Simultaneous estimation of contraceptive steroids from electrospun fibers by RP-HPLC method: development, validation and application

Nanofibers-based drug delivery systems are promising alternative to formulate transdermal drug formulations, which are suitable for sustained release of dual drugs in combined drug systems. The parameters such as content of active ingredients and physical/chemical stability of a drug are essential to monitor in new drug delivery-based systems, especially with the low-dose formulations. It plays an important role in the development of new drug delivery systems under the category of nanomedicines. The objective of the study was to develop a simple, precise, authentic analytical method for the simultaneous estimation of both contraceptive steroids from coaxial electrospun fibers and to carry out the validation of the optimized method. The estimation of steroid drugs in pure form as well as from electrospun fiber sheet was performed by reverse-phase high-performance liquid chromatography (RP-HPLC). The method was optimized using different mobile phase combinations. The retention time for ethinylestradiol (EE) and levonorgestrel (LNG) was observed at 4.38 and 6.24 min, respectively, at a wavelength of 225 nm using photodiode array (PDA) detector. The method was found to be linear for both steroid drugs with correlation coefficients of 0.9996 and 0.9991 for LNG and EE, respectively. The method was specific for the simultaneous detection of both the drugs, with accuracy (95-100%) and precision (RSD < 2%). The validated RP-HPLC method was further successfully employed to determine the entrapment efficiency and drug loading of the various drug-loaded fibrous formulations. These formulations were prepared by varying the solution as well as spinning parameters. The method was found to detect and quantify both the drugs efficiently on the wide variations of the fabricated drug-loaded fibers.