Parenteral formulations liposome delivery systems

In pharmaceutical preparations, soybean oil emulsions are primarily used as a fat source in total parenteral nutrition (TPN) regimens. Although other oils, such as peanut oil, have been used for this purpose, soybean oil is now preferred because it is associated with fewer adverse reactions. Emulsions containing soybean oil have also been used as vehicles for the oral and intravenous administration of drugs drug substances that have been incorporated into such emulsions include amphotericin, " diazepam, retinoids, vitamins, poorly water-soluble steroids, fluorocarbons, and insulin. In addition, soybean oil has been used in the formulation of many drug delivery systems such as liposomes, microspheres, dry emulsions, self-emulsifying systems, and nanoemulsions and nanocapsules. ... 

Parenteral is defined as situated or occurring outside the intestine, and especially introduced otherwise than by way of the intestines —pertaining to essentially any administration route other than enteral. This field is obviously too broad for an adequate focus in one book, let alone one chapter. Many have nonetheless used the term synonymously with injectable drug delivery. We restrict ourselves to this latter usage. This would thus include intravenous, intramuscular, subcutaneous, intrathecal, and subdural injection. In this chapter we discuss the theoretical and practical aspects of solubilizing small molecules for injectable formulation development and will examine the role of surfactants and other excipients in more recent parenteral delivery systems such as liposomes, solid-drug nanoparticles and particulate carriers. 

One of the main problems associated with developing a parenteral or any other solution formulation of a compound is its aqueous solubility. For poorly soluble drug candidates, there are several strategies for enhancing their solubility. These include pH manipulation, cosolvents, surfactants, emulsion formation and complexing agents. More sophisticated delivery systems, e.g., liposomes, can also be used in this way. 

Despite the above limitations, the therapeutic promise of liposomes as a drug delivery system is becoming a reality in the following applications (1) Parenteral administration (2) inhalation treatment (3) percutaneous administration (4) oph-thalmics (5) cancer treatment and (6) controlled-release formulations. 

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