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PubMed1991

[A comparative study of the pharmacokinetics and urinary metabolites of sustained-release theophylline syrup, granule and tablet preparations].

Three different theophylline preparations, theophylline syrup, granule and tablets, were examined to determine their pharmacokinetics and changes in urinary metabolites for each steady state phase. The theophylline syrup was as rapidly and as essentially bioavailable as the theophylline granule preparation. In addition, peak to trough differences in serum theophylline concentrations were largest for theophylline syrup and lowest for tablets. Tmax was greater in theophylline tablets and a significant difference was apparent in the tablet-syrup and tablet-granule populations. AUC and T1/2 were similar in these populations. Cmax and Cmin achieved satisfactory therapeutic theophylline levels in three different preparations, and t-test showed no significant difference between them. CL and Vd were also similar. The urinary metabolites of theophylline were expressed as internal standard equivalents on a molar basis. There were no significant changes between either tested preparations different or different age groups. Therefore, we concluded that theophylline syrup and granules should be administered on a 3-times-daily basis, considering trough plasma theophylline levels. Theophylline tablets are preferable, if they can be taken.

Adolescent↗

PubMed1991

Potential cost-avoidance with oral extended-release morphine sulfate tablets versus morphine sulfate solution.

The costs of acquiring, preparing, and administering morphine sulfate extended-release tablets and morphine sulfate solution were compared. Pharmacists at an acute-care community hospital timed the pharmacy and nursing components of the process of preparing and administering single doses of morphine sulfate extended-release tablets 60 mg and morphine sulfate solution 5 mg/mL. The labor cost of each step was determined by multiplying the mean time required to perform the task by the median of the wage scale for the person performing it. Acquisition costs and ancillary supply costs were determined, and the overall cost of each therapy was calculated. The total time required for providing single doses did not differ substantially. However, assuming a total daily morphine sulfate dosage of 120 mg, the time required for administering extended-release morphine sulfate tablets 60 mg twice daily was determined to be 8.90 minutes, compared with 23.44 minutes for solution (4 mL of 5-mg/mL solution) six times daily. Thus, although the cost of acquiring extended-release tablets was considerably higher than that of solution, the total daily cost of therapy with tablets was less than half that of therapy with solution. The potential for cost avoidance and the clinical advantages associated with extended-release morphine sulfate tablets make this formulation an attractive therapeutic alternative.

Administration, Oral↗

PubMed1993

Design and pharmacokinetics of Logimax, a new extended-release combination tablet of felodipine and metoprolol.

A new, once-daily combination tablet containing felodipine and metoprolol has been developed, using extended-release techniques to obtain even plasma concentrations throughout the dosing interval. The tablet consists of a hydrophilic matrix containing felodipine in which many small membrane-coated metoprolol pellets are embedded. On contact with gastrointestinal fluids, felodipine is released at an almost constant rate by erosion of the hydrophilic matrix. The release of metoprolol also follows near zero-order kinetics, and is mainly controlled by diffusion through the membrane covering each individual metoprolol bead. Smooth plasma concentration profiles are obtained for both drugs of the combination, similar to those found with the corresponding single-drug formulations: felodipine extended-release tablets and metoprolol controlled-release tablets. The new fixed combination tablet also consistently provides even plasma concentrations of felodipine and metoprolol after administration together with food and in elderly hypertensive patients. The convenience of one tablet per day for effective antihypertensive treatment with a combination of felodipine and metoprolol should improve patient compliance with the prescribed regimen.

Adult↗

PubMed1995

Double-blind comparative study of sulfasalazine and controlled-release mesalazine tablets in the treatment of active ulcerative colitis.

To evaluate the effect of a controlled-release mesalazine tablet, in patients with ulcerative colitis (UC), a multicenter double-blind study was carried out, using sulfasalazine (500 mg tablet) as the control drug. The mesalazine tablet contained 250 mg of ethyl cellulose-coated mesalazine granules. The patients were assigned to two groups, one to receive mesalazine tablets (1500 mg/day) and a sulfasalazine placebo (group M) and the other to receive sulfasalazine tablets (3000 mg/day) and a mesalazine placebo (group S). The test medications were administered orally for 4 consecutive weeks. The study subjects were selected from among patients with mild to moderate active UC, and 118 patients were enrolled. Concomitant use of steroids and immunosuppressors was prohibited during the study period. Of the 118 patients, 9 dropped out. A total of 109 complete records were thus obtained, 52 in group M and 57 in group S. There was no difference in the improvement of clinical symptoms and endoscopic findings between the two groups. The overall safety, based on adverse reactions and laboratory data, was higher, at 86.5%, for group M (n = 52), compared to 66.7% for group S (n = 57). The general usefulness, based on the improvement and safety, was higher, at 65.3%, for group M (n = 49), compared to 45.6% for group S (n = 57). The controlled-release mesalazine tablet thus appears to be useful in the treatment of mild to moderate active UC.

