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At least 973 records · Page 54Linked to original sources
PubMed1999

Esophageal transit of risedronate cellulose-coated tablet and gelatin capsule formulations.

Risedronate sodium is an orally active antiresorptive agent and a member of the pyridinyl class of bisphosphonates. It has been approved for the treatment of Paget's disease of the bone and is under development as a chronic therapy for the treatment and prevention of osteoporosis. A novel cellulose film-coated tablet formulation was developed to optimize esophageal transit of this bisphosphonate. The aim of the present study was to compare the esophageal transit of the film-coated tablet formulation of risedronate with its original gelatin capsule dose form. A total of 25 elderly, healthy volunteers (mean 66 years), who were dysphagia-free, participated in this randomized cross-over study. On separate occasions, volunteers swallowed radiolabeled placebo formulations with 50 ml water. Dynamic images with participants in a sitting position were recorded for 10 min using a gamma camera. Scintigraphic imaging showed a delay in esophageal transit (greater than 15 s) in 28% of patients in the capsule group but in none of the tablet group (P<0.05). The mean transit times of the capsules and tablets were 23.8 and 3.3 s, respectively. Esophageal transit of film-coated tablets was faster than gelatin capsules, suggesting that film-coated tablets would be the appropriate formulation for all pivotal trials with risedronate and for subsequent commercialization.

Aged↗
PubMed1998

Assay of effervescent tablets by near-infrared spectroscopy in transmittance and reflectance mode: acetylsalicylic acid in mono and combination formulations.

Near-infrared spectroscopy (NIRS) was used to determine acetylsalicylic acid (ASA) in three different effervescent tablet formulations. The nominal ASA concentrations were 14.9% in the single substance formulation (ASA Mono), 17.4% in the combination with ascorbic acid (ASA + C) and 8.7% in the combination with paracetamol and ascorbic acid (ASA Combi). In each case the tablet matrix was composed of seven excipients typical of effervescent tablets. All three formulations were measured as intact tablets in diffuse transmittance and reflectance and as powdered tablets in diffuse reflectance. Calibration was carried out by partial least square (PLS) regression of second derivative spectra. High-performance liquid chromatography (HPLC) was used as the reference method. The relative standard errors of calibration (RSEC) achieved for the three NIR methods were between 1.20 and 2.01% for ASA Mono, between 1.91 and 2.21% for ASA + C and between 2.41 and 4.50% for ASA Combi. The results obtained in transmittance mode were comparable with those obtained in reflectance mode, which is normally used in NIRS. In the test sets of ASA Mono and ASA + C relative root mean square (RRMS) values between 2.21 and 3.13% were obtained. The three NIR methods applied are thus suitable for the quantitative determination of ASA in effervescent tablets and have the advantage over HPLC of being rapid and simply carried out with little sample preparation; they are nondestructive and do not require any environmentally harmful reagents.

Acetaminophen↗
PubMed2003

How do roll compaction/dry granulation affect the tableting behaviour of inorganic materials? Comparison of four magnesium carbonates.

The effect of roll compaction/dry granulation on the particle and bulk material characteristics of different magnesium carbonates was evaluated. The flowability of all materials could be improved, even by the application of low specific compaction forces. The tablet properties made of powder and dry granulated magnesium carbonate were compared. Roll compaction/dry granulation resulted in a modified compactibility of the material and, consequently, tablets with reduced tensile strength. The higher relative tap density of the compacted material does not allow a densification to the same extent as the uncompacted powder. The degree of densification during tableting can be expressed as the ratio of the relative tablet density to the relative tap density of the feed material. Increasing the specific compaction forces resulted in higher apparent mean yield pressure, gained from Heckel plots, of all materials analysed. The partial loss of compactibility leads to the demand of low loads during roll compaction. Comparing the tablet properties of different magnesium carbonates reveals an obvious capping disposition. However, it depends on the type of magnesium carbonate, the specific compaction force and also on the tableting force applied.

Chemistry, Pharmaceutical↗
PubMed2002

Breaking of scored tablets: a review.

The literature was reviewed regarding advantages, problems and performance indicators of score lines. Scored tablets provide dose flexibility, ease of swallowing and may reduce the costs of medication. However, many patients are confronted with scored tablets that are broken unequally and with difficulty, reducing compliance and reliance on the drug. Possibilities to reduce breaking difficulties are breaking instructions, tablet-splitters and breaking in advance. Factors influencing the performance of score lines are shape, size, curvature and thickness of the tablet and the form and deepness of the score line. Performance of score lines can be defined by breaking ease, uniformity of mass of subdivided tablets and loss of mass by the subdivision. For breaking ease, an in-vivo reference test and a routinely applicable in-vitro test need to be established. For the uniformity of mass of subdivided tablets a requirement has recently been set by the European Pharmacopoeia. Loss of mass upon breaking can be limited to not more than 1%.

