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Abstract

Diazepam, a lipophilic drug with CNS activity, serves here as a model to investigate the efficacy of SubMicron Emulsion (SME) as a novel transdermal vehicle. Diazepam was formulated in various topical regular creams and SubMicron Emulsion creams of different compositions. The different formulations were applied topically and protection against Pentamethylenetetrazole induced convulsive effects in mice was monitored. The efficacy of Diazepam applied topically in emulsion creams strongly depends on the oil droplet size and to a lesser degree--on the formulation composition and the oil type. Processing medium-chain-triglyceride (MCT) emulsion with a high-pressure homogenizer causes a drastic reduction in the droplet size, thereby significantly increasing the transdermal activity of Diazepam. In this case both the high-pressure homogenization and the presence of lecithin, an efficient dispersant, contribute to the effective droplet size reduction of below 1 micron, usually between 100-300 nm. The SubMicron Emulsions as vehicles for transdermal delivery of Diazepam generate significant systemic activity of the drug as compared with regular creams or ointments. Transdermal delivery of Diazepam via SME formulations is very effective, and the activity may reach the range of parenteral delivery. A single application of Diazepam in SME cream to mice skin provides pronounced transdermal drug delivery and prolonged protective activity up to 6 hours.

Topical Delivery of Erythromycin from Various Formulations: An in Vivo Hairless Mouse Study

“…The reason for this effect is not clear, but the limited data indicate that the polarity of the oil phase may be an important factor. These results are consistent with the studies of Schwarz et al 18 on the efficacy of diazepam delivery from a variety of emulsion vehicles. These authors found that drug uptake was greatly affected by the type of oil used in the emulsions.…”

Overcoming the Cutaneous Barrier with Microemulsions

“…Several studies show an effect of formulation dispersed phase size on drug transport into/across the skin. Diazepam transport, for example, was enhanced by using formulations with a dispersed phase size below 0.5 micrometers (100–300 nm) compared to standard emulsions [28]. Significant improvement in transdermal delivery of betamethasone valerate and dipropionate, indomethacin, diclofenac, piroxicam and naproxen was demonstrated by Friedman et al [29] using formulations with oil droplets of approximately 100 nm compared to standard creams.…”

“…It has been generally accepted that reducing the droplet size from the macro- to nano-range increases penetration [28,91]. Diazepam transport, for example, was enhanced by decreasing the droplet size of formulations to below one micrometer (100–300 nm) [28].…”

“…It has been generally accepted that reducing the droplet size from the macro- to nano-range increases penetration [28,91]. Diazepam transport, for example, was enhanced by decreasing the droplet size of formulations to below one micrometer (100–300 nm) [28]. Significant improvement in transdermal delivery of betamethasone valerate and dipropionate, indomethacin, diclofenac, piroxicam and naproxen was demonstrated by Friedman et al [29] using formulations with oil droplets of approximately 100 nm compared to standard emulsions.…”

Oil-in-water nanoemulsions for pesticide formulations

“…In addition, high kinetic stability, low viscosity and optical transparency make them very attractive systems for many industrial applications; for example, in the pharmaceutical field as drug delivery systems [2,3], in cosmetics as personal care formulations [4], in agrochemicals for pesticide delivery [5], and in the chemical industry as polymerization reaction media [6]. The use of nanoemulsions as colloidal drug carriers is well-documented [3,[7][8][9]. The bioavailability of drugs was reported to be strongly enhanced by solubilization in small droplets (below 0.2 µm); for example, submicronic emulsions were found to increase the bioavailability of cefpodoxime proxetil from 50 to 98%, compared to other oral formulations [9].…”