Adult↗

PubMed1985

Gastroscopic findings after treatment with enteric-coated and plain naproxen tablets in healthy subjects.

The damaging effect of enteric-coated and plain naproxen tablets on the gastric mucosa was studied in 12 healthy subjects before and after 7 days' treatment in a randomized, double-blind, double-dummy, cross-over trial. Both formulations of the drug caused mucosal lesions, but the extent of the damage was significantly decreased after enteric-coated naproxen as compared with plain tablets. The subjects' preference was significantly in favour of the enteric-coated naproxen tablets. The plasma naproxen concentration was significantly higher after treatment with enteric-coated naproxen than after treatment with plain tablets. In conclusion, the results of the study indicate that naproxen might damage the gastric mucosa by local and systemic effects and that the local effect might be prevented by enteric coating of the tablets.

Adult↗

PubMed2000

Stereoselective pharmacokinetics of indobufen from tablets and intramuscular injections in man.

The influence of administration route (oral or intramuscular (i.m.)) on the pharmacokinetics of total indobufen (INDB) enantiomers was studied in healthy volunteers after a 200 mg dose as a single oral tablet or i.m. injection. Enantiospecific reversed phase (RP) HPLC with UV detection was used for the determination of INDB enantiomers in serum. INDB enantiomers were isolated from serum by solid phase extraction (SPE) procedure using C(18) columns. INDB enantiomers were converted to their L-leucinamide diastereoisomers and separated on a C(18) HPLC column. INDB from i.m. injections is absorbed faster (t(max) = 0.6-0.9 h) than from tablets (t(max) = 1.3-1.8 h). The area under curve (AUC) after administration of the tablet was slightly higher than after i.m. injection. The pharmacokinetic behaviour of (+)-S- and (-)-R-INDB after administration of the tablet was different from i.m. injection of racemic INDB. The (+)-S-enantiomer is more rapidly eliminated than its (-)-R-antipode. Statistically significant differences also occurred between enantiomers in AUC, first order elimination rate constant (k), clearance (Cl). The ratio AUC(R):AUC(S) was similar for the tablet (1.57-1.62) and i.m. injection (1.59-1.62). It was concluded that the formulation and extent of ionisation of rac-INDB (acid or sodium salt of INDB) do not significantly influence its stereoselective pharmacokinetics.

Administration, Oral↗

PubMedDate not supplied

In vitro and in vivo bioequivalence of commercial prednisone tablets.

The purpose of the study was to examine the bioequivalence of five commercially available oral prednisone products. The in vivo study utilized 18 healthy males, each of whom was administered 20 mg of prednisone as a reference solution or as a tablet in a 6-week, six-way crossover design. Blood was collected and serum was assayed, using an HPLC procedure specific for prednisone and prednisolone. Mean pharmacokinetic parameters (t 1/2, ke, Cmax, tmax, and AUC) were determined. ANOVA was performed on the prednisone and prednisolone data (F-test, p less than 0.05) as well as Duncan's multiple range analysis. Dissolution tests were also performed on each of the five products in order to test the relationship between dissolution and bioequivalence among prednisone products. The in vitro study consisted of a standard USP dissolution test which included tablets from the same lots as the tablets used in the in vivo study. The data showed no statistical difference in any of the pharmacokinetic parameters among tableted products, subjects, or dosing periods in the study. There was also no statistical difference in the dissolution study among the five commercial tablet forms.

Adolescent↗

PubMed1992

Bioavailability of lithium from lithium citrate syrup versus conventional lithium carbonate tablets.

The bioavailability of lithium citrate syrup was compared with that of regular lithium carbonate tablets in 18 healthy male human volunteers. Blood samples were collected up to 48 h after dosing. Lithium serum concentrations were determined by means of AAS. The absorption rate following oral administration of the syrup was greater (tmax 0.8 h) than following administration of regular tablets (tmax 1.4 h). Maximum lithium serum concentrations, however, were only about 10 per cent higher after syrup dosing and serum concentrations resulting from syrup and tablets were almost superimposable from 2 h after dosing. The terminal half-life of lithium was found to be 22 h after syrup as well as after tablet dosing. No side-effects were observed during the study. The bioavailability of lithium from syrup relative to tablets was found to be bioequivalent with respect to the maximum lithium serum concentration and the extent of drug absorption (AUC).

Administration, Oral↗

PubMed1981

Effect of magnesium--aluminum hydroxide and kaolin--pectin on absorption of digoxin from tablets and capsules.

