Color Stability of Ascorbic Acid Tablets Measured by Tristimulus Colorimeter

The influence of three different tableting diluents and three different forms of ascorbic acid on the color change of vitamin C have been investigated. Ten different direct compression formulations were made and subjected to accelerated stability study. Color changes in tablets were monitored with a Tristimulus Colorimeter. It has been found that lactose and Emdex influenced the color change of direct compression ascorbic acid tablets to a lesser degree than Sorbitol. Further, Calcium Ascorbate brought changes in the color of the tablets at a faster rate than C-90 or Sodium Ascorbate. A good correlation of 0.998 was found for a linear relation of visual color rating against normalized total color difference values of these tablets.     

Gamma Sorbitol as a Diluent in Tablets

Abstract

Several crystal structures of Sorbitol may be encountered. Eleven Sorbitol samples from five different manufacturers were studied by X Ray diffraction and differential scanning calorimetry. Three crystalline forms were identified. The γ form is the most stable. One of these samples was constituted by the pure γ form.

Sorbitol is usually considered as a very hygroscopic excipient. We studied this most stable Sorbitol for its technological and biopharmaceutical properties in tablet formulation.

Aspirin and Acid Ascorbic tablets were prepared with γ Sorbitol as a diluent, in high concentration, by direct compression. Three disintegrants were tested: maize starch, Kollidon CL^R, Ac Di Sol^R. Using either lactose or γ Sorbitol as a diluent, different batches of tablets were prepared with the same proportion of diluent and in the same conditions.

Compression properties, hardness, disintegration time, dissolution rate and stability in moist conditions were studied.

The tablets containing γ Sorbitol show:

- a better ratio compression force/hardness

- a longer time of disintegration and dissolution

- the very great importance of the choice of the disintegrant: Ac Di Sol was much better than Kollidon CL or Maïze starch in this case of formulation: conserved during one year at 80% Relative Humidity, tablets with γ Sorbitol and Ac Di Sol kept their aspect and their biopharmaceutical properties very well. A slightly greater acid ascorbic alteration with Sorbitol as a diluent than with lactose can be noticed.

It seems that γ Sorbitol is a stable diluent if the Relative Humidity is lower than 80%. Then it should be avoided with drugs too sensitive to moisture like ascorbic acid.

In spite of a slower release time, its hardening power and its very good compression properties can be of great interest.     

Stability of Ascorbic Acid-Zinc Sulphate Tablets

Abstract

Microencapsulation using ethylcellulose and embedding in stearic acid or polyethylene glycol 6000 have been employed to protect ascorbic acid from metallic ion catalysed oxidation in tablets containing zinc sulphate. It is observed that presence of Zn in the tablets do not affect stability of ascorbic acid even at accelerated storage conditions provided the moisture content is controlled.     

Aging of Tablets Prepared by Direct Compression of Bases with Different Moisture Content

Abstract

Properties of aged tablets prepared by the wet granulation method were found to be affected by the moisture content of the granules. In this study, the storage-induced changes in hardness, disintegration and drug release were evaluated for tablets made by direct compression of three different bases with different initial moisture content. Tablets with high initial moisture content were found to increase in hardness upon storage. The magnititude of such increase is dependant upon the physical properties of the base and the absolute moisture content. The increase in hardness may increase the disintegration time and decrease drug release. Tablets with low initial moisture content were minimally affected by storage. The gain of moisture by some of these tablets led to enhancement in disintegration and drug release. Among the tablets studied lactose based tablets with different initial moisture content were found to be the most resistant to changes upon storage.     

Preparation and In-Vitro Evaluation of Powder Solution Tablets of Valproic Acid

Abstract

A tablet dosage form of liquid valproic acid (VPA) was formulated using powder solution technology as an alternative to the manufacturing of soft elastic gelatin capsules (SEGs). Mixing of liquid VPA with suitable adsorbents followed by blending with other excipients resulted in a non-adherent, free flowing powder. Tableting was achieved through standard direct compression. The tablets were acceptable in terms of physical properties. Film coated tablets (FCTs) and sugar coated tablets (SCTs) were also prepared. The in-vitro dissolution rates of these VPA tablets were significantly greater than that of a marketed SEG product. There was no significant change in the dissolution rates of the plain and FCTs after storage under accelerated stability conditions. Powder solution technology was a viable alternative to the commercial preparation of SEGs.     

