Achieving synergism,
often by combination therapy via codelivery
of chemotherapeutic agents, remains the mainstay of treating multidrug-resistance
cases in cancer and microbial strains. With a typical core–shell
architecture and surface functionalization to ensure facilitated targeting
of tissues, nanocarriers are emerging as a promising platform toward
gaining such synergism. Co-encapsulation of disparate theranostic
agents in nanocarriersfrom chemotherapeutic molecules to imaging
or photothermal modalitiescan not only address the issue of
protecting the labile drug payload from a hostile biochemical environment
but may also ensure optimized drug release as a mainstay of synergistic
effect. However, the fate of co-encapsulated molecules, influenced
by temporospatial proximity, remains unpredictable and marred with
events with deleterious impact on therapeutic efficacy, including
molecular rearrangement, aggregation, and denaturation. Thus, more
than just an art of confining multiple therapeutics into a 3D nanoscale
space, a co-encapsulated nanocarrier, while aiming for synergism,
should strive toward achieving a harmonious cohabitation of the encapsulated
molecules that, despite proximity and opportunities for interaction,
remain innocuous toward each other and ensure molecular integrity.
This account will inspect the current progress in co-encapsulation
in nanocarriers and distill out the key points toward accomplishing
such synergism through reciprocity.