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At least 433 records · Page 24Linked to original sources

PubMedDate not supplied

Tablet-breaking ability of older persons with type 2 diabetes mellitus.

PURPOSE: The purpose of this study was to assess the ability of older persons with type 2 diabetes to accurately break in half 2 different formulations of micronized glyburide tablets. METHODS: Thirty persons with type 2 diabetes, over age 70, were recruited from the St Louis University geriatric clinics. Participants were randomly assigned to 2 groups. Group A broke 30 Glynase Prestabs and 30 generic tablets using 2 different manual tablet-breaking methods. Group B broke 15 Glynase Prestabs and 15 generic tablets without instructions. Visual analog scales were used to assess pain and difficulty of tablet breaking. RESULTS: A higher percentage of successful tablet breaking was reported with Glynase Prestabs (80%) compared with the generic tablets (33%). Mean pain scores for breaking Glynase Prestabs were 0.1 (Group A) and 0.9 (Group B). Higher pain scores were obtained for the generic tablets (2.1 for Group A, 3.2 for Group B). Glynase Prestabs were easier to break in both groups, and the resultant half tablets showed less variance from the expected theoretical weight (50% of whole parent tablet weight). CONCLUSIONS: Older adults broke Glynase Prestabs more accurately and with less difficulty than generic micronized glyburide tablets. This variation in ease of tablet breaking and accuracy between different tablet formulations affect bioavailability and patient compliance.

Administration, Oral↗

PubMed1993

Effects of water content on physical and chemical stability of tablets containing an anticancer drug TAT-59.

(E)-4-[1-[4-[2-(Dimethylamino)ethoxy]phenyl]-2-(4-isopropyl) phenyl]-1-butenyl]phenyl monophosphate (TAT-59) is a new drug for the treatment of breast cancer. Physical and chemical stability of a tablet consisting of TAT-59 powder and a few excipients (Formulated tablet), a tablet consisting of only TAT-59 powder (TAT-59 tablet) and TAT-59 powder itself was evaluated based on water content, tensile strength, porosity, the amount of TAT-59 and its hydrolysis product, DP-TAT-59. The water content of Formulated tablet increased with relative humidity (RH), whereas that of TAT-59 tablet and TAT-59 powder scarcely changed. The equilibrium water content of Formulated tablet was much greater than that of the TAT-59 tablet or TAT-59 powder due to adsorbed moisture by the excipients. The tensile strength and porosity of Formulated tablet decreased and increased linearly, respectively, with increasing water content. The degradation rate of TAT-59 decreased in the following order: Formulated tablet > TAT-59 tablet > TAT-59 powder. The relationship between equilibrium water content and degradation rate of the Formulated tablet was determined by the Carstensen equation, in which the interaction order between the drug and water content was 1.9, and the degradation of TAT-59 in Formulated tablet was related to water content. Thus, it was found that the degradation of TAT-59 was accelerated by compression and addition of excipients.

Antineoplastic Agents↗

PubMed2002

[Preparation and evaluation of press-coated aminophylline tablet using crystalline cellulose and polyethylene glycol in the outer shell for timed-release dosage forms].

In an attempt to achieve chronopharmacotherapy for asthma, press-coated tablets (250 mg), which contained aminophylline in the core tablet in the form of low-substituted hydroxypropylcellulose (L-HPC) and coated with crystalline cellulose (PH-102) and polyethylene glycol (PEG) at various molecular weights and mixing ratios in the amounts of PH-102 and PEG as the outer shell (press-coating material), were prepared (chronopharmaceutics). Their applicability as timed-release (delayed-release) tablets with a lag time of disintegration and a subsequent rapid drug release phase was investigated. Various types of press-coated tablets were prepared using a tableting machine, and their aminophylline dissolution profiles were evaluated by the JP paddle method. Tablets with the timed-release characteristics could be prepared, and the lag time of disintegration was prolonged as the molecular weight and the amount of PEG, for example PEG 500,000, in the outer shell were increased. The lag time of disintegration could be controlled by the above-mentioned method, however, the pH of the medium had no effect on disintegration of the tablet and dissolution behavior of theophylline. The press-coated tablet (core tablet:aminophylline 50 mg, L-HPC and PEG 6000; outer shell:PH-102:PEG = 8:2 200 mg) with the timed-release characteristics was administered orally to rabbits for an in vivo test. Theophylline was first detected in plasma more than 2 h after administration; thus, this tablet showed a timed-release characteristics in the gastrointestinal tract. The time (tmax) required to reach the maximum plasma theophylline concentration (Cmax) observed after administration of the press-coated tablet was significantly (p < 0.05) delayed compared with that observed after administration of aminophylline solution in the control experiment. However, there was no difference in Cmax and area under the plasma theophylline concentration-time curve (AUC0-->24) between the press-coated tablet and aminophylline solution. These results suggest that the press-coated aminophylline tablet (with the timed-release characteristic) offers a promising forms of theophylline chronotherapy for asthma.

