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PubMed1989

Formulation studies of tableted oral rehydration salt mixtures.

Dehydration following non-specific diarrhoea may be prevented by oral administration of a simple glucose/salt mixture. A solution tablet of this mixture would have advantages of stability under environmental exposure and transport if the costs could be held within reasonable limits. The moisture adsorption and compression characteristics of Oral Rehydration Salts (ORS) ingredients have been studied. Combinations of ingredients resulted in a moisture adsorption higher than that of the individual components. This may be explained in terms of critical relative humidity, RHo, and environmental relative humidity RHi. Preparation of a stable ORS solution tablet therefore requires protection of moisture adsorbing components from the environment. The present UNICEF ORS mixture compacted easily by direct compression but gave fragile tablets, which were hygroscopic. This can be reduced by film coating the electrolyte component as granules with a resin (Eudragit L), or by simulating direct compression of the glucose as a compression-coating around the precompressed electrolytes. The packaging of compression-coated solution tablets in inexpensive polyethylene bags may lengthen the shelf-life and make the preparation less costly than the currently supplied ORS powders packed in laminated aluminium sachets. The increased dissolution lag time for the compacted tablet is a disadvantage that can be overcome by instructions to crush the product immediately before use.

Absorption↗
PubMed1989

Dissolution of theophylline from film-coated slow release mini-tablets in various dissolution media.

The dissolution of an experimental formulation of film-coated slow release theophylline mini-tablets has been investigated using the USP paddle apparatus in test media at pH 1.2 (hydrochloric acid), pH 5.4 and 7.4 (phosphate buffers) at 37 degrees C. Monitoring of in-vitro theophylline release over 12 h, under identical hydrodynamic conditions, showed that the dissolution rate at pH 1.2 is substantially greater (95% of total drug content released in less than 10 h) than that in phosphate buffers. The maximum release after 12 h was approximately 20 and 30% of total drug content of the tablet at pH 5.4 and 7.4, respectively. However, in vivo bioavailability after oral administration of tablets to rabbits corresponded to over 95% of total drug, compared with the same dose administered intravenously. The retarded drug release during in-vitro dissolution in phosphate buffer was attributed to a possible interaction of phosphate ions with theophylline molecules at the tablet core-coat interface. These findings indicate that both rate and extent of theophylline release from the slow release coated mini-tablets are highly sensitive to phosphate buffers. The data also emphasize the usefulness of an animal model for assessment of in-vivo drug release and subsequent absorption, during the development of modified release dosage forms.

Animals↗
PubMed1990

Effect of compression speed on the tensile strength of tablets of binary mixtures containing aspirin.

Mixtures of aspirin with sodium chloride, sucrose, Starch 1500 or Emcompress have been compressed to two maximum upper punch pressures at two compression speeds. Non-linear relationships between tensile strength and composition, and tablet porosity and composition were found in all cases. Tablets of the individual materials compressed at fast speed showed either little change or a reduction in tensile strength when compared with those compressed at slow speed. For mixtures of aspirin with Starch 1500, tablets compressed at fast speed were weaker and more porous than those compressed at slow speed. However, some mixtures of aspirin with sodium chloride, sucrose or Emcompress gave tablets with greater tensile strength and lower porosity when prepared at fast compression speed compared with tablets prepared at slow speed. This behaviour was attributed to the modification of the consolidation behaviour of the aspirin by the second material.

Aspirin↗
PubMed1994

The role of the displacement-time waveform in the determination of Heckel behaviour under dynamic conditions in a compaction simulator and a fully-instrumented rotary tablet machine.

