Unlike the small organic molecules that have traditionally been used in drugs, proteins have chemical and physical properties that can cause instability and product variability. Instability occurs when protein therapeutics undergo chemical and physical changes during manufacturing, shipping, storage and administration. Physical instability such as aggregation or precipitation can negatively affect drug dosage, efficacy, and…

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With the Nicomp 380 ZLS it is possible to not only size proteins but also determine their isoelectric point (IEP). Ampules of bovine serum albumin (BSA) were purchased from Sigma Aldrich and diluted 1:100 with deionized water. Figure A below shows the volume-weighted mean particle diameter to be 5.5 nm. Aggregates of ~25nm were also detected.…

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The technique of single particle optical sizing (SPOS) is known to produce particle size distribution (PSD) results of highest sensitivity and resolution over a wide size range, making it a uniquely powerful tool for assessing the quality and stability of a wide range of colloidal dispersions and suspensions. In particular, SPOS based on the method…

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The Nicomp 380 was out in the field recently for a demonstration with a major chemical company and the operator was presented with a customer-made bimodal prepared by mixing a 150 nm polystyrene latex and a 350 nm polystyrene latex together to form a bimodal particle size distribution. And once again, without any input from…

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