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PubMed2006

Local and average gloss from flat-faced sodium chloride tablets.

The purpose of this study was to detect local gloss and surface structure changes of sodium chloride tablets. The changes in surface structure were reflected by gloss variation, which was measured using a diffractive optical element-based glossmeter (DOG). By scanning a surface area, we constructed a 2-dimensional gloss map that characterized the tablet's surface structure. The gloss variation results were compared with scanning electron microscopy (SEM) images and average surface roughness values that were measured by conventional diamond stylus profilometry. The profilometry data showed a decrease in tablet surface roughness as a function of compression force. In general, a smoother surface contributes to higher average gloss values. The average gloss values for this material, in contrast, showed a decrease as a function of the compression force. The sequence of particle fragmentation and deformation together with crack formation in sodium chloride particles resulted in a loss of gloss for single sodium chloride particles at the tablet surfaces, which could be detected by the DOG. These results were supported by the SEM images. The results show that detailed information regarding tablets' surface structure changes can be obtained by detection of local gloss variation and average gloss.

Microscopy, Electron, Scanning↗
PubMed1999

An investigation into the erosion behaviour of a high drug-load (85%) particulate system designed for an extended-release matrix tablet. Analysis of erosion kinetics in conjunction with variations in lubrication, porosity and compaction rate.

The effects of the amounts of lubricants (magnesium stearate 0-5% and talc 0-3%) and changes in compaction rate and tablet porosity on the mechanism of drug release from high drug-load controlled-release theophylline tablets have been examined. Drug release was satisfactorily described by a surface-erosion model that takes into account the geometry of the tablet, differential radial and axial erosion rates, and the initial burst effect (r2 > 0.99 for all formulations). The axial and radial erosion rate constants were inversely proportional to the amount of magnesium stearate in the formulation (P < 0.0001). The most dramatic reductions in erosion rate occurred between 0 and 1% magnesium stearate content. For magnesium stearate concentrations > or =2.5% the ratio of radial to axial erosion rate constants was essentially constant at 3 (approx.); however, for formulations with magnesium stearate < or =1% the ratio tended toward unity. Reducing matrix porosity over the range 26 to 14% resulted in reduced erosion rates. However, a threshold of 17% (approx.) porosity was identified below which further reductions in porosity resulted in only incremental changes in release rates. The rate of erosion and drug release was insensitive to changes in machine speed over the range 20 to 100 rev min(-1). For highly loaded matrix tablets containing sparingly soluble drugs, such as theophylline, magnesium stearate at appropriate levels can modulate the erosion rate constants and act as an effective release-controlling excipient. Drug-release profiles are predictable and relatively robust in terms of changes in compaction rate and applied force routinely encountered in large-scale tablet manufacturing.

Chemistry, Pharmaceutical↗
PubMed1997

Rectal absorption of ozagrel from a suppository containing its commercial tablet in healthy human subjects.

A suppository containing an ozagrel tablet was prepared using Witepsol H-15 as a base, and its rectal absorption was studied in male human volunteers. In comparison, a commercially available ozagrel tablet was administered orally to all the individuals in a cross-over design. After rectal dosing, ozagrel was absorbed rapidly at a Tmax of 0.75 h, and its elimination half-life was longer than after oral dosing. The extent of absorption of ozagrel after both administration routes was similar. However, the bioavailability of the rectal suppository is 92 +/- 37% (mean +/- S.D.; n = 6) relative to the oral tablet. The tablet-containing suppository is easy to prepare, with its content being accurate and reproducible. Thus, the present study suggests that the rectal administration of an ozagrel suppository is a practical and promising alternative to oral administration, especially for patients who cannot take tablets orally. This study demonstrated for the first time the possibility of an ozagrel suppository in human subjects.

Adult↗
PubMed1982

The bioavailability of flufenamic acid from aluminum flufenamate tablet and flufenamic acid capsule, and the influence of food and aluminum hydroxide gel.

