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At least 505 records · Page 28Linked to original sources

PubMed2004

Bioequivalence, safety, and tolerability of imatinib tablets compared with capsules.

PURPOSE: Imatinib (Glivec) has been established as a highly effective therapy for chronic myeloid leukemia and gastrointestinal tumors. The recommended daily dosage of 400-600 mg requires simultaneous intake of up to six of the current 100-mg capsules. Due to the need to swallow multiple capsules per dose, there is a potential negative impact on treatment adherence; therefore, a new imatinib 400-mg film-coated tablet has been developed. To improve dosing flexibility, particularly with regard to the pediatric population and the management of adverse events, a scored 100-mg film-coated tablet has also been introduced. EXPERIMENTAL DESIGN: A group of 33 healthy subjects were randomly assigned to one of six treatment sequences, in which they received imatinib as 4 x 100-mg capsules (reference), 4 x 100-mg scored tablets (test), and 1 x 400-mg tablet (test). Blood sampling was performed for up to 96 h after dosing, followed by a 10-day washout period prior to the next sequence. After the third dosing, subjects were monitored to assess delayed drug-related adverse events. Pharmacokinetic parameters were assessed using concentration-time curves for plasma imatinib and its metabolite CGP74588. RESULTS: Median Tmax was 2.5 h for capsules and tablets. Mean AUC((0-inf)) values were 27,094, 26,081 and 25,464 ng.h/ml for 4 x 100-mg capsules, 4 x 100-mg tablets, and 1 x 400-mg tablets, respectively. Cmax values were 1748, 1638 and 1606 ng/ml, and t(1/2) values were 15.8, 15.9 and 15.7 h. The test/reference ratios for AUC((0-inf)), AUC((0-96) (h)), and C(max) were 0.98, 0.98 and 0.95 for 4 x 100-mg tablets versus 4 x 100-mg capsules, and 0.95, 0.95 and 0.92 for 1 x 400-mg tablet versus 4 x 100-mg capsules. The 95% confidence intervals were fully contained within the interval (0.80, 1.25). Eight mild and one moderate adverse event considered to be drug related were reported. These events showed no clustering by type of dosage form and were of little to no clinical significance. CONCLUSIONS: Film-coated 100-mg (scored) and 400-mg tablet dose forms of imatinib are bioequivalent to the commercial 100-mg hard-gelatin capsule, and are as safe and well tolerated.

Adolescent↗

PubMed2004

A novel compression-coated doughnut-shaped tablet design for zero-order sustained release.

A novel coated doughnut-shaped tablet is evaluated as to its ability to be manufactured in a reproducible manner, and as to whether it releases model drugs at a zero-order rate. The doughnut-shaped tablets were compressed using specially designed punches, which make automated production feasible. In the preliminary part of the experiment, HPMC K15M mixed with gelatin was found to be the most suitable coating tablet material with respect to its disintegration and adherence properties. The adherence of the coating tablet to ibuprofen cores was not optimal, so different concentrations of gelatin, to act as a plasticiser and enhance adherence, were further investigated. Friability results of the coated doughnut-shaped tablet indicate that coating tablets containing 20% and 30% gelatin had a percentage weight losses of less than 1% after 100 revolutions in a Roche friabilator. For all the concentrations of gelatin, the granule blends had angle of repose values in the range of 22.01-17.8 degrees. The compressibility factor, as measured from the slopes of the natural logarithm of compressional force versus crushing strength, were 121.91 +/- 2.36, 132.64 +/- 3.60, and 88.54 +/- 11.52 for the coating tablet granules containing 10%, 20%, and 30% gelatin in HPMC K15M, respectively. The composition of the coating tablet did not affect the rate of release of both caffeine and ibuprofen from the coated doughnut-shaped tablets. The coatings also adhered to the core tablets for the entire duration of the release of the drugs.

Compressive Strength↗

PubMed2005

Particle size distribution and evolution in tablet structure during and after compaction.

