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How can dendrimers enhance the solubility of APIs?

There is a growing need to improve the solubility of active pharmaceutical ingredients (APIs) – around 40% of APIs currently on the market show poor solubility and many candidates with potential to enter the market will present solubility issues. Addressing these challenges can be achieved by forming a salt of the API, adding chemical groups to tune solubility, reducing the particle size of the formulation, or using drug carriers.

Polymer Factory’s bis-MPA polyester dendrimers have great potential increasing the solubility of APIs, both through chemical attachment and as drug delivery vehicles where the API is physically entrapped. Bis-MPA dendrimers are shown to present low toxicity and are biodegradable under physiological conditions, making them ideal candidates as drug delivery systems and excipients.

Our dendrons and dendrimers are available with a wide range of chemical functionalities, including click chemistry groups and common bioconjugation motifs such as NHS esters, amines, and carboxylic acids. This allows selection of an appropriate molecule for covalent attachment or physical entrapment of APIs to generate nano-carriers in a straightforward approach.

A research group at Universidade da Madeira has recently reported the loading of bis-MPA dendrimers with anti-cancer drug doxorubicin (DOX). The researchers used generation 4 and 5 dendrimers functionalized with either hydroxyl groups or a combination of hydroxyl and amine end groups. Both dendrimer types were found to be cytocompatible, and the loading and release of DOX could be controlled through variation of the surface functionality.

A study by Frechét, Szoka et al covalently attached DOX to bifunctional bis-MPA dendrimers, to form a sophisticated nano-carrier equipped with pH sensitive linkers and PEG groups capable of extending the circulation time of the conjugate. In studies with mice bearing C-26 colon carcinomas, the dendrimer loaded with DOX was found to be 10 times less toxic than free DOX with tumor uptake 9 times higher. The dendrimer loaded with DOX was found to have a similar effect to liposomal Doxil.

Related bifunctional dendrimers have been launched by Polymer Factory as BowtieD® dendrimers.


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