The Heckel equation has been used widely to characterize the compression behaviour of pharmaceutical powders, yet very little attention has been paid to the role of the displacement-time profile used to generate this relationship. The objective of this study was to evaluate and compare selected standard waveforms with actual and theoretical tablet press waveforms in the Heckel analysis of representative formulations under dynamic conditions in a compaction simulator and to compare such data with that determined on the same formulation using an actual fully-instrumented rotary tablet press. Increased tableting rate and different programmed displacement-time waveforms with the same gross punch-speed changed the Heckel behaviour of all formulations. The results of this study suggest the pressure-volume relationship determined during powder-bed compression is affected by the instantaneous punch-speed profile of the displacement-time waveform for all materials studied, even though they deform by different mechanisms. It appears that the instantaneous punch-speed profile of the particular displacement-time waveform is a confounding factor of Heckel analysis. Compaction simulators programmed to deliver saw-toothed displacement-time traces have the advantage of constant punch-speed and may be a better choice for characterizing a formulation by Heckel indices and the strain-rate sensitivity index. On the other hand, they also carry the liability of not being a realistic representation of tableting on a rotary tablet press.

Calcium Phosphates↗
PubMed1983

Combination of salbutamol inhalational powder and tablets in asthma.

A double-blind cross-over trial was conducted to assess the effects of salbutamol administered by inhalation of dry powder, by tablet, and combined tablet and inhalational powder in a sample of 18 severely asthmatic children. The combined treatment had a rapid onset of effect and sustained action. The onset of action of the tablet treatment was less rapid but sustained, whereas the inhalational powder treatment had rapid onset but fairly short action. The response characteristics of the combined treatment were shown to be an additive function of its tablet and inhaled components. Children on the combined or tablet treatment showed a significant, but slight, increase in pulse rate. Few other side effects were observed.

Administration, Oral↗
PubMed1994

Impaired oesophageal transit of capsule versus tablet formulations in the elderly.

Drug induced oesophageal injury is an important and preventable cause of iatrogenic injury. In most cases the injury is considered to be due to mucosal contact from formulations lodged in the oesophagus. A scintigraphic study was performed comparing the oesophageal transit of enteric coated tablets with similar sized and shaped gelatin capsules, using a population of elderly healthy volunteers similar in age (50-79 years) to the population most likely to be receiving regular treatment. Twenty three volunteers injected the radiolabelled tablet or capsule with 50 ml of water while sitting on two separate occasions according to a randomisation schedule. Oesophageal transit was assessed by gamma scintigraphy. Gastric residence was also assessed in 11 of 23 subjects. While the tablet was readily cleared from the oesophagus, mean transit time 4.3 seconds (range 1.0-14.0), the capsule often showed a comparatively prolonged holdup, mean transit time 20.9 seconds (range 1.5-174.5). Ten of 11 tablets emptied from the stomach intact, while all 11 capsules broke up in the stomach. Gelatin capsules showed a clear tendency to remain within the oesophagus of healthy elderly volunteers, while similar sized enteric coated tablets did not. These studies show the importance of assessing oesophageal transit when designing the formulation of drugs with a potential for oesophageal injury.

Administration, Oral↗
PubMed2000

A randomized crossover evaluation of antianginal efficacy and safety of nitrolingual-spray and nitroglycerin tablet form in coronary artery disease patients.

Twenty-eight coronary artery disease patients with more than 50% stenosis in at least one major coronary artery completed this randomized crossover clinical trial for the comparison of efficacy and safety of Nitrolingual-Spray and nitroglycerin (NTG) tablets. Exercise time was lengthened to 399.1 s (spray) or 408.5 s (tablets), compared to a baseline of 387.3 s. Ischemic burden decreased to about -4.0 mm with both forms, compared to -7.5 mm at baseline (ANOVA: p = 0.003). The ischemic time improved to 137.2 s (spray) or 152.9 s (tablets), compared to 253.4 s at baseline (ANOVA: p = 0. 005). Patients taking tablets experienced more episodes of hypotension and/or headache compared to patients taking the spray. Nitrolingual-Spray is as effective and safe as NTG tablets for the treatment of symptomatic coronary heart disease.

