## 1 Introduction  
In developing countries, the number of maternal deaths has been reduced by increasing the use of contraceptives over the past 30 years, simply by reducing the number of unintended pregnancies [1,2]. Surgical sterilization is the most prevalent method of contraception in the world, mainly including female sterilization (tubal sterilization) and male sterilization (vasectomy). However, surgical sterilization has the risk of death and serious morbidity, furthermore, the risk of ectopic pregnancy still [3]. Nowadays, intrauterine devices (IUDs) are one of the most widely used modern reversible contraception methods. Previous studies have shown that IUDs could cut down the risk of pelvic inflammatory disease and sexually transmitted infections for women but the risk of cervical chlamdial or gonococcal infections increased dramatically [4; 5; 6; 7]. Combined estrogen-progestogen oral contraceptive pills (OCPs) are the other most widely used modern contraceptive method. However, a pooled analysis indicated that OCPs users have an increased risk of cervical cancer and such risk raised with prolongation of using time [8; 9]. Evidence for the safety of woman fitted with IUDs or OCPs with HIV/AIDS was scarce, but existing studies showed that IUDs and/or OCPs still caused some adverse health effects, including disease progression in infected women and HIV transmission to uninfected partners [10]. It is well known that the vaginal route is convenient and effective for contraception [11]. The vaginal route has many advantages due to its large surface area, rich blood supply, relatively high permeability of many drugs, and self-insertion. Apart from this, avoidance of the gastrointestinal absorption and the hepatic first-pass metabolism, the presence of uniform dense vascularization and the high mucosal permeability have made vaginal route widely used for many drugs administrations [12; 13]. For example, the contraceptive vaginal ring (CVR) can eliminate the need for daily dosing and improve the contraceptive effects [14]. [PERSON] et al. designed vaginal ring which was composed of a hydrogel of 2-hydroxyethyl methacrylate (HEMA) and sodium methacrylate (SMA), and the nonhormonal contraceptives and 3'-Azido-3'-deoxythymidine (AZT) as an anti-HIV agent could be delivered by such vaginal ring [15]. A large variety of vaginal forms have been developed and commercialized in recent years including tablets, hydrogels, creams, rings, foams, films, etc [12]. The traditional vaginal forms, such as creams, rings, vaginal suppositories, and tablets, have been associated with some limitations of leakage, messiness, and relatively short residence time mainly due to the self-cleaning action of the vaginal tract [16; 17]. The ideal vaginal drug route should be easy to use (self-administered, surgical procedure free), discreet, reversible, painless to the patient (minimal interference with body function and daily life), cost-effective, widely available (high bioavailability with other medications), and safe for continuous administration [18]. The vaginal condition changes due to numerous physiological and non-physiological factors, such as the menstrual cycle of women or menopause, and also after sexual intercourses. The natural clearance process of vaginal secretions, commonly referred to as mucus, which is another important parameter interfere with the performance of vaginal delivery system [19]. In the vagina, the mucus holds important physiological functions such as lubrication, and the mucus barrier protects the vagina against pathogens. The drugs through vaginal route need to across the mucus layer, then vaginal epithelial cells, and then, were absorbed by the body. Therefore, mucus plays an important role and significantly impact drug absorption or action [20]. Hydrogels with a three-dimensional polymeric matrix are semi-solid, made of small quantities of gelling excipient in relatively large amounts of liquids, but possessing more solid-like character [21].