Aminophylline↗

PubMed2006

Ability of practitioners to identify solid oral dosage tablets.

PURPOSE: Physicians' and pharmacists' ability to correctly identify three commonly used oral dosage forms was assessed. METHODS: A list of physicians and pharmacists was obtained from two urban teaching hospitals. A total of 100 pharmacists and physicians were randomly selected and their ability to correctly identify three commonly used tablets was tested. Participants were also asked about their experiences and views on current resources and alternatives for identifying oral dosage forms. Tablet-identification exercises were performed by physicians and pharmacists in their usual practice settings. Participants could consult the resources usually available to them for the identification of unknown medications. RESULTS: A total of 300 observations were made in the tablet-identification exercise (100 participants, three tablets per participant). The tablet was correctly identified in 190 of the observations (63%). The brand-name tablet, the generic tablet, and the nonprescription generic tablet were correctly identified in 78%, 64%, and 48% of the observations, respectively. Only 18 physicians (36%) and 24 pharmacists (48%) correctly identified all three tablets, whereas 10 physicians (20%) and 5 pharmacists (10%) could not correctly identify any of the tablets. The mean time required to identify a tablet was 3.65 minutes. Pharmacists most often used electronic resources (52%), while physicians relied on print resources. Overall, 77% expressed dissatisfaction with the current system and 91% favored a universal imprint coding system for oral dosage forms. CONCLUSION: Physicians and pharmacists failed to correctly identify three commonly prescribed tablets more than a third of the time. The brand-name tablet was correctly identified more often than were the prescription generic and nonprescription generic products.

Administration, Oral↗

PubMedDate not supplied

Buccoadhesive tablets for insulin delivery: in-vitro and in-vivo studies.

In the present work, insulin (6 U/kg) was formulated into bioadhesive buccal tablets using Carbopol 934, Hydroxypropyl cellulose (HPC) or Hydroxypopylmethyl cellulose (HPMC) and different absorption promoters. The effect of different ratios of HPC or HPMC to Carbopol on the rate of water uptake was studied. The axial and radial detachment force as well as the duration of adhesion of tablets to a porcine buccal tissues were also investigated. Furthermore the hypoglycemic effect of some formulations containing HPMC and Carbopol in different ratios with different additives and enhancers was studied using diabetic male beagle dogs. The rate of water uptake of tablets prepared with 3:1, 1:1 or 1:3 of HPC or HPMC: Carbopol was directly proportion to the Carbopol content of the tablet. The incorporation of enhancers (10%) to tablets prepared with HPMC: Carbopol of 1:1 ratio did not affect to a great extent the rate of tablets hydration. On the other hand, coating one side of the tablet with 50 mg of the impermeable cutina led to a significant reduction in the rate of tablets' water uptake reaching 50% to 75% in comparison with the uncoated tablets. Carbopol had the most influential effect on both mucoadhesion force and duration followed by HPMC. Tablets prepared with 100% HPC completely eroded within 6 hours during the measurement of the duration of adhesion. The incorporation of Carbopol with this polymer significantly improved its mucoadhesion duration reaching more than 24 hours with the 1:3 HPC: Carbopol. Ten percent of either sodium salicylate (NaSal) or sodium deoxycholate (NaDC) did not affect the duration of mucoadhesion of tablets prepared with 1:1 HPMC: Carbopol while 10% of Witepsol or Cacao butter and 1% of polyoxyethylene-9-lauryl ether (POELE) significantly reduced it. Tablets made using a polymer mixture of HPMC: Carbopol 934, 1:3 resulted in improved pharmacodynamic parameters producing a relative hypoglycemia (RH) of 6.72%. Furthermore, tablets made using polymer mixture of HPMC: Carbopol 934 in a ratio of 1:1 and containing 1% POELE resulted in 26% reduction in plasma glucose levels and producing 9.42% RH. Inclusion of other promoters such as 10% sodium deoxycholate or 10% sodium salicylate gave rise to RH values of 7.93 and 8.65% respectively.

