Authors â€“ Dr. S Anoop, Dr. V. Sthevaan, Dr. D.C. Sharma
Palamur Biosciences, is GLP Certified Pre-Clinical facility offering Large Animals studies using Beagle Dogs, Pigs (Minipigs and Conventional Pigs), Sheep/Goat, etc.
Our scientists have been performing many Dermal Studies using Swine Models (both Minipigs and Conventional Pigs). Here we thought to share an overview of Dermal PK studies using Swine models from our experience.
DERMAL PHARMACOKINETIC STUDIES
The Dermal PK is used normally to analyse and quantify the topical drug formulation in the target tissue (Skin). This basically involves assessment of the drug concentration in the outer most layers of the skin with respect to time and to provide information on drug absorption, steady state and drug elimination based on a stratum Corneum concentration-time curve.
Since No correlation exists between the availability of drug in the skin and in blood levels, the evaluation of topical bioavailability must involve the quantification of drug in the skin. In other words the dermal pharmacokinetics study (Skin) could be comparable to a classical pharmacokinetic study (blood, plasma and urine etc.).
This method assumes that
a). Stratum Corneum is the rate-limiting barrier to percutaneous absorption
b). Drug concentration in the Stratum Corneum is directly related to drugâ€™s diffusion into the viable dermis
c). Stratum Corneum drug concentrations are more relevant for estimating local, dermatological efficacy than plasma concentrations
WHY SWINE MODEL IS IDEAL FOR DERMAL PK STUDIES
Porcine skin is increasingly being employed as a substitute model for human skin in various research fields including pharmacology, toxicology and immunology, with particular interest in percutaneous permeation and organ transplantation. Porcine skin shows several anatomical and physiological similarities with human skin as depicted below :
Comparative histological aspect of porcine (A) and human (B) skin (haematoxylin-eosin-saffron staining). HF: hair follicle, Mu and arrowhead: arrector pili muscle, SwG: Sweat gland, SG: sebaceous gland, Ad: Adipocytes (hypodermis). Porcine skin.
Comparison of Human & Animal Skin Thickness
The porcine ear skin is most often used as surrogate to human skin due to average of 20 hairs per cmÂ² as porcine ear skin is similar to 14-32 hairs per cmÂ² in humans.