Tablet Weight Variation Research Articles

The Challenge of Die Filling in Rotary Presses-A Systematic Study of Material Properties and Process Parameters.

For the efficient and safe production of pharmaceutical tablets, a deep process understanding is of high importance. An essential process step during tableting is the die filling, as it is responsible for a consistent tablet weight and drug content. Furthermore, it affects the results of subsequent process steps, compaction and ejection, and thus critical quality attributes. This study focuses on understanding the influences of process parameters and material properties on die filling on a rotary tablet press. By the systematic variation in process parameters as the turret and paddle speeds as well as the fill and dosing depths, five formulations with differing properties are processed. Analysis of the normalized tablet weight, called filling yield, revealed different limitation mechanisms of the filling process, i.e., incomplete filled dies for certain parameter settings. Kinetic limitations occur due to a short residence time under the feed frame (filling time) caused by high turret speeds, which additionally induce high tablet weight variation coefficients. Characteristic maximum turret speeds at certain paddle speeds can be found to still achieve complete filling. At low turret speeds, densification of the powder inside the dies takes place, induced by two mechanisms: either high paddle speeds or high overfill ratios, or a combination of both. The challenge to fill the dies completely as well as avoid densification is dependent on material properties as the flowability. The mass discharge rate from an orifice was found to be in a linear correlation to the filling results of different formulations below complete filling.

Prediction of tablet weight variability in continuous manufacturing.

This paper provides a method for prediction of weight variability of tablets made in rotary tablet presses as a function of material attributes and processing parameters. The goal was to be able to predict whether or not a formulation is suitable for direct compaction continuous manufacturing using the tablet weight variability as a criterion. The work focused on identifying the significant factors affecting the weight variability in tablets, within the design space studied. A wide range of blends with different powder properties were prepared. It was shown that among powder properties, cohesion, bulk density, and particle size were the most significant and sufficient material attributes to explain tablet weight variability. A response surface model was built and validated with three different blends. The model is not formulation dependent and can be expanded to include other blend properties or processing parameters effects.

Impact of blend properties on die filling during tableting

Based on characterization of a wide range of fillers and APIs, thirty divergent blends were composed and subsequently compressed on a rotary tablet press, varying paddle speed and turret speed. The tablet weight variability was determined of 20 grab samples consisting of each 20 tablets. Additionally, the bulk residence time, ejection force, pre-compression displacement, main compression force, die fill fraction and feed frame fill fraction were determined during each run. Multivariate data analysis was applied to investigate the relation between the process parameters, blend characteristics, product and process responses. Blends with metoprolol tartrate as API showed high ejection forces. This behavior could be linked to the high wall friction value of metoprolol tartrate. The main responses related to the die filling could be predicted via a PLS model based on blend characteristics. Tablet weight variability was highly correlated with the variability on pre-compression displacement and main compression force. A good predictive model for tablet weight variability was obtained taking the porosity, wall friction angle, flowability, density, compressibility and permeability into account. Additionally, turret speed and paddle speed were included in the calibration of the model. The applied approach can save resources (material, time) during early drug product development.

Extrusion 3D Printing of Paracetamol Tablets from a Single Formulation with Tunable Release Profiles Through Control of Tablet Geometry

An extrusion-based 3D printer was used to fabricate paracetamol tablets with different geometries (mesh, ring and solid) from a single paste-based formulation formed from standard pharmaceutical ingredients. The tablets demonstrate that tunable drug release profiles can be achieved from this single formulation even with high drug loading (> 80% w/w). The tablets were evaluated for drug release using a USP dissolution testing type I apparatus. The tablets showed well-defined release profiles (from immediate to sustained release) controlled by their different geometries. The dissolution results showed dependency of drug release on the surface area/volume (SA/V) ratio and the SA of the different tablets. The tablets with larger SA/V ratios and SA had faster drug release. The 3D printed tablets were also evaluated for physical and mechanical properties including tablet dimension, drug content, weight variation and breaking force and were within acceptable range as defined by the international standards stated in the US Pharmacopoeia. X-ray powder diffraction, differential scanning calorimetry and attenuated total reflectance Fourier transform infrared spectroscopy were used to identify the physical form of the active and to assess possible drug-excipient interactions. These data again showed that the tablets meet USP requirement. These results clearly demonstrate the potential of 3D printing to create unique pharmaceutical manufacturing, and potentially clinical, opportunities. The ability to use a single unmodified formulation to achieve defined release profiles could allow, for example, relatively straightforward personalization of medicines for individuals with different metabolism rates for certain drugs and hence could offer significant development and clinical opportunities.

