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PubMed1991

Instrumental color measurement: a method for judging the appearance of tablets.

An instrumental method for the quantification of the color and the discoloration of tablets is presented. The results are not influenced by external factors and are more rapidly accessible compared with visual determination. Two of the measured parameters, lightness (delta L*) and yellowishness (delta b*) were found to reflect the changes in coloration observed in stability tests on white metoprolol tablets. Correlation studies between visual judgments and instrumental measurements are presented. The instrumental performance was carefully examined, and the results indicate that the employed instrument gives color parameters in the same range for tablet samples irrespective of whether the examined tablet surface has an engraving on it or not.

Color↗
PubMed1993

Use of hydroxypropyl methylcellulose acetate succinate in an enteric polymer matrix to design controlled-release tablets of amoxicillin trihydrate.

A controlled-release table of amoxicillin trihydrate was developed by use of a matrix formulation based on the enteric polymer hydroxypropyl methylcellulose acetate succinate (HPMCAS). Sustained drug release was shown by in vitro dissolution testing; the polymer could suppress drug release in the presence of gastric pH but could enhance drug release in the presence of small intestinal pH, compared with compacts of pure drug. Grinding or physical mixing of the drug with the polymer, an alteration in normal compaction pressure, or a substitution of other enteric polymers did not markedly affect drug release from compacts. Physicochemical testing of samples confirmed that the method of mixing did not alter powder morphology. An ethanolic granulation procedure was used in the production of final tablets (21 x 10 mm) containing amoxicillin (750 mg), HPMCAS, anhydrous directly compressible lactose, and lubricants. These large tablets showed a promising sustained-release effect in vitro when a variable-pH-shift dissolution procedure was used. However, single-dose studies with a panel of fasting subjects showed that the tablets had a relative bioavailability of only 64.4%. Other pharmacokinetic parameters confirmed a lack of therapeutic advantage of these tablets over an equivalent dose of conventional capsules.

Adult↗
PubMed1993

Evaluation of the bioequivalence of tablet and capsule formulations of granisetron in patients undergoing cytotoxic chemotherapy for malignant disease.

Granisetron is a novel, highly specific 5-hydroxytryptamine receptor antagonist given prophylactically to patients undergoing chemotherapy. An open, randomized, crossover trial was performed with 37 patients (24 females and 13 males) undergoing cytotoxic chemotherapy for malignant disease to compare an oral tablet (1-mg tablet given twice daily) with a clinical-trial capsule (1-mg capsule given twice daily). Complete pharmacokinetic data were determined for 24 patients (14 females and 10 males). The concentration of granisetron in plasma was measured by HPLC; the limit of quantitation was 0.2 ng/mL. The bioavailability evaluation was based mainly on the area under the curve (AUC) (mean values: 52.1 ng.h/mL for the capsule and 54.2 ng.h/mL for the tablet) and the maximum concentration (Cmax) (mean values: 7.42 ng/mL for the capsule and 8.18 ng/mL for the tablet) measured at the steady state after 7 days of continuous therapy. Wide interpatient variability in plasma granisetron levels after oral administration was observed. The 90% standard confidence interval for the geometric mean ratio overlapped the critical range, 0.8-1.25. Point estimates for AUC and Cmax based on two one-sided t tests and log-transformed data showed that the upper limit of the confidence interval was not within 20% of the mean for the capsule; the corresponding power analysis values for AUC and Cmax were 0.89 and 0.81, respectively. Despite bioequivalence not being proven, any differences that exist between the two formulations are likely to be small. There was no difference in efficacy or safety between the two formulations assessed.

Adolescent↗
PubMed1994

Deformation kinetics of potassium bromide crystals predict tablet stress relaxation.

A model relating the interparticulate contact stress within a tablet matrix with the compaction stress was developed previously to permit the nonlinear deformation kinetic analysis of the viscoelastic behavior of pharmaceutical tablets with the known properties of the tablet constituents. The present research was undertaken to determine whether the inverse operation (i.e., using tablet stress relaxation to determine single crystal properties) was possible. The stress relaxation of potassium bromide (KBr) compacts was evaluated as a function of temperature and relative density, and an attempt was made to calculate the deformation kinetic parameters. The stress relaxation of KBr did not fit the model under ambient conditions for two reasons: (1) KBr has two slip systems with approximately the same shear stress at room temperature; and (2) KBr strain-hardens. When these complications were taken into consideration, the stress relaxation behavior could be explained. Therefore, whereas single crystal tests are capable of yielding parameters that can be used to predict compact behavior, the inverse process of quantifying fundamental material parameters from compact behavior is problematic due to the difficulty of determining, a priori, all the processes that operate simultaneously.