Adhesiveness↗

PubMed2001

[Pharmaceutical evaluation of fast-disintegrant tablet containing nicorandil-loaded particles].

AIM: To improve the bioavailability and taste of fast-disintegrating tablet (FD tablet) containing nicorandil-loaded particles. METHODS: A FD tablet containing nicorandil-loaded particles with 1%-4% croscarmellose sodium in addition of D-mannitol and lactose (9:1) was prepared and the dissolution and absorption characteristics were examined, in comparison with FD tablet and commercial tablets of nicorandil. In vivo absorption of nicorandil from FD tablet was evaluated in beagle dogs. RESULTS: The disintegration time of FD tablets containing 1% croscarmellose sodium with 6 mm and 10 mm in diameter were about 12 and 23 seconds, respectively. When nicorandil-loaded particles consist of myristyl alcohol and stearyl alcohol were put in FD tablet, nicorandil release from FD tablet continued until 6 h while nicorandil release from Sigmart and FD tablet containing nicorandil crystals finished within 5 min. In vivo absorption of nicorandil from Sigmart and FD tablet containing nicorandil crystals was very similar after oral administration in beagle dogs and no statistic difference in AUC, Tmax, Cmax was observed between these tablets. However pharmacokinetics parameters of nicorandil after oral administration of FD tablet containing nicorandil-loaded particles showed that nicorandil was delivered into the body at a suitable absorption rate with similar AUC, delayed Tmax and lower Cmax. CONCLUSION: The reports suggest that the modification of properties of myristyl alcohol and stearyl alcohol released from the drug-loaded particles system would lead to more acceptable bioavailability of the system. However, The formulation of particles and may have a masking effect against the bitter taste and irritation of the drug.

Administration, Oral↗

PubMed2005

Pharmacological content of tablets sold as "ecstasy": results from an online testing service.

PURPOSE: This study examined the pharmacological content of tablets sold as ecstasy, the variation of tablet content by geographic region, and change in tablet content between 1999 and 2005. METHODS: The sample was comprised of tablets anonymously submitted for laboratory testing between 1999 and 2005 (n=1214). Tablet height, width, geographic region, and year of submission were all used to predict the pharmacological content of the tablets. RESULTS: Overall, 39% of the tablets were comprised of MDMA only, 46% only contained substances other than MDMA and 15% were mixtures of MDMA and other substances. Tablet height and width were inversely related to tablet purity. Ecstasy tablets from California and Florida had decreased likelihoods of containing non-MDMA substances. The purity of tablets decreased over time, which was largely a result of an increasing number of tablets comprised of MDMA along with other substances. CONCLUSIONS: Ecstasy users may be putting themselves at increased risk of substance-induced anxiety, mood, and psychotic disorders by unknowingly ingesting substances other than MDMA. To decrease detrimental health effects, prevention programs should emphasize the impurity of ecstasy tablets and focus on the health impacts of these substances, particularly for populations at high-risk of substance-induced disorders.

Drug Contamination↗

PubMed2001

Compression forces and amount of outer coating layer affecting the time-controlled disintegration of the compression-coated tablets prepared by direct compression with micronized ethylcellulose.

The influence of compression force to inner core tablet or to outer coating layer of the compression-coated tablet on the function of time-controlled disintegration was investigated. The inner core tablet was directly compacted by sodium diclofenac (model drug) and ethylcellulose (EC) with 4.6-microm particle size was used as an outer coating layer. The immersion time of the compression-coated tablet previously soaked in pH 1.2 solution to simulate the residence time of the tablet in the GI tract affecting the dissolution behavior of the compression-coated tablet was also investigated. The effect of the amount of the outer coating layer used on the drug release was examined. The results indicate that sodium diclofenac released from these compression-coated tablets exhibited a longer lag of a period about 16.3 h in both distilled water and pH 6.8 buffer solution, followed by a different drug release behavior. The lag time was independent of the pH of dissolution medium, and the immersion time in pH 1.2 solution. After that lag time, the outer shell of the compression-coated tablets broke into two halves to make a rapid drug release. However, the drug release behavior of the soaked tablet in pH 6.8 buffer solution was dependent on the immersion time. The compression force < 200 kg/cm(2) to the inner core tablet influenced the release behavior of drug less, but > 200 kg/cm(2) might delay the lag time. The lag time of the compression-coated tablets was linearly correlated with the compression force to the outer coating layer (r = 0.9896). We also found that the more the amount of outer coating layer added, the longer the lag time obtained. The study demonstrates that the time-controlled disintegration of the compression-coated tablet was effectively controlled by the compression force applied and the amount of outer coating layer added.