Optimizing feed frame design and tableting process parameters to increase die-filling uniformity on a high-speed rotary tablet press

Despite the high quantities of tablets produced daily, many tableting processes are still operated at sub-optimal settings and hence lack the necessary flexibility to mitigate for possible process deviations. However, to ensure this flexibility on tableting throughput it is important to select the most robust feed frame design and settings regarding die-filling. In this research study, four paddle designs for a two-compartment forced feeder (equipped with a metering and a feeding paddle wheel) were evaluated at a wide range of process-settings (i.e. tableting speed, paddle speed, overfill level) and feed frame features (i.e. deaeration) for their impact on the die-filling step of a poorly flowing model formulation (i.e. MCC 101) using a quality-by-design approach. No benefit on die-filling was observed when using higher speeds of the metering paddle wheel compared to the feeding paddle wheel, and no convincing arguments were obtained to use the feed frame deaeration opening. Some combinations of paddle design and process-settings significantly increased the risk for inconsistent die-filling (i.e. high tablet weight variability) which can therefore limit the efficiency of the tableting process. The approach used in this study enabled to compare the paddle designs for their die-filling performance in function of varying tableting speeds, eventually resulting in the selection of a feed frame design that is most robust and therefore will provide a uniform die-filling over a wide range of throughputs. Selection of the most robust parameters is an important prerequisite for the ability of using the rotary tablet press as an agile unit-operation.

In line monitoring of the powder flow behavior and drug content in a Fette 3090 feed frame at different operating conditions using Near Infrared spectroscopy

Near infrared (NIR) spectroscopy was used to determine the drug concentration in 3% (w/w) acetaminophen blends within the complex flow regime of the tablet press feed frame just before tablet compaction. NIR spectra also provided valuable information on the powder flow behavior within the feed frame and were used to track when a process enters or leaves the steady state. A partial least squares regression calibration model was developed with powder mixtures that varied from 1.5 to 4.5% (w/w) by obtaining 135 spectra after steady state for each concentration while the feed frame and die disc operated at 30.5 revolutions per minute (rpm). The calibration model determined drug concentration in validation blends with a root mean square error of prediction and bias below 0.1% (w/w). The robustness of the NIR calibration model was evaluated by determining the effect of variation on the operating conditions (paddle wheel speed and die disc speed) on NIR predictions. This work found that the paddle wheel speed can be increased up to 30% and the die disc speed decrease 10% without affecting NIR predictions. The results demonstrated that paddle wheel speed has a significant effect on the wave powder behavior (frequency and amplitude) but does not have significant effect on the mass hold-up within feed frame. The die disc speed does not affect wave powder behavior but affects significantly the mass hold-up inside the feed frame. This information can be used to reduce the tablet weight variability and ensure that this critical attribute is met.

