Transferosomal in situ gel administered through umbilical skin tissues for improved systemic bioavailability of drugs: A novel strategy to replace conventional transdermal route

Abstract

Systemic bioavailability is of prime importance for most of the drugs that are administered via any route to produce required therapeutic efficacy. Many hydrophilic and lipophilic drugs have relied on parenteral and oral routes of administration for several treatments. However, these routes possess numerous disadvantages. Therefore, transdermal route of drug administration has come into existence as an alternative to parenteral and oral routes. Although many transdermal drug delivery systems have achieved better systemic bioavailability, they are associated with several disadvantages, such as poor skin permeability and retention. Additionally, the drugs that need to be administered in larger doses for sustained delivery are facing challenges. Generally, the transdermal formulations are applied on various skin regions (forearm, shoulder, thigh, back, etc.), other than the umbilicus, to deliver a drug into the systemic circulation. However, the supremacy of the umbilicus is that its skin tissues possess a thin stratum corneum and the presence of paraumbilical veins beneath the umbilical skin tissues enables rapid systemic distribution of drugs. The navel therapy has a practical history of more than 2000 years under Traditional Chinese Medicine. Several studies have witnessed the successful treatment of many digestive diseases by placing numerous herbal extracts on the umbilicus. An ample amount of works has compared the drug absorption through skin tissues at the umbilicus and forearm. Upon their results, it seemed the umbilicus could serve as an ideal region for better systemic bioavailability than other skin regions. Therefore, the present hypothesis aimed to put forward to deliver selected hydrophilic or lipophilic drugs through skin tissues at the umbilicus using a transferosomal in situ gel system for better systemic bioavailability than delivering drugs through other skin regions. Thus, the proposed hypothesis would produce better systemic bioavailability of many drugs.