Cellulose↗

PubMed1982

Gastroscopic and pharmacokinetic evaluation of a new pivmecillinam tablet.

Three different pivmecillinam preparations, a conventional 200 mg tablet (P tablet) and two new formulations containing respectively pivmecillinam 200 mg and 400 mg plus Avicel (microcrystalline cellulose) as a disintegrator (PA tablet), were compared in vitro and in a gastroscopic study in 8 healthy volunteers. Disintegration of the PA tablet was significantly more rapid both in vitro and in the stomach. Following disintegration, the content of the PA tablet was spread over a larger area of the gastric mucosa (1088 mm2) than was observed with the P tablets (408 mm2). Three of the 8 volunteers taking the P tablet developed hyperaemia, interstitial bleeding or erosions of the mucosa of the stomach. No such reactions were seen with the PA tablets. Serum concentrations of mecillinam following ingestion of pivmecillinam tablets were determined in three groups of subjects; fasting volunteers, both supine and ambulant, and in ambulant subjects who took the preparation with a light meal. There was a tendency for the new PA tablets to produce a higher peak serum level as well as greater bioavailability of mecillinam. Administration of the PA tablets with a meal significantly increased the peak serum level and total bioavailability of the drug. On the basis of our observations we recommend adoption of the new PA tablet, because of its quick passage through the oesophagus and its more rapid and complete disintegration in the stomach.

Amdinocillin Pivoxil↗

PubMed2004

Is ecstasy MDMA? A review of the proportion of ecstasy tablets containing MDMA, their dosage levels, and the changing perceptions of purity.

AIMS: Not every tablet sold as "ecstasy" contains MDMA (3,4-methylenedioxymethamphetamine). The historical origins and evolution of this mismatch will be reviewed, in order to estimate the proportions of ecstasy tablets containing MDMA at different periods over the past 30 years. METHODS: Surveys into the pharmacological constituents of ecstasy tablets, dosage levels, and empirical reports of their perceived purity, provide the main data for this review. RESULTS: During the 1980s and early 1990s there were few problems with the purity of ecstasy tablets, and the biochemical evidence shows that they nearly always contained MDMA. During the mid-1990s, the majority of ecstasy tablets continued to contain MDMA, while many others comprised MDA (3,4-methylenedioxyamphetamine), MDEA (3,4-methylenedioxyethylamphetamine), or amphetamine drug mixtures. However, a small proportion (4-20% according to survey, time and place), comprised non-amphetamine drugs such as caffeine, ephedrine, ketamine, paracetamol, or placebo. During the late 1990s, the proportion of ecstasy tablets containing MDMA increased to around 80-90%. The latest reports suggest that non-MDMA tablets are now very infrequent, with purity levels between 90% and 100%. Dosage levels of tablets are also highly variable, with low dose tablet often encountered during the mid-1990s, and high dose tablets now seen more frequently. The theoretical and practical implications of these findings will be debated. CONCLUSIONS: The ecstasy purity problem was predominantly a phenomenon of the mid to late 1990s, when many tablets contained substances other than MDMA. Before and since then, the proportion of ecstasy tablets containing MDMA has been very high.

3,4-Methylenedioxyamphetamine↗

PubMedDate not supplied

Pharmacokinetic investigation of a nicotine sublingual tablet.

