Wax matrix tablets

Gl lesions Potassium chloride tablets have caused stenotic or ulcerative lesions of the small bowel and death. These lesions are caused by a concentration of potassium ion in the region of a rapidly dissolving tablet, which injures the bowel wall and produces obstruction, hemorrhage, or perforation. The reported frequency of small bowel lesions is much less with wax matrix tablets and microencapsulated tablets than with enteric coated tablets. Immediately discontinue either type of tablet and consider the possibility of bowel obstruction or perforation if severe vomiting. 

Methylphenidate Ritalin-SR Ritalin LA Metadate ER Metadate CD Concerta Slowly absorbed tablet Capsule with 50% methylphenidate dose as immediate-release beads and 50% as delayed-release beads Slowly absorbed tablet with methylphenidate incorporated in a wax matrix tablet, allowing gradual diffusion Capsule that provides 30% of methylphenidate dose hy immediate-release beads and 70% of the dose by extended-release beads Tablet that contains approximately 22% of the methylphenidate dose in an immediate-release capsule overcoat and 78% within the tablet that is released by an osmotic process over an extended period... 

Emori, Ishizaka, and Koishi. formulated wax matrix tablets for prolonged drug release using a melt-congealing process. They studied the addition of acrylic acid polymer on the release of drug from a wax matrix consisting of carnauba wax and stearyl alcohol in a 1 1 ratio. 

Sustained release wax matrix tablets are generally considered difficult to coat with aqueous polymeric dispersions due to the poor wettability of the hydrophobic tablet surface. "" The physicochemical... 

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. 

While the drug release from wax matrix tablets followed the square root of time relationship, approximately zero-order release of ephedrine hydrochloride and procaine hydrochloride could be obtained with multi-layered matrices of hydrogenated castor oil containing different concentrations of the active compound in each layer. 

Huang, H.-P. Mehta, S.C. Radebaugh, G.W. Fawzi, M.B. Mechanism of drug release from an acrylic polymer-wax matrix tablet. J. Pharm. Sci. 1994, 83, 795-797. 

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. ... 

Remember that the wax matrix of sustained-release tablets of procainamide (Procan SR only) is not absorbed by the body and may be found in the stool. This is normal. 

Tablets, controlled-release 6.7 mEq (500 mg) potassium chloride in a wax matrix Rx) Kaon-CI (Adria)...

Tablets, extended-release 750 mg potassium chloride equivalent to 10 mEq potassium in a wax matrix (Rx) Various...

Tablets, slow-release 410 mg sodium chloride and 150 mg potassium chloride in wax matrix otc) Slo-Salt-K (Mission)...

Sugar-coated products have been marketed that contain KCl in a wax matrix (Slow-K and Kaon-Ct) and are purportedly slow- and controlled-release preparations. Available evidence indicates that these slow-release forms of KCl are occasionally capable of causing local tissue damage and therefore prol5ably should be used with caution for K+ supplementation. Solutions of potassium gluconate, like the tablets, also have been associated with intestinal ulceration. Microencapsulated KCl preparations Micro-K, K-Dur) that are neither enteric coated nor contained within a wax matrix appear to be superior to the wax matrix formulation. 

The incorporation of drugs into inert matrices is a popular approach to prolong the drug release. Sustained-release wax matrix drug delivery systems include wax granules or beads prepared by granulation or extrusion/spheronization, tablets, and wax-filled hard gelatin capsules. 

Drug delivery systems of once-daily products (Concerta, Metadate CD, Ritalin LA, Adderall XR) provide 8 to 12 hours of symptom control. Concerta uses an oral osmotic (OROS) controlled-release delivery system, while other preparations use combinations of immediate-release or extended-release beads containing drug. Concerta is a nondeformable tablet and it should not be given to children with gastrointestinal narrowing due to the risk of obstruction. Older wax-matrix sustained-release products (e.g., Ritalin SR)... 

Mixture models (such as those of Scheffe) are still useful, especially when there are three or more such excipients with fairly large ranges of variation. In solid formulations, this is often the case for diluents (or fillers) and also for the polymers or waxes incorporated into controlled-release tablets to form a matrix through which the drug diffuses slowly out when immersed in aqueous fluid, i.e., in the gastrointestinal tract. 

De Brabander, C. Vervaet, C. Fiermans, L. Remon, J.P. Matrix mini-tablets based on starch/microcrystalline wax mixtures. Int. J. Pharm. 2000, 199, 195-203. 

Microcrystalline wax is also used in oral controlled-release matrix pellet formulations for various active compounds and as a tablet- and capsule-coating agent. In controlled-release systems, microcrystalline wax coatings can also be used to affect the release of drug from ion-exchange resin beads. Microcrystalline wax is also used in confectionery, cosmetics, and food products. 

Matrix mini-tablets based on starch/microcellulose wax mixtures have been described (31,32). The possibility with these and other mini-tablets is that different dose levels can be administered by changing the number of mini-tablets within a capsule for adults or using single units for children. It is also possible to utilize fast-dissolving mini-tablets to prepare liquid dosages extemporaneously. 

Uses Lubricant for sustained release tablets emulsion stabilizer dispersant for pigments emulsifier in phannaceulicals Features Lipophilic matrix for oral solid dosage forms Regulatory USP, Ph.Eur, JCIC compliant Properties Off-wh. powd. sol. in fats, oils, waxes m.p. 54-64 C Imwitoi 928 [Sasol Gennany Sasol N. Am.)... 

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