The bioavailabilities of flufenamic acid (I) from a commercial aluminum flufenamate (II) tablet and I capsule were estimated by measuring urinary excretion of I and its metabolites fluorometrically. The dissolution rates of I from both dosage forms were also determined. The effects of concomitant intake of food or antacid on the bioavailabilities from the II tablet and the I capsule were investigated. The extent on I bioavailability from the II tablet was less than 30% of that from the I capsule. Dissolution tests suggested that the low bioavailability of I from II tablet resulted from the extremely slow release of I from the II complex. Intake of a standard meal retarded I absorption from I capsule, but did not affect that from the II tablet. Ingestion of dried aluminum hydroxide gel granules had little effect on I bioavailability from the I capsule.

Adult↗
PubMed1983

Clinical pharmacokinetics and diuretic effect of furosemide in plain tablet and retard capsule with normal subjects and cirrhotic patients.

The dissolution profiles of furosemide in various solutions were studied with plain tablet and retard capsule of furosemide. The rate constant and percent dissolution in retard capsule were lower than that in plain tablet. Clinical pharmacokinetics and diuretic effect of furosemide after oral administration of two dosage forms were also studied with 3 normal subjects and 3 cirrhotic patients. In normal subjects, the extent of furosemide absorption from retard capsule was 45% of plain tablet. The daily urine volume after oral administration of two dosage forms was comparable, however, quite different profiles were observed between these dosage forms. In patients, the extent of furosemide absorption in retard capsule was one half that of plain tablet. The dose of retard capsule was increased without adverse reactions, thus decreasing of ascites, which was not observed with plain tablet, was achieved with increasing urine volume.

Adult↗
PubMed1992

Design and preparation of pulsatile release tablet as a new oral drug delivery system.

To achieve time-controlled or site specific delivery of a drug in the gastrointestinal tract, an orally applicable pulsatile drug release system with the dry-coated tablet form was developed. The system consisted of a less water permeable outer shell and a swellable core tablet; from such a system, the drug was expected to be rapidly released after a certain period of time on the basis of time-controlled disintegration mechanism. Various model disks of outer shell, consisting of hydrogenated castor oil and polyethyleneglycol 6000, were tested for their water penetration rate. The experimental results showed that water penetration proceeded obeying the boundary retreating mechanism, so that the lag time of the system could be controlled by changing either the thickness or the composition of the outer shell. The swelling force of various commercially available disintegrants was quantitatively compared, and it was found that carboxymethylcellulose calcium was the preferable disintegrant to be used for the core tablet. On the basis of the results of a series of fundamental studies, various pulsatile release tablets of isoniazide with different lag times were designed. In the in vitro dissolution test, typical pulsatile release was achieved for all the tablets prepared, and a good correlation was found between the observed lag time and the estimated lag time calculated from an empirical equation deduced from the thickness and polyethyleneglycol 6000 content of the outer shell.

Administration, Oral↗
PubMed2001

The study of the applicability of content uniformity and weight variation test--the state of commercial tablets and capsules in Japan.

This study intends to determine the rational criteria (e.g., threshold value) for applying the weight variation test and to investigate the adequacy of the acceptance value for existing commercial products in Japan. The studied products were 489 lots (3 lots x 163 products) of compressed tablets (plain, film-coated, sugar-coated) and 42 lots (3 lots x 14 products) of hard capsules marketed in Japan. The individual drug content and the weight of 10 units in a lot were determined for each product and the acceptance values were calculated according to the Japanese Pharmacopoeia thirteenth edition (JP13) Content Uniformity Test (M=100.0, k=2.2). Product-specific intra-lot relative standard deviation of content (RSDD), weight (RSDW) and concentration (RSDC) were calculated by analysis of variance (ANOVA) using three lots of data per product. The RSDD and RSDC tended to increase with the decrease of the label strength for plain tablets, but not for film-coated and sugar-coated tablets, and hard capsules. A good correlation was found between RSDD and RSDC but not between RSDD and RSDW. These findings indicate that 1) it is difficult to rationally set the threshold level for weight variation, especially regarding the dosage forms except for plain tablets, 2) the application of weight variation tests should, in principle, be decided on the mixing homogeneity that is RSDC. 3) Most (99.6%) of the tablets and all the capsules investigated met the requirement of content uniformity test of JP13. Therefore the criteria of the JP13 content uniformity test are considered acceptable from the viewpoint of manufacturing capability.

Capsules↗
PubMed2004

A novel method for predicting disintegration time in the mouth of rapidly disintegrating tablet by compaction analysis using TabAll.

