Effect of different penetration enhancers on diclofenac permeation across horse skin.

The research article investigates the impact of five different penetration enhancers on the transdermal absorption of diclofenac diethylamine, a non-steroidal anti-inflammatory drug, across horse skin. The enhancers successfully increased the permeability, with limonene showing the highest effectiveness.

Study Methodology and Penetration Enhancers Examined

• The main focus of the study was to observe the effect of five specific penetration enhancers (known to increase the ability of drugs to pass through the skin) on diclofenac diethylamine, a commonly used human and animal anti-inflammatory medication.
• The penetration enhancers tested in the study were 10% urea, 15% and 20% oleic acid, and 5% and 10% d-limonene.
• A set of Franz-type diffusion cells were used to evaluate the effects in vitro, meaning the experimentation was conducted outside of a living body.

Key Findings of the Research

• The study found that all penetration enhancers increased the percutaneous absorption of the diclofenac diethylamine through the horse skin significantly.
• Among the tested enhancers, limonene showed the highest enhancing effect at the lowest concentration of 5%.
• The presence of these penetration enhancers did not impact the lag-time — the duration it takes for the maximum absorption of the drug.

Significance and Implications

• This research is the first in vitro study that investigates the impact of penetration enhancers on the transdermal absorption of diclofenac diethylamine across horse skin, opening new avenues in the field.
• The findings suggest that enhancers like urea, limonene, and 5% oleic acid can efficiently boost the transdermal absorption of diclofenac diethylamine, thereby serving a critical role in developing effective transdermal formulations for horses.
• Such transdermal formulations can help ensure the drug’s effective delivery, bypass the gastrointestinal system to reduce chances of side effects, and provide a practical drug administration alternative for animals averse to oral medication.