Chemistry, Pharmaceutical↗
PubMed2003

Influence of hydroxypropyl methylcellulose polymer on in vitro and in vivo performance of controlled release tablets containing alprazolam.

The purpose of this study was to investigate the influence of hydroxypropyl methylcellulose (HPMC) molecular weight on pharmacokinetic and pharmacodynamic parameters of controlled release formulations containing alprazolam. Tablet formulations contained alprazolam, excipients, and either HPMC K4MP or HPMC K100LVP. A ten patient in vivo clinical trial using a randomized, open-label, four-way crossover design was conducted in the fed and fasted states. Plasma alprazolam concentrations were determined for 72 h. The pharmacodynamic effects of alprazolam were monitored using subject rated sedation on visual analogue scale for wakefulness, observer rated sedation, and symbol digit modalities test (SDMT). Results indicated that the tablet formulations containing either HPMC K4MP or HPMC K100LVP had similar dissolution profiles, and the dissolution profiles did not change through 6 months at 40 degrees C/75% RH or 12 months at 25 degrees C/65% Relative Humidity (RH). The area under the plasma concentration-time curve, time to peak concentration, and peak plasma concentration were not significantly different between the two tablet formulations investigated in either the fed or fasted states. Pharmacodynamically, no significant differences in SDMT scores between the two formulations were found. In vitro dissolution results predicted in vivo pharmacokinetic and pharmacodynamic results irrespective of formulation or diet used in the controlled release tablet. The controlled release tablets were bioequivalent and pharmacodynamically equivalent irrespective of the tablet formulation.

Adolescent↗
PubMed1998

Optimization of an effervescent tablet formulation containing spray dried L-leucine and polyethylene glycol 6000 as lubricants using a central composite design.

A rotatable central composite design is used to evaluate the effects of lubricants and compression force on the physical characteristics of effervescent tablets. Effervescent tablets lubricated with a combination of spray dried L-leucine and polyethylene glycol 6000 are prepared by direct compression and examined. Residual force, crushing strength and disintegration time are considered as response variables and related to the L-leucine and polyethylene glycol concentrations and to the compression force. The calculated models are used to assess the influence of the production factors on tablet properties. As increasing amounts of L-leucine, showing good lubricating properties, reduce the crushing strength and prolong tablet disintegration, the L-leucine concentration is kept at a low level. An optimum tablet formulation contains 2% L-leucine and 3% polyethylene glycol 6000. The tablets have a tensile strength of 0.47 MPa and disintegrate in less than 2 min. Predicted and experimental results are in agreement within a 95% CI.

Chemistry, Pharmaceutical↗
PubMed1998

The effect of compression force on surface structure, crushing strength, friability and disintegration time of erythromycin acistrate tablets.

The surface roughness of erythromycin acistrate tablets was studied by non-contact laser profilometry. Seven roughness parameters and 3D fractal dimension were examined. The mechanical properties (including crushing strength, friability and disintegration time) were determined, and SEM data were taken from the tablets. According to the results, the crushing strength and the disintegration time of the tablets increased with increasing compression force. At higher compression forces the crushing strength reached a constant level. The friability of the tablets behaved quite unexpectedly and minimum friability was observed at a compression force of 14 kN. Except for fractal dimension, the roughness parameters behaved very much in the same way as the friability of the tablets. The SEM data supported the friability and surface roughness data of the tablets.

Chemistry, Pharmaceutical↗
PubMed2000

The determination of the mechanical properties of elongated tablets of varying cross section.

The mechanical properties of elongated tablets of different thickness prepared at a range of pressures with surfaces that are flat or curved, have been determined by application of a flexure test. The strength of the tablets in terms of breaking load increases with an increase in the cross-sectional area of the tablets. To provide an improved method of comparing the strength of the tablets, the tensile strength of the specimens has been calculated from equations based on stress analysis. While an allowance for a change in thickness was provided by such a system there was a clear indication that the specimens tensile strength was still dependent on their dimensions. For equivalent central core thickness strength increased with the face curvature. This could be due to changes of the structure within the specimen during the formation process and there were clear indications that tablet porosities for equivalent compaction pressures were not equal. The differences could, however, be utilised to provide optimum conditions of curvature and central core thickness to give maximum tablet strength.