A tableting process analyzer (TabAll) was used to predict disintegration time in the mouth of rapidly disintegrating tablet. Analyzer profiles recorded upper punch displacement and die wall force encountered during tablet processing. Changes in the mixing ratio of spherical sugar granules and microcrystalline cellulose or lactose affected upper punch displacement and die wall force profiles. Analysis of the compaction process revealed a strong association between disintegration time in the mouth and stationary time, relaxation time of upper punch displacement, and relaxation time of die wall force; disintegration time in the mouth decreased as the three parameters increased. Thus, analysis of the compaction process is useful for predicting disintegration time in the mouth of rapidly disintegrating tablet, which can assist the formulation of new rapidly disintegrating tablets.

Compressive Strength↗
PubMed2005

[Radical formation by grinding of commercial tablets according to hospital and pharmacy prescription].

We examined mechanoradical formation in the grinding process of commercial tablets using electron spin resonance (ESR). Mechanoradicals were detected in all tested samples (23 types of commercial tablets) when the ball-milling of tablets was conducted under anaerobic conditions and some were fairly stable even in air. Thus the grinding may cause changes in the physicochemical properties of ingredients included in commercial tablets. Because high quality is demanded in pharmaceuticals, these results suggest more caution should be taken in the grinding of commercial tablets in hospitals and pharmacies.

Adjuvants, Pharmaceutic↗
PubMed2006

Bulk Raman analysis of pharmaceutical tablets.

We compare and contrast two Raman collection geometries, backscattering and transmission, to identify their potential for monitoring the bulk chemical composition of turbid media. The experiments performed on pharmaceutical tablets confirm the expected strong bias of the backscattering Raman collection towards surface layers of the probed sample. However, this bias is largely absent with the transmission geometry, exhibiting gross insensitivity to the depth of impurities within the sample. The results are supported by Monte-Carlo simulations. The applicability of transmission geometry to tablets without any thinning is possible because of long migration times of Raman photons in non-absorbing powder media. The absolute measured intensity of the Raman signal was only 12 times lower in transmission geometry compared with backscattering geometry for a standard paracetamol tablet with a thickness of 3.9 mm. This makes detection relatively straightforward, and detectable Raman signals were observed even after propagation through three paracetamol tablets. Given its properties and instrumental simplicity, the transmission method is particularly well suited to the on-line analysis of bulk content of tablets in pharmaceutical applications.

Algorithms↗
PubMed1981

Caries-preventive effects of fluoride tablets in schoolchildren four years after discontinuation of treatments.

The Wayne County data indicate that administration of fluoride tablets in school should be recommended in nonfluoridated areas as an effective public health measure to prevent dental caries. In addition to reducing dental caries effectively, administering fluoride tablets in school has a number of other desirable features; it is safe and relatively inexpensive; it requires no paper products and thus eliminates waste disposal; it takes little time to administer (less than three minutes per day for a classroom of average size); it is easy for young children to learn and to do; and it can be supervised by teachers, aides, or volunteers after minimal training. Findings that benefits still persist, although perhaps to a slightly lesser degree, four years after treatment is discontinued further accentuate the public health appeal of the procedure. The data give no indication that two fluoride tablets a day are more protective than one tablet a day. Therefore, a single one-mg fluoride tablet daily is recommended for school programs because of lower cost and greater feasibility.

Acidulated Phosphate Fluoride↗
PubMed1992

Induction of labor by vaginal prostaglandin E2. A randomized study comparing pessaries with vaginal tablets.

A prospective randomized study of 267 pregnant women was undertaken to compare the efficacy of a pharmacy-prepared 3-mg prostaglandin E2 (PGE2) vaginal suppository with a 3-mg PGE2 vaginal tablet for induction of labor and cervical ripening. No statistically significant difference in success frequency was found between the two groups, either on the first day (72% and 74%, respectively; p greater than 0.05) or on the second day (89% in both groups). There was an equal proportion of women requiring oxytocin augmentation in the two groups, but the slower releasing properties of the vaginal tablet were reflected in a longer mean induction--delivery interval of about 4 h for this group. In both the pessary and the vaginal tablet groups, women who had not gone into labor on the first day showed a statistically significant increment in the Bishop score on the morning of the second day. The frequency of cesarean section was the same in both groups, but instrumental deliveries were more frequent in the vaginal tablet group. It is concluded that PGE2 vaginal tablets--a chemically stable alternative to pharmacy prepared pessaries--appear to be effective as regards cervical ripening as well as for labor induction.

