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PubMed2004

Effect of degree of esterification of pectin and calcium amount on drug release from pectin-based matrix tablets.

The aim of this work was to assess the effect of 2 formulation variables, the pectin type (with different degrees of esterification [DEs]) and the amount of calcium, on drug release from pectin-based matrix tablets. Pectin matrix tablets were prepared by blending indomethacin (a model drug), pectin powder, and various amounts of calcium acetate and then tableting by automatic hydraulic press machine. Differential scanning calorimetry, powder x-ray diffraction, and Fourier transformed-infrared spectroscopy studies of the compressed tablets revealed no drug-polymer interaction and the existence of drug with low crystallinity. The in-vitro release studies in phosphate buffer (United States Pharmacopeia) and tris buffer indicated that the lower the DE, the greater the time for 50% of drug release (T50). This finding is probably because of the increased binding capacity of pectin to calcium. However, when the calcium was excluded, the pectins with different DEs showed similar release pattern with insignificant difference of T50. When the amount of calcium acetate was increased from 0 to 12 mg/tablet, the drug release was significantly slower. However, a large amount of added calcium (ie, 24 mg/tablet) produced greater drug release because of the partial disintegration of tablets. The results were more pronounced in phosphate buffer, where the phosphate ions induced the precipitation of calcium phosphate. In conclusion, both pectin type and added calcium affect the drug release from the pectin-based matrix tablets.

Calcium↗

PubMed2004

Hydrophilic excipients modulate the time lag of time-controlled disintegrating press-coated tablets.

An oral press-coated tablet was developed by means of direct compression to achieve the time-controlled disintegrating or rupturing function with a distinct predetermined lag time. This press-coated tablet containing sodium diclofenac in the inner core was formulated with an outer shell by different weight ratios of hydrophobic polymer of micronized ethylcellulose (EC) powder and hydrophilic excipients such as spray-dried lactose (SDL) or hydroxypropyl methylcellulose (HPMC). The effect of the formulation of an outer shell comprising both hydrophobic polymer and hydrophilic excipients on the time lag of drug release was investigated. The release profile of the press-coated tablet exhibited a time period without drug release (time lag) followed by a rapid and complete release phase, in which the outer shell ruptured or broke into 2 halves. The lag phase was markedly dependent on the weight ratios of EC/SDL or EC/HPMC in the outer shell. Different time lags of the press-coated tablets from 1.0 to 16.3 hours could be modulated by changing the type and amount of the excipients. A semilogarithmic plot of the time lag of the tablet against the weight ratios of EC/SDL or EC/HPMC in the outer shell demonstrated a good linear relationship, with r = 0.976 and r = 0.982, respectively. The predetermined time lag prior to the drug release from a press-coated tablet prepared by using a micronized EC as a retarding coating shell can be adequately scheduled with the addition of hydrophilic excipients according to the time or site requirements.

Compressive Strength↗

PubMed2004

Tablet formulation containing meloxicam and beta-cyclodextrin: mechanical characterization and bioavailability evaluation.

The purpose of this research was to evaluate beta-cyclodextrin (beta-CD) as a vehicle, either singly or in blends with lactose (spray-dried or monohydrate), for preparing a meloxicam tablet. Aqueous solubility of meloxicam in presence of beta-CD was investigated. The tablets were prepared by direct compression and wet granulation techniques. The powder blends and the granules were evaluated for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to thickness, diameter, weight variation test, drug content, hardness, friability, disintegration time, and in vitro dissolution studies. The effect of beta-CD on the bioavailability of meloxicam was also investigated in human volunteers using a balanced 2-way crossover study. Phase-solubility studies indicated an A(L)-type diagram with inclusion complex of 1:1 molar ratio. The powder blends and granules of all formulations showed satisfactory flow properties, compressibility, and drug content. All tablet formulations prepared by direct compression or wet granulation showed acceptable mechanical properties. The dissolution rate of meloxicam was significantly enhanced by inclusion of beta-CD in the formulations up to 30%. The mean pharmacokinetic parameters (C(max), K(e), and area under the curve [AUC](0-infinity)) were significantly increased in presence of beta-CD. These results suggest that beta-CD would facilitate the preparation of meloxicam tablets with acceptable mechanical properties using the direct compression technique as there is no important difference between tablets prepared by direct compression and those prepared by wet granulation. Also, beta-CD is particularly useful for improving the oral bioavailablity of meloxicam.