Chemistry, Pharmaceutical↗
PubMed2003

Development and validation of a near-infrared method for the quantitation of caffeine in intact single tablets.

A near-infrared spectroscopic method was developed and validated for determining the caffeine concentration of single and intact tablets in a Finnish pharmaceutical product containing 58.82% (m/m) caffeine.The spectral region of interest contained a total of 474 data points. The second derivative of Savitsky-Golay, a standard normal variate, and mean centering were used as spectral preprocessing options. The feasibility study showed nonuniformity of caffeine repartition within each tablet. Thus, spectra were recorded from both faces of the tablets, and the analysis result for a single tablet was reported as the average of both face determinations. Precision of the method was validated because the relative standard deviations from repeatability and intermediate precision tests were below 0.75% (m/m). Accuracy validation proved that the NIR results were not significantly different (P = 0.09, n = 12) from the results obtained with the reference HPLC method. The limit of quantification for caffeine was 13.7% (m/m) in the tablets. The method was found to be unaffected by NIR source replacement, but the repeatability of the results was affected if the sample holder was not placed in the correct position in the light beam. Routine NIR analysis of caffeine in tablet form was found to be more flexible and much faster than that performed with the HPLC method.

Caffeine↗
PubMedDate not supplied

NMR imaging of high-amylose starch tablets. 1. Swelling and water uptake.

Pharmaceutical tablets made of modified high-amylose starch have a hydrophilic polymer matrix into which water can penetrate with time to form a hydrogel. Nuclear magnetic resonance imaging was used to study the water penetration and the swelling of the matrix of these tablets. The tablets immersed in water were imaged at different time intervals on a 300 MHz NMR spectrometer. Radial images show clearly the swelling of the tablets and the water concentration profile. The rate constants for water diffusion and the tablet swelling were extracted from the experimental data. The water diffusion process was found to follow case II kinetics at 25 degrees C. NMR imaging also provided spin density profiles of the water penetrating inside the tablets.

Amylose↗
PubMed2000

Spray-dried lactose composite particles containing an ion complex of alginate-chitosan for designing a dry-coated tablet having a time-controlled releasing function.

PURPOSE: The properties of novel spray-dried lactose composite particles suitable for the coating filler of a dry-coated tablet having a long induction period in drug release were investigated. METHODS: To prepare spray-dried composite particles containing alginate-chitosan complex (SD(L/AL-CS)), an aqueous solution of lactose and sodium alginate and the acetic acid solution of chitosan were concomitantly fed into the rotary atomizer of a spray-dryer. The formation of the alginate-chitosan complex was confirmed by measuring the weight of insoluble portion in the mixture of sodium alginate and chitosan solutions. The dissolution properties of the dry-coated tablet were measured with the JP specified paddle method. RESULTS: The micromeritic properties of SD(L/AL-CS) were compared to those of the SD composite particles of lactose-sodium alginate, having a good compacting property. The drug release profiles of dry-coated tablet with SD(L/AL-CS) contained a long induction period followed by a rapid drug release phase in the artificial intestinal fluid. The induction period for drug release to occur was increased with an increase in the degree of deacetylation of chitosan and in the amount of chitosan in the formulation. The prolongation of induction period was attributed to the formation of an insoluble ion complex between sodium alginate and chitosan in the composite particles, which could form a rigid gel structure on the tablet surface. CONCLUSIONS: A time-controlled release tablet was designed with the composite particles of lactose containing the alginate-chitosan ion complex. The induction period of the dry-coated tablet could be prolonged in order to deliver the drug to the colon by controlling the type and amount of chitosan formulated in the composite particles.

Alginates↗
PubMed2000

Bioequivalence of methylphenidate immediate-release tablets using a replicated study design to characterize intrasubject variability.

