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PubMed2004

High-performance liquid chromatographic method for the bioequivalence evaluation of desloratadine fumarate tablets in dogs.

A simple HPLC method was developed for the determination of desloratadine in dog plasma and was used for evaluating the bioequivalence of desloratadine fumarate tablets and desloratadine tablets in dogs. Chromatographic separation was performed on a Hypersil CN column (150 mm x 5.0 mm, 5 microm) using a mixture of methanol, acetonitrile and phosphate buffer (pH 5.5; 0.01 mol/l) (35:35:30, v/v/v) as mobile phase delivered at a flow rate of 0.8 ml/min. The detection was set at 241 nm. The limit of quantitation was 5.0 ng/ml. The calibration range was from 5.0 to 800.0 ng/ml. Inter- and intra-day precision ranged from 1.8 to 3.8% and from 2.2 to 9.0%, respectively. The recovery of desloratadine from dog plasma ranged from 78.8 to 82.0%. The developed method was applied to the bioequivalence studies of desloratadine fumarate tablets (test preparation) and desloratadine tablets (reference preparation) in five dogs. Pharmacokinetic parameters t(max), C(max), AUC(0-t), AUC(0- infinity ), t(1/2) were determined from plasma concentration-time profiles of both preparations. The analysis of variance (ANOVA) did not show any significant difference between the two preparations and 90% confidence intervals fell within the acceptable range for bioequivalence. Based on these statistical inferences it was concluded that the two preparations exhibited comparable pharmacokinetic profiles and that desloratadine fumarate tablets was bioequivalent to desloratadine tablets.

Animals↗
PubMed2005

Nondestructive determination of the ambroxol content in tablets by Raman spectroscopy.

We describe a method for determining the ambroxol content in tablets nondestructively. To obtain a reliable quantitative calibration, we prepared 20 pellet samples (ambroxol content: 8.30-16.25 wt.%) and acquired their Raman spectra while rotating the pellets. The spectra of the rotated samples reflected the compositional variations better than those that were recorded without rotation. To reduce both the baseline variations and the spectral noise simultaneously, the spectra were pre-processed using wavelet transformation (WT). Then, we used the normalization method before partial least-squares (PLS) regression to correct Raman intensity variation from laser power fluctuation. The achieved standard error of cross validation (SECV) was 0.30%. Two different datasets where Raman intensity was artificially changed were prepared and the corresponding spectra were quantitatively analyzed. The result was reproducible even if laser intensity was fairly changed. Additionally, two different commercial tablets were analyzed and the accuracy of measurement was better for a tablet that had the similar spectral features of the standard pellet samples. The proposed method can be utilized for the analysis of commercial tablets if standard tablets of various ambroxol concentrations that have the same chemical components including additives and the same physical shape of tablets are available.

Ambroxol↗
PubMed2005

Characterization of different laser irradiation methods for quantitative Raman tablet assessment.

Quantitative Raman spectroscopy of conventional wet granulated pharmaceutical immediate release tablets and subsequent data evaluation was investigated. Different aspects of quantitative assessment of active pharmaceutical ingredient (API) in intact tablets with special focus on sub-sampling issues were addressed. Four different geometric laser irradiance patterns were examined to study the effect of sub-sampling within the tablets. The Raman data was evaluated using both univariate and multivariate techniques. UV absorbance spectroscopy was used as a reference method. The best result in terms of prediction error was attained by irradiating a large area of the tablets. Using multivariate calibration with multiplicative signal correction (MSC) the prediction error was 1.7%. In addition, the effect of tablet density on the Raman assessment was investigated. It was found that quantitative Raman assessment of chemical content can be made insensitive to variations in tablet density corresponding to a manufacturing compression interval of 5-20 kN provided that adequate data treatment is used. A short discussion about sample heating in the context of different irradiation patterns is included with reference to previous work. In conclusion, the present study provides a platform for developing an implementation strategy for quantitative Raman spectroscopy for both laboratory analysis and process analytical technology (PAT) applications.

Calibration↗
PubMed1996

Standardization of clinical criteria required for use of the 12.5 millimeter barium tablet in evaluating esophageal lumenal patency.

