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PubMedDate not supplied

Comparative bioavailability of alpha-methyldopa normal and film tablet formulations after single oral administration in healthy volunteers.

In a single dose, randomized, cross-over study, with one week of wash-out period, the relative bioavailability of Dopegyt tablets containing 250 mg alpha-methyldopa (AMD) and Presinol film tablets with identical active ingredient content was examined in 24 healthy volunteers. Since technologically two completely different preparations (a film-tablet and a non-film-tablet) having significantly different in vitro dissolution were to be compared, both preparations were compared to a third one, AMD solution (Dopegyt solution) with 250 mg/50 ml concentration. Plasma concentrations of the drug were measured for 24 hours post-dose, applying HPLC with fluorometric detection. Pharmacokinetic parameters calculated from individual data (AUC0-infinity, AUC0-t, Cmax, Cmax/AUC0-infinity, t(max)) were evaluated statistically. Wilcoxon's nonparametric test and the four-way variance analysis could not detect any significant difference at the usual a=95% probability level in these pharmacokinetic parameters of the two tablet preparations. For AUC0-infinity at the 90% probability level, the confidence interval was 0.883-1.237 (with an estimated geometric mean of 1.045), for the test/reference ratio of Dopegyt and Presinol tablets, thus the two preparations proved to be bioequivalent. The relative bioavailability of Dopegyt (test preparation) and Presinol (reference preparation) calculated from the AUC0-infinity values was 116.7+/-56.7% that also confirmed bioequivalence. The results of all the applied statistical tests suggest that Dopegyt and Presinol can be considered as bioequivalent preparations.

Adrenergic alpha-Agonists↗

PubMed1999

Clinical equivalence between deflazacort oral drops and tablets in active rheumatoid arthritis.

In order to assess the clinical equivalence between deflazacort oral drops and tablets, 18 patients with active rheumatoid arthritis were enrolled in an open, controlled, randomised ('tablets --> drops' sequence, or vice versa), two-period (21 days each) crossover trial (from tablets to drops, or vice versa). Individual dose titration of deflazacort drops or tablets was made weekly on the basis of clinical need. Primary outcome measures of efficacy were changes in the joint swelling count (JSC), erythrocyte sedimentation rate (ESR), hand-grip strength (HGS), joint pain (JP), duration of morning stiffness (MS), physician's global evaluation and patient's self-assessment. Sixteen patients were available by the end of the study. The formulations were equivalent with respect to HGS and improvement in duration of MS, and close to equivalence with respect to JSC and ESR decrease; the drops seemed to be more effective than tablets with respect to JP reduction. No differences between the two formulations were observed with respect to physician's and patient's assessment. The minimum effective dose of each preparation and the relative potency ratio were also established. Drops and tablets were found to have the same potency.

Administration, Oral↗

PubMed2006

Raman mapping of low-content API pharmaceutical formulations. I. Mapping of Alprazolam in Alprazolam/Xanax tablets.

PURPOSE: Raman chemical imaging of API was carried out to provide information on whether there is any structural difference between the commercial Xanax and Alprazolam tablets (the API content less than 1% w/w in both cases) in the batches with low and good recovery. MATERIALS AND METHODS: Raman mapping spectra were collected from the flattened surfaces of six tablets. The mapping spectra were analyzed by principal component analysis because the Raman signal of the API (Alprazolam) was not reliably detected from the raw spectra. The complexity of the obtained grey-scale score images was such that no information about the domain sizes of the API could be obtained and thus binarization was applied to simplify these images. RESULTS: It was found that reliable detection of the Raman signal of the API was only achieved after principal component analysis was employed with the mapping being facilitated by a surprising similarity between a high principal component loading and the spectrum of the API. The binarization was successful only if the outlying pixels in the score images are eliminated. SUMMARY: The final chemical images represent quantitative characterization of the domains of the API in the tablets in contrast to chemical images of tablets that have been reported so far in the literature which have usually been descriptive only. The abundance of Alprazolam in all six tablets of Xanax and Alprazolam, respectively, was very similar. The domain sizes were found to be below 75 mum in diameter for all the tablets analyzed.