Development and evaluation of miconazole mucoadhesive tablets for oropharyngeal candidiasis

Purpose: To develop mucoadhesive tablets containing miconazole (MCZ) for the treatment of oropharyngeal candidiasis, using chitosan and hydroxypropyl methylcellulose (HPMC) as mucoadhesive polymers.Methods: Mucoadhesive tablets were formulated and optimized using a 23 factorial design and direct compression method. The independent variables were compression force and concentrations of chitosan and HPMC, while mucoadhesion time and in vitro drug release were dependent variables. Tablet characterization was carried out by evaluating hardness, thickness, tablet weight variation, content uniformity, friability and in vitro drug release at salivary pH (pH 6.8).Results: The tablets showed good mucoadhesion for an extended period (8 h), and their physical characteristics were within acceptable ranges. Drug release ranged from 60.5 % to 80.8 %.Conclusion: These results indicate that the mucoadhesive MCZ tablets formulated with chitosan and HPMC possess potential for the development of therapeutic preparations for management of oropharyngeal candidiasis.Keywords: Miconazole, Oropharyngeal candidiasis, Factorial design, Mucoadhesion, Chitosan, Drug release

Setting Ideal Lubricant Mixing Time for Manufacturing Tablets by Evaluating Powder Flowability.

We investigated the effectiveness of using Carr's flowability index (FI) and practical angle of internal friction (Φ) as indexes for setting the target Mg-St mixing time needed for preparing tablets with the target physical properties. We used FI as a measure of flowability under non-loaded conditions, and Φ as a measure of flowability under loaded conditions for pharmaceutical powders undergoing direct compression with varying concentrations of Mg-St and mixing times. We evaluated the relationship between Mg-St mixing conditions and pharmaceutical powder flowability, analyzed the correlation between the physical properties of the tablets (i.e., tablet weight variation, drug content uniformity, hardness, friability, and disintegration time of tablets prepared using the pharmaceutical powder), and studied the effect of Mg-St mixing conditions and pharmaceutical powder flowability on tablet properties. Mg-St mixing time highly correlated with pharmaceutical powder FI (R 2=0.883) while Mg-St concentration has low correlation with FI, and FI highly correlated with the physical properties of the tablet (R 2 values: weight variation 0.509, drug content variation 0.314, hardness 0.525, friability 0.477, and disintegration time 0.346). Therefore, using pharmaceutical powder FI as an index could enable prediction of the physical properties of a tablet without the need for tableting, and setting the Mg-St mixing time by using pharmaceutical powder FI could enable preparation of tablets with the target physical properties. Thus, the FI of the intermediate product (i.e., pharmaceutical powder) is an effective index for controlling the physical properties of the finished tablet.

Dose Uniformity of Scored and Unscored Tablets: Application of the FDA Tablet Scoring Guidance for Industry.

This U.S. Food and Drug Administration (FDA) laboratory study examines the impact of tablet splitting, the effect of tablet splitters, and the presence of a tablet score on the dose uniformity of two model drugs. Whole tablets were purchased from five manufacturers for amlodipine and six for gabapentin. Two splitters were used for each drug product, and the gabapentin tablets were also split by hand. Whole and split amlodipine tablets were tested for content uniformity following the general chapter of the United States Pharmacopeia (USP) Uniformity of Dosage Units <905>, which is a requirement of the new FDA Guidance for Industry on tablet scoring. The USP weight variation method was used for gabapentin split tablets based on the recommendation of the guidance. All whole tablets met the USP acceptance criteria for the Uniformity of Dosage Units. Variation in whole tablet content ranged from 0.5 to 2.1 standard deviation (SD) of the percent label claim. Splitting the unscored amlodipine tablets resulted in a significant increase in dose variability of 6.5-25.4 SD when compared to whole tablets. Split tablets from all amlodipine drug products did not meet the USP acceptance criteria for content uniformity. Variation in the weight for gabapentin split tablets was greater than the whole tablets, ranging from 1.3 to 9.3 SD. All fully scored gabapentin products met the USP acceptance criteria for weight variation. Size, shape, and the presence or absence of a tablet score can affect the content uniformity and weight variation of amlodipine and gabapentin tablets. Tablet splitting produced higher variability. Differences in dose variability and fragmentation were observed between tablet splitters and hand splitting. These results are consistent with the FDA's concerns that tablet splitting can have an effect on the amount of drug present in a split tablet and available for absorption. Tablet splitting has become a very common practice in the United States and throughout the world. Tablets are often split to modify dose strength, make swallowing easier, and reduce cost to the consumer. To better address product quality for this widely used practice, the U.S. Food and Drug Administration (FDA) published a Guidance for Industry that addresses tablet splitting. The guidance provides testing criteria for scored tablets, which is a part of the FDA review process for drugs. The model drugs selected for this study were amlodipine and gabapentin, which have different sizes, shapes, and tablet scores. Whole and split amlodipine tablets were tested for drug content because of a concern that the low-dose strength may cause greater variability. Whole and split gabapentin tablets were tested for weight variation because of their higher dosage strength of 600 mg. All whole tablets met the acceptance criteria for the Uniformity of Dosage Units based on the guidance recommendations. When unscored amlodipine tablets were split by a splitter, all formulations did not meet the acceptance criteria. When fully scored gabapentin tablets were split by hand and by splitter, they met the acceptance criteria. The findings of this FDA study indicated physical characteristics such as size, shape, and tablet score can affect the uniformity of split tablets.

