Semisolids production

Petrolatum a semisolid product, ranging from white to yellow in color, produced during refining of residual stocks. 

As noted earlier, virtually all liquid and semisolid products involve the unit of operation of mixing. In fact, in many instances, it is the primary unit operation. Even its indirect effects, e.g., on heat transfer, may be the basis for its inclusion in a process. Yet, mechanistic and quantitative descriptions of the mixing process remain incomplete (7-9). Nonetheless, enough fundamental and empirical data are available to allow some reasonable predictions to be made. 

The book is divided into six volumes based strictly on the type of formulation science involved in the development of these dosage forms sterile products, compressed solids, uncompressed solids, liquid products, semisolid products, and over-the-counter (OTC) products. Although they may easily fall into one of the other five categories, OTC products are considered separately to comply with the industry norms of separate research divisions for OTC... 

Noveon Polymers in Semisolid Products. Bulletin 8. Cleveland, Ohio Noveon, Inc., 2002. 

The key parameter for any drug product is its efficacy as demonstrated in controlled clinical trials. The time and expense associated with such trials make them unsuitable as routine quality control methods. Therefore, in vitro surrogate tests are often used to assure that product quality and performance are maintained over time and in the presence of change. A variety of physical and chemical tests commonly performed on semisolid products and their components (e.g., solubility, particle size and crystalline form of the active component, viscosity, and homogeneity of the product) have historically provided reasonable evidence of consistent performance. More recently, in vitro release testing has shown promise as a means to comprehensively assure consistent delivery of the active component(s) from semisolid products. 

In vitro release testing is a useful test to assess product sameness under certain scale-up and postapproval changes for semisolid products. 

For semisolid products, any change in the preservative may affect the quality of the product. If any quantitative or qualitative changes are made in the formulation, additional testing should be performed. No in vitro release documentation or in vivo bioequivalence documentation is needed for preservative changes. 

The following changes in the container closure system of nonsterile semisolid products, as long as the new package provides the same or better protective properties and any new primary packaging component materials have been used in and been in contact with CDER-approved semisolid products ... 

A practical example of the possible consequences of the appearance of a new crystalline form is that of the HIV drug Ritonavir. The drug had to be taken off the market by Abbott because of the unexpected (and unwanted) appearance of a new, much less soluble crystal form, which caused a large portion of the drug to precipitate out of the commercialized, semisolid product. A concise history of the problem and how the problem was tackled and eventually solved has recently been published [10]. 

FIGURE 1 Semisolid production machine with heat jacketed vessel, high-shear mixer, scrapper, vacuum attachments, and control station. (Courtesy of Ross, Inc.)... 

Forcinio, H. (1998), Tubes The ideal packaging for semisolid products, Pharm. Tech., 22, 32-36. 

Compressed gas systems were originally developed simply to provide a means of expelling a product from its container when the valve was depressed. Semisolid products such as a cream, ointment, or caulking compound are dispensed as such. A liquid concentrate and a compressed gas propellant (Fig. 3) produce a spray when a mechanical breakup actuator is used. Nitrogen, insoluble in most materials, is generally used as the propellant. 

Dimelhylhydrazine (1.8 g, 30 mmol) is added to (1) (0.5 g, 2.7 mmol) and left at room temperature (24 h). The semisolid product is washed with tetrachloromethane and dried under vacuum to give the crude dimethylhydrazide (0.39 g, 94%). Recrystallization from benzene-methanol gives the pure product, m.p. 277-278°C. 

Two categories of microorganisms are cause for concern in preservation of topical semisolid products. They are those liable to cause pathogenic symptoms and include staphylococci and hemolytic streptococci. Pseudomonas aeruginosa and cepacia, and Escherichia coli, and microorganisms liable to cause spoilage, which include water and airborne molds and yeasts. The following section describes the properties of some commonly used preservatives. 

These mixed-surfactant systems are used not only for their ability to form complex condensed films at the liquid-liquid interface, enhancing the stability of the emulsion, but also because of their ability to impart body to the product, resulting in a semisolid product rather than a liquid. Mixed emulsifiers control the consistency of a cream by forming a viscoelastic network throughout the continuous phase of the emulsion. The network results from the interaction of the mixed emulsifier with water, forming a liquid crystalline phase. 

OR 2,6-Norbornanediol. This polymer was prepared by a procedure similar to that for cyclohexanedimethanol using p-toluenesulfonic acid as catalyst. After concentration of a portion of the benzene solution, a polymer with an inherent viscosity of 0.28 was obtained. When the benzene solution was poured into methanol, a semisolid product was obtained. After being dried, the product, a clear, brittle resin, had an inherent viscosity of 0.49. Its melting range and solubilities are given in Table I. 

Because the initial rotary evaporation is faster with the organic solvent, we have usually prepared DHA in 95% ethanol. In methanol the reaction gives up to 10-20% of a methanol complex of DHA that is only partly reconverted to free DHA on repeated evaporations from water. Extensive rotary evaporation with repeated additions of diethyl ether, followed by lyophilization, yields a more manageable, semisolid product. DHA in the syrup or semisolid form is stable for many weeks when stored at —10° to —20°C. Analysis of the products prepared as described above was done by NMR, one of the few analytical techniques that gives unambiguous results on the purity and identity of this compound. 

Niazi SK. Handbook of Pharmaceutical Manufacturing Formulations, Vol. 4 Semisolid Products. Boca Raton, PL CRC Press, 2004. 

Grease a solid to semisolid product that is a lubricating fluid that has been gelled with a thickening agent so that the lubricant... 

Building B of ABC Pharmaceutical is designed to manufacture liquids and semisolid products. The conventional pharmaceutical dosage forms include drops, syrups, suspensions, creams/ointments, and suppositories. 

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