The importance of controlled-release injections in drug delivery, including
the recent technological developments in injectable emulsions, liposomes, and
nanosuspensions for parenteral drug delivery, is discussed in four major sections in the
current chapter. The 1st section delves into the application of these systems for poorly
soluble drugs, proteins/peptides, vaccines, and gene therapeutics, highlighting their
potential to overcome challenges associated with bioavailability, stability, and targeted
delivery. In the 2n
d section, injectable emulsions are discussed as a formulation to
overcome key formulation tasks such as solubilization of poorly water-soluble drugs as
well as drugs susceptible to hydrolysis. The utility of injectable nanoemulsions exhibits
enhanced stability and tissue penetration, while multiple emulsions show promise
despite inherent complexity. Microemulsions offer a thermodynamically stable option
for parenteral drug delivery. Tactics for improving poorly water-soluble drug delivery,
sustained release, and targeted delivery using injectable emulsions are discussed. It also
offers an overview of the physical and chemical properties and approaches used for the
preparation of emulsion formulations. Emulsion stability assessments and
characterization parameters essential for formulation development are also highlighted.
An overview of the physicochemical characteristics of liposomes and the process by
which drug-containing liposomes are formed is given in the 3rd part. It reviews a
number of liposome preparation techniques, along with the number of drug loading and
encapsulating methods. Examples of marketed and experimental products are provided
while discussing the usage of injectable liposomes as a medication delivery vehicle. In
the 4th section, nanosuspensions as a promising tactic for the formulation using the
poorly water-soluble and poorly bioavailable drug candidates is discussed. The section
navigates the complexities of manufacturing, emphasizing the importance of particle
size distribution for stability. It explores diverse nanoparticle manufacturing techniques
for formulating injectable nanosuspensions. Focusing on injectable nanosuspensions, it
involves the application in controlled release, highlighting the significance of
excipients, particle size, syringeability, and sterility for successful formulation.
Keywords: Controlled-release injections, Injectable nanoemulsions, Injectable nanosuspensions, Injectable liposomes, Microemulsions.