The objective of this study was to investigate the effect of the distribution in size of free-flowing particles for the evolution in tablet structure and tablet strength. For sucrose and sodium chloride, three powders of different size distributions were prepared by mixing predetermined quantities of particle size fractions. For paracetamol, three batches with varying particle size distributions were prepared by crystallisation. The powders were formed into tablets. Tablet porosity and tensile strength were determined directly after compaction and after short-term storage at two different relative humidities. Tablets were also formed after admixture of a lubricant (magnesium stearate) and the tablet tensile strength was determined. For the test materials used in this study, the spread in particle size had no influence on the evolution in tablet porosity and tensile strength during compression. However, the spread in particle size had a significant and complex influence on the short-term post-compaction increase in tablet tensile strength. The effect of the spread was related to the instability mechanism and the presence of lubricant. It is concluded that the distribution in size of free-flowing particles is not critical for the tablet porosity but may give significant effects on tablet tensile strength due to a post-compaction reaction.

Acetaminophen↗

PubMed2006

Pharmacokinetic and pharmacodynamic studies following oral administration of erythropoietin mucoadhesive tablets to beagle dogs.

Oral administration of mucoadhesive tablets containing erythropoietin (EPO) and an absorption enhancer Labrasol was studied in rats and dogs. Mucoadhesive tablets were prepared using Sylysia 550 holding the absorption enhancer and Carbopol 974P as a mucoadhesive agent. Mucoadhesive tablets were covered with a water-insoluble backing layer made of cellulose acetate and a pH-sensitive covering layer made of Eudragit L/Eudragit S. Tablet was administered into the rat jejunum at EPO dose of 100 IU/kg and serum samples were collected for 6h. Serum EPO level was analysed with a standard ELISA procedure. After administration, rats showed a maximum serum EPO level of C(max) 70.6 +/- 8.9 mIU/ml. Oral administration of a single tablet containing 100 IU/kg EPO to beagle dogs showed a C(max) of 24.6 +/- 4.1. When EPO dose was increased to 500 IU/kg and the number of tablets was also increased to 5, the C(max) was 54.8 +/- 9.0 mIU/ml. However, when EPO, 100 IU/kg dose was divided into five tablets, the C(max) was 15.5 +/- 1.8 mIU/ml. In the absence of absorption enhancer, the C(max) was 35.8 +/- 3.8 with 500 IU/kg dose distributed among five tablets. Pharmacodynamic studies were carried out following oral administration of mucoadhesive tablets for 6 consecutive days at an EPO dose of 500 IU/kg. Whole blood samples were collected and percent circulating reticulocytes were counted using Miller technique. The increase in percent circulating reticulocytes was found to be 1.7% on day 8 following oral administration. As a control study, EPO was administered by i.v. route at a dose of 300 IU/kg for 3 consecutive days and the percent circulating reticulocytes were counted. Mucoadhesive tablets showed promising results as an oral drug delivery system for protein therapeutics.

Acrylates↗

PubMed2005

Evaluation of rapidly disintegrating tablets manufactured by phase transition of sugar alcohols.

The aim of the present study was to assess the properties of rapidly disintegrating (RD) tablets manufactured by the phase transition method. RD tablets were produced by compressing powder containing erythritol (melting point: 122 degrees C) and xylitol (melting point: 93 approximately 95 degrees C), and then heating at about 93 degrees C for 15 min. The hardness and oral disintegration time of the heated tablets increased with an increase of the xylitol content. These results suggested that the heating process and xylitol content might influence the properties of RD tablets. Then we evaluated the physicochemical properties of the RD tablets, including the median pore size, crystallinity, hardness, and oral disintegration time of tablets made with and without heating. After heating, the median pore size of the tablets was increased and tablet hardness was also increased. The increase of tablet hardness with heating and storage did not depend on the crystal state of the lower melting point sugar alcohol. It is concluded that a combination of low and high melting point sugar alcohols, as well as a phase transition in the manufacturing process, are important for making RD tablets without any special apparatus.