BACKGROUND: Although the barium tablet is commonly used in evaluating lumenal patency of the esophagus, the conditions under which the tablet should traverse a normal esophagus have not been established. This study was designed to standardize the minimal criteria required to ensure successful esophageal transit of a commercially available barium tablet in normal subjects. METHODS: Each of 20 volunteers swallowed a standard 12.5 mm barium tablet under fluoroscopy in the supine, 45 degrees incline, and upright positions. Tablets were swallowed dry and with fixed volumes of water (15, 30, 60, and 100 cc). Success of pill passage into the stomach was determined by fluoroscopy at 20, 40, 60, and 90 seconds. RESULTS: Successful pill passage correlated significantly with position (passing 17.0%, 66.5%, and 69.7% in the supine, incline, and upright position, respectively; p < .0001) and volume of water ingested (passing 9.1% when swallowing dry, and 38.7%, 55.8%, 70.0%, and 81.6% with 15, 30, 60, and 100 cc of water, respectively; p < or = .004). Duration of time beyond 20 seconds failed to affect rate of pill passage. Ingestion of 60 cc of water in the incline position was associated with a 95% pill passage, a rate significantly greater than any position at lower volumes. Increasing water volume above 60 cc or assuming the upright position did not increase this passage rate further. CONCLUSIONS: The minimum criteria required to optimize successful transit of a 12.5 mm barium tablet through a normal esophagus is to perform the test in the 45 degrees incline position with 60 cc of water for a period of 20 seconds. Failure of the pill to pass under these conditions may suggest a true structural abnormality of the esophagus.

Administration, Oral↗
PubMed2004

Efficacy and tolerability of sumatriptan tablets in a fast-disintegrating, rapid-release formulation for the acute treatment of migraine: results of a multicenter, randomized, placebo-controlled study.

BACKGROUND: Sumatriptan tablets have been developed in a fast-disintegrating, rapid-release formulation designed to facilitate tablet disintegration and drug dispersion and to potentially mitigate the effects of gastric stasis that can accompany migraine. OBJECTIVE: This study was conducted to evaluate the efficacy and tolerability of sumatriptan 50- and 100-mg tablets in a fast-disintegrating, rapid-release formulation compared with those of placebo in patients with migraine. METHODS: This clinical trial had a randomized, double-blind, placebo-controlled, parallel-group design. Exclusion criteria included >6 migraines monthly during either of the 2 months before screening; uncontrolled hypertension; suspected or confirmed cardiovascular or cerebrovascular disease; and ophthalmic, basilar, or hemiplegic migraine. Sumatriptan 50 and 100 mg and placebo were taken on an outpatient basis during the mild-pain phase of a single migraine attack. Patients recorded details of the treated migraine on a diary card and rated pain severity immediately before dosing and 30 minutes, 45 minutes, 1 hour, and 2 hours after dosing using a 4-point scale (from 0 = none to 3 = severe). The primary efficacy end point was the proportion of patients who were pain free 2 hours after dosing. Additional efficacy end points were the proportion of patients who were pain free at 30 minutes, 45 minutes, and 1 hour after dosing; the proportion who were migraine free through 2 hours after dosing; and the proportion with a sustained pain-free response. RESULTS: Patients' mean age ranged from 39.7 to 41.5 years across the 3 groups, and the majority were women (79.7%-85.9%) and white (98.7%-100%). One hundred thirty-seven patients received sumatriptan 50 mg, 142 sumatriptan 100 mg, and 153 placebo. In the intent-to-treat population (n = 432), 51.1% of patients who received sumatriptan 50 mg and 66.2% of patients who received sumatriptan 100 mg were pain free 2 hours after dosing, compared with 19.6% of the placebo group (P < 0.001, each sumatriptan dose vs placebo). In an exploratory analysis, the 2-hour pain-free rate with sumatriptan 100 mg was significantly better than that with sumatriptan 50 mg (P = 0.007). Significantly more patients who received sumatriptan 100 mg were pain free compared with placebo at 30 minutes (P < 0.01), 45 minutes (P < 0.001), and 1 hour after dosing (P < 0.001); similar pain-free results were observed in patients who received sumatriptan 50 mg at 45 minutes (P < 0.05) and 1 hour (P = 0.01). In the per-protocol population (n = 313), pain-free efficacy 2 hours after dosing was 52.7% with sumatriptan 50 mg and 74.8% with sumatriptan 100 mg, compared with 21.0% with placebo (P < 0.001, each sumatriptan dose vs placebo). These rates were greater than those in the overall study population, approximately 12.0% of whom treated moderate or severe pain. The only drug-related adverse events reported in >/=3% of patients in any treatment group were nausea and vomiting (<1%, 5%, and 2% in the sumatriptan 50 and 100 mg and placebo groups, respectively), chest symptoms (2%, 3%, and 0%), and malaise and fatigue (1%, 3%, and <1%). No serious adverse events were reported. CONCLUSIONS: In this study, sumatriptan tablets in a fast-disintegrating, rapid-release oral formulation provided pain-free efficacy in the acute treatment of migraine. Efficacy was maximized with the 100-mg dose compared with the 50-mg dose, and by treating early when pain was mild. In the intent-to-treat population, 51.1% of patients who received sumatriptan 50 mg and 66.2% of those who received sumatriptan 100 mg were pain free 2 hours after dosing. In the per-protocol population, 3 of 4 patients taking the 100-mg tablets for mild pain within 1 hour of its onset were pain free at 2 hours. Sumatriptan tablets were generally well tolerated.

