Direct Tablet Research Articles

The changes in the Mechanic Properties of a direct tableting agent Microcrystalline Cellulose by Precompression

AbstractIn the manufacturing of tablets, direct tableting agents are not only used in direct compression, but are also used in wet granulation and slugging methods. These agents are effective only if their particle size and form is appropriate. However, the precompression, milling and grinding which are applied in the slugging method changes the particular properties of these agents.In this study, microcrystalline cellulose tablets were prepared both by direct compression and slugging. The consolidation, compressibility and flow properties of the two mixed powders were compared. Finally, it was observed that the compressibility of the mixed powder was influenced negatively by the slugging method.

Calcium phosphates in pharmaceutical tableting. 1. Physico-pharmaceutical properties.

Ten commercially available calcium phosphates used for direct tableting were evaluated. The particle size distributions, powder properties, sorption isotherms and pH values of aqueous slurries were compared. All samples showed good or at least sufficient flowability. Scanning electron micrographs illustrated the different kinds of manufacturing and gave hints on their expectable behaviour under compaction pressure. The sorption isotherms of identical chemical substances, which had been manufactured by different methods, differed strongly. This can be related to their specific surface areas. Most of the hydroxylapatites have large surface areas and can absorb up to more than 15% water at 93% relative humidity. Dibasic calcium phosphate dihydrate was non-hygroscopic and absorbed less than 1% water. With the exception of monobasic calcium phosphate monohydrate all calcium phosphates behaved quite neutral in water. Monobasic calcium phosphate monohydrate can be regarded as a solid acid. Although the calcium phosphates are usually stable substances, the role of crystal water in the case of dibasic calcium phosphate dihydrate and monobasic calcium phosphate monohydrate is problematic due to possible interactions with active ingredients.

Excipient ability of chitosan for direct tableting

This paper describes an investigation of the usefulness of krill chitosan in the production of tablets that meet the standard requirements following long-term storage; 49% (A) and 66% (B) deacetylated chitosans were used. Examination of the granulometric and flow properties of multi-component mixtures containing B and testing of the direct compressibility of chitosan B and B mixtures showed that chitosan fulfills the general requirements for auxiliary substances in the process of direct tableting. When used as a filter or binder, chitosan did not affect mass flow; however, on addition in the proportion of 50% of tablet mass, rapid tablet disintegration resulted. Following long-term storage, tablets produced with the addition of B may be less resistant mechanically (tablet hardness decreases), nevertheless, the tablet disintegration time either remains unaffected or even decreases.

トルブタミド錠の生物学的利用能の向上と小型化をめざした直接打錠用結晶の設計法の開発

トルブタミド錠の生物学的利用能の向上と小型化をめざした直接打錠用結晶の設計法の開発

Antimycotic buccal and vaginal tablets with chitosan

On the basis of the biomedical properties of 66% deacetylated krill chitosan, formulations of tablets containing nystatin or clotrimazole were prepared. Tablets obtained by direct compression disintegrate either slowly in water (buccal), or rapidly in a 0.1% lactic acid solution (vaginal). The stability of the tablet properties, as well as the microbiological and chemical stability of the applied drugs, both recorded after storage, considerably extend the applicability of chitosan as an auxiliary substance for use in direct tableting.

Evaluation of maltodextrins as excipients for direct compression tablets and their influence on the rate of dissolution

The maltodextrins Maltrin M700, M500 and M150 have been evaluated as excipients for direct tablets and their influence on the rate of dissolution was examined. The amount of lubricant appears to play an important role and significantly affects and rate of releasel of drug from the tablet, particularly when the drug is insoluble in water, while the release rate of a soluble drug remains unaffected. All the formulations prepared showed excellent flow and compressibility. Storage of the tablets for 90 days at 45°C was found to have almost no influence on their properties.

Particle Design for Antidiabetic Drugs by the Spherical Crystallization Technique. IV. Assessment of Compressibility of Agglomerated Tolbutamide Crystals Prepared by Crystallization Technique.

Three different crystallization methods, i.e., the solvent change (SC) method, neutralization (NT) method and quasi-emulsion solvent diffusion (QESD) method, were employed to prepare agglomerated tolbutamide crystals (referred to as SC-A, SC-B, NT and QESD). Each of the agglomerated crystals or unagglomerated tolbutamide crystals (abbreviated as bulk) alone (single formulation), magnesium stearate (MgSt; a lubricant)-added single formulation sample (formulation A), and Kollidon CL (a disintegrating agent)-added formulation A samples (formulation B) were compacted into tablets by the direct tableting method. With the objective of elucidating the compressibility of these samples, the following parameters were analyzed : (1) the course of change in the powder bed volume as a function of the applied compression pressure, (2) the pressure-transmission ratio from the upper punch to the lower punch, (3) the course of decompression (ejection force) and (4) the tensile strength of the tablets determined by the diametric compression method. The results of each sample were compared.For each of the single-formulations, formulation A and formulation B, Kawakita's equation was able to be applied to each stage of the compaction process over the tested compression pressure range of 50-1500kg/cm2. The limiting value of the compaction ratio of the samples was higher in the order of SC-B>NT>SC-A>QESD>bulk, and each agglomerate showed much higher compressibility than the bulk. Although the agglomerates and bulk showed the same pressure-transmission ratio from the upper punch to the lower punch, the bulk showed a smaller ejection force during decompression. The agglomerates, whose primary crystal diameter is small, showed much larger tensile strength of the compacted tablet than the bulk. The addition of MgSt improved the compaction process, but it weakened the tensile strength of the compacted tablets, especially in the case of the bulk. The addition of Kollidon CL decreased the ejection force due to a decrease in the adhesion force of the tablet to the surface of the die wall. Because Kollidon CL suppressed the effect of MgSt, the tensile strength of the compacted tablets was increased.The above results revealed that the compressibility of the agglomerates, especially SC-B and NT, is much superior to that of the bulk, and that these agglomerates have the properties necessary for direct tableting. Moreover, formulation B was suggested to be useful as a practical formulation for direct tableting.