Adhesion of Tablets in a Rotary Tablet Press II. Effects of Blending Time,Running Time,and Lubricant Concentration

Abstract

Of the three essential functions of tablet lubricants, only the true lubricant and glidant properties have been studied in detail by objective means. Only recently has instrumentation which permits the objective measurement of the antiadhesion activity in a rotary tablet press been developed. Using a rotary press instrumented to measure the adhesion of tablets to the lower punch face, this study focuses on the adhesion of tablets in two direct compression systems. At any given compression force, adhesion of microcrystalline cellulose tablets lubricated with magnesium stearate appeared to decrease with increases in blending time or intensity of blending. Over a three-hour running time, adhesion force was found to increase to peak values and then to decline with both microcrystalline cellulose and hydrous lactose lubricated with magnesium stearate. However, ejection forces decreased gradually to apparently limiting values in each case. The adhesion of tablets to the lower punch face appeared to be affected partly by the condition of the tablet - die wall interface. Studies comparing lubricated and unlubricated microcrystalline cellulose suggest two opposing effects on tablet adhesion: (1) enhancing adhesion due to an increased reaction at the lower punch resulting from reduced die wall friction; and, (2) reducing the adhesion of tablets via the “antiadherent” effect. At the lubricant levels studied, stearic acid generally appeared to be less efficient than magnesium stearate in reducing both the adhesion and ejection forces in microcrystalline cellulose blends. However, with hydrous lactose blends, the true lubricant and antiadherent activities of stearic acid appeared to be greater than those of magnesium stearate at the 1.00% level of addition.     

Effect of Storage Conditions on The Physical Properties and In Vitro Dissolution of Directly Compressed Tablets

Abstract

Tablets of aspirin, ascorbic acid and pyridoxine hydrochloride were prepared by direct compression, using bone powder or Emcompress, respectively as direct compression fillers. Tablet properties such as mean weight, thickness, breaking strength and friability were monitored before and after storage for 30 days under specified temperature and relative humidity conditions. The tablet properties were apparently unaffected by the conditions of storage, while release parameters were, however, modified. In vitro dissolution rate constant, was found to exhibit good correlation with the dissolution efficiency.     

Ontrolled-Release Theophylline Tablet Formulations Containing Acrylic Resins. I. Dissolution Properties of Tablets

Abstract

The dissolution properties of controlled-release theophylline tablets containing acrylic resins are presented. Four different resins (Eudragit RSPM, RLPM, Sl00 and Ll00) were incorporated into theophylline tablets by direct compression techniques and the properties of the resulting dosage form were evaluated in dilute acid, buffer media pH 4.0 and simulated intestinal media pH 7.5. Tablets (500 mg) containing 300 mg of theophylline were prepared with each of the four resins and compressed to a hardness level of 6.5 to 7.5 kg. Excellent flow properties, weight uniformity and drug content uniformity were observed with all tablet formulations. Preliminary data suggest that three of the four resins tested showed great promise as a retardant in a matrix controlled drug delivery system. The dissolution properties of three commercially available sustained-release theophylline tablets were also determined. A comparison of profiles from Theodur^R (300 mg) in acid and simulated intestinal media showed a similarity in release properties to those of theophylline in tablets containing the RLPM resin.     

Preparation and Properties of Tablets Prepared from Furosemide-PVP Solid Dispersion Systems

Abstract

Tablets were prepared from the solid dispersion of furosemide: PVP by using different techniques such as direct compression and double compression. The results were compared with similar tablets prepared by physical mixture. Direct compression was much prefered, as it provided tablets with acceptable mechanical and physical qualities. On the other hand, the choice of disintegrant is very important in the formulation of furosemide: PVP solid dispersed tablets. With Kollidon CL, the best result was obtained. Disintegration mechanism of this system was also discussed. The other effective factor is the particle sizes of coprecipitates. Fine particle exhibited compression difficulty. The drug release from these tablets was 17 times greater than that from tablets prepared from physical mixture.     

Gas chromatographic determination of oxazepam from tablets and micro capsules in urine

Abstract

Three new and two commercially available sugar matrices were comparatively evaluated for several fundamental properties of direct compression powder systems. These properties included: particle size distribution, powder flow (determined by a recording powder flow meter), bulk density and moisture content. The matrices studied were Dipac, Nutab, and California and Hawaiian (C & H) Products A, B, and C. These matrices were formulated into chewable ascorbic acid, multivitamin, and antacid tablets, and analyzed for: weight uniformity, thickness, diameter, hardness, disintegration, resistance to impact stress, friability, dissolution and effect due to aging.

The data obtained showed that the new products (C & H products) were comparable, and in some cases, even superior to the commercially available ones.     

Investigation of Ethylcellulose as a Matrix Former and a New Method to Regard and Evaluate the Compaction Data

Abstract

Three types of ethylcellulose—having different molecular weights, i.e., different viscosity grades (7, 22, 50 cP)-were used for our polymer compression tests for the production of matrix tablets. The production methods used were direct compression and wet granulation. We tested the compactability, the compressibility, and the energy involved in compaction by the use of F-D curves and the controlled drug release from the ethylcellulose matrix tablets using the above-mentioned methods. A lower viscosity grade in ethylcellulose is more compressible than the higher grade. Wet-granulated ethylcellulose also shows a better compactibility than directly compressed ethylcellulose. Our investigation indicates also that the dissolution rates are indirectly proportional to the hardness of the tablets. Furthermore, wet-granulated tablets produce a more rapid drug release than those which are directly compressed.     