Evaluation of the Pharmaceutical Quality of Different Brands of Ranitidine Tablets Manufactured in Bangladesh: A Pharmaceutical and Public Health Prospective

Drug counterfeiting and production of substandard drug is a global problem. This study was aimed to assess the pharmaceutical quality of ranitidine hydrochloride tablets manufactured in Bangladesh. Tablets were collected from different parts of Bangladesh and quality parameters were evaluated according to the United States Pharmacopoeia and the British Pharmacopoeial methods. The potency of tablets was measured spectrophotometrically. Weight variation and disintegration time were performed according to pharmaceutical monographs. Among 43 brands tested, 8 failed to comply with the USP specification (active ingredient: 90±10%) due to containing of less amount of ranitidine of which 6 brands were spurious and 2 were substandard in nature. Two brands did not comply with the specification for weight variation of tablets whereas all brands passed disintegration time test. The findings clearly demonstrate the production of substandard ranitidine tablets in Bangladesh. The drug control authority of Bangladesh should take effective steps to prevent the production of substandard drugs to secure public health.

Formulation and Evaluation of Liquid Loaded Tablets Containing Docetaxel-Self Nano Emulsifying Drug Delivery Systems

Purpose: To prepare and characterize tablets loaded with self-nanoemulsifying drug delivery system (SNEDDS) containing docetaxel (DTL).Method: SNEDDS of docetaxel were prepared using various oils, surfactants, co-surfactant and solvents to improve the dissolution rate and bioavailability of the poorly water-soluble chemotherapeutic agent. The SNEDDS components were preliminarily screened for the solubility of the drug in various vehicles, miscibility of excipients, rate of emulsification and ternary phase diagrams. The tablets were prepared by direct compression process with a porous carrier, magnesium alumino-metasilicate, and subsequently loaded with SNEDDS by a simple absorption method. The tablets were then characterized for physical parameters, including tablet hardness, weight variation, disintegration, drug content and invitro drug release.Results: Cremophor-EL, polysorbate-80 and dehydrated alcohol mixture in the ratio 85:10:5 yielded docetaxel SNEDDS with droplet size of 12.16 nm and polydispersity (PDI) of 0.039. Tablets with high porosity suitable for loading with SNEDDS and containg the super-disintegrants, crosscarmellose sodium and sodium starch glycolate, in a concentration of 3, 4 and 5 %, achieved complete dissolution of docetaxel from the tablets. In vitro release of docetaxel from SNEDDS and the tablets was similar (p &lt; 0.05).Conclusion: SNEDDS of docetaxel is a promising approach to achieving a solid dosage form of the liquid-loaded drug delivery systems for enhancing the solubility and dissolution rate of the drug, and hence also its bioavailability.Keywords: Docetaxel, Drug carrier, SNEDDS, Self-nanoemulsifying, Solubility, Drug release, Anicancer, Surfactant, Co-surfactant

