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At least 19 recordsLinked to original sources
PubMed2002

Roller compaction and tabletting of St. John's wort plant dry extract using a gap width and force controlled roller compactor. II. Study of roller compaction variables on granule and tablet properties by a 3(3) factorial design.

The purpose of this study was to investigate the influence of roller compaction parameters and the amount of magnesium stearate used in dry granulation on granule and tablet properties of a dry herbal extract from St. John's wort (Hypericum perforatum L.). Two different extract batches were blended with magnesium stearate and compacted using a gap width and force controlled roller compactor. A 3(3) factorial design was used to evaluate the influence of the three independent variables, the amount of magnesium stearate, the roller compaction force, and the granulating sieve size on the mean particle size of granulated extracts and on the disintegration time of tablets containing these granulated extracts. The evaluation was done by multilinear stepwise regression analysis. The mean particle size d50 (R2 > 0.9) of both compacted extracts increased with increasing compaction force and with granulating sieve size. The disintegration time of the tablets was mostly in the range 5-15 min and increased slightly with increasing magnesium stearate concentration in the compacted extract and with decreasing compaction force of the roller compaction. The incorporation of magnesium stearate into the granulated extract reduced its potential negative influence on the disintegration time, while maintaining its functionality as a lubricant.

Compressive Strength↗
PubMed2005

Effect of the variation in the ambient moisture on the compaction behavior of powder undergoing roller-compaction and on the characteristics of tablets produced from the post-milled granules.

Effect of variation in the ambient moisture levels on the compaction behavior of a 10% acetaminophen (APAP) powder blend in microcrystalline cellulose (MCC) powder was studied by comparing the physical and mechanical properties of ribbons prepared by roller compaction with those of simulated ribbons, i.e., tablets prepared under uni-axial compression. Relative density, moisture content, tensile strength, and Young's modulus were used as key compact properties for comparison. Moisture was found to facilitate the particle rearrangement of both, the APAP and the MCC particles, as well as the deformation of the MCC particles. The tensile strength of the simulated ribbons also showed an increase with increasing moisture content. An interesting observation was that the tensile strength of the roller compacted samples first increased and then decreased with increasing moisture content. Variation in the ambient moisture during roller compaction was also found to influence the characteristics of tablets produced from the granules obtained post-milling the ribbons. A method to study this influence is also reported.

Acetaminophen↗
PubMed1999

The evaluation of fine-particle hydroxypropylcellulose as a roller compaction binder in pharmaceutical applications.

In solid dosage manufacturing, roller compaction technology plays an important role in providing cost control and a quality product. The objective of this study was to evaluate the effectiveness of fine-particle hydroxypropylcellulose (HPC) as a dry binder in roller compaction processing. The formula included acetaminophen (APAP), microcrystalline cellulose, fine-particle HPC, croscarmellose sodium, and magnesium stearate. The fine-particle HPC was incorporated into the formula at 4%, 6%, and 8% w/w levels. Three compaction pressures (30, 40, and 50 bars) were used for each formulation. The roller compaction equipment used in this study had a processing capacity of 40 to 80 kg/hr. A tablet compression profile was generated on a rotary tablet press, and compression forces used were 5, 10, 15, 20, and 25 kN. The significant criteria for tablet evaluation were capping, hardness, friability, ejection force, and drug dissolution. As the binder concentration of HPC increased, tablet capping decreased, and tablet friability improved. As the concentration of HPC increased, only slight differences were noted in tablet hardness. All the formulations pass the USP requirement of 80% APAP dissolved within 30 min. Using 8% HPC could eliminate the formula capping problem. The friability results were less than 1% at all compression forces. The minimum tablet ejection forces were found in the formulations prepared under 40 bars compaction pressure. The utility of fine-particle HPC as a roller compaction binder was established. The applicable binder concentrations and roller compaction pressures were found. Using HPC at these binder levels and operating parameters could overcome capping and friability problems and achieve the optimal tablet dosage forms.

Cellulose↗
PubMed2004

Simulation of roller compaction using a laboratory scale compaction simulator.

A method for simulation of the roller compaction process using a laboratory scale compaction simulator was developed. The simulation was evaluated using microcrystalline cellulose as model material and ribbon solid fraction and tensile strength as key ribbon properties. When compacted to the same solid fractions, real and simulated ribbons exhibited similar compression behavior and equivalent mechanical properties (tensile strengths). Thus, simulated and real ribbons are expected to result in equivalent granulations. Although the simulation cannot account for some roller compaction aspects (non-homogeneous ribbon density and material bypass) it enables prediction of the effects that critical parameters such as roll speed, pressure and radius have on the properties of ribbons using a fraction of material required by conventional roller compaction equipment. Furthermore, constant ribbon solid fraction and/or tensile strength may be utilized as scale up and transfer factors for the roller compaction process. The improved material efficiency and product transfer methods could enable formulation of tablet dosage forms earlier in drug product development.

