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Preparation and Characterization of Self-Microemulsifying Drug Delivery System of Olmesartan Medoxomil for Bioavailability Improvement.

Prajapati ST, Joshi HA, Patel CN - J Pharm (Cairo) (2012)

Bottom Line: The optimized formulation S2 contained OLM (20 mg), Tween 80 (33%v/v), Transcutol P (33%v/v), and Acrysol EL 135 (34%v/v) had shown the smallest particle size, maximum solubility, less emulsification time, good optical clarity, and in vitro release.The in vitro and ex vivo diffusion rate of the drug from the SMEDDS was significantly higher than that of the plain drug suspension.It was concluded that SMEDDS would be a promising drug delivery system for poorly water-soluble drugs by the oral route.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutics and Pharmaceutical Technology, Shri Sarvajanik Pharmacy College, Near Arvind Buag, Gujarat, Mehsana 384001, India.

ABSTRACT
Olmesartan medoxomil (OLM) is an angiotensin II receptor blocker (ARB) antihypertensive agent administered orally that has absolute bioavailability of only 26% due to the poor aqueous solubility (7.75 μg/ml). The aim of the present investigation was to develop a self-microemulsifying drug delivery system (SMEDDS) to enhance the oral absorption of OLM. The solubility of OLM in various oils, surfactants, and cosurfactants was determined. Pseudoternary phase diagrams were constructed using Acrysol EL 135, Tween 80, Transcutol P, and distilled water to identify the efficient self-microemulsification region. Prepared SMEDDS was further evaluated for its emulsification time, drug content, optical clarity, droplet size, zeta potential, in vitro dissolution, and in vitro and ex vivo drug diffusion study. The optimized formulation S2 contained OLM (20 mg), Tween 80 (33%v/v), Transcutol P (33%v/v), and Acrysol EL 135 (34%v/v) had shown the smallest particle size, maximum solubility, less emulsification time, good optical clarity, and in vitro release. The in vitro and ex vivo diffusion rate of the drug from the SMEDDS was significantly higher than that of the plain drug suspension. It was concluded that SMEDDS would be a promising drug delivery system for poorly water-soluble drugs by the oral route.

No MeSH data available.


(a) Surfactant/co-surfactant 1 : 1, (b) surfactant/co-surfactant 1.5 : 1, and (c) surfactant/co-surfactant 2 : 1. Pseudoternary phase diagram of the system, Acrysol EL 135, Tween 80: Transcutol P, and water.
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fig2: (a) Surfactant/co-surfactant 1 : 1, (b) surfactant/co-surfactant 1.5 : 1, and (c) surfactant/co-surfactant 2 : 1. Pseudoternary phase diagram of the system, Acrysol EL 135, Tween 80: Transcutol P, and water.

Mentions: Pseudoternary phase diagrams were constructed in the absence of OLM to identify the self-emulsifying regions and to optimize the concentration of oil, surfactant, and co-surfactant in the SMEDDS formulations. A series of the SMEDDSs were prepared, and their self-emulsifying properties were observed visually. The phase diagrams were constructed at surfactant/co-surfactant ratios of 1 : 1, 1.5 : 1, and 2 : 1 (v/v). Phase diagram of different surfactant and co-surfactant ratio is shown in Figure 2. The gel-like region was found to become large with the increasing concentration of Tween 80, while the self-microemulsifying region decreased. The maximum self-microemulsifying region had to be at a ratio of 1 : 1. However, the drug precipitation was observed after several hours at ratios of 1.5 : 1 and 2 : 1. Cosurfactants are beneficial to form a microemulsion at a proper concentration range. However, an excessive amount of the co-surfactant will cause the system to become less stable for its intrinsic high aqueous solubility and lead to the droplet size increasing as a result of the expanding interfacial film [21]. Hence, the optimal ratio of surfactant to co-surfactant was selected to be 1 : 1 as shown in Figure 3.