Administration, Inhalation↗
PubMed2003

Lansoprazole fast disintegrating tablet: a new formulation for an established proton pump inhibitor.

Lansoprazole is a proton pump inhibitor (PPI) which is an effective and well-tolerated treatment option in the management of acid-related disorders. Lansoprazole fast disintegrating tablet (LFDT)--a new, patient-friendly and more convenient formulation of lansoprazole which can be taken with or without water--is the first PPI to be made available as an orally disintegrating tablet. It represents an innovative drug delivery system, comprising enteric-coated microgranules of lansoprazole compressed with an inactive, rapidly dispersing matrix to form a tablet. When the tablet is placed on the tongue and sucked gently it disintegrates rapidly in the mouth, releasing the enteric-coated microgranules which are swallowed with the patient's saliva without water. Alternatively, the tablet can be swallowed with a drink of water. Studies have shown that the bioavailability of LFDT is comparable to lansoprazole capsules, at both 15 and 30 mg doses; the indications and recommended dosages for LFDT are therefore identical to lansoprazole capsules. The new formulation may be of particular benefit to those with active life-styles who do not always have water available, patients who have difficulty in swallowing, and elderly patients.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1980

Pharmacokinetics of metronidazole in healthy adult volunteers after tablets and suppositories.

A cross-over study on metronidazole was carried out with 10 healthy adult volunteers who received tablets (250, 500 and 1,000 mg) and suppositories (500, 1,000 and 2,000 mg). The bioavailability of the suppositories was approximately 90% of the corresponding tablet dose as judged by area under the serum curves and amounts excreted in urine. The absorption was faster after the tablets. The mean curve peaks of unchanged metronidazole after the tablets occurred within 1 h and were 3.7 microgram/ml after 250 mg, 9.8 microgram/ml after 500 mg, and 11.8 microgram/ml after 1,000 mg. The suppositories rendered peaks of 5.5, 9,5 and 14.0 microgram/ml 4 h after doses of 500, 1,000 and 2,000 mg, respectively. In the dosage range 250-1,000 mg, the relationship between the dose and the total area under serum curves was similar for tablets and suppositories. Parts of the drug in serum and urine were antibacterially active metabolites. The mean recovery in urine within 36 h was 7-14% of the dose. The serum half-life of unchanged metronidazole (chemical assay) was 8.8-10.5 h. The terminal phase half-life of the total biologically active compound (microbiological assay) was 7.8-15.1 h.

Adolescent↗
PubMed1986

Distribution and retention of salivary fluoride from a sodium fluoride tablet following various intra-oral dissolution methods.

The distribution and retention of salivary fluoride were investigated according to the following intra-oral dissolution methods of a sodium fluoride tablet: active chewing/swishing, active sucking/swishing, and passive dissolution in the maxillary and mandibular labial vestibule. The results suggested that the oral cavity was somewhat compartmentalized, in that homogeneous distribution of a dissolved fluoride tablet did not occur throughout the mouth, but rather each site sampled was influenced by various rates of clearance and retention. Tablet chewing may have an advantage over tablet sucking in terms of salivary fluoride retention, and there was a tendency for fluoride to be preferentially retained in the maxillary labial vestibule following swishing. The passive tablet dissolution methods resulted in a less homogeneous distribution of fluoride. Although the fluoride retention values for passive dissolution were impressively superior to either active dissolution method, the alarmingly high salivary fluoride concentrations (4000 ppm F) recorded at the passive dissolution sites should discourage its use until the potential cytotoxicity of this approach is thoroughly investigated.

Administration, Oral↗
PubMed2003

Levetiracetam: relative bioavailability and bioequivalence of a 10% oral solution (750 mg) and 750-mg tablets.

