An emulsion is a biphasic dosage form comprising of dispersed phase containing droplets that are uniformly distributed into a surrounding liquid which forms the continuous phase. An emulsifier is added at the interface of two immiscible liquids to stabilize the thermodynamically unstable emulsion. Various types of emulsions such as water-in-oil (w-o), oil-in-water (o-w), microemulsions, and multiple emulsions are used for delivering certain drugs in the body. Water (aqueous) phase is commonly used for encapsulating proteins and several other drugs in water-in-oil-in-water (w-o-w) emulsion technique. But this method has posed certain problems such as decreased stability, burst release, and low entrapment efficiency. Thus, a novel “solid-in-oil-in-water” (s-o-w) emulsion system was developed for formulating certain drugs, probiotics, proteins, antibodies, and tannins to overcome these issues. In this method, the active ingredient is encapsulated as a solid and added to an oil phase, which formed a solid-oil dispersion. This dispersion was then mixed with water to form a continuous phase for enhancing the drug absorption. This article focuses on the various studies done to investigate the effectiveness of formulations prepared as solid-oil-water emulsions in comparison to conventional water-oil-water emulsions. A summary of the results obtained in each study is presented in this article. The s-o-w emulsion technique may become beneficial in near future as it has shown to improve the stability and efficacy of the entrapped active ingredient. Graphical abstract

Any medicinal product introduced in the market ought to have the highest safety, quality, purity and efficacy as it is received by an ailing patient. Parenteral products are sterile pharmaceutical preparations that are injected, infused or implanted in the body. These products must maintain their quality and sterility as they are introduced directly into the bloodstream. Negligence associated with parenteral preparations can lead to severe or fatal adverse events. Although each country has its own regulatory body to keep a check on medication errors, defects keep occurring in pharmaceutical products. It should be the top priority of pharmaceutical companies to avoid these defects and related issues. This study focuses on three such real life defective parenteral products obtained from the hospital pharmacy. The probable root cause, remediation and clinical significance of the noted defect is also mentioned. These case studies can help pharmaceutical manufacturers minimize defects, quality issues to avoid product recalls and to achieve better therapeutic compliance.