Twelve healthy fasting volunteers received two 0.2-mg digoxin capsules or tablets with 60 ml water, 60 ml Maalox, or 60 ml Kaopectate in a randomized, single-dose, six-way crossover study. Concentrations of digoxin in multiple plasma samples and in all urine collected during the 24 hours after each dose were determined by radioimmunoassay. Compared to the water treatment, administration of both tablets and capsules with Maalox or Kaopectate reduced the peak digoxin plasma concentrations but did not significantly influence the time of peak concentration. Neither Maalox nor Kaopectate influenced the area under the 24-hour plasma concentration--time curve for either tablets or capsules. However, 24-hour urinary recovery of digoxin from tablets tended to be reduced by Maalox and Kaopectate; this was not the case with capsules. Digoxin capsules may have an advantage over currently available tablets in clinical situations requiring digoxin coadministration with nonabsorbable gastrointestinal preparations.

Adult↗

PubMed1990

Clinical pharmacology of predisintegrated ibuprofen 800 mg tablets: an endoscopic and pharmacokinetic study.

Thirty-five healthy adults were randomized to receive either: (1) ibuprofen 800 mg tablets; (2) ibuprofen 800 mg aqueous suspension; (3) ibuprofen 800 mg orange juice suspension; or (3) 325 mg aspirin tablets. All treatments were tid for 7 days. Pharmacokinetic sampling was conducted on days 1, 4 and 8. Gastroduodenoscopy was performed on days 1 and 8. Side effects and safety laboratory tests were monitored throughout the study. On day 8 the aspirin group showed significantly more gastric irritation than all of the ibuprofen groups (P less than .005). Both ibuprofen suspension groups showed more gastric irritation than the ibuprofen tablet group (P less than .1). The duodenal scores did not differ among the treatment groups. The aspirin group experienced a higher rate of tinnitus and abdominal pain. The rate and extent of absorption of the ibuprofen suspensions were significantly less than that of the tablets. These data suggest that the taking of ibuprofen as an extemporaneous suspension is therapeutically inferior to ibuprofen tablets and therefore should be discouraged.

Adult↗

PubMed2003

Modeling of adhesion in tablet compression--I. Atomic force microscopy and molecular simulation.

Adhesion problems during tablet manufacturing have been observed to be dependent on many formulation and process factors including the run time on the tablet press. Consequently, problems due to sticking may only become apparent towards the end of the development process when a prolonged run on the tablet press is attempted for the first time. It would be beneficial to predict in a relative sense if a formulation or new chemical entity has the potential for adhesion problems early in the development process. It was hypothesized that favorable intermolecular interaction between the drug molecules and the punch face is the first step or criterion in the adhesion process. Therefore, the rank order of adhesion during tablet compression should follow the rank order of these energies of interaction. The adhesion phenomenon was investigated using molecular simulations and contact mode atomic force microscopy (AFM). Three model compounds were chosen from a family of "profen" compounds. Silicon nitride AFM tips were modified by coating a 20-nm iron layer on the surfaces by sputter coating. Profen flat surfaces were made by melting and recrystallization. The modified AFM probe and each profen surface were immersed in the corresponding profen saturated water during force measurements using AFM. The work of adhesion between iron and ibuprofen, ketoprofen, and flurbiprofen in vacuum were determined to be -184.1, -2469.3, -17.3 mJ. m(-2), respectively. The rank order of the work of adhesion between iron and profen compounds decreased in the order: ketoprofen > ibuprofen > flurbiprofen. The rank order of interaction between the drug molecules and the iron superlattice as predicted by molecular simulation using Cerius(2) is in agreement with the AFM measurements. It has been demonstrated that Atomic Force Microscopy is a powerful tool in studying the adhesion phenomena between organic drug compounds and metal surface. The study has provided insight into the adhesion problems occurring during tablet compression and a direction for continued study.

Adhesiveness↗

PubMed2005

Quantifying errors in tableting data analysis using the Ryshkewitch equation due to inaccurate true density.

Although inaccurate true density affects analysis of powder compaction data, such effects have not been systematically evaluated in the literature. This work is aimed at quantitatively evaluating effects of inaccurate true density on tableting data analysis using the Ryshkewitch equation, sigma = sigma0 e - bepsilon, where epsilon is tablet porosity, sigma is tensile strength, sigma(0) and b are constants that are used to characterize tableting properties of a powder. Mathematical expressions are derived to enable reliable prediction of the influence of inaccurate true density on sigma(0) and b. The validity of the expressions is suggested by modeling the effects of inaccurate true density based on a set of accurate literature tableting data and confirmed using multiple sets of tableting data of water-containing powders that exhibit inaccurate helium pycnometry densities. Percentage errors in fitted sigma(0) and b as functions of errors in true density follow the derived mathematical expressions. With increasing percentage error in true density, percentage errors increase exponentially in fitted sigma(0) and increase linearly in fitted b, while R(2) is not affected. According to the mathematical expressions, true density with <0.28% error is required to achieve 4% accuracy in fitted sigma(0) for typical pharmaceutical powders.