Levetiracetam, an antiepileptic drug, is used worldwide as an adjunctive treatment for partial-onset seizures. The availability of a new oral solution formulation would provide an additional treatment option for patients who have difficulty swallowing tablets. A phase I single-center, randomized, open-label, two-way crossover, single-dose study was conducted to confirm that a 10% oral solution of levetiracetam was bioequivalent to the 750-mg oral tablet and to characterize its pharmacokinetics. Each of 24 healthy subjects received a single oral 750-mg dose of the randomized levetiracetam formulation (7.5 mL of 10% solution or 750-mg tablet) on day 1 and a single oral dose of the alternate formulation on day 8. Serial blood samples were collected from 0 to 36 hours after each dose administration for determination of plasma levetiracetam concentrations. Pharmacokinetic parameters were calculated, and bioequivalence of the two formulations was evaluated. The mean levetiracetam plasma concentration-time curves and pharmacokinetic parameters essentially were identical for the oral 10% solution and tablet and consistent with previously reported levetiracetam pharmacokinetics. The 90% confidence limits of the geometric mean ratio of the two formulations for area under the plasma concentration-time curve from time 0 to infinity, area under the plasma concentration-time curve from time 0 to last measurable time point, and maximum plasma concentration were within the 80% to 125% range, demonstrating bioequivalence of the two formulations. Both levetiracetam formulations were well tolerated. The levetiracetam 10% oral solution is a bioequivalent, well-tolerated alternative to the tablet formulation in patients who have difficulty swallowing.

Administration, Oral↗
PubMed2006

A comparative study of sirolimus tablet versus oral solution for prophylaxis of acute renal allograft rejection.

This multicenter, open-label study compared the efficacy, safety, and pharmacokinetic parameters of sirolimus (rapamycin) tablet and liquid formulations for prevention of efficacy failure. A total of 477 renal allograft recipients were randomly assigned (1:1) to receive either tablet or solution formulations of sirolimus for 12 months, plus cyclosporine (CsA) and steroids. Pharmacokinetic parameters were analyzed based on trough concentrations and 24-hour pharmacokinetic profiles. There were no significant differences in efficacy failure at 3 or 12 months between tablet and solution groups. Graft survival, patient survival, rate of first biopsy-confirmed acute rejection, time to and severity of acute rejection, and laboratory parameters were not significantly different between groups. Mean steady-state sirolimus and CsA pharmacokinetic parameters on days 30 and 90 were not significantly different by formulation, except for longer sirolimus t(max) after tablet administration. Multivariate logistic regression analysis indicated that low sirolimus C(min,TN) and more human leukocyte antigen mismatches were predictors of acute rejection. The tablet and solution formulations of sirolimus demonstrated therapeutic equivalence.

Administration, Oral↗
PubMed1989

Absorption of digoxin from tablets and capsules in subjects with malabsorption syndromes.

The relative steady-state bioavailability of two oral digoxin dosage forms was studied in 17 subjects with malabsorption syndromes. Male subjects received the following treatments in randomized crossover fashion for 14 days: three 0.125-mg digoxin tablets or three 0.1-mg digoxin capsules once daily. Female subjects received digoxin on the same schedule but at two-thirds the dose. Serum and urine samples were collected and analyzed for digoxin by radioimmunoassay, and treatments were compared by evaluating pharmacokinetic parameters. The mean area under the serum concentration versus time curve for tablets (28.1 h.nmol/L [21.9 h.ng/mL]) was smaller (p less than 0.03) than that for capsules (31.1 h.nmol/L [24.3 h.ng/mL]), and the mean maximum serum digoxin concentration for tablets (2.9 nmol/L [2.3 ng/mL]) was lower (p less than 0.02) than that for capsules (4.0 nmol/L [3.1 ng/mL]). There was no difference in cumulative urinary excretion of digoxin between the two treatments. In contrast to previous reports, we observed that digoxin from Lanoxin Tablets appears to be well absorbed in subjects with malabsorption. Nevertheless, these subjects absorbed digoxin from capsules better than from tablets, with the greatest differences occurring in subjects without a colon and in those subjects with the lowest serum carotene concentrations.

