*Lipid Nanoparticulate Drug Delivery Systems: Approaches toward Improvement in Therapeutic… DOI: http://dx.doi.org/10.5772/intechopen.104510*

biodegradable lipid materials, surfactants, and co-surfactants that are generally recognized as safe (GRAS) by food and drug admirations [3].

Vesicles-based drug delivery was the first among the different LNs targeted carrier formulations discovered in 1965 and is still widely accepted in the fabrication of novel pharmaceutical formulations [4]. The word liposome is derived from the Greek words "lipid" which means fat and "soma" which means body. Liposomes are spherical vesicles with a hydrophobic internal sac-like structure enclosed with a lipid bilayer membrane. Moreover, several advantages associated with VDDs include low toxicity, flexibility, cyto-compatibility, biodegradable, protection of active moiety from enzymatic degradation, and non-immunogenicity [5–7]. However, most of the uses in formulations indicate limitations due to specific disadvantages such as low encapsulation efficacy, poor stability, limited shelf-life, and intermembrane transfer [8].

Solid lipid nanoparticles were introduced in the late 90,s as a potential substitute against the carrier-based VDD, emulsion, and polymeric nanoparticles. These carrierbased nanoparticulate offers advantages of spherical size (40–1000 nm), shape, and morphology, composed of single or multiple combined lipids with surfactants, where the dispersed phase is solid lipid fats and surfactant, which act as an emulsifier [9]. The selection and composition of lipid and surfactant affect the physicochemical properties and quality such as drug loading and particle size. The proper combination of lipids and surfactants used in the fabrication of solid lipid nanoparticles demonstrate excellent drug stability and prolonged release compared with VDDs and other polymeric carriers due to the evasion of organic solvent in their fabrication. However, associated disadvantages such as the formation of the crystalline structure of lipids due to inherent low incorporation rates and unpredictable gelation tendency [10, 11].

Nanocapsules have been one of the most widely studied nanosystems for the delivery of functional compounds. Moreover, nanocapsules are also known as nanoparticulate in food science constituted as external polymeric membrane and inner part composed of polymeric matrix containing bioactive compounds. Furthermore, nano-encapsulation involves the incorporation, absorption, or scattering of combinations of bioactive solid, liquid, or gas into small vesicles with nanometer-scale

**Figure 2.** *Total number of publications on LNs from 1936 to 2021 exported from the SCOPUS database on 2 March 2022.*

**Figure 3.**

*Total number of publications on lipid nanocarriers subject-wise from 1936 to 2021 exported from the SCOPUS database on 2 March 2022 (for interpretation of the results to color in this figure legend, the reader referred to the web version of this chapter or color print).*

diameters. However, lipid nanocapsules are defined as nanovesicular delivery systems with a core-shell structure consisting of polymeric membrane or coating and target active moiety formulation added within the cavity. Moreover, lipid nanocapsules are considered as a sandwich of liposome and nanoemulsion. In addition, nanocapsules have functional properties that are maintained by encapsulation in simple solutions, colloids, emulsions, and biopolymers in food. Lipid nanocapsules are submicron particles with a broader surface area and size below the endothelium fenestration (>100 nm) that present advantages compared to multi-lamellar liposomes, especially with prolonged stability up to 18 months. Thus the lower size of lipid nanocapsules increases the transparency of solution when utilized in clear liquids such as beverages and sauces. Additionally, these lipid carriers can encapsulate efficiently lipophilic drugs, which is a much-needed feature for pharmaceutical colloidal formulations. This chapter presents an overview of the various LNs materials as a potential carrier for the delivery of poorly water-soluble drugs with enhanced therapeutic efficacy. Furthermore, a brief on various fabrication and characterization techniques involved with VDDs and SLNs with their prospect and market challenges concerning the stability. **Figures 2** and **3** indicates the yearly trends of publication for retrieved data from the Scopus database system on keywords "nanocarriers\*".
