Physical characterization of HPMC and HEC and investigation of their use as pelletization aids

Croscarmellose Sodium as Pelletization Aid in Extrusion-Spheronization

Only few excipients are known to be suitable as pelletization aids. In this study, the potential use of croscarmellose sodium (CCS) as pelletization aid was investigated. Furthermore, the impact of cations on extrusion-spheronization (ES) of CCS was studied and different grades of CCS were tested. The influence of different cations on the swelling of CCS was investigated by laser diffraction. Mixtures of CCS with lactose monohydrate as filler with or without the inclusion of different cations were produced. The mixtures were investigated by mixer torque rheometry and consequently extruded and spheronized. Resulting pellets were analyzed by dynamic image analysis. In addition, mixtures of different CCS grades with dibasic calcium phosphate anhydrous (DP) and a mixture with praziquantel (PZQ) as filler were investigated. Calcium and magnesium cations caused a decrease of the swelling of CCS and influenced the use of CCS as pelletization aid since they needed to be included for successful ES. Aluminum, however, led to an aggregation of the CCS particles and to failure of extrusion. The inclusion of cations decreased the uptake of water by the mixtures which also reduced the liquid-to-solid-ratio (L/S) for successful ES. This was shown to be dependent on the amount of divalent cations in the mixture. With DP or PZQ as filler, no addition of cations was necessary for a successful production of pellets, however the optimal L/S for ES was dependent on the CCS grade used. In conclusion, CCS can be used as a pelletization aid.

MUPS Tableting-Comparison between Crospovidone and Microcrystalline Cellulose Core Pellets

Multi-unit pellet system (MUPS) tablets were fabricated by compacting drug-loaded pellets of either crospovidone or microcrystalline cellulose core. These pellets were produced by extrusion-spheronization and coated with ethylcellulose (EC) for a sustained drug release function. Coat damage due to the MUPS tableting process could undermine the sustained release function of the EC-coated pellets. Deformability of the pellet core is a factor that can impact the extent of pellet coat damage. Thus, this study was designed to evaluate the relative performance of drug-loaded pellets prepared with either microcrystalline cellulose (MCC) or crospovidone (XPVP) as a spheronization aid and were comparatively evaluated for their ability to withstand EC pellet coat damage when compacted. These pellets were tableted at various compaction pressures and pellet volume fractions. The extent of pellet coat damage was assessed by the change in drug release after compaction. The findings from this study demonstrated that pellets spheronized with XPVP had slightly less favorable physical properties and experienced comparatively more pellet coat damage than the pellets with MCC. However, MUPS tablets of reasonable quality could successfully be produced from pellets with XPVP, albeit their performance did not match that of vastly mechanically stronger pellets with MCC at higher compaction pressure.

Development of a Robust Control Strategy for Fixed-Dose Combination Bilayer Tablets with Integrated Quality by Design, Statistical, and Process Analytical Technology Approach

Control strategy and quality by design (QbD) are widely used to develop pharmaceutical products and improve drug quality; however, studies on fixed-dose combination (FDC) bilayer tablets are limited. In this study, the bilayer tablet consisted of high-dose metformin HCl in a sustained-release layer and low-dose dapagliflozin l-proline in an immediate-release layer. The formulation and process of each layer were optimized using the QbD approach. A d-optimal mixture design and response surface design were applied to optimize critical material attributes and critical process parameters, respectively. The robust design space was developed using Monte Carlo simulations by evaluating the risk of uncertainty in the model predictions. Multivariate analysis showed that there were significant correlations among impeller speed, massing time, granule bulk density, and dissolution in the metformin HCl layer, and among roller pressure, ribbon density, and dissolution in the dapagliflozin l-proline layer. Process analytical technology (PAT) was used with in–line transmittance near-infrared spectroscopy to confirm the bulk and ribbon densities of the optimized bilayer tablet. Moreover, the in vitro drug release and in vivo pharmacokinetic studies showed that the optimized test drug was bioequivalent to the reference drug. This study suggested that integrated QbD, statistical, and PAT approaches can develop a robust control strategy for FDC bilayer tablets by implementing real-time release testing based on the relationships among various variables.