Preliminary investigations of the binding ability of lima bean (Phaseolus lunatus) starch in paracetamol tablets

The binding properties of starch obtained from Lima bean (Phaseolus lunatus) were evaluated. The starch from the seeds was extracted and the binding ability of its mucilage compared with that of maize starch mucilage in paracetamol based tablets at concentrations of 0, 2.5, 5, 7.5 and 10% w/v. The following properties of the starch powders were evaluated; organoleptic properties, microscopy and reaction with iodine solution while for the paracetamol granules prepared with their mucilages; particle size analysis, moisture content, flow rate, and angle of repose. The starches and granules were also evaluated for bulk and tapped density, Hausner’s ratio and Carr’s compressibility index. Paracetamol tablets formulated using the starch mucilages were evaluated for uniformity of weight, dimensions, hardness, friability, disintegration time and dissolution rate. The paracetamol granules and tablets formulated with 0 to 10% w/v P. lunatus starch mucilage were comparable in granule flow properties, tablet weight variation and hardness, friability, disintegration times and dissolution rate with the granules and tablets prepared with maize starch B.P mucilage. The study revealed that the mucilage of P. lunatus starch when used as binder produced tablets of acceptable pharmaceutical quality. Key words: Paracetamol tablets, wet granulation, Phaseolus lunatus starch, mucilage binder.

Enabling Tablet Product Development of 5-Fluorocytosine Through Integrated Crystal and Particle Engineering

The antifungal drug, 5-fluorocytosine (FC), is marketed as a capsule (250 or 500 mg strength) instead of the preferred tablet dosage form. Through systematic characterization of solid-state properties, including mechanical properties, we identify tabletability and poor physical stability of FC as the problems that likely have prevented the successful development of a FC tablet product. We then design an FC oxalate 2:1 salt (FCOXA21), based on established relationship between crystal structure and properties, to address these deficient properties. FCOXA21 is subsequently used to develop a direct compression tablet product using predictive and material-sparing powder characterization tools, that is, ring shear cell for powder flowability and compaction simulator for powder tabletability. The initial tablet formulation, which contains 84.5% (wt %) FCOXA21, exhibits excellent tabletability but inadequate flowability. We solve the powder flowability problem through controlling the particle size of FCOXA21. A batch of FCOXA21 tablets (500 mg FC equivalent dose) is then prepared. Finally, systematic evaluation on tablet weight variation, content uniformity, friability, and dissolution using standard methods confirms the commercial manufacturability of FC tablets. Through this work, we have demonstrated the potential of integrated crystal and particle engineering in expediting the development of tablet products of challenging drugs using the economical direct compression process.

Reduction of tablet weight variability by optimizing paddle speed in the forced feeder of a high-speed rotary tablet press

Context: Tableting is a complex process due to the large number of process parameters that can be varied. Knowledge and understanding of the influence of these parameters on the final product quality is of great importance for the industry, allowing economic efficiency and parametric release.Objective: The aim of this study was to investigate the influence of paddle speeds and fill depth at different tableting speeds on the weight and weight variability of tablets.Materials and methods: Two excipients possessing different flow behavior, microcrystalline cellulose (MCC) and dibasic calcium phosphate dihydrate (DCP), were selected as model powders. Tablets were manufactured via a high-speed rotary tablet press using design of experiments (DoE). During each experiment also the volume of powder in the forced feeder was measured.Results and discussion: Analysis of the DoE revealed that paddle speeds are of minor importance for tablet weight but significantly affect volume of powder inside the feeder in case of powders with excellent flowability (DCP). The opposite effect of paddle speed was observed for fairly flowing powders (MCC). Tableting speed played a role in weight and weight variability, whereas changing fill depth exclusively influenced tablet weight.Conclusion: The DoE approach allowed predicting the optimum combination of process parameters leading to minimum tablet weight variability. Monte Carlo simulations allowed assessing the probability to exceed the acceptable response limits if factor settings were varied around their optimum. This multi-dimensional combination and interaction of input variables leading to response criteria with acceptable probability reflected the design space.

