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The solvent-assisted active loading technology (SALT) was developed for encapsulating a water insoluble weak base into the liposomal core in the presence of 5% DMSO. In this study, we further examined the effect of various water miscible solvents in promoting active loading of other types of drugs into liposomes. To achieve complete drug loading, the amount of solvent required must result in complete drug solubilization and membrane permeability enhancement, but must be below the threshold that induces liposomal aggregation or causes bilayer disruption. We then used the SALT to load gambogic acid (GA, an insoluble model drug that shows promising anticancer effect) into liposomes, and optimized the loading gradient and lipid composition to prepare a stable formulation (Lipo-GA) that displayed >95% drug retention after incubation with serum for 3 days. Lipo-GA contained a high drug-to-lipid ratio of 1/5 (w/w) with a mean particle size of ∼75 nm. It also displayed a prolonged circulation half-life (1.5 h vs. 18.6 h) and enhanced antitumor activity in two syngeneic mice models compared to free GA. Particularly, complete tumor regression was observed in the EMT6 tumor model for 14 d with significant inhibition of multiple oncogenes including HIF-1α, VEGF-A, STAT3, BCL-2, and NF-κB., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

We have developed a polymer conjugate (Cellax) composed of acetylated carboxymethylcellulose (CMC), docetaxel (DTX), and PEG, designed to enhance the pharmacokinetics (PK) and antitumor efficacy of DTX. Our design placed an emphasis on nanoparticle self-assembly to protect DTX during blood transport, stability of the nanoparticle, and PEGylation to enhance PK. Compared to Taxotere, Cellax exhibited a 38.6 times greater area under the curve (AUC), and significantly lower clearance (2.5%) in PK. Less than 10% of DTX was released from Cellax in the blood circulation, indicating that Cellax were stable during blood transport. Cellax reduced non-specific distribution of DTX to the heart, lung and kidney by 48, 90, and 90%, respectively, at 3 h, compared to Taxotere. The uptake of Cellax at 3 h in the liver and spleen was high (15-45 μg DTX/g) but declined rapidly to <10 μg DTX/g in 24 h, and induced no measurable toxicity at 170 mg DTX/kg. Taxotere, on the other hand, displayed non-specific uptake in all the examined normal tissues and induced significant apoptosis in the lung and kidney at 40 mg DTX/kg. The tumor uptake of Cellax was 5.5-fold more than that by Taxotere and the uptake occurred within 3 h after injection and persisted for 10 days. The conjugate exhibited enhanced efficacy in a panel of primary and metastatic mouse tumor models. These results clearly demonstrated that Cellax improved the pharmacokinetics, biodistribution and efficacy of DTX compared to Taxotere with reduced toxicity., (Copyright © 2011 Elsevier Ltd. All rights reserved.)