Delayed-Action Preparations↗

PubMed1998

Assessment of a tablet drug delivery system incorporating nonoxynol-9 coprecipitated with polyvinylpyrrolidone in preventing the onset of pregnancy in rabbits.

OBJECTIVE: To assess the in vivo efficacy of the tablet drug delivery system containing nonoxynol-9 coprecipitated with polyvinylpyrrolidone by delivering the spermicidal agents vaginally and evaluating their ability to prevent the onset of pregnancy in rabbits. DESIGN: Controlled clinical study. SETTING: Division of Laboratory and Animal Resources, College of Pharmacy, University of Kentucky. ANIMAL(S): Forty-two New Zealand White female rabbits. INTERVENTION(S): The rabbits were artificially inseminated at various intervals after vaginal insertion of the tablet drug delivery system containing either polyvinylpyrrolidone only (0 minutes) or nonoxynol-9 coprecipitated with polyvinylpyrrolidone (polyvinylpyrrolidone/nonoxynol-9; 0, 3, 30, 180, and 360 minutes). The rabbits were induced to ovulate 6 hours before insemination by i.m. injection of hCG (200 IU). MAIN OUTCOME MEASURE(S): The onset of pregnancy in the rabbits was evaluated after insertion of the tablet drug delivery system containing polyvinylpyrrolidone only or polyvinylpyrrolidone/nonoxynol-9 at various intervals, followed by artificial insemination. RESULT(S): The onset of pregnancy was not reduced significantly when the tablet drug delivery system containing polyvinylpyrrolidone or polyvinylpyrrolidone/nonoxynol-9 was used and insemination was performed immediately after tablet insertion (time 0). However, pregnancy rates (PRs) were reduced significantly in the rabbits that received the tablet drug delivery system containing polyvinylpyrrolidone/nonoxynol-9 and were inseminated at 3, 30, 180, and 360 minutes after tablet insertion. The highest PR reduction occurred between 30 and 180 minutes after insertion of the tablet drug delivery system containing polyvinylpyrrolidone/nonoxynol-9. CONCLUSION(S): The tablet drug delivery system is an efficient method of delivering the tested spermicidal agents vaginally. The design and dosage used in preparing the tablet drug delivery system provide short- and long-term release of the spermicidal agents, which results in almost immediate and extended enhancement of their contraceptive properties.

Administration, Intravaginal↗

PubMed2000

Monolithic osmotic tablet system for nifedipine delivery.

The monolithic osmotic tablet system, which is composed of a monolithic tablet coated with cellulose acetate (CA) membrane drilled with two orifices on both side surfaces, has been described. The influences of tablet formulation variables including molecular weight (MW) and amount of polyethylene oxide (PEO), amount of potassium chloride (KCl), and amount of rice starch as well as nifedipine loading have been investigated. The optimal tablet formulation and the osmotic-suspending co-controlled delivery mechanisms have been proposed. Orifice size and membrane variables including nature and amount of plasticizers as well as thickness on drug release have also been studied. The in vitro release profiles of the optimal system have been evaluated in various release media and different agitation rates, and compared with commercialized conventional capsule and push-pull osmotic tablet. It was found that PEO with MW of 300000 g/mol was suitable to be thickening agent, both amount of KCl and amount of PEO had comparable and profoundly positive effects, while nifedipine loading had a strikingly negative influence on drug release. It could be found that the optimal orifice size was in the range of 0.25-1.41 mm. It has also been observed that hydrophilic plasticizer polyethylene glycol (PEG) improved drug release, whereas hydrophobic plasticizer triacetin depressed drug release when they were incorporated in CA membrane. The monolithic osmotic tablet system was found to be able to deliver nifedipine at the rate of approximate zero-order up to 24 h, independent of both environmental media and agitation rate, and substantially comparable with the push-pull osmotic tablet. The monolithic osmotic tablet system was simple to be prepared as exempting from push layer and simplifying in the orifice drilling compared with the push-pull osmotic tablet. The monolithic osmotic tablet system may be used in drug controlled delivery field, especially suitable for water-insoluble drugs.