Alprazolam↗

PubMed1983

Plasma levels and pharmacokinetics of norethindrone and ethinylestradiol administered in solution and as tablets to women.

Twenty-four normal adult female volunteers were dosed orally with a solution and tablet formulation containing the contraceptive combination of norethindrone (NET, 1.0 mg) and ethinylestradiol (EE2, 0.12 mg) in a crossover bioequivalence study. Blood was sampled sequentially following single oral doses and the plasma separated for analysis of NET and EE2 by specific radioimmunoassays. Comparisons of both drugs following a dose in solution and tablets were made with respect to the following parameters: (a) plasma concentrations at each sample time; (b) maximum plasma concentration (Cpmax); (c) time to maximum plasma concentration (Tmax); (d) total area under the plasma concentration vs. time curve (AUC), and (e) plasma half-life (t1/2). It was found that the tablet and solution doses were bioequivalent with respect to EE2 absorption. However, absorption of NET from solution and tablet doses exhibited significant differences with respect to plasma levels at certain time points as well as AUC (which were higher following the tablet dose), but Cpmax, Tmax and t1/2 were not significantly different. Pharmacokinetic analysis of both drugs following the tablet dose was carried out using a two-compartment open model. The absorption rate constant (ka) and peripheral to central compartment transfer rate constant (k21) were similar for NET and EE2, but statistically significant differences were observed with respect to the distribution rate constant (alpha), the central to peripheral transfer rate constant (k12), the overall elimination rate constant (ke1), and volume of distribution (V1/F). The elimination rate constant (beta) for both drugs showed a difference of borderline statistical significance.

Adolescent↗

PubMed1977

Triiodothyronine and thyroxine content of desiccated thyroid tablets.

Triiodothyronine (T3) and thyroxine (T4) were measured by radioimmunoassay in Pronase hydrolysates of four lots each of 1- and 2-grain tablets of desiccated thyroid (Thyroid, Armour) and thyroglobulin (Proloid, Warner-Chilcott). The methodology used was verified by studies of tablets containing known quantities of T4 and T3. One grain of desiccated thyroid contained 12 +/- 1 and 64 +/- 3 microgram (mean +/- SD) of T3 and T4 per tablet, respectively (T4/T3 molar ratio, 4.3). A 1-grain tablet of thyroglobulin contained 16 +/- 2 and 55 +/- 5 microgram of T3 and T4, respectively with a T4/T3 ratio of 2.9. Two-grain tablets generally contained twice the quantity of T3 and T4 in the 1-grain preparations. The variation in T3 and T4 content between the four lots of each tablet strength for each product was 10% or less. These estimates of T3 and T4 content are 1.5- to 2-fold greater than those previously published. This difference probably results from the more sophisticated methodology now available which does not require chromatographic separation of T3 and T4 or iodometry. Using calculations based on published estimates of T4 and T3 absorption and of the T3/T4 potency ratio, it would appear that the T3 content of desiccated thyroid and thyroglobulin provide approximately 39% and 51%, respectively, of the thyromimetic activity of these two medications.

Chemistry, Pharmaceutical↗

PubMed1992

Comparison of febantel tablets and Vercom paste against gastrointestinal nematodes of dogs.

Thirty adult dogs with naturally acquired gastrointestinal nematode infections were assigned at random to ten replicates and treated daily for 3 days with either a combination febantel/praziquantel (Vercom) paste, febantel tablets or placebo tablets. Numbers of hookworm and whipworm eggs after treatment were reduced similarly for both drug formulations when compared with pretreatment egg counts, whereas these counts increased in the controls. Vercom paste reduced the hookworm egg count by 99.9% and the whipworm egg count by 99.6%. The febantel tablet decreased the hookworm egg count by 99.9% and the whipworm egg count by 100%. As determined at necropsy, the controlled test efficacy against adult hookworms and whipworms was similar for the Vercom paste and the febantel tablets. The controlled test efficacies of Vercom paste against Ancylostoma caninum, Ancylostoma braziliense, and Trichuris vulpis were, respectively, 99.7%, 100% and 95.8% and those of febantel tablets were 98.2%, 100% and 99.7%. These results indicate that the nematocidal efficacy of febantel against these nematodes remains unchanged in these two formulations. No adverse reactions to either febantel tablets or to Vercom paste were observed.

