TY - JOUR
T1 - Investigation of effects of terpene skin penetration enhancers on stability and biological activity of lysozyme
AU - Varman, Rahul M.
AU - Singh, Somnath
N1 - Funding Information:
This study was funded by the Health Future Foundation, Creighton University, Omaha, Nebraska.
PY - 2012/12
Y1 - 2012/12
N2 - The transport of proteins through skin can be facilitated potentially by using terpenes as chemical enhancers. However, we do not know about the effects of these enhancers on the stability and biological activity of proteins which is crucial for the development of safe and efficient formulations. Therefore, this project investigated the effects of terpene-based skin penetration enhancers which are reported as nontoxic to the skin (e.g., limonene, p-cymene, geraniol, farnesol, eugenol, menthol, terpineol, carveol, carvone, fenchone, and verbenone), on the conformational stability and biological activity of a model protein lysozyme. Terpene (5% v/v) was added to lysozyme solution and kept for 24 h (the time normally a transdermal patch remains) for investigating conformational stability profiles and biological activity. Fourier transform infrared spectrophotometer was used to analyze different secondary structures, e.g., α-helix, β-sheet, β-turn, and random coil. Conformational changes were also monitored by differential scanning calorimeter by determining midpoint transition temperature (Tm) and calorimetric enthalpy (ΔH). Biological activity of lysozyme was determined by measuring decrease in A 450 when it was added to a suspension of Micrococcus lysodeikticus. The results of this study indicate that terpenes 9, 10, and 11 (carvone, l-fenchone, and l-verbenone) decreased conformational stability and biological activity of lysozyme significantly (p <0.05) less than other terpenes used in this study. It is concluded that smaller terpenes containing ketones with low lipophilicity (log K ow ∼2.00) would be optimal for preserving conformational stability and biological activity of lysozyme in a transdermal formulation containing terpene as permeation enhancer.
AB - The transport of proteins through skin can be facilitated potentially by using terpenes as chemical enhancers. However, we do not know about the effects of these enhancers on the stability and biological activity of proteins which is crucial for the development of safe and efficient formulations. Therefore, this project investigated the effects of terpene-based skin penetration enhancers which are reported as nontoxic to the skin (e.g., limonene, p-cymene, geraniol, farnesol, eugenol, menthol, terpineol, carveol, carvone, fenchone, and verbenone), on the conformational stability and biological activity of a model protein lysozyme. Terpene (5% v/v) was added to lysozyme solution and kept for 24 h (the time normally a transdermal patch remains) for investigating conformational stability profiles and biological activity. Fourier transform infrared spectrophotometer was used to analyze different secondary structures, e.g., α-helix, β-sheet, β-turn, and random coil. Conformational changes were also monitored by differential scanning calorimeter by determining midpoint transition temperature (Tm) and calorimetric enthalpy (ΔH). Biological activity of lysozyme was determined by measuring decrease in A 450 when it was added to a suspension of Micrococcus lysodeikticus. The results of this study indicate that terpenes 9, 10, and 11 (carvone, l-fenchone, and l-verbenone) decreased conformational stability and biological activity of lysozyme significantly (p <0.05) less than other terpenes used in this study. It is concluded that smaller terpenes containing ketones with low lipophilicity (log K ow ∼2.00) would be optimal for preserving conformational stability and biological activity of lysozyme in a transdermal formulation containing terpene as permeation enhancer.
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U2 - 10.1208/s12249-012-9840-1
DO - 10.1208/s12249-012-9840-1
M3 - Article
C2 - 22930344
AN - SCOPUS:84871641533
VL - 13
SP - 1084
EP - 1090
JO - AAPS PharmSciTech
JF - AAPS PharmSciTech
SN - 1530-9932
IS - 4
ER -