Adult↗
PubMedDate not supplied

Comparative bioavailability characteristics of commercial quinidine polygalacturonate and sulfate tablets.

This study compared the relative bioavailability characteristics of quinidine polygalacturonate (QP) and quinidine sulfate (QS) after oral administration of commercial tablets and a liquid form prepared from crushed tablets in 13 healthy adult male volunteers. Each subject received the following four single-dose treatments in a randomized, crossover manner with a one-week washout period between treatments: 400 mg QS liquid, two 200-mg QS tablets, 550 mg QP liquid, and two 275-mg QP tablets. All four treatments were equivalent in terms of the dose of quinidine base. Multiple serum samples and two 24-hour urine specimens were collected over 24 and 48 hours, respectively, and assayed for quinidine with a specific HPLC assay method. For the absorption and disposition parameters measured (maximum serum concentration, time to reach maximum concentration, area under the concentration-time curve [0-48 hours], absorption and elimination rate constants, absorption and elimination half-lives, apparent total body clearance, apparent volume of distribution, and dose fraction excreted in the urine) no significant differences were observed for any of the parameters among the four treatments (p greater than 0.05). The results of the present investigation demonstrated that QP and QS produced identical serum quinidine concentration-time curves when given in the form of a tablet or liquid. The clinical implications of these observations with respect to the dosing of QP are discussed.

Adult↗
PubMed2005

Single-dose and steady-state bioequivalence of fexofenadine and pseudoephedrine combination tablets compared with individual formulations in healthy adults.

OBJECTIVE: A 24-h extended-release formulation of fexofenadine HCl 180 mg/pseudoephedrine HCl 240 mg (FEX 180 mg/PSE 240 mg) has recently been approved by the US Food and Drug Administration for symptom relief of seasonal allergic rhinitis, including nasal congestion. When considering a combination formulation, it is important to confirm that the metabolism and pharmacokinetics of the drugs remain unchanged when combined. Thus, the aim of this study was to evaluate single-dose and steady-state bioequivalence of FEX 180 mg/PSE 240 mg 24-h compared with the individual formulations taken concurrently. RESEARCH DESIGN AND METHODS: This was an open-label, randomized, two-treatment, two-period, 10-day, crossover study. In Treatment A, healthy subjects received a single, oral dose of FEX 180 mg/PSE 240 mg combination tablet on Day 1 followed by 6 days of once-daily dosing beginning on Day 4. Participants in Treatment B were concurrently administered a single oral dose of FEX 180 mg immediate-release tablet and a PSE 240 mg extended-release tablet with a similar dosing schedule. After an 8-day washout period, subjects crossed over to the alternate treatment. Plasma concentrations of FEX and PSE were determined using high-performance liquid chromatography/mass spectrometry. RESULTS: Pharmacokinetic parameters AUC0-infinity1 and Cmax1 following a single-dose (Day 1, dose 1), Cmax7, AUC0-24(7) at steady-state and Cmin7 measured at the end of the dosing interval (Day 9, dose 7) revealed bioequivalence between FEX 180 mg/PSE 240 mg combination tablet and the individual components taken concurrently. The 90% confidence intervals for the treatment ratios fell entirely within the bioequivalence range (80% to 125%). The combination tablet was well tolerated by all subjects, with a safety profile comparable to the individual components. CONCLUSIONS: These findings demonstrate that the pharmacokinetics of the new 24-h FEX 180 mg/PSE 240 mg combination formulation are bioequivalent to the concurrent administration of the individual drug components. Furthermore, both treatments were well tolerated in this population.

Adolescent↗
PubMed2003

Wet granulation fine particle ethylcellulose tablets: effect of production variables and mathematical modeling of drug release.