Administration, Oral↗

PubMed1995

An ivermectin tablet for sheep: efficacy against gastro-intestinal nematodes and a bioavailability comparison with a liquid ivermectin formulation.

An ivermectin tablet for oral administration to sheep was developed for use in countries where it is customary to treat sheep with anthelmintic tablets. Tablets require no special administration equipment, and offer convenience for storage and transport. The ivermectin tablet, which delivers 10 mg of ivermectin (200 micrograms kg-1 in a 50 kg sheep), had similar bioavailability to a liquid formulation of ivermectin (IVOMEC Liquid for Sheep) as determined by peak plasma ivermectin concentrations and area under the concentration curve in plasma (P > 0.10). In dose confirmation trials in which nematode infections were induced in helminth-naive sheep, animals treated with the ivermectin tablet had significantly fewer adult and fourth-stage larval nematodes than untreated control sheep (P < 0.01) with efficacies > 99% against all nematode species tested. In six field trials evaluating the efficacy of the ivermectin tablet in 240 Merino sheep, the reductions in faecal nematode egg counts ranged between 98 and 100%, as determined by comparison of pre- and post-treatment counts for the ivermectin-treated group.

Administration, Oral↗

PubMed1996

Vibrational spectrometry for the assessment of active substance in metoprolol tablets: a comparison between transmission and diffuse reflectance near-infrared spectrometry.

Near-infrared spectrometry (NIR) was used to quantify metroprolol succinate in controlled release tablets. Metoprolol tablets were made according to an experimental design using different strengths around a central strength of 47.5 mg per tablet. A comparison was made between NIR in the diffuse reflectance mode and the transmission mode. This showed that, although a narrower wavelength range was available in the transmission mode, predictions were much better for models based on transmission spectra than for models based on diffuse reflectance spectra. The main reason for this is that in the reflectance mode NIR spectrometry is very sensitive to the inhomogeneity of the material, while in the transmission mode this problem is less severe. This is due to the larger volume of the material scanned in the transmission mode compared to that in diffuse reflectance. Spectra were taken before and after the tablets were stored under humid conditions. This allowed the final calibration models to be made more robust towards variations in the amount of water in the tablet. Different batches of metoprolol pellets and microcrystalline cellulose were used during the production of the tablets. this resulted in models that were more robust towards possible batch-to-batch differences in the main constituents.

Drug Storage↗

PubMed1996

Determination of SB 216469-S during tablet production using near-infrared reflectance spectroscopy.

A near-infrared method was developed for analyzing SB 216469-S tablets at various stages of tablet processing, particularly after (i) high shear granulation, (ii) lubrication, (iii) core tablet compression, and (iv) aqueous film coating. Tablets with three different drug concentrations ranging from 1.5% (w/w) to 6.0% (w/w) were examined along with a placebo. Similarly, moisture levels during the granulation drying process were measured, along with the thickness of the tablet coating. Tablet identification inside blister packaging for clinical supplies was also demonstrated.

Chemistry, Pharmaceutical↗

PubMed2005

Maintenance of ovulation inhibition with the 75-microg desogestrel-only contraceptive pill (Cerazette) after scheduled 12-h delays in tablet intake.

BACKGROUND: In contrast to traditional progestagen-only pills (POPs), the desogestrel-only pill Cerazette consistently inhibits ovulation. This study was performed to test the hypothesis that desogestrel alone will keep inhibiting ovulation even when pills are taken 12 h late, indicating that delays in tablet intake of up to 12 h do not jeopardize contraceptive efficacy. METHODS: Women aged between 19 and 40 years with confirmed ovulation were admitted to this open-label pharmacodynamic study. They were treated with Cerazette for 56 days with three tablets to be taken 12 h late, having been randomized to a regimen with scheduled late tablets on Days 39, 42 and 49 (Group A) or on Days 11, 14 and 21 (Group B). The occurrence of ovulation during treatment was determined by measuring progesterone serum levels every 2 days. RESULTS: One of the 103 treated subjects ovulated during treatment. The ovulation incidence thus amounts to 1.0% (two-sided 95% confidence interval 0.02-5.29%). There was no apparent relationship between these ovulations and scheduled late tablets. The minimum time to first posttreatment ovulation was 7 days, whereas it took 17.2 days on average from last tablet intake until ovulation. CONCLUSIONS: Ovulation inhibition with Cerazette is maintained after 12-h delays in tablet intake and return of ovulation takes at least 7 days. These properties distinguish Cerazette from all other POPs.