PURPOSE: To determine the relative bioavailability of two marketed, immediate-release methylphenidate tablets. The study used a replicated study design to characterize intrasubject variability, and determine bioequivalence using both average and individual bioequivalence criteria. METHODS: A replicated crossover design was employed using 20 subjects. Each subject received a single 20 mg dose of the reference tablet on two occasions and two doses of the test tablet on two occasions. Blood samples were obtained for 10 hr after dosing, and plasma was assayed for methylphenidate by GC/MS. RESULTS: The test product was more rapidly dissolved in vitro and more rapidly absorbed in vivo than the reference product. The mean Cmax and AUC(0-infinity) differed by 11% and 9%, respectively. Using an average bioequivalence criterion, the 90% confidence limits for the Ln-transformed Cmax and AUC(0-infinity), comparing the two replicates of the test to the reference product, fell within the acceptable range of 80-125%. Using an individual bioequivalence criterion the test product failed to demonstrate equivalence in Cmax to the reference product. CONCLUSIONS: The test and reference tablets were bioequivalent using an average bioequivalence criterion. The intrasubject variability of the generic product was greater and the subject-by-formulation interaction variance was borderline high. For these reasons, the test tablets were not individually bioequivalent to the reference tablets.

Adult↗
PubMed2001

Compression shear strength and tableting behavior of microcrystalline cellulose agglomerates modulated by a solution binder (polyethylene glycol).

PURPOSE: To investigate the possibility of modulating the compression shear strength of agglomerates by the incorporation of a solution binder and to study the subsequent effect on the deformation behavior and tablet forming ability of the agglomerates. METHOD: Various concentrations (0.5 to 10%) of polyethylene glycol were incorporated as a solution binder into microcrystalline cellulose agglomerates of different porosity (10 and 20%) and the shear strength of the agglomerates, as evaluated by the 1/b value of the Kawakita equation, and the permeability to air and tensile strength of tablets formed from them were determined. RESULTS: Increased agglomerate porosity and concentration of polyethylene glycol reduced the 1/b values, which led to the formation of tablets with a lower permeability. A decreased tablet permeability corresponded to an increased tablet tensile strength except that the highest binder content was associated with a drop in the tablet tensile strength. CONCLUSIONS: The solution binder reduced the agglomerate shear strength, which was expressed as an increased degree of agglomerate deformation during compression. The latter seemed to be controlled by both agglomerate porosity and shear strength. The main role of the solution binder in improving the agglomerate compactability was to increase the degree of deformation of agglomerates during compression.

Cellulose↗
PubMed1996

Relationship between gelation rate of controlled-release acetaminophen tablets containing polyethylene oxide and colonic drug release in dogs.

PURPOSE: We hypothesized that sufficient gelation of orally administered hydrophilic matrix tablets before they reach the colon could, as a result of continuous erosion of the gelated matrix, prevent the decrease in colonic drug release which normally occurs here. The purpose of this study was to elucidate the effect of gelation of hydrophilic matrices containing polyethylene oxide on colonic drug release in dogs using controlled-release (CR) acetaminophen tablets. METHODS: Two types of CR tablets were prepared, a slow gelling tablet (SG) and a rapid gelling tablet (RG) containing an extra highly water soluble filler. In vitro and in vivo performance were examined. RESULTS: SG and RG showed similar drug release behavior in vitro. In oral administration to dogs, the two formulations showed similar gastrointestinal transit, reaching the colon within 2-4 h after oral dosing. Further, they showed similar maximum plasma levels (Cmax) and time to Cmax (Tmax). In contrast, however, the two tablets produced different plasma levels from 2 h post-dosing, with plasma levels of RG higher than those of SG and with smaller individual variation. Directly observed colonic drug release behavior of RG was similar to in vitro drug release, whereas that from SG was suppressed. CONCLUSIONS: Colonic drug release is closely related to the gelation of hydrophilic matrix, and rapid gelation provides continuous in vivo drug release.

Acetaminophen↗
PubMed1995

Compressed donut-shaped tablets with zero-order release kinetics.

PURPOSE: Simple uncoated compressed tablets with a central hole (donut-shape) are proposed to provide a constant drug release over a long period of time (> 20 hrs). The effect of hole size and drug solubility on the release kinetics is investigated. METHODS: The donut-shaped polyethylene oxide (PEO, Mw = 4 x 10(6)) tablets (600 mg and 12 mm diameter) are bored with a drill bit (3/32", 7/64", 1/8", and 5/32"). RESULTS: The release of theophylline from the donut-shaped tablets is zero order (80-90% release) before rapidly decreasing. As the hole size is increased from 7/64" to 5/32", the release rate increases and the release time is shortened. However, the release of theophylline from the donut-shaped tablet with a hole size of 3/32" follows the same anomalous release profile from a tablet without a hole. As drug solubility increases, the duration of linear drug release is shortened to 65-70% release followed by a severe tailing at the later stage of the release. CONCLUSIONS: Donut-shaped PEO tablets with a hole provide zero-order release kinetics because the effect of the releasing surface area on the release kinetics is reduced.