Administration, Intravaginal↗
PubMed1990

Gastrointestinal transit and release of mesalazine tablets in patients with inflammatory bowel disease.

Gastrointestinal transit and release of a delayed-release, enteric-coated tablet of mesalazine (Claversal) were studied in 13 patients with Crohn's disease and ulcerative colitis. The tablets disintegrated a mean of 3.2 h after leaving the stomach, resulting in drug dispersion in the distal small intestine or proximal colon. Tablet disintegration closely correlated with onset of drug absorption. Peak mean concentrations of mesalazine and its main metabolite, Ac-5-ASA, were 0.5 microgram/ml and 1.0 microgram/ml, respectively, and occurred 3 to 4 h after gastric emptying. The plasma levels correlated with scintigraph images of tablet disintegration. It is concluded that the tablets effectively deliver mesalazine to the terminal ileum and proximal colon in patients with inflammatory bowel disease.

Aminosalicylic Acids↗
PubMedDate not supplied

Development and evaluation of controlled-release diclofenac microspheres and tabletted microspheres.

Diclofenac wax microspheres were prepared using the congealable dispersephase encapsulation method. Emulsifiers, glyceryl monostearate (GMS) and stearic acid, were added to improve the efficiency of emulsification. Microspheres containing either of the emulsifiers or both showed a high drug content (80-90%) and the particle size distribution was log-normal compared with microspheres without the emulsifiers. Increase in GMS concentration decreased the drug release and, in contrast, stearic acid appeared to channel the drug from the wax matrix. The addition of both emulsifiers at different concentrations modified drug release. Increase in dispersant (PVP) concentration, and decrease in microsphere size accelerated the rate of drug release. Higuchi/Baker Londsdale spherical matrix dissolution kinetics was followed. Disintegrating tableted microspheres were prepared with Avicel and Explotab. With the increase in compression pressure the crushing force and disintegrating time increased, but the thickness decreased, and the dissolution profile did not appear to be affected. Slightly faster release was noticed with tableted microspheres compared with that of uncompressed microspheres. Tablets containing 40 and 60% microsphere loadings had disintegration times of 5.12 +/- 0.63 and 57.73 +/- 3.53 min, respectively. In contrast, tablet formulation containing 80% microsphere load had a significant increase in disintegration time (130.83 +/- 4.26 min). The dissolution from this formulation also showed a lag time of 30 min in contrast with the other two formulations, which showed no lag time. Increased microsphere size from 215 to 630 microns had no effect on tableting properties (such as hardness and thickness); and only very little effect on dissolution. The microspheres appeared deformed but intact irrespective of compression pressures on scanning electron micrographs.

Delayed-Action Preparations↗
PubMed1998

Zero-order release of theophylline from a core-in-cup tablet in sequenced simulated gastric and intestinal fluid.

Core-in-cup tablets containing theophylline were evaluated for their dissolution characteristics in sequenced simulated gastric fluid (SGF) followed by simulated intestinalfluid (SIF). Core-in-cup tablets containing 10% w/w, 20% w/w, and 30% w/w acacia as binder were evaluated for their effects on the time course of release of theophylline. This was done to optimize a formula that could release theophylline at a zero-order rate of release for 8-16 hr in simulated gastrointestinal fluids. Theophylline was released and dissolved from the core-in-cup tablets at a rate that is more consistent with a zero-order dissolution rate than a first-order dissolution rate in both SIG and SIF. The dissolution rates of theophylline from the 10%, 20%, and 30% acacia core-in-cup tablets were 0.87 mg/min, 0.53 mg/min, and 0.27 mg/min, respectively in SGF, and 0.61 mg/min, 0.30 mg/min, and 0.20 mg/min, respectively in SIF. The results indicate that a concentration of 32% w/w acacia in the core tablet will release theophylline at a rate of 0.14 mg/min in SGF for 2 hr followed by SIF for 10 hr.