Adolescent↗

PubMed2004

The effect of wet granulation on the erosion behaviour of an HPMC-lactose tablet, used as a rate-controlling component in a pulsatile drug delivery capsule formulation.

The purpose of this study was to investigate the variability in the performance of a pulsatile capsule delivery system induced by wet granulation of an erodible HPMC tablet, used to seal the contents within an insoluble capsule body. Erodible tablets containing HPMC and lactose were prepared by direct compression (DC) and wet granulation (WG) techniques and used to seal the model drug propranolol inside an insoluble capsule body. Dissolution testing of capsules was performed. Physical characterisation of the tablets and powder blends used to form the tablets was undertaken using a range of experimental techniques. The wet granulations were also examined using the novel technique of microwave dielectric analysis (MDA). WG tablets eroded slower and produced longer lag-times than those prepared by DC, the greatest difference was observed with low concentrations of HPMC. No anomalous physical characteristics were detected with either the tablets or powder blends. MDA indicated water-dipole relaxation times of 2.9, 5.4 and 7.7x10(-8)ms for 15, 24 and 30% HPMC concentrations, respectively, confirming that less free water was available for chain disentanglement at high concentrations. In conclusion, at low HPMC concentrations water mobility is at its greatest during the granulation process, such formulations are therefore more sensitive to processing techniques. Microwave dielectric analysis can be used to predict the degree of polymer spreading in an aqueous system, by determination of the water-dipole relaxation time.

Capsules↗

PubMed2005

Properties of hot-melt extruded tablet formulations for the colonic delivery of 5-aminosalicylic acid.

Hot-melt extruded tablets were prepared using Eudragit S 100 as the polymeric carrier to target delivery of 5-aminosalicylic acid (5-ASA) to the colon. Scanning electron microscopy, modulated differential scanning calorimetry and X-ray diffraction analysis of the hot-melt tablet extrudates demonstrated that 5-ASA remained crystalline and was homogeneously dispersed throughout the polymer matrix. A pre-plasticization step was necessary when incorporating triethyl citrate (TEC) into the formulation in order to achieve uniform mixing of the polymer and plasticizer, effectively reduce the polymer glass transition temperature (T(g)), and to lower the processing temperatures. The concentration of TEC in the extrudates not only influenced the processing temperature, but also influenced the drug release rates from the extruded tablets due to leaching of the TEC during dissolution testing. Citric acid monohydrate was found to plasticize Eudragit S 100, and when combined with TEC in the powder blend, the temperatures required for processing were reduced. Tablets containing citric acid released drug at a slower rate as a result of the suppression of polymer ionization due to a decrease in the micro-environmental pH of the tablet. The drug release profiles of the extruded tablets were found to fit both diffusion and surface erosion models.

Chemistry, Pharmaceutical↗

PubMed2004

Comparison of different mathematical models for the tensile strength-relative density profiles of binary tablets.

During the last decade the evolution of the pharmaceutical dosage form design has been important. In controlled release matrix tablets, the tensile strength is an essential parameter to consider, because a minimal mechanical strength is needed for tablet production, handling and avoidance of any dose dumping during its use. Recent developments in percolation theory led to the theoretical proposal of lattice strength that was applied to the tensile strength of tablets. This mechanical property was described as a power law of the relative density involving a critical value that corresponds to the percolation threshold. The objective of the present work is to estimate these mechanical thresholds in KCl-Ethocel100 tablets that were manufactured from different sieve fractions (100-150, 150-200, 250-300 microm). Three power law models are compared regarding the best fit of the tensile strength-relative density profiles. The main criteria for this choice are the Akaike's Information Criterion (AIC), the analysis of the residuals in conjunction with the soundest physical meaning of the models. Accordingly, a power law model was chosen that assumes an initial strength parameter. No correlation could be established between the different mixture ratios or sieve fractions with the critical relative densities. The study showed that an equation based on percolation theory can adequately model tablet strength-density profiles from matrix tablets.