Adult↗

PubMed2005

The effects of physical parameters on laser-induced breakdown spectroscopy analysis of intact tablets.

With the advent of the Food and Drug Administration initiatives to investigate and encourage the use of process analytical technologies, laser-induced breakdown spectroscopy (LIBS) is considered an excellent analytical tool to understand the processability of solid dosage form. In this article, the feasibility of the LIBS system for quantitation of active drug within a solid dosage form, as well as the effects of various physical parameters on its signal, is investigated. A model drug containing chlorine and sulfur was used. The examination of the specificity and reproducibility of the measurements led to the use of chlorine and carbon as the internal standard. An overall relative SD of 1.1% for the signal was found. For quantitation purposes, calibration curves using compound-X in formulated tablets were generated. It was found that curves generated from roller-compaction tablets generally gave higher LIBS signal than those generated using direct-compressed (DC) process. To investigate these differences, effect of LIBS signals from several physical properties of the tablets were examined. It was found that unmilled compound-X used in the manufacture of the tablets gave a LIBS signal 30% lower than when milled compound-X was used. However, by using multiple crushing-recompression DC process of the milled compound-X, the LIBS results were comparable with those found from both processed tablets using milled compound-X. Other physical parameters, such as wide ranges of granule size and tablet hardness found in the typical manufacturing process, had limited effect on the LIBS signal. From these results, it was noted that for accurate quantitation, it is necessary to use the same physical properties of compound-X and the same manufacturing process in the calibration standards as the actual samples.

Chromatography, High Pressure Liquid↗

PubMed2006

Formulation and in vitro, in vivo evaluation of extended- release matrix tablet of zidovudine: influence of combination of hydrophilic and hydrophobic matrix formers.

The aim of the present study was to prepare and characterize extended-release matrix tablets of zidovudine using hydrophilic Eudragit RLPO and RSPO alone or their combination with hydrophobic ethyl cellulose. Release kinetics was evaluated by using United States Pharmacopeia (USP)-22 type I dissolution apparatus. Scanning electron microscopy was used to visualize the effect of dissolution medium on matrix tablet surface. Furthermore, the in vitro and in vivo newly formulated sustained-release zidovudine tablets were compared with conventional marketed tablet (Zidovir, Cipla Ltd, Mumbai, India). The in-vitro drug release study revealed that either Eudragit preparation was able to sustain the drug release only for 6 hours (94.3% +/- 4.5% release). Combining Eudragit with ethyl cellulose sustained the drug release for 12 hours (88.1% +/- 4.1% release). Fitting the in vitro drug release data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release. In vivo investigation in rabbits showed sustained-release pharmacokinetic profile of zidovudine from the matrix tablets formulated using combination of Eudragits and ethylcellulose. In conclusion, the results suggest that the developed sustained-release tablets of zidovudine could perform therapeutically better than conventional dosage forms, leading to improve efficacy and better patient compliance.

Animals↗

PubMed1995

Application of curdlan to controlled drug delivery. II. In vitro and in vivo drug release studies of theophylline-containing curdlan tablets.