Administration, Oral↗
PubMed1998

Evaluation of fast disintegrants in terfenadine tablets containing a gas-evolving disintegrant.

Effects of four fast disintegrants on the dissolution of terfenadine tablets containing the gas-evolving disintegrant, CaCO3, were evaluated. In addition, effects of presence of starch along with the fast disintegrants on the dissolution of the tablets were examined. Dissolution data were treated to give dissolution parameters which reflected efficiency of the disintegrant combinations. The four fast disintegrants improved disintegration/dissolution of the original formulation. The relative efficiency of improvement was in the order crospovidone > Ac-Di-Sol > Primojel > low substituted hydroxypropylcellulose. The presence of starch advertently affected the role of the fast disintegrants. Scanning electron microscope studies revealed that starch covered the drug-containing granules and other particles of the tablet. pH changes during dissolution of representative tablets in 0.1 N HCl solutions were determined at specific time intervals. The progressive decrease in rates of acid consumption as a function of the amount of starch, along with the SEM studies, suggested that a barrier existed around the tablet particles. The barrier was generated by the swelled starch grains and was responsible for the loss of the dissolution-improving capacity of the fast disintegrants. Furthermore, the barrier interfered with the diffusion of the hydronium ions and therefore, impaired the function of the disintegrant combination.

Calcium Carbonate↗
PubMed2000

Effect of three different diets on the bioavailability of a sustained release lithium carbonate matrix tablet.

BACKGROUND: Food-induced changes on the bioavailability of a sustained release lithium carbonate matrix tablet, which uses an acrylic matrix of Eudragit RSPM as sustaining agent, have been studied in healthy male volunteers. The tablet was developed in our laboratory using conventional technology. SUBJECTS, MATERIALS AND METHODS: The study design was a 4 x 4 Latin square involving 12 subjects who received a single dose of the tablet while fasting or with a standardized normal, high fat or high fat/high protein meal. RESULTS: The results showed no differences in half-lifebeta, renal clearance, Vdbeta, AUC, tmax, Xinfinite(u), fraction absorbed and MRT. Higher Cmax (mg/l) were obtained when the tablet was administered with any kind of meal: 2.09 +/- 0.47 (fast), 2.95 +/- 1.04 (normal diet), 2.64 +/- 0.54 (high fat diet) and 2.87 +/- 0.67 (high fat/high protein diet). The analysis of the ratio Cmax/AUC indicated that changes in Cmax were more probably due to changes in the rate of absorption. To evaluate if the magnitude of the change could be clinically relevant, Cmax and C at 12 hours (dosing interval) were treated by the superposition method in order to establish maximum and minimum concentrations at steady-state. For all the experimental conditions both concentrations would remain in the therapeutic range (4.2 10 mg/l or 0.6 - 1.4 mEq/l). CONCLUSION: The behavior of the formulation is appropriate for a sustained release tablet and fasting or non-fasting state seems not to be a major consideration for bioavailability when deciding on the regimen administration.

Antimanic Agents↗
PubMed1995

Effects of the antacids in didanosine tablets on dapsone pharmacokinetics.

OBJECTIVE: To investigate 1) the effects of the magnesium-aluminum antacids in didanosine tablets on dapsone absorption in healthy volunteers and 2) the effects of the antacid formulation of active didanosine tablets on dapsone pharmacokinetics in patients seropositive for human immunodeficiency virus (HIV). DESIGN: Two separate, randomized, two-period, two-treatment, crossover studies with a 21-day washout period between treatments. SETTING: Clinical investigation unit of a university hospital. PARTICIPANTS: Six healthy men and six HIV-positive men. MEASUREMENTS: Serial dapsone plasma concentrations were measured when dapsone, 100 mg, was administered alone and with either the third of four doses of didanosine placebo tablets (group 1) or the 27th of 28 doses of active didanosine tablets (group 2). In each study, pharmacokinetic variables were determined using noncompartmental methods and compared by analysis of variance. RESULTS: When dapsone was administered alone, pharmacokinetic variables did not significantly differ from those with dapsone given in either combination (P > 0.10 for all comparisons). CONCLUSIONS: Didanosine, antacids, and other excipients in the currently used didanosine chewable tablets did not significantly affect plasma concentrations of dapsone.

Absorption↗