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A sensitive and effective method has been developed for the rapid determination of polysorbate-80 content in therapeutic monoclonal antibody (mAb) products. The method is based on the detection of the fluorescence emission of 4,4 0 -dianilino-1,1 0 -binaphthyl-5,5 0 disulfonic acid dipotassium salt (bis-ANS) enhanced by the presence of polysorbate-80. The developed method includes two approaches. One requires removal of the mAb from solution prior to analysis, while the other requires only simple sample dilution. The limits of detection and quantitation, calculated from the calibration curve generated in the absence of mAb-A, were 1.5 and 4.7 parts per million, respectively. Given the comparable linear range and linearity of the linear line between the solutions, with or without mAb, the limit of detection and quantitation is assumed to be similar. The dilution method is not only fast and simple in terms of sample preparation, but it is also particularly useful for analyzing the level of polysorbate-80 contained in highly concentrated mAb products. However, given that this method does require availability of polysorbate-80-free materials of mAb for preparation of calibration standards, the protein removal method may be useful for the cases where appropriate protein materials for standard preparation are limited or unavailable.

PEGylated poly(carboxylic acid)s, PEG-b-PCAs, were evaluated as additives for solubilized oral formulations of weakly acidic compounds. Micelles of poly(ethylene glycol)-block-poly(acrylic acid), PEG-b-PAA, and poly(ethylene glycol)-block-poly(methacrylic acid), PEG-b-PMAA, were prepared. Fluorescence spectroscopy and dynamic light scattering revealed that both polymers assemble into nanoscopic structures (200 nm) in acidic media and exhibit pH-sensitive colloidal phase behavior. Using a solvent evaporation technique, the block copolymers and corresponding PCA homopolymers were incorporated into PEG3350-based solid dispersions. The kinetic solubility profile of a BMS compound, BMS-A (Seq ~ 12.5 μg/mL at pH 1.1) in 0.1 N HCl was monitored as a function of polymer composition. While BMS-A precipitated rapidly in 0.1 N HCl in the absence of PEG-b-PCAs, a supersaturated level of ca. 400 μg/mL was maintained for variable lengths of time in the presence of PEG-b-PCAs. Although the kinetic solubility of BMS-A was also enhanced in the presence of the PCA homopolymers, the relative magnitude and duration of supersaturation as a function of polymer composition suggests that micellar solubilization, rather than specific interaction, contributes to enhanced solubility of BMS-A in 0.1 N HCl. Under acidic conditions, pH-responsive PEG-b-PCAs may offer the kinetic supersaturation necessary to minimize precipitation of compounds which have limited solubility in acidic milieu.

Derivatives of poly(ethylene oxide)-block-poly(beta-benzyl-aspartate), 12:25 have been prepared via aminolysis of the benzyl protecting group with 6-amino-1-hexanol, followed by subsequent acylation with acetic anhydride, hexanoic acid, lauric acid, or stearic acid. A series of amphiphilic diblock copolymers based on poly(ethylene oxide)-block-poly(N-hexyl-aspartamide)acyl conjugates with various acyl chain lengths have been prepared. The extent of esterification was determined by 1H-NMR. Aqueous micelle solutions were prepared by a dialysis method and the polymer series was characterized as a function of the acyl chain length. Transmission electron microscopy and dynamic light scattering revealed micelle-like structures of nanoscopic dimensions (< 100 nm). Environmentally sensitive fluorescent probes were loaded into the micelles in order to study the properties of the hydrophobic microdomain and to determine the critical micelle concentration (CMC). Steady-state fluorescence measurements indicated that the relative apparent core viscosity and polarity are modulated by the relative length of the attached acyl chains, as is the CMC. Increasing the acyl chain length results in a decreased CMC and a more viscous and less polar core region. Carefully chosen chemical moieties can be introduced in order to influence the properties of the poly(L-Asp) blocks of the micelles. As a result, the micellar properties can be altered via chemical modification in order to impact several key properties relevant to drug delivery.