Calcium Channel Blockers↗

PubMed2000

Preparation of enteric coated timed-release press-coated tablets and evaluation of their function by in vitro and in vivo tests for colon targeting.

As a new oral drug delivery system for colon targeting, enteric coated timed-release press-coated tablets (ETP tablets) were developed by coating enteric polymer on timed-release press-coated tablets composed of an outer shell of hydroxypropylcellulose and core tablet containing diltiazem hydrochloride (DIL) as a model drug. The results of the in vitro dissolution tests in JP 1st fluid (pH 1.2) and JP 2nd fluid (pH 6.8) indicated that these tablets showed both acid resistance and timed-release. To clarify whether ETP tablets could have been of use in the gastrointestinal tract, ETP tablets with a layer of phenylpropanolamine hydrochloride (PPA) (a marker of gastric emptying) between the enteric coating layer and outer shell were prepared, and were administered to beagle dogs. The gastric emptying time and lag time after gastric emptying were evaluated by determining the times at which PPA and DIL first appeared in the plasma (TFA(PPA) and TFA(DIL), respectively). TFA(PPA) and TFA(DIL) were about 4 and 7 h, respectively. This value of TFA(PPA) indicated that ETP tablets displayed acid resistance in the stomach as well as in JP Ist fluid. Subtraction of TFA(PPA) from TFA(DIL) gave a value of about 3 h which agreed well with the lag time determined by in vitro dissolution test in JP 2nd fluid. Also, the results seemed to be in accordance with the time at which the tablets reached the colon after gastric emptying. Therefore, ETP tablets seemed to be an effective tool for oral site-specific delivery including targeting of the colon.

Administration, Oral↗

PubMed2001

Influence of storage on in-vitro release of ibuprofen from sugar coated tablets.

Studies performed on ibuprofen tablets (one brand of 400 mg, two brands of 200 mg sugar coated and one brand of film coated tablets) are reported. Tablets were subjected to conditions of 23 degrees C, 30 degrees C and 40 degrees C; at 75% RH and 96% RH for periods of up to 4 weeks. Tablets were stored in different ways--unpacked, packed in air-tight/moisture proof containers, packed in tablet vials and packed in two unit dose packs. Dissolution was carried out in pH 7.2 phosphate buffer using USP or FDA conditions for ibuprofen (Basket-150 rpm or Paddle-50 rpm) with sampling and UV analysis up to 90 or 120 min. Serious reduction in dissolution was noted for the 400 mg sugar coated tablets exposed to moisture. Mean % released at 30 mm (USP conditions) was as low as 1% and, for these tablets, dissolution continued to proceed extremely slowly for the full dissolution period. The film coated tablets were not affected. The tablet vials and unit dose packs showed some protection. Investigation showed not only a change in the subcoat properties (which did not break down easily) but also in the tablet core, which became hard and non-disintegrating.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2002

A three-layer guar gum matrix tablet for oral controlled delivery of highly soluble metoprolol tartrate.

The objective of the study is to design oral controlled drug delivery systems for highly water-soluble drugs using guar gum as a carrier in the form of a three-layer matrix tablet. Metoprolol tartrate was chosen as a model drug because of its high water solubility. Matrix tablets containing either 30 (M1), 40 (M2) or 50% (M3) of guar gum were prepared by wet granulation technique using starch paste as a binder. Three-layer matrix tablets of metoprolol tartrate were prepared by compressing on both sides of guar gum matrix tablet granules of metoprolol tartrate M1, M2 or M3 with either 50 (TL1M1, TL1M2 or TL1M3) or 75 mg (TL2M1, TL2M2 or TL2M3) of guar gum granules as release retardant layers. Both the matrix and three-layer matrix tablets were evaluated for hardness, thickness, drug content uniformity, and subjected to in vitro drug release studies. The amount of metoprolol tartrate released from the matrix and three-layer matrix tablets at different time intervals was estimated by using a HPLC method. Matrix tablets of metoprolol tartrate were unable to provide the required drug release rate. However, the three-layer guar gum matrix tablets (TL2M3) provided the required release rate on par with the theoretical release rate for metoprolol tartrate formulations meant for twice daily administration. The three-layer guar gum matrix tablet (TL2M3) showed no change either in physical appearance, drug content or in dissolution pattern after storage at 40 degrees C/75% RH for 6 months. The FT-IR study did not show any possibility of metoprolol tartrate/guar gum interaction with the formulation excipients used in the study. The results indicated that guar gum, in the form of three-layer matrix tablets, is a potential carrier in the design of oral controlled drug delivery systems for highly water-soluble drugs such as metoprolol tartrate.