Cellulose↗
PubMed2005

Influence of ambient moisture on the compaction behavior of microcrystalline cellulose powder undergoing uni-axial compression and roller-compaction: a comparative study using near-infrared spectroscopy.

This study evaluates the effect of variation in the ambient moisture on the compaction behavior of microcrystalline cellulose (MCC) powder. The study was conducted by comparing the physico-mechanical properties of, and the near infrared (NIR) spectra collected on, compacts prepared by roller compaction with those collected on simulated ribbons, that is, compacts prepared under uni-axial compression. Relative density, moisture content, tensile strength (TS), and Young modulus were used as key sample attributes for comparison. Samples prepared at constant roller compactor settings and feed mass showed constant density and a decrease in TS with increasing moisture content. Compacts prepared under uni-axial compression at constant pressure and compact mass showed the opposite effect, that is, density increased while TS remained almost constant with increasing moisture content. This suggests difference in the influence of moisture on the material under roller compaction, in which the roll gap (i.e., thickness and therefore density) remains almost constant, vs. under uni-axial compression, in which the thickness is free to change in response to the applied pressure. Key sample attributes were also related to the NIR spectra using multivariate data analysis by the partial least squares projection to latent structures (PLS). Good agreement was observed between the measured and the NIR-PLS predicted values for all key attributes for both, the roller compacted samples as well as the simulated ribbons.

Cellulose↗
PubMed2004

Roller compaction of crude plant material: influence of process variables, polyvinylpyrrolidone, and co-milling.

Roller compaction of a milled botanical (Baphicacanthus cusia) with and without a binder, polyvinylpyrrolidone (PVP) was conducted. Effects of co-milling on binder function and flowability of the powder blend was also investigated. Flakes were comminuted, and the size and size distribution, friability, Hausner ratio, and Carr index of the granulations were determined. Crude herb should be reduced to a suitable size for it to be successfully roller compacted. Larger-sized and less friable granules were obtained with decreasing roller speed. Addition of PVP affected the flowability and binding capacity of the herbal powder blend, which influenced size and friability of the granules. Co-milling of PVP with the herbal powder enhanced the flow of the blends and the effectiveness of the binder, which contributed favorably to the roller-compacted product. Roller compaction is a convenient and cost-effective granulating technique suitable for milled botanicals. Co-milling can be used to improve the properties of roller-compacted products.

Apocynaceae↗
PubMed2002

Roller compaction and tabletting of St. John's wort plant dry extract using a gap width and force controlled roller compactor. I. Granulation and tabletting of eight different extract batches.

The purpose of this study was to investigate the influence of roller compaction parameters on granule and tablet quality of a dry herbal extract from St. John's wort (Hypericum perforatum L.), which is widely used in the treatment of mild to moderate depressive disorders. Eight different extract batches were blended with 0.5, 2, and 5% of magnesium stearate and were compacted at different compaction forces using a gap width and force controlled roller compactor. The ribbon formed was milled into granules having mean particle sizes up to 700 microns. The roller compaction of the extracts decreased significantly the angle of repose from about 45 to 32 degrees and the Hausner ratio from about 1.2 to 1.1. Tabletting of granulated extract instead of extract powder effectively reduced not only dust and feeding problems during the tabletting process but also prevented capping. The incorporation of 2 and 5% of magnesium stearate into the roller compacted extract reduced significantly the sticking of the dry herbal extracts to the punch faces without affecting the crushing strength of the tablets. Tablets containing granulated extracts exhibited a 3-fold lower disintegration time of about 12 min compared to tablets containing extract powder. Dissolution studies revealed that hyperforin, hypericin, and rutin were more rapidly released from tablets containing granulated extract. Therefore, roller compaction leveled out the differences in technological properties between the eight dry herbal extracts and compression of granulated extract significantly improved tablet quality.

Compressive Strength↗
PubMed2004

Nondestructive measurements of the compact strength and the particle-size distribution after milling of roller compacted powders by near-infrared spectroscopy.