A Comprehensive Review on Pellets as a Dosage Form in Pharmaceuticals

Oral route of administration is widely accepted and desired because of its versatility, convenience, and, most importantly, patient compliance. Multiparticulate systems like granules and pellets are more advantageous when compared to single-unit dosage forms, as they are capable of distributing the drug more evenly in the gastrointestinal tract. The current paper focuses on pellets, the merits and demerits associated, various pelletization techniques, and their characterization. It also focuses on how pellets can be employed for drug delivery is controlled and sustained release formulations. It gives a complete emphasis on the drug and excipients that can be used in pellet formation, the marketed formulations, and the research pertaining to pellets.

Influence of the surface tension of wet massing liquid on the functionality of microcrystalline cellulose as pelletization aid

This study designed to investigate the impact of surface tension of moistening liquid on the functionality of MCC as pelletization aid. For this purpose, sodium dodecyl sulfate (SDS), poloxamer 188 (PL), di-potassium hydrogen phosphate (K₂HPO₄) and combinations thereof were incorporated into the powder blend comprised of MCC and dicalcium phosphate (DCP) at different levels. Physical mixture (PM) and co-processed composite (Cop) of MCC and sodium carboxymethyl cellulose (SCMC) replaced MCC as pelletization aids. The pellets prepared were characterized for their median diameter (D₅₀), particle size distribution (PSD), sphericity, porosity, tensile strength and disintegration. SDS induced a drop in the surface tension of water from 68.7 to 23.7 mN/m at 0.1% (w/w). In contrast, the surface tension values of PL and K₂HPO₄ solutions were 2.08- and 3.07-fold higher than that of SDS solutions, respectively. MCC based pellets obtained with SDS showed wider PSD and lower sphericity than those made with PL, K₂HPO₄ and their combinations. In addition, the PSD and porosity increased with rise of SDS concentration from 0.05 to 0.25% (w/w). It was thus inferred that a critical surface tension of moistening liquid was essential for functionality of MCC as pelletization aid but not for PM and Cop.

Non-aqueous formulations for ram and screen extrusion-spheronisation

The use of non-aqueous cellulose-based formulations for extrusion-spheronisation (E-S) is investigated. A 10 wt% hydroxypropyl cellulose/isopropyl alcohol solution (HPC/IPA) was identified as a suitable sticky liquid binder for preparing non-aqueous pastes. Preliminary tests were performed on a series of pastes using a ram as well as a laboratory roller screen extruder, since the former is commonly used in batch testing and the latter replicates the shear range in a manufacturing screen extruder. Pellets with acceptable size and shape distributions were obtained with Avicel® HFE-102 NF/HPC/IPA for ram E-S, and with Avicel® RC-591/HPC/IPA for screen E-S. Further investigation was performed with calcium carbonate added as a model active pharmaceutical ingredient. Both formulations were able to generate pellets with acceptable size and shape characteristics at up to 50 wt% carbonate loading: further work is required to optimise yields.

Development of oral site-specific pellets containing flavonoid extract with antioxidant activity

Herbal medicines are recognized as an effective treatment of common diseases, mainly associated with oxidative stress. Therefore developing drug delivery systems of these biological active ingredients are gaining interest. Parsley (Petroselinum crispum L.) is a well-known culinary herb and its leaf contains high amount of apigenin, therefore it is suitable as a natural source of this flavonoid. Apigenin possess many health effects such as antioxidant, anti-inflammatory and anticancer activities. Unfortunately, these benefits are limited due to the low water solubility and bioavailability, it was recently classified as BCS II group compound. Therefore the aim of this study was to develop a carrier system for Petroselinum crispum extract, containing high amount of apigenin. Microcrystalline cellulose inert pellet cores were chosen and enteric coatings were applied. The produced multiparticulates had spherical shape, narrow size distribution and low moisture content. 10% (w/w) Eudragit® L 30 D-55 and 15% (w/w) Eudragit® FS 30 D coating was adequate for the modified release in vitro. The layered pellets demonstrated antioxidant activity. It was concluded that development of oral site-specific pellets containing flavonoid extract successful and the therapeutic effectiveness could be hypothesized.

Preparation and physicochemical characterization of matrix pellets containing APIs with different solubility via extrusion process

In this study, a multiparticulate matrix system was produced, containing two different active pharmaceutical ingredients (APIs): enalapril-maleate and hydrochlorothiazide. The critical control points of the process were investigated by means of factorial design. Beside the generally used microcrystalline cellulose, ethylcellulose was used as matrix former to achieve modified drug release ensured by diffusion. The matrix pellets were made by extrusion-spheronization using a twin-screw extruder. Some pellet properties (aspect ratio, 10% interval fraction, hardness, deformation process) were determined. The aim of our study was to investigate how the two different APIs with different solubility and particle size influence the process. The amount of the granulation liquid plays a key role in the pellet shaping. A higher liquid feed rate is preferred in the pelletization process.