Adult↗
PubMed2000

Nifedipine controlled delivery by sandwiched osmotic tablet system.

The sandwiched osmotic tablet system (SOTS), which is composed of a sandwiched osmotic tablet core surrounded by a cellulose acetate membrane with two orifices on both side surfaces, has been successfully prepared with the purpose of delivering nifedipine. The sandwiched osmotic tablet core consists of a middle push layer and two attached drug layers. Influences of tablet formulation variables, orifice size and membrane variables on nifedipine release of SOTS have been studied. It was found that potassium chloride amount of push layer and polyethylene oxide amount of drug layer had markedly positive effects on nifedipine release. A push layer/drug layer co-controlled osmotic delivery mechanism and the optimal core formulation have been proposed. The appropriate orifice size was observed in the range of 0.50-1.41 mm. It was also found that the drug release rate of SOTS could be increased by incorporating hydrophilic plasticizer in the membrane, whereas it decreased with hydrophobic plasticizer. It has been observed that the SOTS gives fairly comparable in vitro release features as that of commercialized push-pull osmotic tablet system, such as an approximately constant rate up to 24 h and independence of release media and agitation rate. Exempting side identification before drilling, it is easier to prepare the SOTS than the push-pull osmotic tablet system.

Calcium Channel Blockers↗
PubMed2001

An in vitro investigation of the suitability of press-coated tablets with hydroxypropylmethylcellulose acetate succinate (HPMCAS) and hydrophobic additives in the outer shell for colon targeting.

To develop a new colon targeting formulation, which can suppress drug release completely during 12 h in the stomach and release the drug rapidly after a lag time of 3+/-1 h in the small intestine, the use of press-coated tablets with hydroxypropylmethylcellulose acetate succinate (HPMCAS) in the outer shell was investigated. The release of diltiazem hydrochloride (DIL) as a model drug contained in the core tablets in the 1st fluid (pH 1.2) was suppressed by preparing with higher compression force, but the lag time in the 2nd fluid (pH 6.8) could not exceed 1.5 h. Therefore, to improve the dissolution characteristics, the effects of addition of various hydrophobic additives to HPMCAS were examined. All of the additives examined suppressed the release rate in the 1st fluid, and prolonged the lag time in the 2nd fluid compared to HPMCAS alone. However, although none of the additives examined fulfilled all of the desired criteria, magnesium stearate (MgSt) and calcium stearate (CaSt) showed interesting effects; the former suppressed drug release completely in 1st fluid, while the latter markedly prolonged the lag time in 2nd fluid. To integrate the merits of each additive, press-coated tablets with a powder mixture of HPMCAS, MgSt and CaSt in the outer shell (HMC tablets) were prepared and in vitro tests were performed. The results indicated that HMC tablets with a mixing ratio of 80% HPMCAS, 5-15% MgSt and 15-5% CaSt in the outer shell met the desired criteria and the lag time in 2nd fluid could also be controlled from 2 to 9 h. At a mixing ratio of 80% HPMCAS, 10% MgSt and 10% CaSt, the dissolution profiles of DIL in 1st fluid and 2nd fluid were not remarkably affected by agitation intensity, and addition of bile salts, pretreatment time or anticipated higher pH except for pH 6.0, respectively. These results indicated the usefulness of HMC tablets with the desirable functions for colon-targeting formulations.

