Biodegradable Self-Assembling PEG-Copolymer as Vehicle for Poorly Water-Soluble Drugs

Abstract

Purpose. To develop self-assembling systems increasing the solubility of poorly water-soluble drugs. Methods. Low molecular weight liquid biodegradable copolymers were synthesized by ring-opening polymerization using caprolactone (CAP) and trimethylenecarbonate (TMC) as monomers. Various initiators were evaluated. The emulsifying and self-assembling properties were investigated by a water titration method. The selfassembling systems were characterized for size, shape, isotropic behavior, cloud point, surface charge, and critical micellar concentration in order to optimize the polymer synthesis. Finally, the improvement of solubility of model drugs was assessed. Results. Only diblock monomethyl ether PEG-CAP/TMC copolymers synthesized with monomethyl ether polyethyleneglycol 550 to 2000 as initiator have shown self-assembling properties: upon dilution, these copolymers formed an isotropically clear solution with droplet sizes in the range of 20 to 100 nm. The hypothesis that these diblock polymers form micelles was confirmed by their low critical micellar concentration (10 −5 g/ml). The copolymers initated with mmePEG750 had a higher cloud point and better colloidal stability than those initiated with mmePEG 550. The solubility of the poorly water-soluble drugs was increased by 1 to 2 orders of magnitude. Good reproducibility was observed from batch to batch. Conclusions. The polyester diblock copolymer mmePEG750-CAP/ TMC forms spontaneously stable micelles in aqueous medium and increases the solubility of lipophilic drugs. They are very promising vehicles for the oral delivery of poorly water-soluble drugs.

Paclitaxel-loaded micelles enhance transvascular permeability and retention of nanomedicines in tumors

“…The weight-averaged molecular weight (M w ) of mmePEG 750 -p-(CL-co-TMC) were 5242 Da (PD = 1.9). The polymer critical micellar concentration was previously determined, using the fluorescent probe method, in the range of 20 mg/ ml (0.002%; w/v) (Ould-Ouali et al, 2004). The polymers were liquid at room temperature and formed micelles spontaneously in the presence of aqueous media.…”

Efficient Peroral Delivery of Insulin via Vitamin B12 Modified Trimethyl Chitosan Nanoparticles

“…Transepithelial electrical resistance (TEER) of the monolayer was measured using a Millicell-ERS (Millipore, MA, USA) to determine the integrity formation of the monolayer before the experiment. Typical TEER values exceeded 550 Ω·cm (25).…”

Fate of polymeric nanocarriers for oral drug delivery

“…This polymer spontaneously self-assembles in micelles in aqueous solutions, increases the solubility of poorly soluble drugs by 1 to 3 orders of magnitude [38] and enhances their oral bioavailability [39,40].…”

“…Much work has been carried out on the design and preparation of polymeric nanocarriers (nanoparticles and micelles) [1][2][3][4][10][11][12][13][14][15][27][28][29][30]37,38]. Their use as oral delivery system has been rather extensively studied but the behaviour of these nanocarriers in the GI tract has been given less attention.…”