OBJECTIVE: To evaluate the pharmacokinetics of a new 2-mg nicotine sublingual tablet under varying conditions of use. METHODS: The pharmacokinetics of the 2-mg nicotine sublingual tablet were investigated in four separate studies involving healthy adult volunteer smokers: (1) a multiple-dose comparison with 2-mg nicotine chewing gum (n=24; 13 males, 11 females), (2) a dose-proportionality study comparing single doses of 2, 4 and 6 mg (n=21, 10 males, 11 females), (3) an evaluation of the effect of incorrect tablet use, i.e. chewing the tablet followed by either immediate or delayed swallowing (n = 19, 10 males, 9 females), and (4) the effect of oral and gastric pH on nicotine absorption from the tablet (n=20; 11 males, 9 females). Study parameters were maximal plasma concentration (Cmax), time to Cmax (tmax), and area under the plasma concentration-time curve (AUC). RESULTS: The plasma nicotine profiles were similar following repeated administration of the sublingual tablet and the 2-mg nicotine chewing gum (mean Cmax 13.2 versus 14.4 ng/ml, median tmax 20 versus 20 min, mean AUC11-12 12.4 versus 13.5 ng/ml per hour) with no statistically significant difference between the two treatments. The pharmacokinetics of the 4- and 6-mg doses were non-linear compared to the 2-mg dose, probably as a result of more of the dose being swallowed and undergoing first-pass metabolism in the liver. The mean Cmax for the 2-, 4- and 6-mg dose was 3.8 +/- 1.0, 6.8 +/- 2. 1, and 9.0 +/- 3.3 ng/ml, respectively, and in terms of dose proportionality the relative bioavailability of the 4- and 6-mg dose was 0.82 and 0.71, respectively. Incorrect tablet use, i.e. chewing the tablet and immediate swallowing decreased nicotine bioavailability both in terms of rate and extent. Mean Cmax was 12.1 ng/ml (correct use), 10.3 ng/ml (chewing and immediate swallowing), and 12.1 ng/ml (chewing and delayed swallowing). Corresponding mean values for AUC9-10 were 11.6, 9.6 and 11.2 ng/ml per hour. There were no significant differences between 'alkaline mouth' versus control, 'acidic mouth' versus control or 'alkaline stomach' versus control, but the rate of nicotine absorption was increased at alkaline compared to acidic oral pH (mean Cmax 6.1 versus 4.9 ng/l ml, P = 0.003; median tmax 60 versus 90 min, P= 0.0002). CONCLUSION: The pharmacokinetic profile of the nicotine 2-mg tablet was similar to that of the 2-mg nicotine chewing gum. Absorption of nicotine from the tablet was nonlinear at higher doses (two or three tablets). Chewing the tablet and keeping the remains in the mouth or concurrent use of acidic beverages or antacids are equivalent to recommended sublingual use during normal oral pH conditions.

Administration, Sublingual↗

PubMed2002

Plaque-inhibiting effect of bioadhesive mucosal tablets containing chlorhexidine in a 4-day plaque regrowth model.

BACKGROUND AND AIM: Compliance in the use of daily oral antiseptics can probably be enhanced by prescribing easily-applied bioadhesive tablets which slowly release chlorhexidine (CHX). This could also be of use in patients with difficulties in rinsing or performing mechanical plaque control. The aim of the present study was to evaluate the capacity of bioadhesive tablets containing either 30 mg or 40 mg of CHX to inhibit de novo plaque formation. METHOD: In this single, examiner-blinded, crossover study, 22 volunteers between 21 and 25 years of age refrained from oral hygiene for 4 days. Bioadhesive mucosal tablets containing 30 mg or 40 mg of CHX were applied in the canine region. Rinses with a 0.2% CHX solution and placebo tablets served as controls. Plaque regrowth was evaluated with the Quigley-Hein Index modification of Turesky and by an automatic image analysis system (AIA) using slides of stained plaque. Rinsing and application of the tablets were done under supervision twice daily. RESULTS: According to the plaque index, plaque regrowth was significantly inhibited by CHX rinses ( P<0.001) and by tablets with 40 mg of CHX ( P<0.02) for all teeth and surfaces. Placebo tablets and 30-mg CHX tablets had no plaque-inhibiting effect. For taste, the subjects preferred the placebo and the 30-mg tablets more than the rinses and 40-mg tablets. In 3/22 of the subjects, superficial mucosal lesions were found at the side of application of the 40-mg tablets. Using the AIA system for evaluation of plaque regrowth, similar results for plaque inhibition were found. CONCLUSION: It can be concluded that bioadhesive mucosal tablets containing 40 mg of CHX can inhibit plaque regrowth as well as 0.2% CHX rinses. However, unpleasant taste and superficial mucosal lesions are local side effects to be considered.

Adhesiveness↗

PubMed2006

Calculation of the penetration depth of X-rays in intact pharmaceutical film-coated tablets by microdiffractometry.