Preparation and evaluation of duloxetine hydrochloride enteric-coated pellets with different enteric polymers

The main purpose of the present study was to prepare duloxetine hydrochloride (DXH) enteric-coated pellets using different enteric polymers. Three layers (drug-loaded layer, barrier layer, and enteric-coated layer) were applied to the inert core pellets, successively. The optimal formulation was manufactured by employing suspension layering method in fluidized bed processor (FBP) with varieties of enteric polymers like Aqoat^® AS-LF, Eudragit^® L30D55 and HPMCP-HP55. The prepared pellets were measured for physical characterization and the in vitro dissolution profile. Scanning electron microscopy (SEM) was conducted to observe the morphology of pellets, and different kinetic models were applied to analyze the release mechanism of Cymbalta^® and home-made pellets. The coating weight gain of enteric-coated layer containing Eudragit^® L30D55, Aqoat^® AS-LF and HP-55 were determined to be 35%, 26% and 24%, respectively. The similarity factors (f₂) of self-made capsules with above polymers and commercially available capsules (Cymbalta^®) were above 50 in the dissolution medium of pH 6.8 phosphate buffer solution (PBS). SEM figures showed the smooth surfaces of self-prepared pellets using Eudragit^® L30D55 and Aqoat^® AS-LF, whereas rough surface was found in the HP-55 pellets at day 0, and an impurity was appearing in the condition of 40 °C/75% relative humidity for 1 month. In conclusion, the pellets prepared by utilizing Eudragit^® L30D55 and Aqoat^® AS-LF were the optimal preparations based on the dissolution profile and stability.

Polyacrylamide grafted guar gum based glimepiride loaded pH sensitive pellets for colon specific drug delivery: fabrication and characterization

The purpose of this study was to prepare pH-sensitive pellets using an extrusion-spheronization pelletization (ESP) technique.

Spheronization process particle kinematics determined by discrete element simulations and particle image velocimentry measurements

Spheronization is an important pharmaceutical manufacturing technique to produce spherical agglomerates of 0.5-2mm diameter. These pellets have a narrow size distribution and a spherical shape. During the spheronization process, the extruded cylindrical strands break in short cylinders and evolve from a cylindrical to a spherical state by deformation and attrition/agglomeration mechanisms. Using the discrete element method, an integrated modeling-experimental framework is presented, that captures the particle motion during the spheronization process. Simulations were directly compared and validated against particle image velocimetry (PIV) experiments with monodisperse spherical and dry γ-Al2O3 particles.

RESULT

demonstrate a characteristic torus like flow pattern, with particle velocities about three times slower than the rotation speed of the friction plate. Five characteristic zones controlling the spheronization process are identified: Zone I, where particles undergo shear forces that favors attrition and contributes material to the agglomeration process; Zone II, where the static wall contributes to the mass exchange between particles; Zone III, where gravitational forces combined with particle motion induce particles to collide with the moving plate and re-enter Zone I; Zone IV, where a subpopulation of particles are ejected into the air when in contact with the friction plate structure; and Zone V where the low poloidal velocity favors a stagnant particle population and is entirely controlled by the batch size. These new insights in to the particle motion are leading to deeper process understanding, e.g., the effect of load and rotation speed to the pellet formation kinetics. This could be beneficial for the optimization of a manufacturing process as well as for the development of new formulations.

Moistening liquid-dependent de-aggregation of microcrystalline cellulose and its impact on pellet formation by extrusion-spheronization

The wet-state particle size of microcrystalline cellulose (MCC) dispersed in different moistening liquids was characterized to elucidate the effect of moistening liquid type on the extent of MCC particle de-aggregation. Cohesive strength of moistened MCC masses was also assessed and pellet production by extrusion-spheronization attempted. MCC dispersed in alcohol or water-alcohol mixtures with higher alcohol proportions generally had larger particle sizes. Moistened mass cohesive strength decreased and poorer quality pellets were obtained when water-alcohol mixtures with higher alcohol proportions were used as the moistening liquid. MCC comprise aggregates of small sub-units held together by hydrogen bonds. As MCC particle de-aggregation involves hydrogen bond breaking, moistening liquids with lower polarity, such as water-alcohol mixtures with higher alcohol proportions, induced lesser de-aggregation and yielded MCC with larger particle sizes. When such water-alcohol mixtures were employed during extrusion-spheronization with MCC, the larger particle size of MCC and lower surface tension of the moistening liquid gave rise to moistened masses with lower cohesive strength. During pelletization, agglomerate growth by coalescence and closer packing of components by particle rearrangement would be limited. Thus, weaker, less spherical pellets with smaller size and wider size distribution were produced.