Compact strength and the particle-size distribution of milled roller compacted compacts were correlated to the slope of the best-fit line through near-infrared spectra for samples prepared under different roll speeds and feed rates. The above correlations were found to hold for compacts prepared from microcrystalline cellulose powder as well as from a typical direct compression pharmaceutical powder blend containing tolmetin sodium dihydrate, microcrystalline cellulose, and dicalcium phosphate dihydrate. Near-infrared spectra were also collected real time for the compacts prepared from the tolmetin powder blend. The real-time slope values for the spectra showed good agreement with the off-line data. The strength of compacts was determined using three-point beam bending method and the particle-size distribution of the milled compacts was determined using sieve analysis. The results suggest that the real-time values of the slope of the best-fit line through the near-infrared spectrum offers a robust, yet simple and fast quality control tool to monitor/control manufacturing and scale-up processes involving dry granulation by roller compaction.

Calcium Phosphates↗
PubMed2005

Real-time near-infrared monitoring of content uniformity, moisture content, compact density, tensile strength, and Young's modulus of roller compacted powder blends.

A method for real-time in-line near-infrared (NIR) monitoring of roller compaction is reported. Multivariate analysis using partial least square projections to latent structures (PLS) was used to relate the spectral data with key compact attributes: content uniformity, moisture content, relative density, tensile strength, and Young's modulus. NIR calibration curves were generated using the spectral data collected on simulated ribbons, that is, tablets prepared under uni-axial compression, and tested on the data collected on another set of simulated ribbons and by monitoring the ribbons as they exited the roller compactor. For all compact attributes, the NIR predicted values agreed well with the values measured using a reference method.

Acetaminophen↗
PubMed1999

Modeling of a roller-compaction process using neural networks and genetic algorithms.

In this study, roller-compaction of acetaminophene was studied to model the effect of binder type (hydroxypropyl methyl cellulose (HPMC), polyethylene glycol (PEG), Carbopol), binder concentration (5, 10 and 20%), number of roller-compaction passes (one or two), and extragranular microcrystalline cellulose addition on the properties of compressed tablets. Forty-two batches resulted from the experimental design. The artificial neural network methodology (ANN) along with genetic algorithms were used for data analysis and optimization. ANN and genetic models provided R2 values between 0.3593 and 0.9991 for measured responses. When a set of validation experiments was analyzed, genetic algorithm predictions of tablet characteristics were much better than the ANN. Optimization based on genetic algorithm showed that using HPMC at 20%, with two roller-compaction passes would produce mechanically acceptable acetaminophene tablets. PEG and carbopol would also produce acceptable tablets perhaps more suitable for sustained release applications. Using PEG as a binder had the additional advantage of not requiring an external lubricant during tablet manufacturing.

Acetaminophen↗
PubMed2004

Effect of formulation composition on the properties of controlled release tablets prepared by roller compaction.

This study discusses the effect of formulation composition on the physical characteristics and drug release behavior of controlled-release formulations made by roller compaction. The authors used mixture experimental design to study the effect of formulation components using diclofenac sodium as the model drug substance and varying relative amounts of microcrystalline cellulose (Avicel), hydroxypropyl methylcellulose (HPMC), and glyceryl behenate (Compritol). Dissolution studies revealed very little variability in drug release. The t70 values for the 13 formulations were found to vary between 260 and 550 min. A reduced cubic model was found to best fit the t70 data and gave an adjusted r-square of 0.9406. Each of the linear terms, the interaction terms between Compritol and Avicel and between all three of the tested factors were found to be significant. The longest release times were observed for formulations having higher concentrations of HPMC or Compritol. Tablets with higher concentrations of Avicel showed reduced ability to retard the release of the drug from the tablet matrix. Crushing strength showed systematic dependence on the formulation factors and could be modeled using a reduced quadratic model. The crushing strength values were highest at high concentrations of Avicel, while tablets with a high level of Compritol showed the lowest values. A predicted optimum formulation was derived by a numerical, multiresponse optimization technique. The validity of the model for predicting physical attributes of the product was also verified by experiment. The observed responses from the calculated optimum formulation were in very close agreement with values predicted by the model. The utility of a mixture experimental design for selecting formulation components of a roller compacted product was demonstrated. These simple statistical tools can allow a formulator to rationally select levels of various components in a formulation, improve the quality of products, and develop more robust processes.

Cellulose↗
PubMed2006

Reduced tabletability of roller compacted granules as a result of granule size enlargement.