Colon↗
PubMed2001

Effect of molecular weight and glass transition on relaxation and release behaviour of poly(DL-lactic acid) tablets.

Different molecular weight grades of poly(DL-lactic acid) were applied as release controlling excipients in tablets for oral drug administration. The role of molecular weight and glass transition in the mechanism of water-induced volume expansion and drug release of PDLA tablets was investigated. Modulated differential scanning calorimetry (MDSC) was used to determine the glass transition temperature of both dry and hydrated PDLA samples. The absorption rate and total amounts of sorbed water by the polymer were determined by dynamic vapour sorption (DVS). Expansion behaviour of PDLA tablets was measured using thermal mechanical analysis (TMA). At 95% relative humidity all molecular weight grades of PDLA sorbed 1.1-1.3% w/w water, as was determined with DVS. MDSC showed glass transition temperature reductions of 10-11 degrees C for all molecular weight grades of PDLA in water. Volume expansion studies using TMA showed that the molecular relaxation time and equilibrium porosity of the tablets increased with molecular weight. The mean relaxation time increased exponentially with the temperature interval T(g)-T. The onset temperature of shape recovery of hydrated tablets was approximately 8 degrees C lower than for dry samples. Drug release was only slightly affected by molecular weight. It is concluded that volume expansion of compressed PDLA tablets is related to the glass transition behaviour, originates from water-induced and thermally stimulated shape memory behaviour and is therefore highly dependent on the molecular weight of PDLA.

Lactic Acid↗
PubMed1998

Development of metoprolol tartrate extended-release matrix tablet formulations for regulatory policy consideration.

This research study was designed to develop model extended-release (ER) matrix tablet formulations for metoprolol tartrate (100 mg) sufficiently sensitive to manufacturing variable and to serve as the scientific basis for regulatory policy development on scale-up and post approval changes for modified-release dosage forms (SUPAC-MR). Several grades and levels of hydroxypropyl methylcellulose (Methocel K4M, K15M, K100M and K100LV), fillers and binders and studied. Three granulation processes were evaluated; direct compression, fluid-bed or high-shear granulation. Lubrication was performed in a V-blender and tablets were compressed on an instrumented rotary tablet press. Direct compression formulations exhibited poor flow, picking and sticking problems during tableting. High-shear granulation resulted in the formation of hard granules that were difficult to mill but yielded good tablets. Fluid-bed granulations were made using various binders and appeared to be satisfactory in terms of flow and tableting performance. In vitro drug release testing was performed in pH 6.8 phosphate buffer using USP apparatus 2 (paddle) at 50 rpm. At a fixed polymer level, drug release from the higher viscosity grades (K100M) was slower as compared to the lower viscosity grades (K100LV). In addition, release from K100LV was found to be more sensitive to polymer level changes. Increased in polymer level from 10 to 40% and/or filler change from lactose to dicalcium phosphate resulted in about 25-30% decrease in the amount of metoprolol release after 12 h. The results of this study led to the choice of Methocel K100LV as the hydrophilic matrix polymer and fluid-bed granulation as the process of choice for further evaluation of critical and non-critical formulation and processing variables.

Adrenergic beta-Antagonists↗
PubMed1999

Absorption and bioavailability of oestradiol from a gel, a patch and a tablet.

