In recent years, herbal drugs have flourished as the method of rehabilitation of choice in numerous parts of the world and most of populations consider them as alternative conventional medicaments. However, most of the herbal drugs show poor solubility and bioavailability, which ultimately leads to diminished efficacy and frequency of administration. Consequently, self-emulsifying drug delivery system has been highlighted for poor water-soluble herbal medicaments. Self-emulsifying drug delivery system is an isotropic mixture of phytoconstituents, oil, surfactant, and cosurfactant, and subsequent to oral administration spontaneously endures self-emulsification and forms without emulsion as soon as it comes in contact gastric fluid. Most of the researchers and industrialists are attracted towards this novel and emerging technology as it offers various advantages. The chapter focuses on the mechanism of self-emulsifying, benefits of herbal SEDDS, factors affecting herbal SEDDS with formulation and characterisation of it.
Top1. Introduction
In India herbal medicaments are considered as safe and utilized consistently since from ancient times and believed as an ancient science of medication (Vaidya et al., 2007).To a certain extent, the term herbal medicines are well-defined in “Ayurveda”, (Sharma, 2003; Mukherjeeet al., 2007). “Unani” system of medicine. and Chinese practice(Holland, 2000; Porkert, 1974). India’s Ayurvedic medicine custom is thought to be more than 5,000 years old and herbal medicines stay a vital component of life (Garodia et al., 2007). Today, still most of countries depend on herbal medicines to fulfil the essential needs of medications. Even the World Health Organization (WHO) stated that 80% of the promising world’s population rely on traditional medicament for therapy and considered as prime treatment (Yadav, et .al., 2014).In current years, many of the Phyto constitutes which are strongly utilized in major diseases shows poor water solubility, low bioavailability and many other restrictions including lack of dose proportion, intrasubject and intersubject variability. (Robinson, J.R. 1996)
Major barrier in the development of formulations are low dissolution and bioavailability due to poor water solubility of these phytoconstituents. For this the various techniques are widely utilized including solid dispersion, micronization, salt formation for solubility enhancement. In micronization, due to size reduction phyto-constitutes causes poor wettability whereas salt formation may lead to aggregate formation which restricts use of these techniques.
Currently, lipid based technology widely accepted as a novel approach to increase solubility and bioavailability of water insoluble phytoconstituent’s.
On the basis of literature, one of the phytoconstituent, curcumin is isolated from the rhizomes of turmeric(Curcuma longa Linn.) having enormous assortment of valuable pharmacological effects including antioxidant, anti-inflammatory, anticarcinogenic (Ruby et. al., 1995; Gescher et. al., 2001; Sharma et. al., 2005; Sharma et al., 2001), hypocholesterolemic (Rao et al., 1970), antibacterial(Ramaprasad et al., 1956), wound healing, antispasmodic, anticoagulant, antitumor(Ammon et al., 1991) and hepatoprotective (Subramanian et al., 1999)activities and effectively inoculated in SEDDS formulations .It shows additional benefits such as compelling free radical scavenger, having superoxide anions, singlet oxygen, hydroxyl radicals scavenging and lipid peroxidation inhibitory actions (Ukil et. al., 2005; Tonnesen et. al., 1992). Similarly phytoconstituents having hepatoprotective activity derived from Cardus Marianus (L.) Gaertn. (Family-Asteraceae).is also incorporated in SEDDS formulation due to its poor water solubility(Dixit et. al., 2007) .Numerous updated literature reports that self-emulsifying drug delivery system can be successfully utilized for hydrophobic phytoconstituent’s showing improvement in dissolution and bioavailability Self emulsifying formulations rapidly diffuse in gastrointestinal fluids and leads to the formation of micro and nano emulsion containing soluble phytoconstituent with rapid absorption through lymphatic pathways.
In a nutshell this chapter furnishes an efficient compilation of ample ranging information on all the crucial vistas of the self-emulsifying formulations in herbal medicaments. Thus pave the way in the formulation and application in SEDDS for accelerated advancement into the herbal Phyto constitutes.
Definition and Bioavailability of SEDDS
SEDDS are defined as isotropic mixtures of drug/ phytoconstituents, oil, surfactant and co-surfactant that have unique ability of forming fine o/w micro-emulsion upon mild agitation followed by dilution in aqueous media, such as gastrointestinal fluid as shown in Figure 1. The self –emulsification occurs due to motility of the stomach and intestine and as shown in Figure 2 SNEDDS shows improvement in bioavailability by lymphatic transport phenomenon. (P.P. Constantin ides, 1995; Jessy Shaji et al., 2005; Swati et al., 2015).
Figure 1. Formulation Process of Phytoconstituents SEDDS
Figure 2. SEDDS improving bioavailability of Phytoconstituents after oral adsorption