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38 January 2015 Tablets & Capsules glidant, binder, disintegrant, and stabilizing agent. Magnesium silicate. This com - pound of magnesium oxide and sili - con dioxide (CAS# 1343-88-0) has the chemical formula MgO SiO 2 xH 2 O. In its crystalline form, it occurs na turally as a mineral, e.g., talc. But un like talc, the synthetic carrier of liquids (e.g., vitamin E) in oral solid dosage forms. As a filler aid, it can increase tablet hardness and reduce friability. It has also been used to increase the dissolution of poorly soluble APIs and to improve API stability. Its rapid disintegration makes it useful in formulating "fast- melt" tablets, also know as orally dissolving tablets (ODTs). There are various grades and suppliers of calcium silicate. Table 1 lists some of the more common phar - maceutical grades available, their properties, and their applications. Metal oxide silicas The most common materials in this group of silica excipients are magnesium aluminum silicate, magnesium silicate, and magnesium trisilicate. Magnesium silicate and magnesium trisilicate are mostly used as glidants and anti-caking ingre - dients. These agents are also used as antacids. Magnesium aluminum silicate serves as an adsorbent, vis - cosity modifier, anti-caking agent, form is amor phous and is prepared by reacting soluble sodium silicate (waterglass) with a magnesium salt, such as mag nesium sulfate. The porous particles that result can reach BET surface areas of several hundred square meters per gram (m 2 /g). Magnesium silicate is a tasteless, odorless, fine white powder free from Table 1 Excipient-grade calcium silicates Florite a Zeopharm b 600 RxCipients b FM1000 Particle size (d50, microns) 28 8 3 Bulk density (g/cc) 0.07 0.10 0.53 Tap density (g/cc) 0.11 0.14 0.90 Surface area ( m2/cc) 141 250 2.0 Oil adsorption (ml/g) 5.1 4.75 <<0.1 Angle of repose (degrees) 43.8 Not available Not available Application Adsorbent Adsorbent Disintegrant Compressibility aid Anti-caking agent ODT aid Anti-caking agent Dissolution aid Stability aid a.Trademark of Tomita Pharmaceutical, Tokyo, Japan b.Trademark of J.M. Huber Corp., Atlanta, GA • Separation Anxiety: Addressing Variation in Blend and Content Uniformity Data in Compression/Encapsulation Processes • Dissolution Testing: New Performance Acceptance Criteria for Calibrator Tablets and Sources of Error • Formulation of Solids 101: Excipients and Dosage Form Development • Capsule Filling: How to Assess Production Performance during R&D • Developing a Dissolution Test Method Employing QbD • Powder Flow, Dispersion, and Mixing/Blending • Tablet Formulation and the Principles of QbD • Introduction to Aqueous Film Coating • Liquid Filling of Two-Piece Capsules • Direct Powder Blends for Tabletting • Granulation: Trends and Strategies • Optimizing Tablet Manufacturing • Is It Your Press or Your Powder? • Regulation of Excipients Missed a Tablets & Capsules Webinar? These webinars are now for sale in the Tablets & Capsules bookstore. www.tabletscapsules.com/bookstore