psoralen, curcuminoids, meloxicam, ketoprofen, and betamethasone dipropionate

(Butani et al. 2016; Vaghasiya et al. 2013; Fang et al. 2008a, b; Zamarioli et al. 2015;

Khurana et al. 2013; Kheradmandnia et al. 2010; Kong et al. 2016).

14.3.4 Nanostructured Lipid Carriers (NLCs)

The second-generation NLCs have gained attraction in the field of pharmaceuticals

and cosmetic industries. Currently, there are approximately 40 cosmetic products in

the market for NLC-based formulations (Obeidat et al. 2010). Compared to SLNs,

NLCs have higher drug loading, which results in higher concentration and permits

penetration into the skin. The smaller the particle size of NLCs, the higher the

permeability (Gaba et al. 2015; Phatak and Chaudhari 2013). NLCs were prepared

to improve the penetration of the drugs, drug stability, and controlled release

property and increase hydration (Puglia et al. 2014; Fan et al. 2014). Researchers

have claimed that NLC-loaded gels do not show an adverse effect on topical use

(Gaba et al. 2015).

Different lipodermal carriers and drugs have been listed in Tables 14.2 and 14.3.

14.4

Technological Advances in Dermaceuticals

Delivery of actives by the use of skin could be the alternative pathway to the oral

route. The primary task is to deliver the drugs into the skin by crossing the stratum

corneum. However, in the previous four decades, technologies have modified the

ancient techniques, and novel approaches gained interest. The application of

dermatokinetic modeling is required nowadays to understand the drug concentration

present inside the skin and the effect of toxic molecules (Thotakura et al. 2017). The

kinetic study in the skin starts from the administration of the drug and with the

absorption (Shah 2001). The dermal pharmacokinetic study depends on various

parameters such as Cmax (maximum drug concentration), Tmax (time required to

reach Cmax), and AUC (area under curve) (Nicoli et al. 2009). The dermatokinetic

calculation is based on the one-compartment model (Raza et al. 2013) and calculated

by the following equation:

CSkin ¼ ^Kp:Cmax

ðKp  KeÞ ^{ðeKet  eKptÞ}

ð14:1Þ

where Cskin is the concentration of drug at time t, Kp is the permeation constant for

dermal, Cmax is the maximum concentration achieved in skin, and Ke is the skin

elimination constant. These parameters can be calculated by WinNonlin software

using Wagner-Nelson method (Raza et al. 2013). There are various in vivo and

in vitro techniques for dermatokinetic assessment of topical formulations. These

include tape stripping method, microdialysis method, vasoconstrictor assay, and

confocal scanning microscopy (Thotakura et al. 2017).

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