Influence of starting material particle size on pellet surface roughness

The purpose of this study was to investigate the effect of pelletization aids, i.e., microcrystalline cellulose (MCC) and cross-linked polyvinyl pyrrolidone (XPVP), and filler, i.e., lactose, particle size on the surface roughness of pellets. Pellets were prepared from powder blends containing pelletization aid/lactose in 1:3 ratio by extrusion-spheronization. Surface roughness of pellets was assessed quantitatively and qualitatively using optical interferometry and scanning electron microscopy, respectively. Both quantitative and qualitative surface studies showed that surface roughness of pellets depended on the particle size of XPVP and lactose used in the formulation. Increase in XPVP or lactose particle size resulted in rougher pellets. Formulations containing MCC produced pellets with smoother surfaces than those containing XPVP. Furthermore, surface roughness of the resultant pellets did not appear to depend on MCC particle size. Starting material particle size was found to be a critical factor for determining the surface roughness of pellets produced by extrusion-spheronization. Smaller particles can pack well with lower peaks and valleys, resulting in pellets with smoother surfaces. Similar surface roughness of pellets containing different MCC grades could be due to the deaggregation of MCC particles into smaller subunits with more or less similar sizes during wet processing. Hence, for starting materials that deaggregate during the wet processing, pellet surface roughness is influenced by the particle size of the material upon deaggregation.

Preparation and characterization and release properties of Eudragit RS based ibuprofen pellets prepared by extrusion spheronization: effect of binder type and concentration

OBJECTIVE

The effects of type and concentration of binding agent on properties of Eudragit RS based pellets were studied.

MATERIALS AND METHODS

Pellets containing ibuprofen (60%), Eudragit RS (30%), Avicel (10%) were prepared by extrusion spheronization. PVP K30, PVP K90, HPMC 6cp, HPMC K100LV or HPMC K4M were used as binders in concentrations of 2, 4 or 6% based on the total weight of formulation. The process efficiency, pellet shape, size distribution, crushing strength, elastic modulus and drug release were examined. The effect of curing on pellet properties was also investigated.

RESULTS

The process of extrusion spheronization became difficult with increase in binder viscosity and/or concentration. An increase in binder viscosity and/or concentration resulted in reduction in the yield of pellets, wider particle size distribution and departure from spherical shape especially in the case of HPMC binder. The crushing strength and elastic modulus of pellets decreased with increase in PVPs concentration. However this was not the case for pellets containing HPMCs. Drug release rate increased as the concentration of binder increased. Pellets containing 2%w/w of PVP K30 showed the slowest release rate. For those pellets with brittle nature, curing changed the behavior of pellet under mechanical test to plastic deformation. Yield point and elastic modulus of all formulations decreased after curing. Curing decreased the drug release rate.

CONCLUSION

Binder type and concentration significantly affected the properties of pellets. For production of sustained release ibuprofen Eudragit RS based pellets lower viscosity binders (PVP K30) with concentrations less than 4%w/w was optimum.

Quantification of mass transfer during spheronisation

Spherical granules (pellets) are quite useful in many pharmaceutical applications. The extrusion spheronisation technique is well established as a method of producing pellets of a spherical shape and narrow size distribution. After the extrusion, the cylindrical extrudates are transformed to spherical pellets by spheronisation. The frequently used models consider deformation and breakage during this process. However, the adhesion of fine particles has been neglected as a mechanism in spheronisation for many years. This study quantifies the mass transfer between pellets during spheronisation. During the investigation, the pelletisation aids (microcrystalline cellulose and kappa-carrageenan), the drug (acetaminophen and ibuprofen) and water content were varied systematically. A novel parameter, namely, the "mass transfer fraction" (MTF), was defined to quantify the mass transfer between the pellets. All four investigated formulations had an MTF between 0.10 and 0.52 that implies that up to 50 % of the final pellet weight was involved in mass transfer. Both pelletisation aids showed similar MTF, independent of the drug used. Furthermore, an increase of the MTF, with respect to an increase of the water content, was found for microcrystalline cellulose formulations. In conclusion, the mass transfer between the pellets has to be considered as a mechanism for spheronisation.

