofen trometamol was designed by combining both immediate release and colon-targeted mini tablets in a one dosage form
Tablets and some equations for determination of forces affecting tablet compaction
No full textTablet is the most common pharmaceutical dosage form in drug industry. It is classified as a solid dosage form. Due to its advantage, it is widely produced and used. Excipient type and level are very important for tablet formulation. Presence of a lubricant in a tablet formulation is necessary for production. Lubricants determine the specification of the final product and improve tablet performance. Lubricants also show glidant effects. During tablet production, the frictional forces between the compression machine components must be reduced with the use of an ideal lubricant. By adding a lubricant to the formulation, a layer is built around each powder particle which causes lesser tablet deformation. The effect of the lubricants on tablet's mechanical property is related to their binding mechanism. The principle of tablet press instrumentation is to measure the forces on the dies and those transferred from the dies to other components of the press. Lubricant activity of the excipients can be evaluated using the formulated data that include tensile strength, cohesion index, lubricant effectiveness and transmission ratio
IN VITRO EVALUATION OF ACECLOFENAC MONOLITHIC OSMOTIC PUMP TABLETS CONTAINING A SWELLABLE POLYMER
No full textIn this study, monolithic osmotic pump tablets which contain a swellable polymer and involve a RCS Class II nonsteroidal anti-inflammatory drug (NSAID). aceclofenac, have been generated and studied. Aceclofenac is mainly used for the relief of pain and inflammation in osteoarthritis, rheumatoid arthritis and ankylosing spondylitis; however. there are also several studies in the literature about the effectiveness of aceclofenac on colon cancer as well as other NSAIDs. In this present study, eight batches were produced using five different core tablet compositions, three different semipermeable membrane compositions. and having two different orifice sizes. The physical properties and in-viuo dissolution profiles of the generated formulations were examined and evaluated both in 0.1 M HCl and in pH 6.8 phosphate buffer. The effect of the orifice diameter size, molecular weight of polyoxyethylene, thickness of the semipermeable membrane, and coating solvent were observed. Drug releases from all formulations showed approximately zero order kinetics. Observed regression coefficients (r(2)) were found between 0.965 - 0.997 for zero order kinetics and maximum cumulative drug release was observed as 42.2% +/- 0.6 at 48 hours. Maximum drug release of up to 2.7% +/- 0.5 within the first six hours in dissolution tests showed that our monolithic osmotic pump tablets containing a swellable polymer were promising for oral colon-specific drug delivery
Compression parameters of hexagonal boron nitride on direct compression mixture of microcrystalline cellulose and modified starch
No full textThe objective of this study was to investigate the effects of conventional lubricants including a new candidate lubricant hexagonal boron nitride (HBN)'' on direct compression powders. Lubricants such as magnesium stearate (MGST), glyceryl behenate, stearic acid, talc and polyethylene glycol(6000) were studied and tablets were manufactured on a single station instrumented tablet press. This study comprised the continuation of our previous one, so mixture of microcrystalline cellulose and modified starch was used as a master formula to evaluate effects of lubricants on pharmaceutical excipients that undergo complete plastic deformation without any fragmentation under compression pressure. Bulk and tapped densities, and Carr's index parameters were calculated for powders. Tensile strength, cohesion index, lower punch ejection force and lubricant effectiveness values were investigated for tablets. The deformation mechanisms of tablets were studied during compression from the Heckel plots with or without lubricant. MGST was found to be the most effective lubricant and HBN was found very close to it. HBN did not show a significant negative effect on the crushing strength and disintegration time of the tablets when we compared with MGST. Based on the Heckel plots at the level of 1%, formulation prepared with HBN showed the most pronounced plastic character
Effects of hexagonal boron nitride on dry compression mixture of Avicel DG and Starch 1500