OBJECTIVES: To compare oestradiol and oestrone concentrations and bioavailability after a single dose and at a steady state during oral oestradiol valerate, transdermal oestradiol gel and transdermal oestradiol patch treatments. METHODS: Two open, randomised, cross-over studies were conducted. In the first study, 12 healthy postmenopausal women received 1.5 mg oestradiol as a transdermal gel or a 2 mg oestradiol valerate tablet daily for 14 days. In the second study, 15 postmenopausal women were treated for 18 days with 1.5 mg oestradiol gel or a transdermal patch releasing oestradiol 50 microg/24 h (replaced every 72 h). Venous blood samples for serum oestradiol and oestrone measurements with RIA were taken until 24 or 72 h after the first and last doses. RESULTS: The tablet and the transdermal gel yielded similar serum oestradiol profiles with a peak concentration 4-5 h after administration. The patch resulted in relatively stable oestradiol levels during the mid third of the wearing time whereas much lower levels were observed in the beginning and towards the end. There was no difference in the fluctuation between the peak and trough oestradiol levels between the gel (56 or 67%) and the tablet (54%) while the fluctuation was greater with the patch (89%). The bioavailability of oestradiol from the gel was 61% as compared with the tablet and 109% as compared with the patch. The gel was not bioequivalent with the tablet or the patch. CONCLUSIONS: The doses used of the transdermal gel and the patch roughly corresponded to each other with regard to the amount of oestradiol absorbed whereas the bioavailability from the tablet was significantly higher than from the gel. The lack of bioequivalence, the different serum oestradiol profiles and the large intersubject variability suggest that individual dose adjustments may be needed when changing administration form.

Administration, Cutaneous↗
PubMed2001

Effect of magnesium stearate or calcium stearate as additives on dissolution profiles of diltiazem hydrochloride from press-coated tablets with hydroxypropylmethylcellulose acetate succinate in the outer shell.

Effect of magnesium stearate (MgSt) or calcium stearate (CaSt) on the dissolution profiles of diltiazem hydrochloride in the core of press-coated (PC) tablets with an outer shell composed of hydroxypropylmethylcellulose acetate succinate (HPMCAS) was evaluated by porosity and changes in IR spectra of tablets. In JP first fluid (pH 1.2), the lag time increased with decreasing porosity and was greatest by the addition of MgSt to HPMCAS. While, in JP second fluid (pH 6.8), it increased with decreasing porosity by the addition of CaSt, but hardly changed by the addition of MgSt. Thus, using tablets prepared with the same composition as the outer shell, the changes in IR spectra and uptake amount of the dissolution media after immersion in first fluid and second fluid were determined. The results suggested that some physicochemical interaction occur between MgSt and HPMCAS in tablets with HPMCAS and MgSt and the uptake increased markedly in each dissolution medium. These phenomena seem to cause a prolongation of lag time in first fluid but a shortening of it in second fluid in PC tablets with HPMCAS and MgSt. In contrast, CaSt and HPMCAS did not show such interactions and increased the hydrophobic properties of the outer shell. Consequently, the lag time was only slightly prolonged in first fluid, however, markedly prolonged in second fluid due to suppression of second fluid penetration into micro pores in the outer shell and HPMCAS gel formation on the surface in PC tablets with HPMCAS and CaSt.

Antihypertensive Agents↗
PubMed2001

In vivo evaluation of hydrochlorothiazide liquisolid tablets in beagle dogs.

This study was carried out to evaluate the absorption characteristics of experimentally developed hydrochlorothiazide liquisolid tablets using six male beagle dogs. Comparison with reference commercial tablets was made. As no bibliographic data were found for the pharmacokinetic parameters of the drug in dogs, an intravenous drug administration was included in the study. The drug was administered orally as a single 25 mg dose of commercial and liquisolid tablets on two occasions in a randomized two-way crossover design. The pharmacokinetic parameters of the drug post intravenous dosing were reported for the first time. The results of the oral administration revealed statistically significant differences between the liquisolid and the commercial tablets in the area under the plasma concentration-time curve, the peak plasma concentration, and the absolute bioavailability. On the other hand, no significant differences were observed between the two formulations with regard to the mean residence time, the mean absorption time, and the rate of absorption. The absolute bioavailability of the drug from the liquisolid tablets was 15% higher than that from the commercial one. The parametric 90% confidence intervals for the different parameters were higher than the commonly expected intervals for bioequivalency, indicating greater bioavailability of the liquisolid tablets.