Chemistry, Pharmaceutical↗

PubMed1976

Quantitative assessment of factors contributing to mottling of colored tablets II: formulation variables.

The effects of several formulation variables were quantified with respect to factors affecting tablet mottling. Tablet mottling occurred with several commonly used binders and could not be prevented by using highly viscous binding solutions. However, mottling was reduced initially by increasing granule strength. Tablet diluents and dye-adsorbent materials had a profound effect on mottling, not by preventing dye migration but by affecting granule fragmentation on compression and the extent to which the dye-deficient material at the center of the granule was revealed. The lake form of FD&C Blue No. 1 was found to bleed in the presence of diluents that raised the pH of the granulating fluid above 6.4. Anionic impurities in the diluents also caused leaching of free dye and, consequently, increased tablet mottling. The conclusions from this study and previous papers were drawn together to give general principles for the production of uniformly colored tablets by aqueous granulation techniques.

Adsorption↗

PubMed1976

Effects of film coatings on tablet hardness.

The effects of five conventional film-coating materials on tablet hardness were studied. Placebos showed apparently linear increases in hardness as coatings were applied. Completely coated samples exhibited hardness increases from 50 to 140%, with a corresponding 3% increase in tablet weight. Equations were derived relating hardness changes to the "breaking strength" of the film on the tablet. Findings indicate that the coatings exert their influence primarily along the diameter of the tablet in a direction perpendicular to an applied compressional force. Furthermore, the coating process itself did not alter core hardness since tablets from which the film could be stripped showed original values.

Cellulose↗

PubMed1976

Dissolution testing of nitroglycerin tablets.

The available types of dissolution testing apparatus for tablets and capsules are inapplicable to sublingual tablets, since these tablets are formulated to release their drug content within minutes in a small volume of fluid. A simple dissolution test method was developed for nitroglycerin tablets based on the reduction of nitroglycerin at a rotating platinum electrode, which provides reproducible stirring. The system provides instantaneous and continuous measurement of dissolved nitroglycerin in a small constant volume of buffered isotonic sodium chloride solution over a period of seconds to several minutes, when reduction is complete as shown by the current-time curve. Since the height of the curve is directly proportional to the amount of nitroglycerin in solution, the method also can be used to determine the drug content of individual tablets.

Chemistry, Pharmaceutical↗

PubMed1976

Disaggregation of compressed tablets.

Tablets of dibasic calcium phosphate containing varying proportions of intra- to extragranular maize starch were prepared at three compaction pressures. The surface area generated per tablet after 10 and 30 min of disintegration was measured with an automated counter by a new technique. The optimum starch combination that produced the maximum surface area in a tablet formulation was either 2.5% intra-12.5% extragranular or 15% intragranular starch alone. The distribution of starch did not affect the resultant strength of the tablets, and maximum generation of surface area was achieved by compacting the tablets at as low a pressure as practical.

Chemistry, Pharmaceutical↗

PubMed1977

Plastic flow during compression of directly compressible fillers and its effect on tablet strength.

The effects of the duration of the overall compression cycle and of the duration of the maximum compressive force on tablet strength were studied using an instrumented rotary tablet press. Various direct compression fillers were evaluated. Increasing the overall compression cycle duration to 10 sec resulted in significantly greater tablet tensile strengths with microcrystalline cellulose and compressible starch fillers but not with lactose or compressible sugar. Increasing the duration of the maximum compressive force to 20 sec significantly increased the tensile strength in all cases, but microcrystalline cellulose and compressible starch tablets were affected more than lactose or sugar tablets. The maximum compressive force decayed with time for all fillers but at a greater rate with microcrystalline cellulose and compressible starch. This behavior was attributed to differences in the extent of plastic flow. The decay curves were analyzed using the Maxwell model.

Calcium Phosphates↗

PubMed1978

Bioavailability of acetazolamide tablets.

Plasma acetazolamide levels were measured by an enzymatic assay following single 250-mg oral tablet doses to 20 healthy volunteers; five different lots of acetazolamide tablets from a single manufacturer were used in a balanced incomplete block design. From the measured plasma levels, estimates of the bioavailability parameters (area under the plasma concentration versus time curve, time to peak plasma concentration, and peak plasm concentration) were obtained by least-squares digital computer fitting. No significant differences among the tablets were observed (alpha = 0.05) for the analysis of variance of the area under the curve or time to peak parameters. Two tablets, however, provided statistically higher peak plasma concentrations than the other three. Thus, lot-to-lot bioinequivalence of acetazolamide tablets was observed. Some in vitro tests employed showed general trends for correlation with the in vivo data. However, considerable refinement of these technique appears necessary for in vitro prediction of the observed lot-to-lot bioinequivalence.

Acetazolamide↗