Compositions comprising polymers comprising one or more ketal, monothioketal, and/or thioketal bonds are provided, as well as related methods and kits. In some embodiments, a polymer may comprise one or more repeat units comprising one or more ketal, monothioketal, and/or thioketal bonds and a precursor of a pharmaceutically active agent. The precursor of the pharmaceutically active agent may be located in the backbone or may be a pendant group. The polymer may degrade in certain environments (e.g., aqueous environments, acidic environments, in vivo, etc.) to produce the pharmaceutically active agent and other biocompatible degradation f) products, such as certain ketones, alcohols, and/or thiols. Regardless of the location of the precursor of the pharmaceutically active agent in the repeat unit(s), the polymer may have a prolonged degradation time and/or release of the pharmaceutically active agent in certain environments. Various compositions, described herein, may be particularly well suited for applications requiring extended release of pharmaceutically active agents, such as the treatment of ophthalmic disorders.