Bromides↗
PubMed1990

Comparative antidotal efficacy of activated charcoal tablets, capsules and suspension in healthy volunteers.

The efficacy of several formulations of activated charcoal (AC) was compared by measuring the intestinal absorption of a solution of 1 g paracetamol administered 2 min before administration of 5 g AC as suspension (200 ml), tablets (40 of 125 mg) or capsules (25 of 200 mg). The suspension medium without AC was used as the control treatment. Based on the results of a pilot experiment, an 8 subject panel was used in a two 4 x 4 Latin square design. All treatments with AC resulted in a statistically significant decrease in paracetamol absorption compared to the control treatment. The suspension was considerably and significantly more effective than the tablets or capsules. Treatment with tablets was slightly but significantly more effective than capsules. The intake of large numbers of tablets and capsules was difficult. In the hospital AC suspensions are available. For first aid elsewhere, at home, at the working place or in the general practitioner's surgery a preservable and easily redispersible AC formulation would be preferable to the present solid forms.

Acetaminophen↗
PubMed1982

Lithium treatment regimen and renal water handling: the significance of dosage pattern and tablet type examined through comparison of results from two clinics with different treatment regimens.

For many year two Danish psychiatric hospitals having used different lithium treatment regimens. In one, slow-release tablets were given in two daily doses and, in the other conventional tablets were given in a single daily dose. In both hospitals many patients developed polyuria. Multiple regression analyses with sex, age, treatment duration, serum lithium concentration, and treatment regimen as predictor variables showed that the two treatment regimens did not affect the glomerular filtration rate or the proximal reabsorption differently, but that distal water reabsorption was significantly less affected and polyuria less pronounced in the patients given conventional tablets once daily than in those give slow-release tablets twice daily. The authors are divided among themselves as regards the implications of these findings.

Adult↗
PubMed1981

A pharmacodynamic and pharmacokinetic comparison of pindolol 20 mg retard and a conventional tablet.

In 10 healthy volunteers the time course of cardiac beta-adrenoceptor blocking activity, plasma levels and cumulative urinary excretion of pindolol were compared during a 4-day course of pindolol 5 mg (Visken) t. d. s., and one tablet of pindolol 20 mg retard (Visken retard) once a day. After oral administration of the 20 mg retard tablet, plasma concentrations of pindolol higher than half the maximum value (1/2 Cp (tmax)) were maintained about 2.5 times as long as after administration of the conventional 5 mg tablet. This is evidence for an important and marked retardation of drug release. During treatment with pindolol 20 mg retard once daily, cardiac beta-adrenoceptor blockade, measured by the reduction in exercise-induced tachycardia and in the exercise-induced rise in systolic blood pressure, at almost all times throughout the 24 h period was at least as great as during treatment with pindolol 5 mg t. d. s. This suggests that patients successfully treated with pindolol 5 mg t. d. s. can be maintained with the same beta-adrenoceptor blockade by a single tablet of pindolol 20 mg retard once daily.

Administration, Oral↗
PubMed1980

Comparative bioavailability of disopyramide after multiple dosing with standard capsules and controlled-release tablets.

Plasma concentrations and bioavailability of disopyramide following repeated administration of standard capsules and controlled-release tablets have been compared. Ten patients were randomized into two groups; Group I received disopyramide capsules 150 mg every 6 h for five days. Group II received the same preparations in the reverse order. There was a more rapid rise in disopyramide concentration after the capsules: the maximum of 10.7 +/- 0.6 mumol/l (mean +/- SEM) was reached within 1.8 +/- 0.4 h as compared to 10.6 +/- 0.4 mumol/l within 4.0 +/- 0.3 h after the controlled-release tablets. No significant difference in the fluctuations in individual plasma concentrations during each dose interval at steady state were observed after ordinary capsules compared to controlled-release tablets. The extent of bioavailability was the same. Eight patients reported some side-effects during the capsule period and nine during the controlled-release tablet period.

Aged↗
PubMed1986

Dose response and length of action of nifedipine capsules and tablets in patients with essential hypertension: a randomised crossover study.

