Estrogen, through binding to its receptors in the female endometrium, promotes the proliferation, differentiation, and angiogenesis of endometrial stromal cells, thereby playing a critical role in endometrial injury repair, regeneration, and the prevention and treatment of intrauterine adhesions. Currently, various estrogen-based pharmaceutical formulations are applied in clinical practice, and the development of related products is progressively advancing. This review systematically outlines the etiology of endometrial injury and the mechanisms by which estrogen facilitates endometrial repair and regeneration. Furthermore, it highlights recent research progress and clinical applications of estrogen-based therapies in endometrial regeneration, aiming to provide a valuable reference for relevant scientific research and clinical practice.

Estrogen, through binding to its receptors in the female endometrium, promotes the proliferation, differentiation, and angiogenesis of endometrial stromal cells, thereby playing a critical role in endometrial injury repair, regeneration, and the prevention and treatment of intrauterine adhesions. Currently, various estrogen-based pharmaceutical formulations are applied in clinical practice, and the development of related products is progressively advancing. This review systematically outlines the etiology of endometrial injury and the mechanisms by which estrogen facilitates endometrial repair and regeneration. Furthermore, it highlights recent research progress and clinical applications of estrogen-based therapies in endometrial regeneration, aiming to provide a valuable reference for relevant scientific research and clinical practice.

Objective:To establish a high-performance liquid chromatography (HPLC) for determining the content of levonorgestrel (LNG) and ethinylestradiol (EE) in compound levonorgestrel sustained-release microsphere injection.Methods:C18 column Inertsil ODS-3 (4.7 mm×250 mm, 5 μm) was used. The mobile phase was acetonitrile-water (50∶50, V/V). The flow rate was 1.0 mL/min. The column temperature was 35 ℃. The detection wavelength was 265 nm, and the injection amount was 20 μL. The content of microspheres was determined after validation of HPLC detection methodology.Results:The linear relationship was good in the range of 5.03-201.20 μg/mL LNG, 1.55-61.92 μg/mL EE ( r2=0.999 8). The specificity, precision, recovery, repeatability, stability, etc, met the requirements. The content of LNG in the compound LNG sustained-release microspheres injection was 16.26%, and the content of EE was 2.58%. Conclusion:This HPLC can determine the content of compound levonorgestrel sustained-release injection microspheres, and the method is simple, stable, and has good reproducibility, providing a reference for the determination of levonorgestrel and ethinylestradiol in compound sustained-release preparations.

Objective:To establish a high-performance liquid chromatography (HPLC) for determining the content of levonorgestrel (LNG) and ethinylestradiol (EE) in compound levonorgestrel sustained-release microsphere injection.Methods:C18 column Inertsil ODS-3 (4.7 mm×250 mm, 5 μm) was used. The mobile phase was acetonitrile-water (50∶50, V/V). The flow rate was 1.0 mL/min. The column temperature was 35 ℃. The detection wavelength was 265 nm, and the injection amount was 20 μL. The content of microspheres was determined after validation of HPLC detection methodology.Results:The linear relationship was good in the range of 5.03-201.20 μg/mL LNG, 1.55-61.92 μg/mL EE ( r2=0.999 8). The specificity, precision, recovery, repeatability, stability, etc, met the requirements. The content of LNG in the compound LNG sustained-release microspheres injection was 16.26%, and the content of EE was 2.58%. Conclusion:This HPLC can determine the content of compound levonorgestrel sustained-release injection microspheres, and the method is simple, stable, and has good reproducibility, providing a reference for the determination of levonorgestrel and ethinylestradiol in compound sustained-release preparations.

Objective:To develop an etonogestrel (ENG)/ethinyl estradiol (EE) compound vaginal ring with good sustained-release properties, studying its in vitro release assay methodology, and establishing an accelerated release method with good correlation with real-time release methods. Methods:Ethylene-vinyl acetate copolymer (EVA) was used as the matrix to prepare ENG/EE compound vaginal ring by hot melt extrusion method, and an in vitro real-time release assay method and an accelerated release assay method based on shake flask method were established. The in vitro release behavior and release mechanism of ENG/EE compound vaginal ring were investigated, and the correlation between real-time release and accelerated release over time was analyzed. Results:The obtained vaginal ring had a round appearance and a smooth surface, and the drug was slowly released under the optimal real-time release conditions in vitro (release medium: 200 mL of pure water, shaking at 60 r/min in a constant temperature water bath shaker at 37 ℃), and the cumulative release of ENG and EE on the 21st day were 54.39% and 46.80%, respectively. The correlation coefficients of drug release and its mechanism under the optimized in vitro accelerated conditions (release medium: 200 mL of 0.6% sodium dodecyl sulfate aqueous solution, shaking at 60 r/min at 55 ℃) with the results under real-time release conditions were all greater than 0.99. Conclusion:The ENG/EE compound vaginal ring obtained in this study has a significant in vitro sustained-release effect, and the established accelerated release conditions have a good correlation with real-time release conditions, which can provide a useful reference for the quality evaluation research of such vaginal ring products and the formulation of guidelines for in vitro release research methods.

