**5.2 Disadvantages of microemulsion**


*Perspective Chapter: Microemulsion as a Game Changer to Conquer Cancer with an Emphasis… DOI: http://dx.doi.org/10.5772/intechopen.101479*

## **6. Future perspectives**

Microemulsions are the lipid based drug delivery systems that are being studied by a wide group of researchers. Even though the microemulsion has various advantages like loading of both hydrophilic and lipophilic drug, thermodynamic stability and improved patient compliance etc. They lack behind when it comes to the surfactant concentration. The main ingredient used to decrease the interfacial tension between the oil phase and aqueous phase is surfactant and the co-surfactant. Being the main ingredient, they may be used in large quantity. This turns out to be one of the major disadvantages, which thereby leads to toxicity. Usually only 40% of the surfactant should be used in the formulation. Thus, a suitable surfactant that is capable of decreasing the interfacial tension at a low concentration must be employed in the formulation [80]. The microemulsions are usually suitable for scale up process, which is more important from industrial point of view that can be done at a low cost. Apart from the treating various cancers and diseases, the microemulsions are also being used for the cosmetic formulations [81], because of their increased permeability and action on the skin for a prolonged period of time. Though they are being used for various route of delivery for treating a wide range of cancer, the surfactant concentration should be considered which plays a major role in deciding the fate of microemulsion.

## **7. Conclusions**

Microemulsions are lipid based drug delivery system that comprises of oil, surfactant and a co-surfactant. This can solubilize both the hydrophilic as well as lipophilic drugs. Thus, helps in increasing the absorption and bioavailability of the drugs. Since, the bioavailability is increased; the desired therapeutic activity can be obtained with minimum dose of the drug. Thu, we can also overcome the toxicity due to higher dose of the drug. Most of the herbal compounds like flavonoids, terpenes and caratinoids are possessing the anti-cancer activity. But only because of their poor solubility and poor permeability, they are not being widely studied for conquering cancer cells. This fate of herbal compounds can be changed once they are being incorporated into a safe and effective carrier or vehicle. Even though various carrier systems are available and being studied widely by researchers, the microemulsion plays a vital role and standalone compared to others because of their property like thermodynamic stability, increasing the solubility and permeability of drug and also easy scale up process. They act as a stalwart supporter in the delivery of potential anti-cancer compounds, without affecting the nature of the drug and maintaining their stability by overcoming various hurdles like GI (Gastrointestinal) degradation, first pass metabolism and also toxicity due to higher dose of the drug. Thus, as a nutshell it can be said that the microemulsions are prominent carriers in delivering the effective anti-cancer drug and also responsible for increasing the patient compliance and enhancing the therapeutic activity. But, apart from this, the limitations of the carrier should also be taken into consideration, like use of desired oil, surfactant and co-surfactant as well as their concentrations. By meticulously pondering the above points, one can develop an effective formulation for the rehabilitation of the cancer with the aid of microemulsions.

#### **Acknowledgements**

The authors would like to thank Indian Council of Medical Research (ICMR), New Delhi for awarding Senior Research Fellowship (SRF)-"3/ 2/2/2/2020-NCD-III." The authors would like to thank the Department of Science and Technology – Fund for Improvement of Science and Technology Infrastructure in Universities and Higher Educational Institutions (DST-FIST), New Delhi for their infrastructure support to our department.