Tablets (300 mg) having two different surface areas were prepared from spray-dried particles of curdlan (100 mg)/theophylline(200 mg). Drug release from the tablets was studied in vitro and in vivo. The in vitro drug release from a tablet with a larger surface area (Tab L) was faster than that with a smaller one (Tab S). The water uptake of Tab L was larger than that of Tab S, probably due to the difference in the tablets' surface areas. However, the water uptake was not a rate-determining step for the drug release from curdlan tablets containing a large amount of theophylline. A straight line was obtained when release % was plotted vs. time. The slope of each curve was calculated as 0.59 for Tab L and 0.58 for Tab S. This indicates that the release mechanism is non-Fickian diffusion controlled. In addition, the curdlan tablets or theophylline powder were administered orally to 5 healthy volunteers, and saliva concentrations of theophylline were determined. Each saliva concentration was converted to plasma concentration using the saliva to plasma ratio of the drug in each subject. The AUC of Tab L was nearly the same as that of powder, while the AUC of Tab S was smaller than that of powder. The mean residence times (MRTs) of theophylline powder, Tab S and Tab L were 11.1 +/- 1.5, 25.4 +/- 6.3 and 17.1 +/- 1.5 h (N = 4-5, mean +/- S.D.), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Availability↗

PubMed1981

The bioavailabilities of aspirin from an aspirin aluminum and an aspirin tablet and the effects of food and aluminum hydroxide gel.

The bioavailability of aspirin from an aspirin aluminum tablet was compared with that from an aspirin tablet in humans by determining total salicylate excreted in the urine. The effects of concomitant intakes of antacid or food on the bioavailability of aspirin were also investigated. The bioavailability of aspirin from an aspirin aluminum tablet was nearly 60% of that from an aspirin tablet. The low bioavailability of aspirin from an aspirin aluminum tablet was caused by slow release of aspirin from the aluminum complex, and not increased by concomitant intake of food. Intake of food, however, reduced both rate and extent of bioavailability of aspirin from an aspirin tablet, but dried aluminum hydroxide gel granules had no effect on the bioavailability of it.

Adult↗

PubMed1996

Preparation and evaluation of a compressed tablet rapidly disintegrating in the oral cavity.

In order to make a compressed tablet which can rapidly disintegrate in the oral cavity, microcrystalline cellulose and low-substituted hydroxypropylcellulose were used as disintegrants, and ethenzamide and ascorbic acid were chosen as poorly and easily water soluble model drugs, respectively. The mixture of microcrystalline cellulose and low-substituted hydroxypropylcellulose was compressed at 100--500 kgf in the absence of an active ingredient. The properties of these tablets, such as hardness, porosity, the time required for complete wetting of a tested tablet (wetting time), water uptake and disintegration time determined by a new disintegration apparatus, were investigated to elucidate the wetting and disintegration characteristics of these tablets, When the MCC/L-HPC ratio was in the range of 8:2 to 9:1, the shortest disintegration time was observed. The disintegration of tablets containing ethenzamide or ascorbic acid was examined next. Tablet disintegration time in the oral cavity was also tested, and good correlation between the disintegration behaviors in vitro and in the oral cavity was recognized.

Ascorbic Acid↗

PubMed1996

Development of oral dosage form for elderly patients: use of agar as base of rapidly disintegrating oral tablets.

Rapidly disintegrating tablets as an oral dosage form for elderly patients with impaired swallowing were investigated using agar powders (AG) or treated agar powders (TAG). When the compression pressure was changed from 0.4 to 2.0 ton/cm2, the disintegration time of AG tablets increased from about 60 to about 160s, and the hardness significantly increased from 3 to 13 kgw. The disintegration time and hardness of the TAG tablets were scarcely affected by the compression pressure: the disintegration time was 5--6s, and the hardness was 2--3 kgw. The rapid disintegration of the TAG tablets seemed due to the rapid water penetration into the tablet resulting from the large pore size and large overall pore volume. It was found that rapidly disintegrating oral tablets with proper hardness can be prepared using TAG.

Absorption↗

PubMed1998

Formation of water-insoluble gel in dry-coated tablets for the controlled release of theophylline.