PURPOSE: (i) Develop a method to calculate the penetration depth of X-rays in intact film-coated tablets, and validate it using model bilayer tablets. (ii) Characterize the physical form of drug in intact pharmaceutical film-coated tablets by XRD. MATERIALS AND METHODS: An equation for the calculation of the penetration depth of X-rays, as a function of the incident angle, was derived. Model bilayer tablets were prepared to validate the calculation method. The upper layer of the tablets consisted only of microcrystalline cellulose, while the lower layer was a mixture of cerium oxide (10% w/w), blue dye (5% w/w) and microcrystalline cellulose. The total tablet thickness was 3,500 microm, with the upper layer thickness ranging from 200 to 700 microm. The diffracted intensity of a cerium oxide peak in the lower layer was determined using a microdiffractometer system (CuKalpha radiation) with a two-dimensional area detector. The calculated penetration depth of X-rays was compared with that determined by XRD. After validation of the XRD method, commercial ibuprofen tablets were characterized. RESULTS: The penetration depth calculated by the method developed in this study was, in general, in good agreement with that determined experimentally by XRD. In commercial ibuprofen tablets, the coating material exhibited peaks due to TiO2 (25.4 degrees 2 theta) and Fe2O3 (33.3 degrees). However, these did not interfere with the characteristic peak of ibuprofen (22.2 degrees). CONCLUSION: We developed a method for calculation of penetration depth of X-rays in film-coated tablets and validated it using the model bilayer tablets. This method enables the characterization of the active pharmaceutical ingredient in different regions (at different depths) of the film-coated tablet. Since the technique is nondestructive, the same tablet can be repeatedly analyzed during stability studies.

Absorption↗

PubMed2005

Effect of pulverization of the bulk powder on the hydration of creatine anhydrate tablets and their pharmaceutical properties.

The hydration behavior and expansion properties of untreated and pulverized creatine anhydrate (CRA) tablets were studied under 60 and 75%RH at 25 degrees C by using differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The tablet hardness of untreated and pulverized CRA tablets was significantly decreased after hydration. There was a linear relationship between the degree of hydration and the tablet hardness of untreated CRA tablets compressed at 1000 kg/cm2. In contrast, the relationship between the degree of hydration and the tablet hardness of pulverized CRA tablets was nonlinear. These results suggest that the reduction in hardness of pulverized CRA tablets does not depend solely on the hydration level of crystal water. PXRD analysis indicated that the diffraction pattern of the pulverized CRA powder was similar to that of the untreated CRA powder. However, the diffraction intensity of the pulverized CRA powder was slightly lower than that of the untreated CRA powder at high angle. The micropore radius of both untreated and pulverized CRA tablets was significantly increased after hydration, but analysis of the relationship between micropore radius and fractional hydration of crystal water showed that untreated CRA tablets were more affected than pulverized CRA tablets. Therefore, the reduction in tablet hardness depends not only on the hydration behavior but also on the crystal orientation of the CRA powder.

Calorimetry, Differential Scanning↗

PubMed2006

Detection of the breakage of pharmaceutical tablets in pneumatic transport.

Pneumatic transport of pharmaceutical tablets is very convenient, compact and greatly reduces contamination. A potential problem, however, is the breakage of a significant fraction of the transported tablets, causing serious product quality problems. Since the flowrate of tablets transported through a given pneumatic transport line increases with gas velocity, lines are often operated at gas velocities slightly below the velocity at which tablets break. Minor changes in operating conditions can have a large effect on the impact resistance of tablets and on the observed tablet breakage rate. Therefore, maintaining a constant gas velocity is not sufficient to keep the tablet breakage rate below an acceptable level. The objective of the present study was to develop a reliable and non-invasive on-line method for the detection of tablet breakage. Pharmaceutical acetaminophen tablets were transported pneumatically in a 0.1 m diameter pipeline consisting of a 5 m vertical and a 4.0 m horizontal section made of either re-enforced PVC or steel. The pipeline flow regime was determined by visual observation through clear pipeline sections. Tablet breakage was quantified by screening tablet samples. Acoustic measurements were recorded at different locations along the pipeline. Analysis of the signals from microphones attached to the wall of the elbow and horizontal section provided a reliable detection of conditions leading to tablet breakage.

Acetaminophen↗

PubMed2002

Rapid at-line analysis of coating thickness and uniformity on tablets using laser induced breakdown spectroscopy.