Administration, Oral↗

PubMed2002

Bioavailability of hydrochlorothiazide from isomalt-based moulded tablets.

The bioavailability of hydrochlorothiazide (HCT) from moulded isomalt-based tablets was evaluated after oral administration of 50 mg HCT to healthy volunteers as an oral moulded tablet and as a lozenge, in comparison with a conventional tablet formulation (Dichlotride 50 mg). Moulded tablets had a high relative bioavailability (F(rel)) as the pharmacokinetic parameters (C(max), t(max), t(1/2), AUC(0-->24 h)) determined from HCT plasma concentration versus time profiles were not significantly different (P>0.05; two-way ANOVA) in comparison with the conventional tablet. The relative bioavailability of the moulded tablet administered as a lozenge and as an oral tablet was 106.2+/-30.9% and 89.4+/-25.9%, respectively, in relation to the conventional tablet formulation. Direct moulding of isomalt tablets proved to be a suitable technique to administer a poorly soluble drug either as a conventional tablet or as a lozenge.

Administration, Oral↗

PubMed2003

Biphasic drug release from film-coated tablets.

A study was carried out into the biphasic drug release properties of film-coated paracetamol tablets. The tablet cores were formulated without a disintegrant and film-coated with a coating formulation consisting of pectin, chitosan and hydroxypropylmethylcellulose in a ratio of 6:1:0.37. The tablet cores and the film-coated tablets with coat weight gains (CWGs) of 6, 9 and 13% were evaluated for their water absorption (swelling) and drug release properties. All the tablets absorbed water from pH 6.0 Sorensen's phosphate buffer and the amount of water absorbed increased with an increase in tablet CWG. The addition of 100 microl/50 ml pectinolytic enzymes to the medium resulted in at least a 40% reduction in the amount of water absorption by the tablets, as compared to the medium without enzymes. When the enzyme concentration was increased to 200 microl/50 ml, there was a further reduction ( approximately 8% w/w) in the amount of water absorbed by the tablets. Drug release was controlled in upper gastrointestinal fluids and decreased with an increase in tablet CWG. Drug release was, however, accelerated in the presence of pectinolytic enzymes, consistent with the entry of the tablets in the colon. An evaluation of the drug release data by the Korsmeyer-Peppas equation showed the involvement of molecular diffusion and other factors such as film/tablet erosion and drug dissolution in drug release.

Acetaminophen↗

PubMed1999

Effect of magnesium stearate on bonding and porosity expansion of tablets produced from materials with different consolidation properties.

The negative effect of magnesium stearate on tablet strength is widely known. This strength reduction is always considered to be the result of reduction of interparticle bonding. It is also known that interparticle bonding affects relaxation of tablets. Relaxation increases with decreasing bonding. Microcrystalline cellulose is an example of a material with a high lubricant sensitivity, which effect is caused by its plastic deformation behavior during compression. This paper shows for microcrystalline cellulose that the porosity under pressure was equal for unlubricated tablets and for tablets containing 0.5% magnesium stearate. This points to equal densification properties. The lubricated tablets show, however, a much larger relaxation than the tablets without magnesium stearate. This difference can be ascribed to the reduction of interparticle bonding by the lubricant, because a strong interparticle bonding counteracts tablet relaxation. In contrast to microcrystalline cellulose, aggregated gamma-sorbitol (Karion Instant) has a low lubricant sensitivity. Both porosity under pressure and tablet relaxation were found to be equal for lubricated and unlubricated sorbitol tablets. This phenomenon is caused by the particle structure of gamma-sorbitol. During compression, a lubricant film will be destroyed by fragmentation of the sorbitol aggregates. For this reason, magnesium stearate will hardly affect the interparticle bonding between sorbitol particles and hence have only a small or no effect on tablet relaxation.