English

The aim of this research is to prepare orodispersible tablets of Meclizine Hydrochloride (MHCl). MHCl is used to treat or prevent nausea, vomiting, and dizziness. Wet granulation method was used to prepare the orodispersible tablets of MHCl using different super disintegrant; crospovidone (CP), sodium starch glycolate (SSG), croscarmellose sodium (CCS), and microcrystalline cellulose (MCC) at different concentrations. Camphor and ammonium carbonate were also incorporated in preparation as subliming agents. Co processing of super disintegrant with MCC is a new approach to increase disintegration rate which we tried. The prepared tablets were evaluated for weight variation, content uniformity, hardness, disintegration time, and friability of tablets. All the formulations showed low weight variation with&nbsp;in-vitro&nbsp;disintegration time less than 71 s. The drug content of all the formulations was within the acceptable limits. Crospovidone shows the shortest disintegration time among super disintegrants while use of subliming agent produced friable tablets. Although use of combination of super disintegrant with MCC decreases disintegration time, the use of co processed super disintegrant (10%CP with 20% MCC) provides the optimum properties of orodispersible tablets (F11). Stability study of selected formula showed no significant changes in tablet properties. &nbsp; Key words:&nbsp;Meclizine hydrochloride, wet granulation method, subliming agent, orodispersible tablet, co process.

Spherical Crystallization as Particle Engineering Technique to Improve Processability of Poor Flowing Furosemide

The pharmaceutical industry is focusing on developing simple and economical formulations to meet desired drug delivery challenges. Tablet continues to be the most popular dosage form. From the manufacturing point of view tablets can be produced at much higher rate than any other dosage forms. The formulation of tablet must be optimized to achieve desired goals. Poor flow of active pharmaceutical ingredient may raise issues like loss of tablet hardness and weight variation. This may restrict the formulator to use granulation techniques or higher levels of lubricants and glidants to impart the flow, which may adversely affect dissolution and compaction. Furosemide is a class IV drug from BCS classification and possesses poor flow properties. The main objective of study was to improve the flow properties of furosemide and thereby improve its solubility leading ultimately improvements in its bioavailability. We used two different techniques of spherical crystallization to improve the flow properties of furosemide. Our results reveal that the spherical crystallization by neutralization technique is better method than wet spherical crystallization to improve the flow properties of furosemide. Flow properties of excipients also affect the compression process. In conclusion, spherical crystallization technique could be used to enhance the flow properties of furosemide.&#x0D;

Influence of physical factors on tablet splitting, weight and content uniformity of atenolol tablets

Tablet splitting is widely practiced worldwide. Several studies have considered weight variation of split tablets as a mean of estimating drug content uniformity but the analysis of their drug content and physical factors that may affect splitting are limited. The aim of this study is to evaluate the impact of manufacturing parameters and splitting on content and weight uniformity of atenolol tablets. Atenolol tablets (100 and 50 mg) were prepared under the same manufacturing conditions and using the same excipients. The obtained tablets were checked for hardness, weight, and disintegration. The weight and the content of the two strength atenolol tablets after splitting into two halves were evaluated. Atenolol tablets (100 mg) showed higher values of hardness, disintegration time and diameter than atenolol tablets (50 mg). Atenolol tablets (100 mg) passed both weight and content uniformity while atenolol tablets (50 mg) failed these tests. Half tablet weight appears to be directly correlated with its drug content. Manufacturers should investigate physical factors such as tablet hardness, diameter, and disintegration time that may play an important role in achieving both weight and content uniformity in the resultant tablet halves.