In the present study, the applicability of fine particle ethylcellulose (FPEC) to produce matrix tablets by a wet granulation technique was evaluated. The effect of various formulation and process variables, such as FPEC content, hardness of the tablet, and solubility of the drug, on the release of drug from these tablets was examined. Tablets were prepared by wet granulation of drug and FPEC in an appropriate mass ratio. Theophylline, caffeine, and dyphylline were selected as nonionizable model drugs with solubilities from 8.3 to 330 mg/mL at 25 degrees C. Ibuprofen, phenylpropanolamine hydrochloride, and pseudoephedrine hydrochloride were selected as ionizable drugs with solubilities from 0.1 to 2000 mg/mL at 25 degrees C. Drug release studies were conducted in 37 degrees C water with UV detection. As the FPEC content and the hardness of the tablets increased, the release rate of the drug decreased. The drug release rate increased with an increase in the solubility of the drug. Model equations, intended to elucidate the drug release mechanism, were fitted to the release data. Parameters were generated and data presented by SAS software. The Akaike Information Criterion was also considered to ascertain the best-fit equation. Fickian diffusion and polymer relaxation were the release mechanisms for nonionizable and ionizable drugs.

Cellulose↗
PubMed2003

A study on moisture isotherms of formulations: the use of polynomial equations to predict the moisture isotherms of tablet products.

The objectives of this study were to investigate the effects of manufacturing parameters on the moisture sorption isotherms of some tablet formulations and to predict the moisture isotherms of the final formulations using polynomial equations. Three tablet formulations including a placebo and 2 drug products were prepared through wet granulation, drying, compression, and coating processes. Equilibrium moisture content of excipients and granules at 25 degrees C with different relative humidities were determined using a dynamic moisture sorption microbalance, while such data for tablets were determined using desiccators. Moisture sorption isotherms were expressed in polynomial equations. Excipient isotherms were used to predict the moisture sorption isotherms of the 3 tablet products. Results showed that different physical properties of granules and tablets, such as particle size distribution, density, and porosity resulting from different granulation and compression conditions did not have significant effect on the moisture isotherms of the materials. Changing coating materials from a powder mixture to a film also did not change the moisture sorption characteristics significantly. The predicted moisture sorption isotherms of the formulations agreed well with the experimental results. These results show that moisture isotherms of solid pharmaceutical products manufactured with conventional processes may be predicted using the isotherms of excipients, and polynomial equations may be used as a tool for the prediction of moisture isotherms.

Chemistry, Pharmaceutical↗
PubMed2003

Once-daily sustained-release matrix tablets of nicorandil: formulation and in vitro evaluation.

The objective of the present study was to develop once-daily sustained-release matrix tablets of nicorandil, a novel potassium channel opener used in cardiovascular diseases. The tablets were prepared by the wet granulation method. Ethanolic solutions of ethylcellulose (EC), Eudragit RL-100, Eudragit RS-100, and polyvinylpyrrolidone were used as granulating agents along with hydrophilic matrix materials like hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose, and sodium alginate. The granules were evaluated for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to thickness, diameter, weight variation test, drug content, hardness, friability, and in vitro release studies. The granules showed satisfactory flow properties, compressibility, and drug content. All the tablet formulations showed acceptable pharmacotechnical properties and complied with in-house specifications for tested parameters. According to the theoretical release profile calculation, a once-daily sustained-release formulation should release 5.92 mg of nicorandil in 1 hour, like conventional tablets, and 3.21 mg per hour up to 24 hours. The results of dissolution studies indicated that formulation F-I (drug-to-HPMC, 1:4; ethanol as granulating agent) could extend the drug release up to 24 hours. In the further formulation development process, F-IX (drug-to-HPMC, 1:4; EC 4% wt/vol as granulating agent), the most successful formulation of the study, exhibited satisfactory drug release in the initial hours, and the total release pattern was very close to the theoretical release profile. All the formulations (except F-IX) exhibited diffusion-dominated drug release. The mechanism of drug release from F-IX was diffusion coupled with erosion.

Antihypertensive Agents↗