Continuous contact- and contamination-free ultrasonic emulsification—a useful tool for pharmaceutical development and production

Abstract

A novel concept was developed here for the continuous, contact- and contamination-free treatment of fluid mixtures with ultrasound. It is based on exciting a steel jacket with an ultrasonic transducer, which transmitted the sound waves via pressurised water to a glass tube installed inside the jacket. Thus, no metallic particles can be emitted into the sonicated fluid, which is a common problem when a sonotrode and a fluid are in direct contact. Moreover, contamination of the fluid from the environment can be avoided, making the novel ultrasonic flow-through cell highly suitable for aseptic production of pharmaceutical preparations. As a model system, vegetable oil-in-water emulsions, fed into the cell as coarse pre-emulsions, were studied. The mean droplet diameter was decreased by two orders of magnitude yielding Sauter diameters of 0.5 microm and below with good repeatability. Increasing the residence time in the ultrasonic field and the sonication power both decreased the emulsion mean diameter. Furthermore, the ultrasonic flow-through cell was found to be well suited for the production of nanoparticles of biodegradable polymers by the emulsion-solvent extraction/ evaporation method. Here, perfectly spherical particles of a volume mean diameter of less than 0.5 microm could be prepared. In conclusion, this novel technology offers a pharmaceutically interesting platform for nanodroplet and nanoparticle production and is well suited for aseptic continuous processing.

Continuous synthesis of drug-loaded nanoparticles using microchannel emulsification and numerical modeling: effect of passive mixing

“…Consequently, ions or particles can be emitted into the product by cavitational abrasion of the sonotrode since they consist of metallic alloys, promoting a feasible product contamination. 28 In addition, high-energy inputs involved during the ultrasonic emulsion could also induce the loss of the functional properties of thermal or shearsensitive encapsulated molecules. Consequently, alternative production approaches are demanded to enable a scaled-up production.…”

Ultrasonic innovations in the food industry: From the laboratory to commercial production

“…Relatively low energy input can result in the formation of very fine, highly stable emulsions (Canselier, Delmas, Wilhelm, & Abismail, 2002;Freitas, Hielscher, Merkle, & Gander, 2006). This has been well commercialized in the petrochemical, polymer, chemical, textile, cosmetics and pharmaceutical industries and is now being developed in-line for food products such as fruit juices, mayonnaise and tomato ketchup (Wu, Hulbert, & Mount, 2000).…”

Preparation of Polyamide Nanocapsules of Aloe vera L. Delivery with In Vivo Studies

“…There is now less said about doubts as to the efficacy of the material, although there are some warnings of allergic side effects (13,14). However, many commentators clearly distinguish between the two parts and describe in some detail how the gel is prepared (15)(16)(17). The action of aloe gel as a moisturizing agent is still a popular concept and may account for much of its effect.…”

“…Nevertheless, it should be noted that active glycoproteins have also been demonstrated in aloe gel and may well play some part in their therapeutic activity, either immunologically as lections or as proteasessuch as antibradykinins. There seems to be an ever-decreasing doubt that aloe gel has genuine therapeutic properties, certainly for the healing of skin lesions and perhaps many other conditions (16).…”