新規エマルション‐溶媒‐拡散法による直接打錠を目指した付着凝集性薬剤粉末の粒子設計

The novel emulsion-solvent-diffusion technique developed by the authors was proved to be a versatile particle design method to improve the particulate properties of adhesive pharmaceutical powders for direct tabletting, irrespective of the crystallization solvent system employed, viz. miscible or immiscible good-poor solvent system. The spherically designed agglomerates of the crystals with the miscible solvent system were free flowing and easily packable into a die, which were directly compressed into a tablet without any capping even at higher compression pressure. This excellent compressibility was attributed to the preferable stress relaxation that occurred rapidly after the compression, indicating the plastic behavior of the agglomerated crystals under the compression.

Comparing the Compressibility of Ludipress with the Other Direct Tableting Agents by Using Acetaminophen as an Active Ingredient

AbstractLudipress is a direct tableting agent which acts as an unique component, is really a multi component. In this study Ludipress compressibility and powder technological properties are compared with the other kind of DC agents (Avicel PH 102, Elcema G 250 and Elcema P 050) which are structurally based on cellulose. Acetaminophen has been chosen as an active ingredient.The compression properties of powders and three direct tableting agent were investigated using the Heckel and Kawakita equations. Each formulations and compressed tablets which are compacted by hydraulic press with different pressure value were photographed by scanning electron microscope.As a result Ludipress shows stable flow properties and the dilution potential of Ludipress is lower than the other DC agents.

Prediction of Tablet Properties by Compression Force-Time Profile Parameters

AbstractThe compression force-time profile parameters proposed by Chilamkurti el al. (1) have proved to be no better than maximum compression force for prediction of the properties of three series of direct compression microcrystalline cellulose tablet formulations containing various proportions of prednisone, phenobarbital or isoniazide and punched under various compression forces. The usefulness of the Chilamkurti parameters is nevertheless not ruled in the case of formulations for which maximum compression force has little predictive value.

Degrees of crystallinity and polymerization of modified cellulose powders for direct tableting

The degrees of crystallinity and of polymerization of 21 celluloses used in direct tableting were determined, using X-ray diffraction and viscosimetry respectively. The crystallinity of the microcrystalline celluloses varied widely from one product to another. Average degrees of polymerization were less than the usually accepted value of the “level-off degree of polymerization”. Degrees of crystallinity of powdered celluloses were generally lower than those of microcrystalline celluloses, although some were as high as those of certain hydrolyzed samples. Degrees of polymerization of powdered celluloses did not differ as much as those of microcrystalline celluloses. The observed ranges for both parameters were wider than previously reported; the differences could be explained by structural considerations.

Evaluation of Some Properties of Powder Mixtures

AbstractFollowing previous work on the relation between tablet weight variation and the measured flow properties of direct tabletting vehicles, a study was made on binary powder mixtures. Two different tablet vehicles were used, Dipac and lactose while the added drug was fine aspirin.Flow properties of various mixtures (up to 40% aspirin by weight) were measured in a Flow Factor Tester and tablet weight variation was also established. It was found that little inter-relationship exists between the shear cell parameters (flow factor and effective angle of friction) and the coefficient of tablet weight variation. It is suggested that one reason for the lack of correlation is the mixtures are complex and in addition have angles of friction which vary considerably with consolidating load.

Application of gluconolactone in direct tablet compression.

Gluconolactone was evaluated as an excipient for tablets prepared by direct compression using various drugs known to be difficult to compress. The physical properties of the tablets were evaluated after compression and after storage and were satisfactory. Comparative studies were conducted between gluconolactone and anhydrous lactose, a common direct compression diluent, for development of static charges during blending, flow, drug distribution, drug stratification, color distribution, compressibility, and preservation against mold growth. Gluconolactone possesses those properties necessary to produce high quality tablets by the direct compression process. Separate powdered mixtures of aspirin USP with gluconolactone, anhydrous lactose, spray-dried lactose, mannitol, and sorbitol were stored at various humidities and temperatures for specified periods and tested for the integrity of aspirin. Gluconolactone contributed least to the degradation of the drug as compared to other excipients studied. A preliminary in vivo study also was conducted on the bioavailability of aspirin from separate and similar mixtures with gluconolactone, anhydrous lactose, and starch. Gluconolactone did not show any inhibitory effect on aspirin absorption.

Compressional Properties of some Directly Compressed Griseofulvin Tablet Formulations

AbstractAs an extension of previously reported work on the formulation of direct compression griseofulvin tablets studies were conducted on an instrumented tablet press to determine the relationship between applied compression force, ejection force and tablet weight, thickness, apparent density. hardness (Frweka), and disintegration time. Quantitative data is included on the use of Emcompress(R) in direct compression griseofulvin tablets.

Direct tableting of piperazine adipate

Direct tableting of piperazine adipate

Anhydrous Lactose in Direct Tablet Compression

The use of anhydrous lactose U.S.P. XVII, tablet grade, as a diluent in direct tablet compression was investigated. It was found that it possesses excellent tableting properties and can be run on a high-speed tablet machine. The placebo and active tablets produced were not affected by elevated temperatures, high humidity, and direct sunlight.