Factors Influencing the Release of Aminophylline from Tableted Ethylcellulose Microcapsules

Abstract

Microcapsules containing aminophylline cores in ethylcellulose walls have been prepared and tableted. The mechanical properties and the release characteristics of tablets obtained by direct compression at six different pressures (ranging from 265 to 1060 Kg.cm^?2) were studied. The release rate of the drug from tableted microcapsules increased with the increase of compression force and was higher than from uncompressed microcapsules, indicating that some damage of the polymeric wall occurred during the compression process. Among the various excipients tested as binding and protective agents, paraffined starch (a mixed system appositely set up) gave the best results, producing the slowest drug release rate. No important effect on drug release rate was found by changing the size of the microcapsules.     

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

Abstract

Ludipress 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.     

Comparative Evaluation of Several Direct Compression Sugars II

Abstract

The formulation efficiency of several sucrose based direct compression vehicles has been evaluated. The effect of compression force on various fundamental tablet properties has been investigated.

It has been observed that even chemically similar matrices may show differences in formulation efficiencies if there are subtile changes in the structure of the particles.

A simple method for evaluating acid neutralizing efficiency of antacid tablets, particularly when aging is concern, has been presented.     

Comparative Evaluation of Several Direct Compression Sugars

Abstract

Three new and two commercially available sugar matrices were comparatively evaluated for several fundamental properties of direct compression powder systems. These properties included: particle size distribution, powder flow (determined by a recording powder flow meter), bulk density and moisture content. The matrices studied were Dipac, Nutab, and California and Hawaiian (C & H) Products A, B, and C. These matrices were formulated in to chewable ascorbic acid, multivitamin, and antacid tablets, and analyzed for: weight uniformity, thickness, diameter, hardness, disintegration, resistance to impact stress, friability, dissolution and effect due to aging.

The data obtained showed that the new products (C & H products) were comparable, and in some cases, even superior to the commercially available ones.     

Should Magnesium Stearate be Assessed in the Formulation of Solid Dosage Forms by Weight or by Surface Area ?

Abstract

Three batches of magnesium stearate differing in morphology, particle size, bulk density and specific surface area were compared in the preparation of Pyrazinamide direct compression tablets. When the lubricants were used in the same amount they gave rise to tablets differing in hardness, disintegration and dissolution. When they were used in such amounts to develop equivalent lubricating areas, the final characteristics of the tablets were almost identical. A direct correlation was found between lubricating areas and ejection force.     

The Effect of Lubricants on the Properties of Chloroquine Phosphate Tablets

Abstract

The properties of tablets prepared from different size fractions of chloroquine phosphate granules using different lubricants were evaluated. Lubricants used were magnesium stearate, stearic acid and talc, tablet properties studied include weight variation, crushing strength, friability and disintegration time

The effects obtained were largely dependent on the type and concentration of lubricant. Generally, as granule size increased, tablets were found to show increased weight variation, decreased hardness and increased friability. With tablets containing talc as lubricant, disintegration time was shown to decrease with increase in granule size.

There appears to be an optimum lubricant concentration for the compression of different granule size fractions.     

Evaluation of Mic Roc Rystal Line Cellulose Prepared from Absorbent Cotton as a Direct Compression Carrier

Abstract

A study has been carried out to examine the feasibility of the use of microcrystalline cellulose (MCC-A) prepared from the absorbent cotton as a direct compression carrier. Tablets made with MCC-A were of equally good quality. The release of test drug diazepam from the tablets was faster than from the tablets made with two MCC commercial grades (MCC-B and MCC-C). The compressional forces - disintegration profile was also comparable.     

The Tabletting Properties of Dika Fat Lubricant

Abstract

The lubricant property of dika fat, a solid vegetable oil extracted from the kernels of Irvingiaqabonensis var gabonensis and var excelsia was investigated. An instrumented tablet machine (ITM) was used to evaluate the effect of dika fat on the unit ejection force (EJF/A) of a model direct compression formulation. Dika fat, at equivalent concentration levels, performed better than magnesium stearate, stearic acid and a hydrogenated vegetable oil STEROTEX, in reducing EJF/A of tablets compressed from the model direct compression formulation. Dika fat imparted no adverse effect on the hardness, disintegration and dissolution of directly compressed hydrochlorothiazide tablets prepared in this study.     

Formulation of Griseofulvin Tablets

Abstract

Difficulties in the formulation of griseofulvin tablets are reviewed. A number of griseofulvin direct compression, pre-compression and polyvinylpyrrolidone granulated tablet formulation have been successfully produced and evaluated, in all cases a mixture of dicalcium phosphate dihydrate and calcium phosphato-carbonate complex was used as tablet matrix. Attempts to use other direct compression tablet matrices proved unsuccessful. The tablets produced have been compared with two commercially available products and the data obtained indicated that the formulations developed in this study have potential for further exploitation.