In vitro and in vivo evaluation of capsaicin-loaded microemulsion for enhanced oral bioavailability.
BACKGROUND
Capsaicin, as a food additive, has attracted worldwide concern owing to its pungency and multiple pharmacological effects. However, poor water solubility and low bioavailability have limited its application. This study aims to develop a capsaicin-loaded microemulsion to enhance the oral bioavailability of the anti-neuropathic-pain component, capsaicin, which is poorly water soluble.


RESULTS
In this study, the microemulsion consisting of Cremophor EL, ethanol, medium-chain triglycerides (oil phase) and water (external phase) was prepared and characterized (particle size, morphology, stability and encapsulation efficiency). The gastric mucosa irritation test of formulated capsaicin was performed in rats to evaluate its oral feasibility, followed by the pharmacokinetic study in vivo. Under these conditions, the encapsulated capsaicin revealed a faster capsaicin release in vitro coupled with a greater absorption in vivo when compared to the free capsaicin. The oral bioavailability of the formulated capsaicin-loaded microemulsions was 2.64-fold faster than that of free capsaicin. No significant irritation was observed on the mucosa from the pathological section of capsaicin-loaded microemulsion treated stomach.


CONCLUSIONS
These results indicate that the developed microemulsion represents a safe and orally effective carrier for poorly soluble substances. The formulation could be used for clinical trials and expand the application of capsaicin.
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Yuan
Y
Zhu
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Jiajia
J
Zhang
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Qianfeng
Q
Zheng
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Miaomiao
M
Wang
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Wenwen
W
Deng
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Qiang
Q
Li
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Caleb Kesse
CK
Firempong
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Shengli
S
Wang
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Shanshan
S
Tong
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Ximing
X
Xu
Department of Pharmaceutics, School of Pharmacy, Center for Nano Drug/Gene Delivery and Tissue Engineering, Jiangsu University, Zhenjiang, 212013, People's Republic of China.
Jiangnan
J
Yu
D000284:Administration, Oral; D000700:Analgesics / Q000008:administration & dosage / Q000493:pharmacokinetics; D000818:Animals; D001682:Biological Availability; D002211:Capsaicin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002212:Capsicum / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D004655:Emulsions; D005753:Gastric Mucosa / Q000187:drug effects; D008297:Male; D010316:Particle Size; D010936:Plant Extracts / Q000008:administration & dosage* / Q000493:pharmacokinetics; D017207:Rats, Sprague-Dawley; D012995:Solubility
D000700:Analgesics; D004655:Emulsions; D010936:Plant Extracts; D002211:Capsaicin
bioavailability; capsaicin; in vitro release; irritation; microemulsion