Lipid vesicles and other colloids as drug carriers on the skin.

Microemulsions as transdermal drug delivery vehicles.

Influence of microemulsions on cutaneous drug delivery.

Nanoemulsions are isotropic, thermodynamically stable transparent (or translucent) systems of oil, water, and surfactants with a droplet size usually in the range of 10–100 nm (1,2). Their long-term stability, ease of preparation (spontaneous emulsification), and high solubilization of drug molecules make them promising as a drug delivery tool. They have found wide applications in oral drug delivery to enhance the solubility and bioavailability of the lipophilic drugs (3–5). Recently, there has been a surge in the exploration of nanoemulsions for transdermal delivery (6–8). They are also being investigated ardently for potential applications in ocular (9,10), pulmonary (11), nasal (12,13), vaginal (14,15), and parenteral drug delivery (16–18).

The use of nanoemulsions in drug delivery has been reviewed, and it was noted that most studies have not been very systematic with regard to selection of surfactants and cosurfactants. The main objective of this study was to provide an efficient screening approach for the proper selection of oils, surfactants, and cosurfactants for the nanoemulsion formulation development. Ropinirole was selected as a model lipophilic drug for this purpose (Log P = 3.32). These systems often require high surfactant concentration, and this may lead to toxicity and irritancy problems. Therefore, judicious selection of surfactants along with their optimum concentration is required, which has been discussed in this report. Determination of the influence of the surfactant-to-cosurfactant mass ratio (Smix) on the nanoemulsion formation region also formed an important aspect of the study. Optimum selection would aid in better formulation with desirable attributes.

/pdf/nanoemulsion-components-screening-and-selection-a-technical-37a8e9apr5.pdf

Nanoemulsion Components Screening and Selection: a Technical Note

Nanoemulsions have attracted great attention in research, dosage form design and pharmacotherapy. This is as a result of a number of attributes peculiar to nanoemulsions such as optical clarity, ease of preparation, thermodynamic stability and increased surface area. Nanoemulsions also known as submicron emulsions serve as vehicles for the delivery of active pharmaceutical ingredients as well as other bioactives. They are designed to address some of the problems associated with conventional drug delivery systems such as low bioavailability and noncompliance. The importance of design and development of emulsion nanocarrier systems aimed at controlling and/or improving required bioavailability levels of therapeutic agents cannot be overemphasized. Reducing droplet sizes to the nanoscale leads to some very interesting physical properties, such as optical transparency and unusual elastic behaviour. This review sheds light on the current state of nanoemulsions in the delivery of drugs and other bioactives. The morphology, formulation, characteristics and characterization of nanoemulsions were also addressed.

/pdf/current-state-of-nanoemulsions-in-drug-delivery-57zjfyrh6t.pdf

Jung-Gyo Choi

Papers

Transdermal delivery of ketoprofen using microemulsions.