Nowadays, the aging of China's population is becoming increasingly serious, and fertility of women under the national three-child policy is declining, both middle-aged and elderly women and women of childbearing age are facing reproductive health problems. Traditional oral preparations have a short acting time and some varieties have low bioavailability problems, while the long-acting sustained-release preparations have the advantages of convenient use, stable blood drug concentration and higher safety. Their development provides theoretical basis and technical support for the development and application of reproductive contraceptives. In the decades of research, a variety of different drug delivery systems have been born. Among them, the polymer-based membrane-controlled reservoir preparations, as a common drug sustained-release system, is mostly used in reproductive health and has broad market prospects. In this paper, polymer-based membrane-controlled reservoir drug delivery systems in the field of reproductive health was briefly reviewed, and four key issues including polymer material selection, in vitro drug release model, preparation types and research progress, and challenges were discussed, which can provide reference for the development of related contraceptives in the future.

Nowadays, the aging of China's population is becoming increasingly serious, and fertility of women under the national three-child policy is declining, both middle-aged and elderly women and women of childbearing age are facing reproductive health problems. Traditional oral preparations have a short acting time and some varieties have low bioavailability problems, while the long-acting sustained-release preparations have the advantages of convenient use, stable blood drug concentration and higher safety. Their development provides theoretical basis and technical support for the development and application of reproductive contraceptives. In the decades of research, a variety of different drug delivery systems have been born. Among them, the polymer-based membrane-controlled reservoir preparations, as a common drug sustained-release system, is mostly used in reproductive health and has broad market prospects. In this paper, polymer-based membrane-controlled reservoir drug delivery systems in the field of reproductive health was briefly reviewed, and four key issues including polymer material selection, in vitro drug release model, preparation types and research progress, and challenges were discussed, which can provide reference for the development of related contraceptives in the future.

Objective:To develop an etonogestrel (ENG)/ethinyl estradiol (EE) compound vaginal ring with good sustained-release properties, studying its in vitro release assay methodology, and establishing an accelerated release method with good correlation with real-time release methods. Methods:Ethylene-vinyl acetate copolymer (EVA) was used as the matrix to prepare ENG/EE compound vaginal ring by hot melt extrusion method, and an in vitro real-time release assay method and an accelerated release assay method based on shake flask method were established. The in vitro release behavior and release mechanism of ENG/EE compound vaginal ring were investigated, and the correlation between real-time release and accelerated release over time was analyzed. Results:The obtained vaginal ring had a round appearance and a smooth surface, and the drug was slowly released under the optimal real-time release conditions in vitro (release medium: 200 mL of pure water, shaking at 60 r/min in a constant temperature water bath shaker at 37 ℃), and the cumulative release of ENG and EE on the 21st day were 54.39% and 46.80%, respectively. The correlation coefficients of drug release and its mechanism under the optimized in vitro accelerated conditions (release medium: 200 mL of 0.6% sodium dodecyl sulfate aqueous solution, shaking at 60 r/min at 55 ℃) with the results under real-time release conditions were all greater than 0.99. Conclusion:The ENG/EE compound vaginal ring obtained in this study has a significant in vitro sustained-release effect, and the established accelerated release conditions have a good correlation with real-time release conditions, which can provide a useful reference for the quality evaluation research of such vaginal ring products and the formulation of guidelines for in vitro release research methods.

In recent years, the world community has aroused interest in family planning as a prioritized strategy to improve maternal health, and China has also incorporated reproductive health into its national development strategies. Safe and effective contraceptive methods for women of childbearing age to prevent unwanted pregnancy and reduce abortion, is an important measure to improve their reproductive health. This paper firstly summarizes the global market demand for female contraceptive products. Then, starting from the early research and development (R&D) stages such as raw materials selection, pre-formulation and formulation investigations, this paper discusses the R&D thoughts of contraceptives including long-acting biodegradable implants and microsphere injections. Finally, we review the application prospects of 3D printing, computer simulation and artificial intelligence in this field. Interdisciplinary integration of pharmaceutical and computer science is expected to inspire and change the development mode of traditional preparations, as well as to help accelerate the industrialization of contraceptives.

In recent years, the world community has aroused interest in family planning as a prioritized strategy to improve maternal health, and China has also incorporated reproductive health into its national development strategies. Safe and effective contraceptive methods for women of childbearing age to prevent unwanted pregnancy and reduce abortion, is an important measure to improve their reproductive health. This paper firstly summarizes the global market demand for female contraceptive products. Then, starting from the early research and development (R&D) stages such as raw materials selection, pre-formulation and formulation investigations, this paper discusses the R&D thoughts of contraceptives including long-acting biodegradable implants and microsphere injections. Finally, we review the application prospects of 3D printing, computer simulation and artificial intelligence in this field. Interdisciplinary integration of pharmaceutical and computer science is expected to inspire and change the development mode of traditional preparations, as well as to help accelerate the industrialization of contraceptives.