Elasticity↗

PubMed2003

In vivo pharmacokinetics in human volunteers: oral administered guar gum-based colon-targeted 5-fluorouracil tablets.

The objective of the present study is to compare the guar gum-based colon-targeted tablets of 5-fluorouracil against an immediate release tablet by in vitro dissolution and in vivo pharmacokinetic studies in human volunteers. Twelve healthy volunteers participated in the study. 5-Fluorouracil was administered at a dose of 50 mg both in immediate release tablet and colon-targeted tablet. On oral administration of colon-targeted tablets, 5-fluorouracil started appearing in the plasma at 6 h, and reached the peak concentration (C(max) of 216+/-15 ng/ml) at 7.6+/-0.1 h (T(max)), whereas the immediate release tablets produced peak plasma concentration (C(max) of 278+/-21 ng/ml) at 0.6+/-0.01 h (T(max)). The AUC(0- infinity ) for 5-fluorouracil from colon-targeted tablet and immediate release tablet were found to be 617+/-39 and 205+/-21 ng/ml/h, respectively. Colon-targeted tablets showed delayed t(max), delayed absorption time (t(a)), decreased C(max) and decreased absorption rate constant when compared to the immediate release tablets. The results of the study indicated that the guar gum-based colon-targeted formulation did not release the drug in stomach and small intestine, but delivered it to the colon resulting in a slow absorption of the drug and making it available for local action in colon.

Adolescent↗

PubMed2001

Cold extrusion as a continuous single-step granulation and tabletting process.

The potential of cold extrusion as a continuous granulation/tabletting technique was investigated. Extrudates (X, 9 mm) were produced using twin-screw extrusion, cut manually into tablets (thickness, 4 mm) and dried at 25 degrees C for 20 h. alpha-Lactose monohydrate (200 M) was used as an excipient, PVP (Kollidon K30) and water as binders, and hydrochlorothiazide as the model drug. The influence of formulation (water content, PVP addition, drug incorporation) and process (total input rate and screw speed) parameters on the process (torque, die pressure, visual evaluation of tablets) and on the tablet properties (tensile strength, friability, disintegration time, porosity) was evaluated. Formulation, as well as process parameters, affected the process feasibility, but had only a minor effect on the tablet properties at conditions that allowed continuous tablet production. All alpha-lactose monohydrate tablets formulated without and with PVP and produced at optimum conditions showed tensile strengths above 0.7 and 1.5 MPa, friabilities below 1.0 and 0.9%, and disintegration times below 1 and 8 min, respectively. This technique allows single-step granulation/tabletting of pure alpha-lactose monohydrate, indicating that cold extrusion could be used as alternative tablet production technique for ingredients with poor compaction properties. As the tablets prepared by extrusion have a much higher porosity compared with conventional tablets, this technique could also be useful for tablet production of formulations with poor disintegrating properties.

Chemistry, Pharmaceutical↗

PubMed1999

Evaluation of a novel, natural oligosaccharide gum as a sustained-release and mucoadhesive component of calcitonin buccal tablets.