Melt-in-mouth pellets of fexofenadine hydrochloride using crospovidone as an extrusion-spheronisation aid

Microcrystalline cellulose (MCC) is well established as an extrusion spheronisation aid for the preparation of pellets. Crospovidone (Polyplasdone XL-10) is compared with microcrystalline cellulose for the preparation of melt-in-mouth pellets. Taste-masked fexofenadine hydrochloride was incorporated in the melt-in-mouth formulation. Crospovidone was found to be well suited as extrusion-spheronisation aid for the preparation of melt-in-mouth pellets. The great advantage of crospovidone is, however, the disintegrating properties of the pellets after only a short time of exposure to liquid. Crospovidone was successfully employed as an extrusion-spheronisation aid to produce melt-in-mouth pellets obviating the need of a traditional extrusion-spheronisation aid, MCC. Dual properties of Crospovidone were explored viz. as an extrusion-spheronisation aid and a disintegrant.

The influence of Surelease and sodium alginate on the in-vitro release of tamsulosin hydrochloride in pellet dosage form

The objective of this study was to prepare controlled-release pellets containing 0.2 mg tamsulosin hydrochloride using a pelletizer-equipped piston extruder and double-arm counter-rotating rollers with Surelease and sodium alginate. The release of tamsulosin HCl from pellets coated with the commercial aqueous ethylcellulose dispersion (Surelease) was investigated at different coating loads. In addition, the effect of sodium alginate on drug release was investigated by varying the ratio of sodium alginate to microcrystalline cellulose (MCC). Dissolution studies were first performed in 500 mL simulated gastric fluid (pH 1.2) containing 0.003% (w/w) polysorbate 80 and then in simulated intestinal fluids (pH 7.2). The morphology of pellet surfaces and cross sections were examined by scanning electron microscopy (SEM). Apparently, the spherical pellets were prepared using a pelletizer-equipped piston extruder and double-arm counter-rotating rollers. The release profiles of tamsulosin HCl from Surelease-coated pellets were significantly affected by changing the content of Surelease, the pH of the dissolution medium and the ratio of sodium alginate to MCC. The drug release rates not only decreased with increase in the coating load, but also increased when the pH of the dissolution medium was increased from 1.2 to 7.2 regardless of the sodium alginate-to-MCC ratio. Moreover, the drug release rate at pH 7.2 was gradually increased by increasing the ratio of sodium alginate to MCC. SEM showed smooth surfaces of Surelease-coated pellets. These results suggest that Surelease and sodium alginate would be useful excipients in the preparation of controlled-release pellets with the desired release profiles.

Investigation on drug dissolution and particle characteristics of pellets related to manufacturing process variables of high-shear granulation

There is a growing interest for multiparticulate solid dosage forms such as pellets, because of their several advantages over tablets during drug therapy. It is essential to investigate the drug dissolution process which can be influenced by the composition and manufacturing process technology, too. This study was performed applying experimental design in order to evaluate the effects of independent process variables during high-shear pelletisation, taking the impeller speed (x1) and granulation binder flow rate (x2) as factors into consideration. Theophylline containing pellet formulation was prepared using a matrix consisted of ethylcellulose, microcrystalline cellulose and lactose. Dissolution profiles were modeled by the Weibull function to evaluate the power of process variables. Both process variables were powerful to influence the particle agglomeration. A linear regression was found between the particle size and the diffuse reflectance values after the Kubelka-Munk transformation. Differences in the diffuse reflectance spectra of pellet samples related to particle size offer a fast instrumental method for the in-process control.

Functionality of Cross-Linked Polyvinylpyrrolidone as a Spheronization Aid: A Promising Alternative to Microcrystalline Cellulose

PURPOSE

This work seeks to explore and demonstrate the functionality of cross-linked polyvinylpyrrolidone (crospovidone) as a spheronization aid and a promising alternative to microcrystalline cellulose (MCC).

METHODS

Pellets were prepared with various grades of crospovidone using both small- and large-scale extrusion-spheronization. A Box-Behnken experimental design was employed to elucidate the effects of operating variables on the quality of the pellets. Size and shape analyses of these pellets were conducted and compared to those prepared using MCC.

