Tablet hydrophilic matrix

Parojclc J, Duric Z, Jovanovic M, Ibric S. An investigation into the factors influencing drag release from hydrophilic matrix tablets based on novel carbomer polymers. Drag Deliv 2004 11 59-65. 

Siepmann, J., Streubel, A., and Peppas, N. Understanding and predicting drug delivery from hydrophilic matrix tablets using the sequential layer model. Pharm. Res. 19 306-314, 2002. 

S. K Baveja, K. V. Ranga Rao, and K. Padmalatha Devi. Relationship between gum content and half-life of soluble P-blockers from hydrophilic matrix tablets. Int. J. Pharm. 47(1-3) 133-139, 1988. 

Case Study Estimation of Percolation Thresholds in Acyclovir Hydrophilic Matrix Tablets... 

Soluble drugs are considered to be released by diffusion through the matrix and poorly soluble drugs are released by erosion of the matrix. Moreover, it is considered that factors affecting swelling and erosion of these polymers may account for differences between in vitro dissolution results and subsequent in vivo performance when hydrophilic matrix tablets are compared [15]. 

The process of water penetration into hydrophilic matrix tablets was also studied using a modified Enslin apparatus. This apparatus contains a fritter and a system to regulate the water level. When the tablet is placed on the fritter, the water is absorbed from a reservoir which is placed on a precision balance. The amount of water uptake at each time point was read from the balance as weight loss in the reservoir. Figure 46 shows the obtained release profiles. 

B. Baveja, S. K., Ranga Roa, K. V., and Padmalatha Devi, K. (1987), Zero-order release hydrophilic matrix tablets of P-adrenergic blockers, Int. J. Pharm., 40, 223-234. 

The release process for hydrophilic matrix tablets can be schematically described as in Figure 5. The left side of the figure shows a hydrophilic tablet undergoing dissolution, swelling, and release. An interface between the solution and gel layer, here... 

Koerner, A., Larsson, A., Piculell, L., and Wittgren, B. (2005),Tuning the polymer release from hydrophilic matrix tablets by mixing short and long matrix polymers, J. Pharm. Sci., 94,759-769. 

Heng, P. W., Chan, L. W., Easterbrook, M. G., and Li, X. (2001), Investigation of the influence of mean HPMC particle size and number of polymer particles on the release of aspirin from swellable hydrophilic matrix tablets, J. Controlled Release, 76, 39-49. 

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. 

Vueba, M. L., Batista De Carvalho, L. A. E., Veiga, F, Sousa, J. J., and Pina, M. E. (2004), Influence of cellulose ether polymers on ketoprofen release from hydrophilic matrix tablets, Eur. J. Pharm. Biopharm., 58, 51-59. 

Maggi, L., Segale, L., Torre, M. L., Ochoa Machiste, E., and Conte, U. (2002), Dissolution behaviour of hydrophilic matrix tablets containing two different polyethylene oxides (PEOs) for the controlled release of a water-soluble drug. Dimensionality study, Biomaterials, 23,1113-1119. 

Adyeeye, C. M., Rowley, J., Madu, D., Javadi, M. and Sabnis, S. S. (1995). Evaluation of crystallinity and drug-release stability of directly compressed theophylline hydrophilic matrix tablets stored under varied moisture conditions. Int. J. Pham., 116, 65-75. [5]... 

Katzhendler, I. Azoury, R. Friedman, M. Crystalline properties of carbamazepine in sustained release hydrophilic matrix tablets based on hydroxypropyhnethyl cellulose. J. Contr. Rel. 1998, 54, 69-85. 

Perez-Marcos B, Iglesias R, Gomez-Amoza JL, et al. Mechanical and drug-release properties of atenolol-carbomer hydrophilic matrix tablets. / Control Release 1991 17 267-276. 

Jeko ZB, Sipos T, Kertai EH, Mezey G. Comparison of dissolution-rate curves of carbamazepine from different hydrophilic matrix tablets. Acta Pharm 1999 49 267-273. 

Lactose anhydrous has been used experimentally in hydrophilic matrix tablet formulations and evaluated for dry powder inhalation applications. Partial hydration of anhydrous lactose increases the specific surface area and reduces the flow properties of powders but has no effect on compactibility. A specification for lactose is included in the Food Chemicals Codex (FCC) see Factose, Monohydrate. The EINECS number for lactose anhydrous is 200-559-2. 

Qiu Y, Hui HW. Qieskin H. Formulation development of sustained-release hydrophilic matrix tablets of zileuton. Pharm Dev Tech 1997 2(3) 197-204. 

The mechanism of drug release from hydrophilic matrix tablets after ingestion is complex but it is based on diffusion of the drug through, and erosion of, the outer hydrated polymer on the surface of the matrix. Typically, when the matrix tablet is exposed to an aqueous solution or gastrointestinal fluids, the surface of the tablet is wetted and the polymer hydrates to form a gelly-like structure around the matrix, which is referred to as the gel layer . This process is also termed as the... 

Hydrophilic matrix tablets are manufactured using traditional tablet manufacturing methods of direct compression (DC), wet granulation or dry granulation (roller compaction or slugging) depending on formulation properties or on manufacturer s... 

As shown in this chapter, formulating HPMC matrices can be a complex process critical factors being drug solubility, dosage level, rate-controlling polymer and excipient choice. In order to help the pharmaceutical scientists with a starting formula for hydrophilic matrix tablets, Colorcon, hic. has developed a predictive formulation service called HyperStart [97]. This system is based on mathematical models and relationships, validated with extensive experimental data. Use of the HyperStart formulation service may help to simplify the formulation and development process and reduce the time to market. 

In order to help pharmaceutical scientists with a starting formula for hydrophilic matrix tablets predictive mathematical models such as HyperStart has been developed [97]. Use of this service will simplify the development process and reduce the time to market. 

Timmins, P, Delargy, A.M. and Howard, J.R. (1997) Optimization and characterization of a pH independant extended release hydrophilic matrix tablet. Pharm Dev Technol, 2, 25-31. 

Siepe, S., Lueckel, B., Kramer, A., Ries, A. and Gurny, R. (2006) Strategies for the design of hydrophilic matrix tablets with controUed microenvironmental pH. Int J Pharm, 316, 14-20. 

Baumgartner S, Lahajnar G, Sepe A, et al. (Quantitative evaluation of polymer concentration profile during swelling of hydrophilic matrix tablets using H NMR and MRI methods. Eur J Pharm Biopharm 2005 59(2) 299-306. 

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