The objective of this study was to evaluate the gum from Hakea gibbosa (hakea) as a sustained-release and mucoadhesive component in buccal tablets for a model peptide, namely, salmon calcitonin. Flat-faced core tablets containing either 12 or 32 mg of hakea and 40 microg (200 IU) of salmon calcitonin (sCT) per tablet were formulated using a direct compression technique and were coated with Cutina on all but one face. The in vitro release profiles were sigmoidal in nature and according to a mathematical model indicated super Case II transport as the primary mechanism of release. The resulting plasma sCT and calcium concentrations were determined following both intravenous administration and buccal application of mucoadhesive tablets in rabbits. Following intravenous administration, the mean values determined for t(1/2) (alpha), t(1/2) (beta), V(d), and CL for sCT were 0.76 +/- 0.06 min, 67 +/- 18 min, 1484 +/- 454 mL/kg, and 19 +/- 2 mL/min.kg, respectively. Following the application of the mucoadhesive buccal tablets which contained 40 microg of sCT and either 12 or 32 mg of hakea, the calculated apparent bioavailability (F) and clearance (CL) were 37 +/- 6% and 19 +/- 3.3 mL/min.kg and 16 +/- 8% and 18 +/- 0.4 mL/min. kg, respectively. Serum calcium concentrations indicated that biologically active sCT was delivered across the rabbit buccal mucosa. The strength of mucoadhesion of the tablets was also quantitated in terms of the force of detachment as a function of time. The force of detachment for the mucoadhesive buccal tablets containing either 12 or 32 mg of hakea and 40 microg of sCT increased from 4.47 +/- 0.68 to 8.41 +/- 1.0 N and 8.23 +/- 1.62 to 14.98 +/- 1.63 N, respectively, from 5 to 90 min following application to excised rabbit intestinal mucosa. These results demonstrate that the novel, natural gum from Hakea gibbosa may be used to sustain the release of sCT from a unidirectional-release buccal tablet. The mechanism of in vitro release is likely to involve peptide diffusion/polymer dissolution. The mucoadhesive strength, as measured by the force of detachment, can be modulated by altering the amount of hakea in the tablet. The mucoadhesive buccal tablets described in this paper represent an improved transbuccal delivery system for therapeutic polypeptides.

Adhesives↗

PubMed1992

In vivo evaluation of enteric-coated naproxen tablets using gamma scintigraphy.

Seven healthy, male volunteers were entered into a randomized, open crossover study of the gastrointestinal transit of two enteric-coated 500-mg naproxen tablets. Two radiolabeled tablets were given to each volunteer on two occasions separated by 7 days, once in the fasted state and once after breakfast. Radiolabeling of tablets was achieved by the incorporation of samarium-152 oxide during manufacture, followed by neutron activation of the tablet to produce the gamma-emitting isotope samarium-153. No loss of tablet integrity was seen in the stomach and all tablets disintegrated in the small intestine. Onset of tablet disintegration was controlled predominantly by gastric emptying. Time in the small intestine prior to tablet disintegration was independent of food intake. Naproxen blood levels with time were consistent with the delayed release of naproxen from the tablets. Overall, transit, disintegration, and absorption were as expected from an enteric-coated tablet.

Adult↗

PubMed2003

Analysis of the meal-dependent intragastric performance of a gastric-retentive tablet assessed by magnetic resonance imaging.

BACKGROUND: Modern medical imaging modalities can trace labelled oral drug dosage forms in the gastrointestinal tract, and thus represent important tools for the evaluation of their in vivo performance. The application of gastric-retentive drug delivery systems to improve bioavailability and to avoid unwanted plasma peak concentrations of orally administered drugs is of special interest in clinical and pharmaceutical research. AIM: To determine the influence of meal composition and timing of tablet administration on the intragastric performance of a gastric-retentive floating tablet using magnetic resonance imaging in the sitting position. METHODS: A tablet formulation was labelled with iron oxide particles as negative magnetic resonance contrast marker to allow the monitoring of the tablet position in the food-filled human stomach. Labelled tablet was administered, together with three different solid meals, to volunteers seated in a 0.5-T open-configuration magnetic resonance system. Volunteers were followed over a 4-h period. RESULTS: Labelled tablet was detectable in all subjects throughout the entire study. The tablet showed persistent good intragastric floating performance independent of meal composition. Unfavourable timing of tablet administration had a minor effect on the intragastric tablet residence time and floating performance. CONCLUSION: Magnetic resonance imaging can reliably monitor and analyse the in vivo performance of labelled gastric-retentive tablets in the human stomach.

Adult↗