Administration, Oral↗
PubMed2002

Performance of USP calibrator tablets in flow-through cell apparatus.

USP dissolution calibrator tablets were analysed by the flow-through cell method with the intention of examining its applicability for the flow-through cell apparatus suitability test. Test was performed with Dissotest CE-6 apparatus, (Sotax, Switzerland) in flow-through cells for tablets and capsules: smaller cells of 12 mm diameter and larger ones of 22.6 mm diameter. Analyses were performed with laminar and turbulent flow of dissolution medium. The flow rates were 16 and 8 ml/min for laminar flow and only 16 ml/min for turbulent flow. From the results it can be concluded that both salicylic acid tablets and prednisone tablets could be used for apparatus suitability test also for the flow-through cell under the conditions of laminar flows of 16 and 8 ml/min in cells phi 12 and 22.6 mm. As regards the turbulent flow of 16 ml/min, without a holder, cells phi 12 mm could be used for salicylic acid tablets and both cells (phi 12 and 22.6 mm) for prednisone tablets.

Calibration↗
PubMed2002

Preparation, characterization, and tabletting properties of a new cellulose-based pharmaceutical aid.

A new cellulose-based tabletting excipient, hereinafter referred to as UICEL, has been developed by treating cellulose powder with an aqueous solution of sodium hydroxide (conc. > or = 5N) and subsequently precipitating it with ethyl alcohol. UICEL is similar in structure to Avicel PH-102, a commercial direct compression excipient commonly referred to as microcrystalline cellulose (MCC). It, however, shows the cellulose II lattice, while Avicel PH-102 belongs to the cellulose I polymorphic form. As produced, UICEL consisted of a mixture of aggregated and non-aggregated fibers. The degrees of polymerization (DP) and crystallinity (DC) of UICEL, determined by the viscosity and powder X-ray methods, were 189-207 and 47-58%, respectively. Avicel PH-102, by comparison, showed an aggregated structure with DP and DC values corresponding to 248 and 76.9%, respectively. Compared to Avicel PH-102, UICEL shows higher true density, bulk density, tap density, Carr's index and Hausner ratio values. The mean deformation pressure (P(y)) values calculated from the linear portion of the Heckel plots for UICEL and Avicel PH-102 were about 104 and 87 MPa, respectively, suggesting that UICEL is less ductile than Avicel PH-102. The hardness values of UICEL tablets increased nearly linearly with increasing compression pressures. Comparatively, Avicel PH-102 formed stronger tablets. Irrespective of the compression pressure used, all UICEL tablets disintegrated within 15 s, whereas Avicel PH-102 tablets of comparable strengths remained intact for over 12 h. In conclusion, the results show that UICEL can be used as a direct compression excipient, especially in the design and development of fast-disintegrating tablets.

Cellulose↗
PubMed2003

Matrix formation in sustained release tablets: possible mechanism of dose dumping.

Conditions under which poly(ethyl acrylate, methyl methacrylate) 2:1 (poly(EA-MMA), Eudragit NE) forms a stable matrix were investigated in tablets with diclofenac sodium (DS) as an active substance. DS was granulated with the aqueous polymer dispersion. Granules and/or tablets were cured under various temperature and humidity conditions. A six position rotating disk (200 rpm) apparatus was used for the release studies conducted in 37 degrees C acid then phosphate buffer (0.4 M) pH 6.8 or buffer only as the dissolution media. Morphological characteristics of the tablet surface were observed under SEM. Changes in tablet structure upon curing were evaluated through changes in tablet mechanical characteristics. Modulus of rupture, Young's modulus, AUC, AUC( max), where AUC=AUC( max), were determined by the three-point bending test. Some poorly cured tablets dose-dumped when placed directly into buffer but not if first placed in acid and then buffer. A higher content of polymer in the matrix, led to formation of a stronger polymer network upon higher curing temperature and/or longer curing duration, whereas relative humidity had a minor effect.

