Table 4.

A summary of lipidic nanosystems for topical treatment of psoriasis in the past few years.

Delivery system	Production technique	Drug	Findings
Particulate systems
SLNs	Modified emulsification and low temperature solidification method	Tacrolimus	Higher skin penetration and retention than marketed ointment (Ruihua, 2012).
	Thin film hydration	Erlotinib + IL α 36SiRNA	Decreased epidermal hyperplasia (Boakye et al., 2017). Decreased infiltration of inflammatory cytokines.
	Hot ultrasonication	Methotrexate + Etanercept	Decreased transdermal permeation (Ferreira et al., 2017).
	Solvent injection	Mometasone Furoate	Higher skin deposition than commercial cream (Madan et al., 2014).
	Solvent injection	Betamethasone 17-valerate	Controlled release (Zhang and Smith, 2011). Drug retention in epidermis.
	Pre-emulsion ultrasonication	Dithranol	Double drug localization than the commercial cream (Zhang and Smith, 2011).
NLCs	Hot emulsion sonication	Thymol	Improved healing of psoriatic plaques in mouse models (Pivetta et al., 2018).
	Microemulsion	Mometasone Furoate	Disappearance of parakeratosisa (Kaur, Sharma and Bedi, 2018). Increased skin deposition 2.5 times than marketed product.
	High-shear homogenization	Methotrexate	Enhanced skin penetration (Pinto et al., 2014).
	Microemulsion technique	Clobetasol propionate	Increased drug accumulation in the stratum corneum (Silva et al., 2012).
	Hot homogenization	Tacrolimus	Higher penetration than commercial product (Nam et al., 2011).
	Thin film hydration	Calcipotriol + Methotrexate	Suppressed skin permeation of calcipotriol only (Fang, 2010). Lower skin irritation.
	A modified microemulsion technique	Fluticasone propionate	Improved drug encapsulation and formulation physicochemical stability (Doktorovová et al., 2010).
A comparative study between SLNs and NLCs	Hot melt homogenization method	Cyclosporin & calcipotriol	Both particulate systems show deeper penetration (Arora et al., 2017). NLCs exhibited higher efficacy than SLNs and commercial gel.
	Solvent diffusion technique	Capsaicin	Both particulate systems minimize skin irritation (Agrawal et al., 2015). NLCs show better stratum corneum permeation and retention than both SLNs and plain drug.
	Microemulsification	Tretinoin	Higher efficacy and biocompatibility than the commercial product containing Tretinoin (Raza et al., 2013). Particulate lipidic systems show higher photostability and skin permeation than vesicular systems.
Lipospheres	Modified emulsion-based method	Thymoquinone	Improved histopathological and psoriatic features of psoriatic skin both in vivo and in vitro (Jain et al., 2017). Decreased TNF-α, IL-2, IL-6 and IL-1β.
	Modified emulsion-based method	Tacrolimus + curcumin	Improved histopathological and psoriatic features of psoriatic skin in vivo (Jain et al., 2016). Decreased TNF-α, IL-17,IL-22.
Liquid crystals	Lipid melting, mixing with the aqueous phase and sonication	siRNAs	Gene downregulation GAPDH suppression (Vicentini et al., 2013).
		siRNAs	Reduction of IL-1α and IL-6 production (Depieri et al., 2016).
Vesicular systems
Liposomes	Thin film hydration	Fusidic acid	A more stable formulation with a higher efficacy (Wadhwa et al., 2016).
	Thin film hydration	Tretinoin	Particulate lipidic systems show higher photostability and skin permeation than vesicular systems (Raza et al., 2013).
	Thin film hydration	Calcipotriol	A smaller particles size (<100 nm) and a unilamellar structure which promoted skin penetration and drug deposition (Knudsen et al., 2012).
	Thin film hydration	Methotrexate	Increased skin permeability (Srisuk et al., 2012).
	Thin film hydration	Tretinoin	Higher skin deposition (Manconi et al., 2011).
Niosomes	Thin film hydration	Anthocyanins	Prolonged antiinfalmmatory effect with no cytotoxicity (Manconi et al., 2011).
Ethosomes	Modified injection method	Psoralen	Improved permeation and skin deposition (Zhang et al., 2014).
	The cold method	Tretinoin	Particulate lipidic systems show higher photostability and skin permeation than vesicular systems (Zhang et al., 2014).
	Thin film hydration	5-aminolevulinic acid	Enhanced accumulation in both normal and hyperproliferative skin (Fang et al., 2009). Higher penetration depth Reduced TNF-α expression
A comparative study between liposomes and niosomes	Thin film hydration	Dithranol	Both vesicles showed better skin permeation both in vitro and in vivo (Agarwal et al., 2001).
A comparative study between emulsomes, liposomes and niosomes	Thin film hydration	Capsaicin	Emulsomes showed to be a convenient carrier achieving higher penetration and retention (R. Gupta et al., 2016).
SECosomesb	Solvent evaporation method	RNAi	Downregulation of the psoriatic genetic marker (human beta-defensin 2) (Desmet et al., 2016).
Emulsion systems
Microemulsion	Titration	Protopanaxdiol	Higher in vivo and in vitro skin deposition (Kim et al., 2018).
	Titration	Methotrexate	Increased epidermal drug accumulation with lower systemic absorption, that is, improved efficacy and safety (Amarji et al., 2016).
	Aqueous phase titration	Betamethasone dipropionate + salicylic acid	Improved and sustained anti-inflammatory activity and higher skin penetration (Baboota et al., 2011).
	Shaking mixtures of the components of the microemulsion with the calculated ratios	Tacrolimus	Superior bioavailability (Baboota et al., 2011).
Nanoemulsion	High shear homogenization	Cyclosporin	Increased drug permeability in vitro and superior skin hydration on human volunteers (Musa et al., 2017).
	Spontaneous emulsification	Clobitasol propionate + calcipotriol	Better uptake by stratum coreum in vitro (Kaur et al., 2017). Better antipsoriatic skin activity in vivo.

^aA type of cell keratinization where the nuclei are retained in the stratum corneum. ^bA liposomal carrier developed by the authors.