Preparation and Characterization of Self-Microemulsifying Drug Delivery System of Olmesartan Medoxomil for Bioavailability Improvement.

Prajapati ST, Joshi HA, Patel CN - J Pharm (Cairo) (2012)

(a) Surfactant/co-surfactant 1 : 1, (b) surfactant/co-surfactant 1.5 : 1, and (c) surfactant/co-surfactant 2 : 1. Pseudoternary phase diagram of the system, Acrysol EL 135, Tween 80: Transcutol P, and water.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4595970&req=5

fig2: (a) Surfactant/co-surfactant 1 : 1, (b) surfactant/co-surfactant 1.5 : 1, and (c) surfactant/co-surfactant 2 : 1. Pseudoternary phase diagram of the system, Acrysol EL 135, Tween 80: Transcutol P, and water.
Mentions: Pseudoternary phase diagrams were constructed in the absence of OLM to identify the self-emulsifying regions and to optimize the concentration of oil, surfactant, and co-surfactant in the SMEDDS formulations. A series of the SMEDDSs were prepared, and their self-emulsifying properties were observed visually. The phase diagrams were constructed at surfactant/co-surfactant ratios of 1 : 1, 1.5 : 1, and 2 : 1 (v/v). Phase diagram of different surfactant and co-surfactant ratio is shown in Figure 2. The gel-like region was found to become large with the increasing concentration of Tween 80, while the self-microemulsifying region decreased. The maximum self-microemulsifying region had to be at a ratio of 1 : 1. However, the drug precipitation was observed after several hours at ratios of 1.5 : 1 and 2 : 1. Cosurfactants are beneficial to form a microemulsion at a proper concentration range. However, an excessive amount of the co-surfactant will cause the system to become less stable for its intrinsic high aqueous solubility and lead to the droplet size increasing as a result of the expanding interfacial film [21]. Hence, the optimal ratio of surfactant to co-surfactant was selected to be 1 : 1 as shown in Figure 3.

Bottom Line: The optimized formulation S2 contained OLM (20 mg), Tween 80 (33%v/v), Transcutol P (33%v/v), and Acrysol EL 135 (34%v/v) had shown the smallest particle size, maximum solubility, less emulsification time, good optical clarity, and in vitro release.The in vitro and ex vivo diffusion rate of the drug from the SMEDDS was significantly higher than that of the plain drug suspension.It was concluded that SMEDDS would be a promising drug delivery system for poorly water-soluble drugs by the oral route.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutics and Pharmaceutical Technology, Shri Sarvajanik Pharmacy College, Near Arvind Buag, Gujarat, Mehsana 384001, India.

ABSTRACT
Olmesartan medoxomil (OLM) is an angiotensin II receptor blocker (ARB) antihypertensive agent administered orally that has absolute bioavailability of only 26% due to the poor aqueous solubility (7.75 μg/ml). The aim of the present investigation was to develop a self-microemulsifying drug delivery system (SMEDDS) to enhance the oral absorption of OLM. The solubility of OLM in various oils, surfactants, and cosurfactants was determined. Pseudoternary phase diagrams were constructed using Acrysol EL 135, Tween 80, Transcutol P, and distilled water to identify the efficient self-microemulsification region. Prepared SMEDDS was further evaluated for its emulsification time, drug content, optical clarity, droplet size, zeta potential, in vitro dissolution, and in vitro and ex vivo drug diffusion study. The optimized formulation S2 contained OLM (20 mg), Tween 80 (33%v/v), Transcutol P (33%v/v), and Acrysol EL 135 (34%v/v) had shown the smallest particle size, maximum solubility, less emulsification time, good optical clarity, and in vitro release. The in vitro and ex vivo diffusion rate of the drug from the SMEDDS was significantly higher than that of the plain drug suspension. It was concluded that SMEDDS would be a promising drug delivery system for poorly water-soluble drugs by the oral route.

No MeSH data available.