biostudies-literatureUnknown9(37)Wang JSodium foscarnet is an antiviral drug against cytomegalovirus retinitis, and clinically it is used <i>via</i> frequent intravitreal injection which causes various ocular complications. Here we propose to use benzathine foscarnet in a new salt form with much lower aqueous solubility, and as a potential long-acting intravitreally injectable solid form for foscarnet. Benzathine foscarnet (1 : 1) microcrystals were synthesized and evaluated both <i>in vitro</i> and <i>in vivo</i>. The aqueous solubility of benzathine foscarnet was 14.2 mM, which is in between those of the currently-used sodium foscarnet and our previously-reported calcium foscarnet salt. In a rabbit model, the injected microcrystals last for about 3 weeks in the vitreous, suggesting its solubility and dissolution profile is apRSC advances21318-21322https://www.ebi.ac.uk/biostudies/studies/S-EPMC9066022biostudies-literature<i>In vitro</i> and <i>in vivo</i> evaluation of benzathine foscarnet microcrystals as a potential intravitreal drug depot.PMC9066022Liu JFeng JHuang YTao YWang JNiu Yfalse<i>In vitro</i> and <i>in vivo</i> evaluation of benzathine foscarnet microcrystals as a potential intravitreal drug depot.Sodium foscarnet is an antiviral drug against cytomegalovirus retinitis, and clinically it is used <i>via</i> frequent intravitreal injection which causes various ocular complications. Here we propose to use benzathine foscarnet in a new salt form with much lower aqueous solubility, and as a potential long-acting intravitreally injectable solid form for foscarnet. Benzathine foscarnet (1 : 1) microcrystals were synthesized and evaluated both <i>in vitro</i> and <i>in vivo</i>. The aqueous solubility of benzathine foscarnet was 14.2 mM, which is in between those of the currently-used sodium foscarnet and our previously-reported calcium foscarnet salt. In a rabbit model, the injected microcrystals last for about 3 weeks in the vitreous, suggesting its solubility and dissolution profile is ap2019-01-01T00:00:00Z2019 Jul2025-04-05T14:43:14.179Z2024-10-15T07:35:35.59ZS-EPMC90660223552134110.1039/c9ra03070k