Block the bitter: Microencapsulation of zidovudine as a taste masking technique for drug inclusion into an oral thin film.

HIV infections among children have been on the decline since the introduction of infant HIV prophylaxis regimens including the HIV reverse transcriptase inhibitor, zidovudine (ZDV). This makes adherence to ZDV and other HIV medications paramount for the survival of young infants and children across the globe. However, the large dose volume and extremely bitter taste of ZDV often results in infants spitting up the medication, resulting in inaccurate dosing. Inclusion of ZDV into an oral thin film (OTF) would reduce the dose volume required, thus improving adherence to the medication regimen. To overcome the poor taste of ZDV, we created encapsulated ZDV (eZDV) formulations via spray-drying and evaluated polymer selection and ZDV particle size as potential avenues for effectively reducing the release of ZDV in simulated salivary fluid (SSF). The combined use of Eudragit E PO (EPO) and ethylcellulose (EC) was found to be the most effective polymer coating for reducing the release of ZDV. The optimal formulation ratio was determined to be 5:20:75 (EC:EPO:ZDV) to maintain high drug load while still reducing the dissolution of ZDV in SSF. Additionally, mortar-and-pestling ZDV prior to spray drying allowed for less variability and a more homogenous spread of eZDV throughout an OTF. These factors ultimately resulted in eZDV loaded OTFs that were able to successfully reduce the release of ZDV in SSF below its taste detection threshold.