Sodium alginate (ALNa) of a natural polysaccharide is known to form a water-insoluble gel when combined with a bivalent metal. In this study, we prepared tablets containing ALNa and calcium gluconate (GLCa) as a bivalent metal, and studied the application of the water-insoluble gel involving the controlled release of a test drug by permeation of water. Dry-coated tablets containing theophylline (TP) as a model drug, ALNa and GLCa were prepared by the dry power compression method. The controlled release of TP was evaluated by the dissolution test according to JP XIII. The release rate was extremely high for the tablets which contained only TP and GLCa. A zero order or sigmoidal release profile was observed for the tablets that contained only TP and ALNa. On the other hand, the lowest dissolution rate and a sigmoidal release profile were observed for the tablet containing TP and GLCa in its core and ALNa in its outer phase. These results suggest that dry-coated tablets containing ALNa and GLCa and prepared by the direct powder compression method would be useful for the controlled release of drugs.

Alginates↗

PubMed2002

Investigation of water mobility and diffusivity in hydrating micronized low-substituted hydroxypropyl cellulose, hydroxypropylmethyl cellulose, and hydroxypropyl cellulose matrix tablets by magnetic resonance imaging (MRI).

The water mobility and diffusivity in the gel-layer of hydrating low-substituted hydroxypropyl cellulose (LH41) tablets with or without a drug were investigated by magnetic resonance imaging (MRI) and compared with those properties in the gel-layer of hydroxypropylmethyl cellulose (HPMC) and hydroxypropyl cellulose (HPC) tablets. For this purpose, a localized image-analysis method was newly developed, and the spin-spin relaxation time (T(2)) and apparent self-diffusion coefficient (ADC) of water in the gel-layer were visualized in one-dimensional maps. Those maps showed that the extent of gel-layer growth in the tablets was in the order of HPC>HPMC>>LH41, and there was a water mobility gradient across the gel-layers of all three tablet formulations. The T(2) and ADC in the outer parts of the gel-layers were close to those of free water. In contrast, these values in the inner parts of the gel-layer decreased progressively; suggesting that the water mobility and diffusivity around the core interface were highly restricted. Furthermore, the correlation between the T(2) of (1)H proton in the gel-layer of the tablets and the drug release rate from the tablets was observed.

Cellulose↗

PubMed2003

Abnormal dissolutions of chlorpromazine hydrochloride tablets in water by paddle method under a high agitation condition.

All sugar-coated tablets of chlorpromazine hydrochloride except for those produced by one manufacture showed concave dissolution profiles in water by paddle method at 100 rpm but not at 50 rpm. The study was undertaken to clarify the agitation-dependent abnormal dissolutions. The strange dissolutions were also observed in water at different ionic strengths but not in buffer solutions of pH 1.2, 4.0 and 6.8. When monitored, the pH's of water in dissolution vessels for the abnormal tablets increased with time at 100 rpm and some of them exceeded pH 8 but did not at 50 rpm. The solubility of chlorpromazine hydrochloride decreased with the increase of pH which was too low to dissolve the whole amount of drug contained in a tablet at pH 8. The elevation of pH seemed to be mainly brought about by dissolution of calcium carbonate popularly used for sugar-coated tablets, because larger amount of calcium ion was dissolved out from the abnormal tablets at 100 rpm than from a normal tablet and from them at 50 rpm. These findings indicate that the concave dissolution profiles should be caused by the decrease of drug solubility with increase in pH of water, probably because of dissolution of calcium carbonate. We should pay attention to the change in pH of water which may differ depending on the agitation speed of dissolution tests.

Antipsychotic Agents↗

PubMed2004

Improvement of impact toughness of sugar-coated tablets manufactured by the dusting method.

