Matrix tablets preparation

A comparison of dissolution properties from matrix tablets prepared from 141... 

A quantitative study of the influence of particle size on the percolation threshold employing inert matrix tablets prepared with KC1 and Eudragit RS-PM as matrix-forming material [44-46] showed that experimental data are in agreement with this hypothesis. 

Crowley, M.M. Schroeder, B. Fredersdorf, A. Ohara, S. Talarico, M. Kucera, S. McGinity, J.W. Physicochemical properties and mechanism of drug release from ethyl cellulose matrix tablets prepared by direct compression and hot-melt extrusion. Int. J. Pharm. 2004, 269(2), 509—522. 

Crowley, M.M. Zhang, F. Koleng, J.J. McGinity, J.W. Stability of polyethylene oxide in matrix tablets prepared by hot-melt extrusion. Biomaterials 2002, 25(21), 4241 248. 

No.21, Nov.2002, p.4241-8 STABILITY OF POLYETHYLENE OXIDE IN MATRIX TABLETS PREPARED BY HOT-MELT EXTRUSION... 

Xu, G, Sunada H, Zhang R. Indomethacin controlled release matrix tablet prepared by wet granulation procedure. Chem Pharm Bull 1997 45(1) 214—216. 

This model can be referred to as a classical model. Some years later, Gxirny et al. described the existence of zero-order release periods in inert matrix tablets prepared with ethylcellulose [7]. These periods were explained by the satxxration of the drug in the water-filled pores of the matrix. When the saturation conditions are kept for a significant time period, the dissolution rate becomes slower than the rate of diffusion and therefore becomes the rate-determining step of the drug release kinetics. Potter et al. and Caraballo et al. also confirmed the existence of these periods in compact and inert matrix tablets, respectively [5,7]. 

Critical Points in Matrix Tablets Prepared by Ultrasound-Assisted Compression... 

At pH 7 (Fig. 6) the 2 1 matrix tablets still show a significantly faster release than does the 1 1 system. The latter system, when prepared under both 5 and 10 kN compressive forces, releases more slowly than either of the two microencapsulated systems, with the latter showing similar percentage release rates to each other. Over the initial 2 h period as far greater percentage was released from the microcap tablets than in pH 2, but the increase in release from the matrix tablets was by comparison small. 

The most common problem manifested due to poor flow property is the variation in fill weight. This problem is much more serious in the case of DC excipients, but coprocessed excipients are devoid of this effect, when compared with the physical mixture of their parent excipients. This is because of the impregnation of one particle into the matrix of another, which reduces the rough particle surfaces and creates a near-optimal size distribution, causing better flow properties. Tablets prepared with M80K, a coprocessed cellulose powder with CSD, showed lesser weight variation than those prepared with Avicel (43). 

FIGURE 42 Acyclovir release from matrix tablet with total drug content of 95, 90, 80, 70, and 60 prepared with acyclovir-HPMC K4M (150-200pm) (mean + SD, n = 3). 

Tahara, K., Yamamoto, K., and Nishihata,T. (1995), Overall mechanism behind matrix sustained release (SR) tablets prepared with hydroxypropyl methylcellulose 2910, I. Controlled Release, 35, 59-66. 

Sheskey, P. J., Cabelka, T. D., Robb, R. T., and Boyce, B. M. (1994), Use of roller compaction in the preparation of controhed-release hydrophilic matrix tablets containing methyl cellulose and hydroxypropyl methyl cellulose polymers, Pharm. Technol., 18,132, 134,136,138,140,142,144,146,148-150. 

Sheskey, P. J., and Williams, D. M. (1996), Comparison of low-shear and high-shear wet granulation techniques and the influence of percent water addition in the preparation of a controlled-release matrix tablet containing HPMC and a high-dose, highly water-soluble drug, Pharm. Technol., 20, 80, 82, 84, 86, 88, 90, 92. 

Wax matrix tablets are prepared either by compression of the wax granules or beads described in the previous section, or, with the higher melting waxes available in powder form, by direct compression of powder blends. When compared with polymeric matrix materials, the amount of waxes within the tablet is limited because of fusion and sticking to the punches at higher wax concentrations. This problem could possibly be overcome by compression at lower temperatures. 

Guar gum is a galactomannan, commonly used in cosmetics, food products, and pharmaceutical formulations. It has also been investigated in the preparation of sustained-release matrix tablets in the place of cellulose derivatives such as methylcellu-lose. ... 

Many solid-dosage forms of potassium chloride exist including tablets prepared by direct compression and granulation effervescent tablets coated, sustained-release tablets " sustained-release wax matrix tablets micro-capsules pellets and osmotic pump formulations. ... 

Although primarily used as a suspending agent, xanthan gum has also been used to prepare sustained-release matrix tablets. ° Controlled-release tablets of diltiazem hydrochloride prepared using xanthan gum have been reported to sustain the drug release in a predictable manner and the drug release profiles of these tablets were not affected by pH and agitation rate.< >... 

Dhopeshwarkar V, Zatz JL. Evaluation of xanthan gum in the preparation of sustained release matrix tablets. Drug Dev Ind Pharm 1993 19 999-1017. 

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