The mechanism for the frequently observed "loss of reworkability or tabletability" of dry-granulated (DG) powders was investigated in detail using microcrystalline cellulose (MCC). It was hypothesized that granule size enlargement is the primary mechanism to the phenomenon. Detrimental effects of size enlargement on tabletability of plastic materials are predictable based on the physical model of interparticulate bonding within a tablet. In absence of extensive fracture of particles/granules, larger particles/granules exhibit lower surface area available for bonding thus lower tensile strength when compressed under identical conditions. Size effects were first demonstrated using different grades of MCC powders, both whole and sieved, of different particle size distributions. Regardless grade and sieve fraction, larger particles always resulted in lower tabletability, that is, lower tensile strength at the same compaction pressure. It was subsequently shown that enlargement of granules also reduced powder tabletability regardless grade of MCC. Tabletability of sieved granules after roller compacted for one, two, and four times decreased monotonically with increasing granule size but independent of the total number of roller compaction. Moreover, tabletability of fine granules (44-106 microm) was higher than that of coarse MCC powder (Avicel PH-200). These results suggest that the primary mechanism for reduced tabletabilty of DG granules of MCC is granule size enlargement rather than "work-hardening."

Cellulose↗
PubMed2005

Effects of roller compaction settings on the preparation of bioadhesive granules and ocular minitablets.

An experimental factorial design was employed to evaluate bioadhesive granules and bioerodible ocular minitablets (6 mg and Psi 2 mm). The purpose of this study was to compare minitablets prepared using roller compacted granules with an optimised minitablet formulation, manufactured on laboratory scale by direct compression. The formulation consisted of drum dried waxy maize starch, Carbopol 974P, and ciprofloxacin in a ratio of 90.5/5/3 (w/w/w). Three roller compactor parameters were varied, i.e. the roller speed, the horizontal screw speed and the compaction force, while the vertical screw speed was kept constant. Afterwards, the ribbons were milled to obtain granules suitable for compression. The friability, the flow properties, the bulk material characteristics (apparent and tap density and porosity) and the particle size distributions of two granule sieve fractions (90-125 and 125-355 microm) were investigated. The roller speed and the compaction force have the largest influence on the granule characteristics, followed by the horizontal screw speed. The physical properties of non- and gamma-irradiated minitablets were determined. From the tablet strength, friability and dissolution results, a low compaction force and a high roller speed were shown to be preferable to prepare granules which can be further tabletted into adequate ocular minitablets.

Eye↗
PubMed2026

A correction factor for bridging compaction simulator and different roller compactors.

Roller compaction (RC) is an important dry granulation technique. Since pilot and commercial scale roller compactors, which operate continuously on a large scale, usually require kilograms of material per run, formulation and process development directly on such roller compactors is not practical. In contrast, a compaction simulator (CS) can produce ribblets, also known as "slugs", using only a few grams of material with sinusoidal displacement profile replicating the motion of a specific point on the roll surface. Thus, it is possible to develop RC formulation and process in laboratory using a CS-based material-sparing approach. However, because of the inherently different configurations for applying pressure between die compression and roll compression, translating uniaxial pressure from CS experiments to roll pressure during RC is often unreliable, leading to significant uncertainties in the critical quality attributes of ribbons, such as ribbon solid fraction (or porosity) and mechanical strength. The objective of this study was to identify a correction factor (Kp = uniaxial die compression pressure/roll pressure), by correlating the compressibility profiles from CS and a roller compactor of interest, to enable more reliable process translation from CS to roller compactor. In this study, a Kp value of 0.5 was determined for Alexanderwerk WP120 and validated for Gerteis Mini-Pactor and Bepex Pharmapactor. This value may serve as a starting point for translating the optimal compaction pressure identified based on CS investigation to common roller compactors, requiring only minor adjustments to attain optimal RC process parameters (i.e., roll force and roll gap) for a chosen roller compactor.

Drug Compounding↗
PubMed2002

Multiple compaction of microcrystalline cellulose in a roller compactor.

The effect of multiple roller compaction was investigated using microcrystalline cellulose as a model substance. Granules were prepared, examined and recompacted in a Gerteis 3 W-Polygran roller compactor up to ten times. Examinations were carried out for granule size distribution, density and flow properties. Ribbons were investigated for quality, and adhesion of ribbons to the rolls was traced. Finally tablets were produced from the granule samples and examined for their compression behaviour. Multicompression reduces the amount of fines, increases mean granule size and flow properties and also improves size distribution. Although roll adhesion diminishes with increasing cycles, this decrease is not sufficient enough to result in a visibly reduced gap variability. By multicompaction, bulk density increases which indicates that the porosity of granules decreased during the multiple compaction cycles. However, the ability of MCC to form bondings with neighbouring particles is diminished during various cycles which results in decreasing crushing forces of the subsequently prepared tablets.