The purpose of this study was to improve the impact toughness of sugar-coated tablets manufactured by a dusting method. The effects of sugar-coating formulations, which were the sugar-coating suspension formulations and the dusting powder formulations, on impact toughness of sugar-coated tablets were investigated. Impact toughness of sugar-coated tablets was measured by the friability test. We found that the dusting powder formulation was a control factor in impact toughness of sugar-coated tablets manufactured by the dusting method. The dusting method using dusting powder containing 20% microcrystalline cellulose (MCC, Avicel PH-F20) was a useful method for improvement of the impact toughness of sugar-coated tablets. The mechanism of improvement of impact toughness was that MCC in the subcoating layer resulted in a tight bond between the subcoating layer and the smoothing layer and prevented separation of the two layers on impact, because MCC improved the wettability of the subcoating layer, increased the surface roughness of the subcoating layer, and played the role of a binder between the two layers. We confirmed that the MCC between the subcoating layer and the smoothing layer acts to prevent separation of the two layers by impact. We demonstrated that MCC is a suitable material for sugar-coating in order to improve the impact toughness of sugar-coated tablets.

Carbohydrates↗

PubMed2005

Tabletting of solid dispersion particles consisting of indomethacin and porous silica particles.

We attempted to make the rapidly dissolving tablet (Tab) containing solid dispersion particles (SD) with indomethacin (IMC) and porous silica (Sylysia350) as carrier prepared by using spray-drying technique. Rapidly dissolving tablet was formulated with mannitol as a diluent and low substituted hydroxypropylcellulose (L-HPC) or partly pre-gelatinized starch (PCS) as a disintegrant. The percent dissolved from Tab (SD) was higher than that of tablet containing physical mixture (PM) at 20 min. Nearly 100% of drug in Tab (SD) was dissolved within 60 min, while the drug dissolution of Tab (PM) was not completed at the same time period. In addition, the tensile strength of Tab (SD) was much higher than that of Tab (PM). Adding L-HPC in Tab (SD) (Tab (SD-L-HPC)), the percent dissolved from Tab (SD-L-HPC) at 5 min became much higher than that from Tab (SD). The dissolution profile of IMC from Tab (SD-L-HPC) was almost the same irrespective of the compression pressure, while the tensile strength of tablet increased with increasing the compression pressure. In comparing the compaction property of these tablets by observing the ratio of residual die wall pressure (RDP) to maximum die wall pressure (MDP) (RDP/MDP), it was found that addition of L-HPC in the tablet formulation improved compactibility. In case that PCS was formulated as disintegrant, Tab (SD-PCS), similar improvement in the dissolution profile and tensile strength was observed, though the dissolution rate of IMC from Tab (SD-PCS) was slightly lower than that from Tab (SD-L-HPC) irrespective of the compression pressure.

Compressive Strength↗

PubMed2006

Evaluation of the disintegration properties of commercial famotidine 20 mg orally disintegrating tablets using a simple new test and human sensory test.

The purpose of this study was to demonstrate the usefulness and broad-applicability of a simple disintegration test method for orally disintegrating tablets (ODT). Eight types of commercial famotidine 20 mg orally disintegrating tablets with different physical properties (formulation, manufacturing method, tablet weight, shape, diameter, thickness, etc.), were used. Disintegration times of these tablets were evaluated employing human sensory test, conventional disintegration test, and the new proposed disintegration test. The human sensory test was performed in 5 healthy volunteers. In the conventional disintegration test, the disintegration apparatus described in the Japanese Pharmacopeia (JP 1(st)) was used. Our proposed new test which is characterized by a rotating shaft with a low weight (10, 15 g) and rotation speed (10, 25, 50 rpm) was evaluated using tablets with and without storage under severe conditions (60 degrees C/75%RH for 1 week). The disintegration times of famotidine 20 mg orally disintegrating tablets in human sensory test varied from 9 to 32 s. In contrast, disintegration times in the conventional test were prolonged to over 300 s. Disintegration times in the new proposed test were close to those in human sensory test. Especially, when the new test was conducted with 15 or 10 g weight and 25 rpm, the slope (human sensory test vs. new proposed test) was almost 1. We were able to demonstrate that the new proposed test was useful to estimate the actual human disintegration time.

