Solid pharmaceutical dosage forms semisolids

Solid pharmaceutical dosage forms (tablets and capsules) are used to illustrate the various stages of product and process development. These principles and practices also apply in a general way to the development of liquid and semisolid pharmaceutical dosage forms (not discussed here). 

It is commonplace in pharmaceutical formulation to combine two or more polymers within a single dosage form, e.g., gel, semisolid, and solid oral dosage form as, in many instances, this ensures enhanced control of dosage form performance, e.g., stability, drug release rate, spreadability, etc. Once more, both the clinical and nonclinical performance of these systems may be related to their (complex) viscoelastic behavior, and, hence, these systems have been characterized using dynamic oscillatory methods. 

Semisolids dosage forms, as a class, are plastic in behavior, i.e., they retain their shape until acted upon by an outside force, in which case they deform and the deformations are permanent. The common denominator to all semisolid systems which gives them their special rheological character is that they all have a permanent three-dimensional structure. This structure is sufficient when undisturbed to impart solid-like properties but which is easily broken down and realigned under some strain or applied force (4). The semisolid systems used pharmaceutically include... 

APV (1981) International Association for Pharmaceutical Technology Praxis der Validierung (Validation in Practice), Symposium (1981-1982, Gelsenkirchen) [6] Terminology, sterile, semisolid, and solid dosage forms in development and production, analytical methods and stability evaluation, packaging development and packaging validation transfer, cost-effectiveness... 

Pharmaceutical products can be classified as liquid solutions, disperse systems (e.g., emulsions, suspensions), semisolids (e.g., ointments), and solid dosage forms. Liquid solutions are homogeneous mixtures of one or more substances in pharmaceutical liquids. The understanding of the physicochemical properties of liquid solutions and processes to prepare the liquid solutions is an important step in preparing final liquid solution dosage forms. In this chapter, the solutions of gases in liquids, liquids in liquids, and solids in liquids, as well as colligative properties of solutions and their application to pharmacy, are discussed. Disperse systems will be discussed in Chapter 4. 

Waxes have been used by the pharmaceutical industry for many years. Their applications in semisolid preparations, including ointments, creams, or lotions, and in suppositories are well known and numerous publications exist on this topic. Because of their lipophilic properties, waxes have been used in sustained-release single or multiple unit solid dosage forms. This article reviews the different uses of waxes as sustained-release carrier or coating materials. 

Drug dosage forms can be classified by consistency as solid, semisoUd, and liquid formulations. Solid formulations include powders, granules, microcapsules, capsules, dragees, suppositories, and decoctions. Ointments, creams, gels, and pastes are semisolid formulations, and solutions, emulsions of low viscosity, and suspensions make up the class of liquid formulations. Products applied to the skin border between pharmaceuticals and cosmetic usage (30). 

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