Development and Evaluation of Optimized Sucrose Ester Stabilized Oleanolic Acid Nanosuspensions Prepared by Wet Ball Milling with Design of Experiments

Abstract

The aim of this study was to develop optimized sucrose ester (SE) stabilized oleanolic acid (OA) nanosuspensions (NS) for enhanced delivery via wet ball milling by design of experiments (DOE). In this study, SEOA NS batches were prepared by wet ball milling method. Mean particle sizes and polydispersity indices were determined using a nanosizer. The percent encapsulation efficiency, saturation solubility and in vitro dissolution rate were obtained with analyses using HPLC. Preparation methods were optimized by DOE using the Minitab software. The in vitro bioefficacy was obtained by methyl thiazolyl tetrazolium (MTT) measurements in A549 human non small cell lung cancer cell line. The in vivo pharmacokinetics profile was determined using LC-electrospray ionization (ESI)-MS/MS. The study produced spherical SEOA NS particles (ca. 100 nm in diameter) which were found to be able to increase OA saturation solubility considerably. Optimized SEOA-GBD NS (milled at 600 rpm for 3 h, sucrose monolaurate (SEL) : sucrose monopalmitate (SEP) at 9 : 1, w/w; SE : OA at 1 : 1, w/w) was found to be physically stable over 14 d at 4°C. The NS showed much higher dissolution rate, cytotoxicity and bioavailability when compared with the free drug. Thus, the prepared OA as SE stabilized NS particles by wet ball milling enhanced the saturation solubility, in vitro dissolution rate, bioefficacy and in vivo bioavailability of OA. The use of sugar esters may also be potentially applied to other hydrophobic drugs.Key words oleanolic acid; sucrose ester; nanosuspension; bioavailability; solubility; design of experiments (DOE)In the search for lead drug compounds, nature-derived compounds remain one of the important sources. Many of them have problems associated with low aqueous solubility, low dissolution rate, and consequently, poor bioavailability which limit their potential therapeutic usefulness. 1,2) Oleanolic acid (OA) is a poorly water-soluble plant-derived triterpenoid which exists widely in natural plants in the form of free acid or aglycones for triterpenoid saponins.3) It has shown to possess hepatoprotective effects, used in both acute liver injury and chronic liver fibrosis and cirrhosis. 4) In addition, OA had been reported to possess anti-cancer effects including inhibition of tumor initiation and promotion, and induction of tumor cell differentiation and apoptosis. 5,6) Other reported pharmacological activities include anti-inflammatory, 7) antimicrobial activity, 8) hypolipidemic and anti-diabetic effects. 9) However, the low bioavailability of OA limits its application.The low dissolution rate and poor bioavailability of poorly soluble drugs may be mitigated by altering drugs' particle sizes. 10,11) The formation of nanosuspension (NS) increased the surface area of a drug due to reduced particle size can improve drug dissolution rate and is often accepted as one of the most expeditious and cost-effective method to improve the dissolution properties of poorly water-soluble drugs. Wet ball milling is a common top-down method ...

An Overview of Discrete Nanoformulated Flavonoids and Its Implication in Cancer

“…The nanosuspension of oleanolic acid is prepared by wet ball milling technique with sucrose ester as a stabilizer. The nanosuspension oleanolic acid showed an increased inefficacy in A549 lung cancer cell line, and elevate the bioavailability of oleanolic acid [39].…”

Solubility and Permeability Enhancement of Oleanolic Acid by Solid Dispersion in Poloxamers and γ-CD

“…OA belongs to the Biopharmaceutics Classification System (BSC) class IV, and it has a very low water solubility of about 1 µg/mL and poor permeability [6,7], which usually results in low oral bioavailability and limited use in clinical treatments. Many attempts have been made to overcome these drawbacks, such as the use of solid lipid nanoparticles [8], nanosuspensions [9][10][11], self-nanoemulsified formulations [12], phospholipid complexes [13], and solid dispersions [14][15][16].…”