Effects of release modifier on Carvedilol release from Kollidon SR based matrix

Sustained release Carvedilol matrix tablets constituting Kollidon SR were developed in this study in an attempt to investigate the effect of release modifiers on the release profile of Carvedilol from matrix. Three matrix tablet formulations were prepared by direct compression of Kollidon SR in combination with release modifier (HPMC and Microcrystalline Cellulose) and magnesium stearate. Tablets containing only Kollidon SR with the active ingredient demonstrated a rapid rate of drug release. Incorporation of HPMC in the matrix tablet prolonged the release of drug but incorporation of Microcrystalline Cellulose showed superimposable release pattern with an initial burst effect as confirmed by mean dissolution time and Higuchi release rate data. After 7 hours of dissolution, Carvedilol release from the matrix systems were 91.42%, 83.41%, from formulation F1 and F2 respectively. Formulation F3 exhibited 100 % release at 4 hours. All the tablet formulations showed acceptable pharmaco-technical properties and complied with the in-house specifications for tablet weight variation, friability, hardness, thickness, and diameter. Prepared tablets also showed sustained release property for carvedilol. The drug release mechanism from the matrix tablets of F1 and F2 was found to be followed by Fickian and F3 by Non-Fickian mechanism.DOI: http://dx.doi.org/10.3329/icpj.v1i8.11248 International Current Pharmaceutical Journal 2012, 1(8): 186-192

Effects of release modifier on Carvedilol release from Kollidon SR based matrix

&lt;p&gt;Sustained release Carvedilol matrix tablets constituting Kollidon SR were developed in this study in an attempt to investigate the effect of release modifiers on the release profile of Carvedilol from matrix. Three matrix tablet formulations were prepared by direct compression of Kollidon SR in combination with release modifier (HPMC and Microcrystalline Cellulose) and magnesium stearate. Tablets containing only Kollidon SR with the active ingredient demonstrated a rapid rate of drug release. Incorporation of HPMC in the matrix tablet prolonged the release of drug but incorporation of Microcrystalline Cellulose showed superimposable release pattern with an initial burst effect as confirmed by mean dissolution time and Higuchi release rate data. After 7 hours of dissolution, Carvedilol release from the matrix systems were 91.42%, 83.41%, from formulation F1 and F2 respectively. Formulation F3 exhibited 100 % release at 4 hours. All the tablet formulations showed acceptable pharmaco-technical properties and complied with the in-house specifications for tablet weight variation, friability, hardness, thickness, and diameter. Prepared tablets also showed sustained release property for carvedilol. The drug release mechanism from the matrix tablets of F1 and F2 was found to be followed by Fickian and F3 by Non-Fickian mechanism.&lt;/p&gt;&lt;p&gt;DOI: &lt;a href="http://dx.doi.org/10.3329/icpj.v1i8.11095"&gt;http://dx.doi.org/10.3329/icpj.v1i8.11095&lt;/a&gt;&lt;/p&gt; &lt;p&gt;International Current Pharmaceutical Journal 2012, 1(8): 186-192&lt;/p&gt;

Determination of Segregation Tendency of Granules Using Surface Imaging

In this study, powder surface imaging was utilized in evaluation of particle size-related segregation behavior of granules during vibration and tableting processes. Altogether, eight granule batches were manufactured using a fluidized bed granulator. The particle size distribution of each batch was measured with sieve and image analysis. Segregation tendency of the batches was studied by a vibrational measurement setup. In addition, segregation during tableting was studied by taking samples during the tableting process. Image analysis was utilized to analyze the segregation in both cases. Roughness parameters (Ra) were calculated from images taken during simulation of segregation. In addition, weight variation of tablets was calculated. Finally, principal component analysis was used to visualize the effect of specific particle size fractions on segregation tendency of granules. According to the results, a broad particle size distribution and large particle size can inflict problems during tableting. Surface imaging was an efficient method to monitor the segregation tendency of granules during vibration and tableting. In addition, the segregation tendency of a granular material can be directly linked to weight variation of tablets during tableting and thus be used in a predictive manner.