Twelve patients with essential hypertension on no other drug treatment were entered into a randomised crossover study of 5, 10 and 20 mg capsules of nifedipine given 3 times a day and 20 mg tablets given twice a day. Each dose was given for 2 weeks in a random order. All forms of nifedipine were effective in lowering blood pressure. However, 5 mg capsules were less effective than the 10 and 20 mg capsules or 20 mg tablets. There was little to choose between the latter. All doses of nifedipine were more effective 1 and 3 h after the dose compared to subsequent times afterwards. Indeed, as time elapsed after the last dose up to 12 h, there was a gradual increase in blood pressure. However, even at 12 h the 10, 20 mg capsules and 20 mg tablets were still causing an approximate 10% reduction in blood pressure. Nifedipine tablets are as effective as capsules though they might be longer acting, particularly around 6 h after the last dose.

Adult↗
PubMed1977

Comparative bioavailability of a sustained release preparation of amitriptyline and conventional tablets.

A sustained release preparation of amitriptyline has been compared with conventional tablets in eight healthy human volunteers. The tablet produced a distinct peak in serum concentration shortly after administration, whereas the sustained release preparation caused a slow rise to a plateau. The maximum serum concentration and the time of its occurrence differed significantly between the two preparations. The differences between the serum concentration curves of the two preparations can be explained on the basis of a two compartment model of amitriptyline pharmacokinetics and from a difference in the absorption rate. The similar clinical effect obtained with a lower daily dose of the sustained release preparation than of the tablet cannot be accounted for in terms of pharmacokinetics. It is possible that a single evening dose of sustained release amitriptyline gives a more appropriate serum concentration profile of amitriptyline and its active metabolite nortriptyline than a conventional tablet taken three times a day.

Adult↗
PubMed1980

Gastrointestinal absorption of quinidine from some solutions and commercial tablets.

The gastrointestinal absorption of quinidine from three commercially available tablet products has been compared to that from a quinidine sulfate solution previously found to have 70% of the systematic availability of an intravenous dose. Quinidine gluconate solution was included in the study to compare the absorption characteristics of the two quinidine salts. The tablets were given in a counterbalanced sequence preceded by one quinidine solution and followed by the other in a crossover design. The three tablets proved to be equivalent to one another with respect to extent and rate of absorption. The absorption properties of the two solutions were indistinguishable. The tablets were equivalent to the solutions in extent but not in rate of absorption.

Adult↗
PubMed1984

Gastric retention of enteric-coated sulfasalazine tablets. A complication of gastroduodenal Crohn's disease.

A case is described in which a patient with known gastroduodenal Crohn's disease developed a picture of gastric outlet obstruction accompanied by gastric retention of many enteric-coated sulfasalazine tablets. The tablets were removed by gastric lavage with a sodium bicarbonate solution. Following this observation, an in vitro study was done in which the rate of disintegration of enteric-coated sulfasalazine tablets was found to be directly related to pH. The case report reveals a potential hazard in using enteric-coated tablets in patients with impaired gastric emptying. Intragastric sodium bicarbonate may be a useful element in the management of this complication.

Adult↗
PubMed1985

Effect of a simethicone-containing tablet on colonic gas elimination in breath.

The effect of a tablet containing the antiflatulent, simethicone, on intestinal hydrogen (H2) elimination in breath was studied. In three trials, normal subjects (age 12-52 years) received, on subsequent days, lactulose or lactulose with two tablets of either simethicone or placebo in randomized order. Breath samples were collected over 210 min and analyzed by gas chromatography for H2. The time course of H2 expiration above baseline levels was calculated and compared for the three tests. No significant differences in transit time were found. Cumulative H2 expiration was significantly lower after simethicone compared to placebo. H2 production from stool incubated with simethicone or placebo indicated that the drug had no effect in reducing the fermentative production of H2 in vitro. Interestingly, the vehicle present in the tablets could be fermented by intestinal bacteria. Simethicone reduced the amount of H2 eliminated in breath, but this effect was offset partially by H2 production from the fermentation of unabsorbable substances used in the formulation of the tablets.

Adolescent↗
PubMed1987

Relations between tablet properties.

With the aid of simple mathematical models the relations between specific crushing strength (i.e. crushing strength divided by the breaking surface), friability and disintegration time of a tablet can be given. The friability is related to the porosity of the tablets and the specific crushing strength, independent of the process conditions. For the disintegration time two models have been used, depending on the disintegration mechanism. In the first one the disintegration time is only dependent on the porosity, in the second on the specific surface by weight of the granules of which the tablets are made. The theoretical relationships were verified for two tablet formulations, made under varying process conditions.

Chemical Phenomena↗
PubMed1988

Sublingual nitroglycerin. I. Comparative evaluation of the physical stability of commercially available tablets.

