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Accurate percent moisture content is essential for maintaining the stability of drug products. If a product is too moist or too dry, it may not be suitable to be administered and will not exert the desired therapeutic effect. Most of pharmaceutical products contain moisture. The percent moisture content is seldom of interest. Rather, it shows … Read more

Equilibrium moisture content: The moisture contained in a material comprises all those substances which vaporize on heating and lead to a weight loss of the sample. The weight is determined by a balance and interpreted as the moisture content. As per this definition, moisture content includes not only water but also other mass losses such … Read more

Drying Drying is a mass transfer process in which water or another solvent is removed by evaporation from a solid, semi-solid, or liquid. Drying is often a final step in the production or packaging of pharmaceutical products. For material to be considered as “dried”, the final product must be solid, in the form of a … Read more

What is molecular distillation? Molecular distillation is a type of short-path vacuum distillation, characterized by extremely low vacuum pressure (≈ 0.01 torr). It is a process of separation, purification, and concentration of natural products, complex and thermally sensitive molecules. This process is characterized by short-term exposure of the distillate liquid to high temperatures in a … Read more

The steam distillation is a process in which the concentration and isolation of essential oil from reliable and often cheaper natural sources is carried out. This is an important technique and has significant commercial applications. Many compounds, both solids, and liquids are separated from complex mixtures by taking advantage of their volatility in steam. A … Read more

The boiling point of water increases when the external pressure is increased whereas decreased external pressure decreases the boiling point. This principle is used in the process of freeze-drying. Many compounds cannot be distilled at atmospheric pressure because their boiling points are so high. At their normal boiling points, the compounds decompose. Thus, some of … Read more

The basic idea behind fractional distillation is the same as simple distillation. The difference between simple and fractional distillation is the number of times that the liquid is vaporized and condensed. Simple distillation condenses the liquid once, so the boiling points of the two liquids must be far apart to make it efficient. Simple distillation … Read more

Flash distillation, also called “equilibrium distillation”, is a single-stage separation technique. Simple flash separations are very common in the industry, particularly petroleum refining. Even when some other method of separation is to be used, it is not uncommon to use a “pre-flash” to reduce the load on the separation itself. Principle of flash distillation The … Read more

Simple distillation is a unit operation in which two liquids with different boiling points are separated. Principle of simple distillation Simple distillation is a process of heating and cooling liquids in order to separate and purify them. As the liquid being distilled is heated, the vapors that form are richest in the component of the … Read more

Historically, distillation has been used since 1200 BC in perfumery operations. Early forms of distillation were batch processes using one vaporization and one condensation. Purity was improved by further distillation of the condensate. Greater volumes were processed by simply repeating the distillation. Chemists were reported to carry out as many as 500 to 600 distillations … Read more