Algorithms↗

PubMed2004

Release behavior and photo-image of nifedipine tablet coated with high viscosity grade hydroxypropylmethylcellulose: effect of coating conditions.

An orally applicable nifedipine-loaded core tablets was coated using high viscosity grade HPMC (100,000 cps) in ethanol/water cosolvent. The release of coated tablet was evaluated using USP paddle method in 900 ml of simulated gastric fluid (pH 1.2) for 2 h followed by intestinal fluid (pH 6.8) for 10 h. The surface morphologies using scanning electron microscope and photo-images using digital camera of coated tablet during the release test were also visualized, respectively. The viscosity of hydro-alcoholic HPMC solution largely decreased as the amount of ethanol increased. There was no significant difference in viscosity among plasticizers used. The distinct and continuous coated layer was observed using scanning electron microscope. However, the surface morphologies were highly dependent on HPMC concentration and ratio of coating solvents. The higher ratio of ethanol/water gave a longer lag time prior to drug release. Lag time also increased as a function of the coating levels based on weight gains due to increased thickness of coated layer. Lag time is inversely correlated with HPMC concentration in ethanol/water (5:1) cosolvent. As the HPMC concentration slightly decreased from 3.8 to 3.2% in hydroalcoholic coating solution, a large increase of lag time was observed. As the swelling (mixing) time of high viscosity grade HPMC in ethanol/water cosolvent increased from 1 to 5 h, the release rate was decreased due to enough plasticization of polymer. Based on photo-imaging analysis, the coated tablet was initially swelled and gelled without erosion and disintegration over 5 h. The disintegration of the coated tablet was occurred approximately 7 h after dissolution, resulting in pulsed release of drug. The high viscosity grade HPMC can be applicable for polymeric coating after careful selection of solvent systems. The release behavior and lag time could be controlled by coating conditions such as HPMC concentration, ethanol/water ratio as a coating solvent, coating level and swelling (mixing) time of coating solution. The current time-controlled release tablet coated with high viscosity grade HPMC with a designated lag time followed by a rapid release may provide an alternative to site specific or colonic delivery of drugs. In addition, the release behavior can be matched with body's circadian rhythm pattern in chronotherapy.

Hypromellose Derivatives↗

PubMed2004

Evaluation of drug physical form during granulation, tabletting and storage.

An active pharmaceutical ingredient (API) was found to dissociate from the highly crystalline hydrochloride form to the amorphous free base form, with consequent alterations to tablet properties. Here, a wet granulation manufacturing process has been investigated using in situ Fourier transform (FT)-Raman spectroscopic analyses of granules and tablets prepared with different granulating fluids and under different manufacturing conditions. Dosage form stability under a range of storage stresses was also investigated. Despite the spectral similarities between the two drug forms, low levels of API dissociation could be quantified in the tablets; the technique allowed discrimination of around 4% of the API content as the amorphous free base (i.e. less than 1% of the tablet compression weight). API dissociation was shown to be promoted by extended exposure to moisture. Aqueous granulating fluids and manufacturing delays between granulation and drying stages and storage of the tablets in open conditions at 40 degrees C/75% relative humidity (RH) led to dissociation. In contrast, non-aqueous granulating fluids, with no delay in processing and storage of the tablets in either sealed containers or at lower temperature/humidity prevented detectable dissociation. It is concluded that appropriate manufacturing process and storage conditions for the finished product involved minimising exposure to moisture of the API. Analysis of the drug using FT-Raman spectroscopy allowed rapid optimisation of the process whilst offering quantitative molecular information concerning the dissociation of the drug salt to the amorphous free base form.

Chemistry, Pharmaceutical↗

PubMed2005

Pharmacokinetic profiles of two tablet formulations of piroxicam.