RESULTS

Crospovidone was believed to behave like a liquid repository in its interaction with water during extrusion-spheronization, although its binding ability was weaker than that of MCC. Spherical pellets of narrow size distribution could be made from the finer crospovidone grades with different lactose grades. However, crospovidone-based formulations required higher water levels than weight-equivalent MCC-based formulations. Crospovidone pellets were of equivalent quality to those prepared with MCC, especially in the shape, size, and yield.

CONCLUSIONS

Crospovidone can be successfully employed as a spheronization aid to produce good pellets without the need of a binder, unlike most of the previously proposed materials. This study exemplified the enormous potential of crospovidone to serve as a competent alternative to MCC in the production of pellets by extrusion-spheronization.

Starch–dextrin mixtures as base excipients for extrusion–spheronization pellets

Extrusion-spheronization pellets are generally produced with microcrystalline cellulose (MCC) as the principal excipient, giving rise to particles of very high quality. A number of alternative excipients have been proposed and evaluated, mostly other cellulose derivatives (e.g. different grades of Avicel), or mixtures of MCCs and other excipients. In the present study, we evaluated the possible use of starch+agglutinant mixtures as principal excipients for extrusion-spheronization pellets, with the aim of producing pellets with more suitable properties for certain types of release. We first characterized the different excipients in terms of morphometry and basic physical properties. Subsequently, torque-rheometry was used to characterize the rheology of wetted masses of the different excipients and excipient mixtures, with the aim of determining optimal amount of wetting agent (water). We also evaluated the water absorption and water retention capacities of each excipient. In view of the results obtained, we produced pellets with the different starch+agglutinant mixtures (but without drug), and used image analysis to characterize pellet morphology. Our results show that some of the mixtures-notably starch (corn starch or wheat starch)+20% white dextrin-gave high-quality pellets with good size and shape distributions. In addition, the properties of the different materials tested suggest that it may be possible to obtain pellets with very different properties.

Study of effect of excipient source variation on rheological behavior of diltiazem HCl-HPMC wet masses using a mixer torque rheometer

In the wet massing of powders and powder blends, the rheological behavior of the wet powder masses not only plays a critical role in the unit process but also influences the attributes of the product. The physical properties of the powder excipients, such as particle size and size distribution, shape, surface area, bulk and tapped density and surface morphology, are a major source of variability in the rheological behavior of wet powder masses and the quality attributes of the final product. The objective of the present investigations was to study the rheological behavior of wet masses containing hydroxypropyl methylcellulose (HPMC) obtained from two sources (Methocel from Dow and Pharmacoat from Shin-Etsu) using a mixer torque rheometer. In order to simulate a real formulation, diltiazem HCl (DTZ) (40% loading) was used as part of the substrate powder mass. Hydroxypropyl cellulose (HPC) was used as the binder. Since HPMC is water-soluble, isopropyl alcohol (IPA) was used as the wet massing liquid. The rheological behavior of the wet powder masses was studied as a function of mixing time and amount of wet massing liquid (IPA). The rheological profiles obtained for DTZ-Methocel and DTZ-Pharmacoat exhibited same magnitude for mean torque, however, for DTZ-Pharmacoat the peak was more extended than that for DTZ-Methocel. The extended peak for DTZ-Pharmacoat indicated that the wet mass will stay suitable during the process for larger quantities of the wet massing liquid before turning into paste and becoming unsuitable for the process as compared with the DTZ-Methocel system. The mixing kinetics of the two powder systems appeared to be quite different. These differences in the rheological behavior of the wet masses may be attributed to the difference in the particulate and surface properties of the two HPMCs. Some of the properties of the two HPMCs, such as particle size and size distribution, surface area, surface morphology and DSC thermograms, explain the difference observed in their rheological behavior. The difference in the rheological profiles of the two DTZ-HPMC systems indicated superiority of Pharmacoat over Methocel considering their wet massing behavior.

Extrusion and spheronization in the development of oral controlled-release dosage forms

The concept of multiparticulate dosage forms was introduced in the 1950s. With the increasing use of multiparticulate controlled release (CR) oral dosage forms, in recent times there has been a rise in interest in the methods of preparing these dosage forms. A method that has gained increased usage over the past few years is that of extrusion and spheronization. It has been extensively explored as a potential technique and also as a future method of choice for preparation of multiparticulate CR dosage forms. In this review an attempt is made to outline the general process of extrusion and spheronization and to assess its importance in the development of multiparticulate CR oral dosage forms.