Because of the functionality of controlled release tablet coatings, it is desirable to have a rapid means of optimizing coating conditions and predicting the performance of a batch at-line, prior to exhaustive lab analysis. In this paper, Laser Induced Breakdown Spectroscopy (LIBS) was utilized for the first time as a rapid means of simultaneously determining the thickness and uniformity of an enteric coating on compressed tablets. In these studies, the core tablets contained a high concentration of calcium, and the coating contained titanium, silicon, and magnesium, all of which are excellent analytical targets for LIBS. The emission spectra of all four elements were simultaneously monitored as a function of the number of laser pulses in the same spatial location, literally drilling through the coating and into the core tablet. The depth penetration of individual laser pulses was calibrated using profilometry, and the thickness of the coating was determined by the incidence of calcium signal and simultaneous decrease in emission from the other probe elements (titanium, silicon and magnesium) as the laser penetrated the coating. Coating thickness measurements were evaluated by sampling coatings ranging from 5 to 21% (100 mg tablet weight basis). Additionally, LIBS spatial resolution capabilities were exploited to evaluate the film coat thickness uniformity across the tablet faces and edges. Furthermore, tablet to tablet uniformity differences were readily assessable. The results indicate that a change in coating application of less than 2 wt.% on a 100 mg tablet can be easily detected. The rapid analysis times for this technique (10 tablets were analyzed in under 15 min) makes it applicable for in-process evaluation of coating thickness, as well as intra- and inter-tablet coating uniformity on compressed tablets.

Calcium↗

PubMedDate not supplied

Solubility and diffusion of nitrogen in maltodextrin/protein tablets.

The gas transport properties of compacted tablets consisting of an amorphous mixture of maltodextrin and sodium caseinate were studied by dissolving nitrogen gas in the tablets and then determining the gas release over time as a function of temperature and water activity. Gas was dissolved in the tablet matrix by heating the tablets under pressure, generally to temperatures above the glass transition temperature of the matrix, holding them at these conditions for a specified time and then rapidly cooling them while maintaining the external pressure. The solubility of nitrogen was found to be largely determined by the free volume of the matrix, which in turn can be influenced to some degree by thermal and pressure treatments during gas loading. At the levels of free volume studied, the dissolved nitrogen is densely packed in the free volume, the packing density being virtually independent of the externally applied pressure. Release of gas from the tablets at temperatures below the glass transition temperature is generally well described by Fickian diffusion. The effective diffusion coefficient of gas release is strongly dependent on the microstructure and porosity of the tablet matrix, and an approximate model describing the relationship between tablet structure and rate of gas release is formulated. The model is in semiquantitative agreement with the rates of gas diffusion obtained for tablets and dense granules. Owing to the structural heterogeneity and variability of the tablets and the history-dependent properties of the tablet matrix, the effective diffusion coefficients of gas release from the tablets showed a relatively large spread. The temperature dependence of diffusional release follows an Arrhenius relation below the glass transition temperature. This allows the prediction of the nitrogen retention in the tablets as function of time, temperature and pressure.

Diffusion↗

PubMed1996

Control of poorly soluble drug dissolution in conditions simulating the gastrointestinal tract flow. 1. Effect of tablet geometry in buffered medium.

The dissolution rate of a solid drug from the gastrointestinal (GI) tract is affected by the properties and flow dynamics of the liquid medium surrounding the tablet, as well as by the chemical nature of the drug. In this study, naproxen was used as a poorly soluble model drug. The dissolution medium was buffered with acetate, citrate, or phosphate buffer of varied concentrations and pH. GI flow conditions around a stationary tablet were simulated in a laminar flow device by anchoring the tablet on the floor of its channel having a rectangular cross section. Fresh, buffered solution was passed across the tablet and the effluent was collected for analysis and calculation of the dissolution rate. The dissolution rate was found to vary nonlinearly with the exposed tablet height, reaching a maximum at a tablet height approximately half the channel height. This maximum rate was attributed to an optimal combination of (1) eddy mixing and local turbulence generated by the flow impingement on the bluff object (tablet) and (2) the exposed tablet surface area available for dissolution. This effect was further confirmed by using dye-enhanced visual analysis of flow patterns at varied flow rates and exposed tablet heights. Elevation of the tablet to approximately the channel half-height significantly magnified the dissolution rate increase observed on exposure to buffered medium. Thus, tablet height and exposed surface area are major factors in determining dissolution rate, especially in conditions where the dissolving species reacts with the solvent. These results suggest that standard in vitro dissolution rate methods do not qualitatively indicate incremental changes in rate with altered tablet geometry or dissolution medium.

Digestive System↗