Delayed-Action Preparations↗
PubMed2003

Characterization of monoclinic crystals in tablets by pattern-fitting procedure using X-ray powder diffraction data.

The purpose of this study is to characterize the monoclinic crystals in tablets by using X-ray powder diffraction data and to evaluate the deformation feature of crystals during compression. The monoclinic crystals of acetaminophen and benzoic acid were used as the samples. The observed X-ray diffraction intensities were fitted to the analytic expression, and the fitting parameters, such as the lattice parameters, the peak-width parameters, the preferred orientation parameter and peak asymmetric parameter were optimized by a non-linear least-squares procedure. The Gauss and March distribution functions were used to correct the preferred orientation of crystallites in the tablet. The March function performed better in correcting the modification of diffraction intensity by preferred orientation of crystallites, suggesting that the crystallites in the tablets had fiber texture with axial orientation. Although a broadening of diffraction peaks was observed in acetaminophen tablets with an increase of compression pressure, little broadening was observed in the benzoic tablets. These results suggest that "acetaminophen is a material consolidating by fragmentation of crystalline particles and benzoic acid is a material consolidating by plastic deformation then occurred rearrangement of molecules during compression". A pattern-fitting procedure is the superior method for characterizing the crystalline drugs of monoclinic crystals in the tablets, as well as orthorhombic isoniazid and mannitol crystals reported in the previous paper.

Acetaminophen↗
PubMed2003

The effect of excipients on the stability of levothyroxine sodium pentahydrate tablets.

Levothyroxine tablets, 50 microg, have been marketed for many decades but have had numerous recalls due to degradation and failure to meet potency. These experiments were devised to study the effects of various excipients on the stability of levothyroxine sodium pentahydrate in aqueous slurries and in formulated tablets. The active alone was found to be stable in the solid state for 6 months at 40 degrees C/75% RH whether stored in open or closed containers, and was found to be non-hygroscopic under normal processing conditions (>30% RH). In aqueous slurries with an excipient, the stability of the active improved as the pH of the slurry was increased from pH 3 to 11. Tablets manufactured with lactose anhydrous, starch, or microcrystalline cellulose failed to meet USP assay requirements at 3 months at 40 degrees C/75% RH. Tablets manufactured with dibasic calcium phosphate or mannitol met USP assay requirements at 3, but not 6 months when stored at 40 degrees C/75% RH. Tablets manufactured with dibasic calcium phosphate and a basic pH modifier, such as sodium carbonate, sodium bicarbonate, or magnesium oxide, met the USP assay requirements at both 3 and 6 months. Thus, the use of basic pH modifiers is a potential technique for improving the stability of levothyroxine sodium pentahydrate tablets.

Adsorption↗
PubMed1999

Chitinosans as tableting excipients for modified release delivery systems.

The term 'chitinosans' embraces the spectrum of acetylated poly(N-glucosamines) ranging from chitin to chitosan. Chitinosans (I), at acidic pH, have protonated amines which can interact with oppositely charged drug ions and, thereby, modify drug release from drug delivery systems. Tablets were compressed from a physical mixture containing salicylic acid (II) as the model drug, I, and magnesium stearate. Five commercial I compounds, varying in degree of deacetylation and molecular weight, were selected. Tablets were compressed at 5000, 10 000, and 15 000 psig using a Carver and a single punch tablet press. The differential scanning calorimetry thermograms provided evidence of I-II interaction in the powder blend. Analysis of variance (ANOVA) indicated that the compression pressure did not significantly affect the crushing strength (CS) or the release profile of II from the I-matrix tablets (P?0.05). Furthermore, the ANOVA also indicated that the tablet press used during manufacture did not affect the above properties (P?0.05); however, the chitinosans significantly affected the CS as well as the release profile of II from I-matrix tablets (P<0.05). This study provides further evidence for the use of commercial I compounds as excipients for use in modified release drug delivery systems.

Acetylation↗