Chemistry, Pharmaceutical↗
PubMed1993

Evaluation of Preflo modified starches as new direct compression excipients. I. Tabletting characteristics.

This investigation evaluated some new (Preflo) and existing commercially available (Starch 1500, Star Tab) modified starches as direct compression excipients. Preflo corn starches (CH-10, CH-20, CH-30) and Preflo potato starches (P-250, PI-10, PJ-20) were evaluated and compared with respect to their pharmaceutical properties such as particle size, density, flowability, friability, and compression properties. Preflo starches showed a high bulk density and good flowability. Preflo corn starches and Star Tab formed harder tablets than Preflo potato starches and Starch 1500. Data from the Athy-Heckel plots indicated that the Preflo starches are soft materials and, unlike Starch 1500, undergo plastic deformation. Tablets containing acetaminophen were also compressed with the starches and disintegration and dissolution studies were conducted. Starch 1500 tablets disintegrated in 3.5 min, whereas none of the Preflo starch tablets disintegrated in 30 min. While complete acetaminophen release occurred in 25 min from Starch 1500 tablets, the drug dissolution time from Preflo starch tablets varied from 4 to 12 hr, indicating a potential use for some of these starches in solid oral modified-release dosage forms.

Acetaminophen↗
PubMed1993

Enhanced bioavailability of cefoxitin using palmitoylcarnitine. II. Use of directly compressed tablet formulations in the rat and dog.

The performance of tablets containing the absorption enhancer palmitoylcarnitine chloride (PCC) and the antibiotic cefoxitin (CEF) was determined by direct placement of tablets in the rat stomach, small intestine, and colon. While the bioavailability (F) of tablets containing 12 mg CEF without PCC ranged from 0.6 to 3.9%, the addition of 24 mg PCC resulted in an enhanced CEF bioavailability in the rat colon (mean +/- SD: F = 57 +/- 19%) and rat jejunum (F = 71 +/- 16%) but not in the rat stomach. Following oral administration to dogs, tablets of 200 mg CEF without or with 600 mg PCC resulted in the same low bioavailabilities (7.0 +/- 10.3 and 7.0 +/- 3.6%, respectively). However, when these tablets were enteric coated, PCC improved CEF bioavailability from 2.44 +/- 1.84 to 29.0 +/- 13.4%. Therefore, the use of enteric-coated direct compressed tablets containing PCC and direct compression excipients improved the peroral bioavailability of a poorly absorbed compound.

Animals↗
PubMed2000

Pharmacokinetics of bambuterol during oral administration of plain tablets and solution to healthy adults.

AIMS: The pharmacokinetics of orally administered bambuterol were investigated in healthy adult subjects, with particular regard to time to steady state, pharmacokinetic linearity, intraindividual variability for the parent drug and its active beta2-adrenergic metabolite terbutaline and bioequivalence between tablet and solution. METHODS: Twenty-six healthy Caucasian subjects were included and 23 (12 women) completed this open, randomised, crossover study. Racemic bambuterol hydrochloride was administered orally as 10 mg, 20 mg, and 10 + 20 mg tablets, and as a solution once daily for 2 weeks at about 19.00 h. Plasma concentrations and urinary recoveries of bambuterol and terbutaline were measured after single doses and during repeated treatments. RESULTS: Absorption of bambuterol was biphasic. The initial rate could not be assessed directly, but it was faster than that during the second phase where absorption was rate-limiting for elimination (mean terminal half-life: 16 h). Steady-state AUC(0,24 h) of bambuterol, reached within 1 week, was not dose-linear. Mean terminal half-life of terbutaline was 22 h and steady-state was reached within one week of bambuterol treatment. Contrary to bambuterol, overall pharmacokinetics of terbutaline indicated dose-linearity. Day-to-day intraindividual variation in AUC(0,24 h) of terbutaline, 15% with the tablet, was half that of bambuterol. Urine data indicated that intraindividual variability was slightly smaller with the solution. Tablets were bioequivalent with the solution with regard to terbutaline (90% confidence interval: 87-100%). CONCLUSIONS: With oral bambuterol steady state was reached within 1 week. Regarding generated terbutaline, pharmacokinetics judged to be were linear, intraindividual variability of AUC at steady state was on average 15% with the tablet, and tablets were bioequivalent with the solution.

Absorption↗