The physical stability of one type of stabilized molded and three types of compressed nitroglycerin tablets was studied. The evaporation rate of nitroglycerin was controlled by its vapour pressure and by the matrix effect of the dosage forms. The four products showed different vapour pressures and matrix effects. In time nitroglycerin escapes from the outmost layers of the tablets; the dosage form in which the drug showed the lowest vapour pressure (the stabilized molded tablet) was found to be the most stable one. However, from the time when the drug had escaped from the outmost layers of the dosage form, the matrix effect became dominant. When nitroglycerin tablets were stored in tightly closed containers at room temperature potency loss was minimal. Even when the bottles were opened regularly this did not result in a significant loss of the drug. Measures are suggested to minimize drug evaporation.

Administration, Sublingual↗
PubMed2005

Analysis of the therapeutic effect of sodium copper chlorophyllin tablet in treating 60 cases of leukopenia.

OBJECTIVE: To evaluate the efficacy and safety of sodium copper chlorophyllin (trademarked as "Yebaike Tablet which is abbreviated as YBK in treating leukopenia. METHODS: One hundred and five patients with leukopenia caused by various factors were randomized into 3 groups. The 60 patients in the YBK group took orally YBK Tablets at the dose of 40 mg, three times per day, the 30 patients in the leucogen group were treated with Leucogen Tablets at the dose of 20 mg, three times per day, and the 15 patients in the placebo group were administered with vitamin C tablets 100 mg, three times per day. All the subjects were treated for 1 month. The change of peripheral leucocytes count after treatment and adverse drug reaction that occurred in patients were studied. RESULTS: In the 60 patients treated with YBK, the treatment proved to be markedly effective in 34 cases, effective in 17 and ineffective in 9, the total effective rate being 85%, which was significantly higher than that in the placebo group (26.7%, P < 0.01) and similar to that in the leucogen group (83.3%, P > 0.05). No adverse reaction was found in the treatment course. CONCLUSION: YBK can be used in the treatment of leukopenia caused by various factors, satisfactory in efficacy and safe in use.

Adolescent↗
PubMedDate not supplied

Pharmacokinetics of nifedipine derived from a new retard tablet formulation.

A nifedipine retard tablet formation (Glopir, 20mg) was developed to reduce the number of daily doses required in the treatment of hypertension. The plasma pharmacokinetics of this oral formulation were examined, in a single study, on 12 healthy volunteers. Single 20 mg doses of nifedipine retard tablet (Glopir, GAP & Co. Athens, Greece) were given after an overnight fast and 10 blood samples were drawn during the first 24 h after administration. Plasma concentrations of nifedipine were measured by high performance liquid chromatography. The mean peak plasma nifedipine concentration was 27.6 ng/ml at a maximum time of 24 h, after tablet ingestion. The mean apparent nifedipine elimination half-life was 16.0 +/- 7.5 h and the mean area under the plasma concentration time curve (0-24 h) 404.1 +/- 134.0 ng/ml.h. The data suggest that the tablet form has properties of a sustained-release preparation, with slow accumulation and elimination phases and can appropriately be given in a twice-daily regimen.

Administration, Oral↗
PubMedDate not supplied

Evaluation of the bioequivalence of tablets and capsules containing the novel anticancer agent R115777 (Zarnestra) in patients with advanced solid tumors.

R115777 (Zamestra) is a novel anticancer agent, currently undergoing phase III clinical testing. An open, cross-over trial was performed in 24 patients with solid tumors to compare the bioavailability of a new tablet formulation with the standard capsule formulation. Both dosage forms were administered once daily in doses of 300 or 400 mg. Patients received R115777 as a capsule on day I and as a tablet on day 2, or vice versa. Blood samples were drawn up to 24 hours after drug intake and R115777 levels were measured using a validated high performance liquid chromatography (HPLC) method. The following pharmacokinetic parameters were determined and compared for the two formulations: time to maximal plasma concentration (Tmax), half-life (t 1/2), maximal plasma concentration (Cmax) and area under the curve at twenty-four hours (AUC24h). For the latter two parameters, 90% classical confidence intervals of the ratio tablet/capsule were calculated after a log-transformation, using an Analysis of Variance (ANOVA). For t 1/2 and Tmax, no statistically significant differences were found between tablet and capsule. The point estimates of the ratio's of the log-normalized Cmax and AUC24h were 0.94 and 0.92, respectively, and the 90% confidence intervals were 0.81-1.09 and 0.83-1.03, which is within the critical range for bioequivalence of 0.80-1.25. In conclusion, the established pharmacokinetic parameters demonstrate that the capsule and tablet formulations of R115777 are interchangeable.

Adult↗