Cellulose↗
PubMed2000

Sustained-release phenylpropanolamine hydrochloride bilayer caplets containing the hydroxypropylmethylcellulose 2208 matrix. II. Effects of filling order in bilayer compression and manufacturing method of the prolonged-release layer on compactibility of bilayer caplets.

The purpose of this study was to establish the manufacturing method of the formulated bilayer caplets containing the hydroxypropylmethylcellulose 2208 (HPMC2208) matrix without lamination. In manufacturing the bilayer caplets containing the HPMC2208 (Metolose 90SH4000) matrix, some bilayer caplets were cracked. We found that cracking of bilayer caplets is not the separation of two layers, but lamination of the prolonged-release layer. It was assumed that Metolose 90SH4000 causes lamination of the prolonged-release layer. Two factors, roller compaction pressure on dry granulation of the prolonged-release layer and filling order of the prolonged-release layer in bilayer compression, were related to lamination of bilayer caplets. The compactibility of the prolonged-release layer decrease with an increase in roller compaction pressure on dry granulation. The compactibility of the prolonged-release layer manufactured by direct compression is superior to that manufactured by dry granulation. The compactibility of the prolonged-release layer in the shape of the second layer, convexo-concave, is superior to that in the shape of the first layer, convexo-convex. This is due to the fact that the density distribution inside the compact in the shape of convexo-concave was more uniform than that in the shape of convexo-convex. The manufacturing method of the formulated bilayer caplets having the prolonged-release layer whose Metolose 90SH4000 content is 60% without lamination is as follows: the prolonged-release layer manufactured by direct compression is fed as the second layer in bilayer compression.

Chemistry, Pharmaceutical↗
PubMed2005

Rapid quantitative analysis of magnesium stearate in tablets using laser-induced breakdown spectroscopy.

PURPOSE: Laser-induced breakdown spectroscopy (LIBS) was evaluated for its potential as a process analytical tool for the rapid determination of magnesium stearate (MgSt) distribution within and between tablets as well as between batches in a typical manufacturing run, and for the comparison of direct-compression and roller-compaction processes. METHODS: These studies were conducted using a prototype instrument and a commercial PharmaLIBS unit, both based on pulsed Nd:YAG laser radiation at 1064 nm. The intensity of a magnesium spectral line either at 517.27 or 518.36 nm was used, depending on the product, to quantitate the MgSt concentration in the tablets. RESULTS: Using internal standardization, it was possible with the prototype instrument to accurately quantitate MgSt at the 0.5% level in two different products. For eight batches of one product, using 10 tablets from each batch, the intra-tablet, intra-batch, and inter-batch MgSt %RSDs were found to be 13.8%, 5.4% and 7.4%, respectively. Further studies were conducted with the commercial LIBS unit, which showed similar performance as the prototype unit. In particular, it was found that different depth-profile distributions of MgSt were associated with roller-compacted tablets and direct-compressed tablets. CONCLUSION: These findings illustrate the potential of LIBS to be developed as a process analytics tool for the direct and rapid determination of MgSt content and distribution in tablets.

Chemistry, Pharmaceutical↗
PubMed2003

Correlation of characteristics of gel extrusion module (GEM) tablet formulation and drug dissolution rate.

The purpose of the study was to characterize the swelling properties of controlled release tablet formulations with compositional and processing differences. A correlation was also established between the drug dissolution rate from the controlled release gel extrusion module (GEM) tablet and the swelling properties of the core tablet. The GEM tablet consisted of a core tablet of water swellable Carbopol polymer, a neutralizing agent, drug, and excipients. The tablet was subsequently coated with a rigid, water impermeable membrane. A number of holes were then drilled by laser through the impermeable membrane. Dynamic mechanical analysis (DMA), Perkin Elmer DMA7, was used to characterize the swelling properties. During the swelling measurements, the measuring probe and sample were completely submerged in the surrounding medium. The results showed that the formulation containing potassium phosphate dibasic as a neutralizing agent had the highest swelling rate. Correspondingly, this formulation had the highest drug dissolution rate over the same time period. The processing difference included wet granulation and dry roller compaction. The compositional differences included different neutralizing agents, binders or Carbopol polymers. The results showed a linear relationship (r(2)=0.954) between the swelling rates of the core tablets and the drug dissolution rates of GEM tablets. No correlation was found between the drug dissolution rates and either the maximum extent of tablet swelling or the time needed to reach the maximum extent of swelling. The results demonstrated that DMA could be used to support both formulation and process development to determine the effects of different compositions and manufacturing processes on drug dissolution rates for swelling controlled release devices.

Chemistry, Pharmaceutical↗