Administration, Oral↗

PubMed2000

[Preparation and clinical evaluation of orally-disintegrating clonidine hydrochloride tablets for preanesthetic medication].

Orally-disintegrating tablets of clonidine hydrochloride, an alpha 2-adrenergic agonist, were prepared by the method of drying an aqueous suspension. The suspension was prepared using powdered lactose, and the composition ratio was 2:1 (powdered lactose: 0.048% clonidine hydrochloride solution). The suspension was dried under 4 +/- 1 degrees C (72 +/- 15% R.H.). We obtained tablets containing clonidine hydrochloride (40 micrograms/tablet). Physical properties of the tablets were as follows: hardness was 4.0 kgf, and disintegration time was 41.7 s (in vitro). In the clinical use, 8 patients, aged 1-2 year and weighing 9-11 kg, received approximately 4 micrograms/kg body weight as clonidine hydrochloride. The tablet was administered 90 min before entering the operating room. All patients were willing to accept the tablet. The quality of separation from parents, sedation and a mask acceptance were excellent on all patients. These results suggest that the orally-disintegrating tablet of clonidine hydrochloride was useful in a clinical situation for the preanesthetic medication of pediatric patients aged 1-2 year.

Administration, Oral↗

PubMed2004

Extemporaneous procedures for dissolving risedronate tablets for oral administration and for feeding tubes.

BACKGROUND: Risedronate (Actonel, Procter & Gamble Pharmaceuticals) is commercially available only as film-coated tablets. Extemporaneous procedures for dissolving tablets for feeding tubes and for preparation of an oral liquid have not previously been evaluated. OBJECTIVE: To evaluate procedures for dissolving risedronate sodium tablets for administration in liquid form and drug recovery following dissolution in cups and following passage through different types of feeding tubes. METHODS: Tablets (5 and 35 mg) were individually dispersed in 2 oz of water. After 2 minutes, the solution was stirred for 30 seconds, dispensed, and rinsed with an additional 4 oz of water. The sample was filtered and analyzed by HPLC. Ten replicates were performed using the various cups. Gastrostomy and nasoenteric tubes were flushed with 1 oz of water. Individual tablets were dispersed in 2 oz of water; after 2 minutes, the solution was stirred for 30 seconds and poured through the tube and flushed with 1 oz of water. Samples were filtered and analyzed by HPLC. Ten replicates were performed for each type of feeding tube. RESULTS: For cups, the mean amount of drug recovered ranged from 95.7% to 100.5% of the label claim, with a relative standard deviation (RSD) range of 1.1-6.3%. For gastrostomy and nasoenteric tubes, the mean amount of drug recovered ranged from 98.3% to 101.9% of label claim, with an RSD range of 0.9-3.3%. CONCLUSIONS: A simple and accurate procedure was developed for dissolving risedronate tablets in water to prepare a liquid formulation for administration orally or through feeding tubes.

Administration, Oral↗

PubMed2004

Validation of macroscopic attenuated total reflection-Fourier transform infrared imaging to study dissolution of swelling pharmaceutical tablets.

Macroscopic attenuated total reflection (ATR) infrared imaging is applied to study the dissolution of realistically sized hydroxypropyl methylcellulose (HPMC) tablets. The water intake into in situ compacted tablets and pre-compacted tablets was studied as a function of compaction pressure. Rigorous analysis of the imaging datasets show that the speed of water intake into HPMC tablet is approximately 4 microm/min and is hardly affected by the studied range of compaction pressures or the type of ATR crystal used (diamond or ZnSe). This constant speed of water intake implies that leakage (''creeping'') of water into the space between the tablet and the ATR crystal does not occur. It is shown that the radius of the HPMC tablet initially expands to twice the original radius due to swelling.

Absorption↗