There is considerable interest in developing new non-steroidal anti-inflammatory drugs (NSAIDs) formulations with faster onset of analgesic action like fast dissolving tablets. An open-label, randomized, single dose, crossover study with a 18 days washout period was conducted in 16 healthy volunteers to compare the pharmacokinetic profile of 20 mg piroxicam freeze-dried tablet (Proxalyoc, Cephalon) with that of 20 mg piroxicam capsule (Feldene, Pfizer). T(lag) with freeze-dried tablet was three times shorter than with capsule (21.6 min versus 59.4 min). Mean AUC(0-30 min), mean AUC(0-1 h), mean plasma concentrations at 15 min, 30 min and 1 h post-dose were significantly higher with the freeze-dried tablet than with the capsule, indicating that piroxicam was more rapidly absorbed from the freeze-dried tablet with higher plasma concentrations achieved at shorter intervals after dosing. The 90% confidence intervals of the ratios of means C(max), AUC(0-t), AUC(0-infinity) and T(1/2) all fell within the acceptance range of 0.8-1.25, demonstrating the bioequivalence of the two formulations. Although the bioavailability of the two formulations was similar, the administration of piroxicam as a freeze-dried tablet gave a much faster absorption rate during the first hour after dosing than the capsule formulation. This faster absorption is an obvious advantage for the treatment of acute episodes of pain.

Adolescent↗

PubMed2005

Application of on-line Raman spectroscopy for characterizing relationships between drug hydration state and tablet physical stability.

Experiments were conducted to elucidate the relationship between risedronate sodium (RS) hydration state and the physical stability of tablets containing RS. The RS crystal lattice contains channels occupied by water, which is removed by drying processes at temperatures below the boiling point of water, causing a reversible contraction of the crystal lattice. In this study, risedronate sodium was wet granulated followed by fluid bed drying to final granulation moisture contents between 1 and 7%, and then compressed into tablets. During drying, the RS solid-state form was continuously monitored using on-line Raman spectroscopy. Raman spectra acquired in these experiments enabled direct monitoring of changes in the RS crystal lattice, due to dehydration, which provided key information relating RS solid-state form characteristics to final granulation moisture content. Final granulation moisture was found to have a significant effect on the change in RS hydration state measured by Raman spectroscopy. As the final granulation moisture decreased, the amount of RS dehydrated form increased. The largest Raman spectral changes were in the CH stretching region and the region including the 3-picoline ring and PO2- stretches. These changes are indicative of substantial changes in the RS solid-state structure. Final granulation moisture also had a significant effect on the change in tablet thickness over time. Lower final granulation moisture caused a greater increase in tablet thickness as the RS rehydrated. In addition, the change in RS hydration state during fluid bed drying, measured by on-line Raman, was correlated to the increase in tablet thickness and subsequent loss of tablet integrity. Raman spectroscopy allowed direct RS hydration state monitoring, rather than inference from a bulk moisture measurement. Development of a Process Analytical Technology (PAT), specifically Raman, to monitor RS solid-state during drying enabled establishment of relationships between fundamental hydration dynamics associated with RS and final product performance attributes.

Chemistry, Pharmaceutical↗

PubMed2006

Dissolution characteristics of cylindrical particles and tablets.

In this paper, dissolution characteristics of primary-particles and compressed tablets were investigated by experiments using a mathematical model. For the primary-particle, it was found that the dissolution rate increased with a decrease in the particle size. Assuming that primary-particles of size distribution were of cylindrical shape and that the dissolution occurs from the total external surface, an extended Nernst-Noyes-Whitney equation fitted to the experimental data well. As the influences of particle size and shape on thickness of a diffusion-boundary film were found to be quite low, the dissolution rate was considered to be affected by the specific surface area dominantly. Furthermore, the same model was applied to a compressed tablet and fitted to the data well. Though the rate constant obtained were not affected by the properties of primary-particles forming the tablet, it was found to increase with the apparent voidage which occupies the inter-particle volume of tablet diluent among less soluble particles. Consequently, an increase in the apparent voidage is presumed to accelerate penetration of water into the internal voids of the tablet. Thus, the dissolution going, the effective surface area inside the tablet is considered to be extended.

Kinetics↗