No full textThe objective of this study was to investigate the lubrication properties of hexagonal boron nitride (HBN) on a (1:1) binary mixture of Avicel DG and Starch 1500 after using the dry granulation-slugging method and compare it with conventional lubricants, such as magnesium stearate (MGST), glyceryl behenate (COMP) and stearic acid (STAC). MGST is one of the most commonly used lubricants in the pharmaceutical industry. However, it has several adverse effects on tablet properties. In our current study, we employed various methods to eradicate the work hardening phenomenon in dry granulation, and used HBN as a new lubricant to overcome the adverse effects of other lubricants on tablet properties. HBN was found to be as effective as MGST and did not show any significant adverse effects on the crushing strength or work hardening. From the scanning electron microscope (SEM) images, it was concluded that HBN distributed better than MGST. As well as showing better distribution, HBN's effect on disintegration was the least pronounced. Semi-quantitative weight percent distribution of B and N elements in the tablets was obtained using EDS (energy dispersive spectroscopy). Based on atomic force microscope (AFM) surface roughness images, formulations prepared with 1% HBN showed better plastic character than those prepared with MGST
DEVELOPMENT OF ORALLY DISINTEGRATING FIXED DOSE COMBINATION TABLETS CONTAINING ONDANSETRON HYDROCHLORIDE AND DEXKETOPROFEN TROMETAMOL
No full textOrally disintegrating tablet formulations that involve active pharmaceutical ingredients in combination with a non-steroidal anti-inflamatory (dexketoprofen trometamol) and 5-HT 3 receptor antagonist (ondansetron hydrochloride) to prevent pain and nausea/vomiting during cancer therapy have been developed; in vitro dissolution profiles of these formulations have been examined and evaluated. 9 different formulations were generated to observe the effect of disintegrants that have various mechanisms of action, and the effect of lubricants on dissolution profiles in several media. Direct compression and wet granulation manufacturing methods were used throughout the trials of 9 formulations. Dissolution tests were conducted for both active pharmaceutical ingredients in pH 1.2 HCl acid, pH 4.5 acetate and pH 6.8 phosphate buffers for 9 formulations. then an optimized formulation was defined. Dissolution profiles of the optimized formulation were compared with two different reference products. Selected formulations, reference products and the optimized formulation were stored in accelerated stability conditions. Then, the alteration of tablets was evaluated. To our knowledge in this study, it was the first time that dexketoprofen trometamol and ondansetron hydrochloride were combined as an orally disintegrating fixed dose combination
Effects of some lubricants and evaluation of compression parameters on directly compressible powders
No full textThe objective of this study was to investigate the effects of conventional lubricants including a new candidate lubricant Hexagonal boron nitride (HBN) on direct compression powders. Lubricants such as magnesium stearate, glyceryl behenate, stearic acid, talc and polyethylene glycol(6000) were studied in this article. Tablets were manufactured on an instrumented tablet press with various lubricant concentrations. Bulk and tapped densities, and Carr's index parameters were calculated for powders. Tensile strength, cohesion index, lower punch ejection force and lubricant effectiveness values were investigated for tablets. The deformation mechanisms of tablets were studied during compression from the Heckel plots with or without lubricants. Powders formulated with MGST and HBN showed better flow properties based on Carr's index. MGST was found to be the most effective lubricant based on lubricant effectiveness for tablets. HBN was found very close to MGST with the same concentrations. Other lubricants showed less effectiveness than that of MGST and HBN. It is observed that an increase in the concentration of HBN leads to decreased tensile strength and cohesion index values because of its surface-covering property. Despite covering property, HBN had no significant effect on disintegration time. Based on the Heckel plots at the level of 1%, HBN showed the most pronounced plastic character
Dendrimers-drug delivery systems
No full textDendrimers consisting a core, branching units around the core and surface groups also named as functional group are new polymeric drug delivery systems. The variety of dendrimers are provided with functional groups. Branching units of the dendrimer provide its growth iteratively. The space in the interior of the dendrimers allows encapsulation of the active ingredient possible. In this way, the controlled release of the active ingredient can be achieved. However, being in a very branched structure and having many functional groups on the surface provide the addition of variety of molecules and active ingredient by conjugation simultaneously. Thus, targeting of active ingredients to a specific site of the body can be achieved as well as the solubility and bioavailability of the active ingredients can be increased. In this paper, the properties of dendrimers and application areas were evaluated
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