*4.2.1.2 X-ray diffractometry (XRD)*

XRD is employed to investigate the physical state of the incorporated drug because it affects both *in vitro* and *in vivo* performance.

#### *4.2.1.3 Scanning electron microscopy (SEM)*

SEM is employed to elucidate the structural and morphological features of s-SEDDS and the raw materials as well as to confirm the physical state of loaded drug [96].

#### *4.2.1.4 Fourier-transform infrared spectroscopy (FT-IR)*

FT-IR is usually employed to investigate any potential interaction between the incorporated drug and the solid carrier or other formulation excipients [76].

#### *4.2.2 Determination of micromeritic properties*

The flow properties of powders are crucial aspect of large-scale production of solid dosage forms because it affects feeding consistency, reproducibility of die filling and dose uniformity. Powder flowability is affected by various physical, mechanical and environmental factors. Thus, various parameters such as angle of repose, bulk density, Carr's index and Hausner's ratio should be assessed to determine s-SEDDS flowability to overcome the subjective nature of individual tests. The angle of repose is a measure of internal cohesiveness of particles. Powders having angles of repose <30° are considered as free flowing powders; while, powders with angles of repose >40° are regarded to have extremely poor flowability. On the other hand, powders with angles of repose up to 35° are regarded passable; while, those between 35 and 40° indicate poor powder flow which requires the addition of a glidant [97]. Powders having Carr's index up to 21% are considered to have acceptable flow. Hausner's ratios <1.25 are usually corresponded to free-flowing powders with minimum interparticle frictions. On the other hand, Hausner's ratios between 1.25 and 1.5 indicate moderate flow which could be acceptable [98].

#### *4.2.3 Droplet size of reconstituted s-SEDDS*

The droplet size of reconstituted s-SEDDS should be similar to that of liquid SEDDS to ensure that the self-emulsification performance of liquid SEDDS is preserved.

### **5. Conclusion**

SEDDS are promising nanocarriers for overcoming various obstacles encountered in the oral delivery of drugs and bioactive agents. The inhibition of P-gp activity by SEDDS relies mainly on the employment of ingredients (i.e., oils and surfactants) with established P-gp inhibition activity in their formulation. Thus, selection of excipients with established P-gp inhibition activity is the first step in the formulation of SEDDS for overcoming P-gp-mediated efflux of substrate drugs and reversing MDR in tumor cells. The effective concentration range for inhibiting P-gp activity should be considered while selecting the formulation ratios. P-gp inhibition activity of SEDDS can be further enhanced by loading other pharmaceutical excipient with established P-gp inhibition activity or traditional P-gp inhibitor. SEDDS are also considered promising systems for the oral delivery of protein therapeutics and genetic materials; however, this role is still in its infancy. Entrapment of these macromolecules within the nanosized emulsion droplets guarantees effective delivery. The bioactive effects of SEDDS ingredients could further enhance the oral bioavailability of protein therapeutics. Liquid SEDDS could be transformed into s-SEDDS to further enhance the formulation stability, allow cost effective largescale production as well as to enhance the patient compliance.

**59**

**Author details**

Egypt

Khaled AboulFotouh, Ayat A. Allam and Mahmoud El-Badry\*

\*Address all correspondence to: elbadry@aun.edu.eg

provided the original work is properly cited.

Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut,

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

*Self-Emulsifying Drug Delivery Systems: Easy to Prepare Multifunctional Vectors for Efficient…*

*DOI: http://dx.doi.org/10.5772/intechopen.88412*

### **Conflict of interest**

None.

*Self-Emulsifying Drug Delivery Systems: Easy to Prepare Multifunctional Vectors for Efficient… DOI: http://dx.doi.org/10.5772/intechopen.88412*
