Physical characteristics and properties of estradiol softgel vaginal inserts

Intravaginal Drug Delivery Systems to Treat the Genitourinary Syndrome of Menopause: Towards the Design of Safe and Efficacious Estrogen-loaded Prototypes

Estrogens locally delivered to the vagina by tablets, capsules, rings, pessaries, and creams are the most common and highly recommended platforms to treat the genitourinary syndrome of menopause (GSM). Estradiol, an essential estrogen, is routinely administered alone, or in combination with progestins, to effectively alleviate the symptoms associated with moderate to severe menopause when non-pharmacological interventions are not indicated. Since the risk and side effects of estradiol use depends on the administered amount and duration of use, the lowest effective dose of estradiol is recommended when long-term treatment is required. Although there is a wealth of data and literature comparing vaginally administered estrogen-containing products, there is a lack of information revealing the effect of the delivery system used and formulation constituent's attributes on the efficacy, safety, and patient acceptability of these dosage forms. This review therefore aims to classify and compare various designs of commercially available and non-commercial vaginal 17β-estradiol formulations and analyze their performance in terms of systemic absorption, efficacy, safety, and patient satisfaction and acceptance. The vaginal estrogenic platforms included in this review are the currently marketed and investigational 17β-estradiol tablets, softgel capsules, creams, and rings for the treatment of GSM, based on their different design specifications, estradiol loads, and materials used in their preparation. Additionally, the mechanisms of the effects of estradiol on GSM have been discussed, as well as their potential impact on treatment efficacy and patient compliance.

Application of Sol–Gels for Treatment of Gynaecological Conditions—Physiological Perspectives and Emerging Concepts in Intravaginal Drug Delivery

Approaches for effective and sustained drug delivery to the female reproductive tract (FRT) for treating a range of gynaecological conditions remain limited. The development of versatile delivery platforms, such as soluble gels (sol–gels) coupled with applicators/devices, holds considerable therapeutic potential for gynaecological conditions. Sol–gel systems, which undergo solution-to-gel transition, triggered by physiological conditions such as changes in temperature, pH, or ion composition, offer advantages of both solution- and gel-based drug formulations. Furthermore, they have potential to be used as a suitable drug delivery vehicle for other novel drug formulations, including micro- and nano-particulate systems, enabling the delivery of drug molecules of diverse physicochemical character. We provide an anatomical and physiological perspective of the significant challenges and opportunities in attaining optimal drug delivery to the upper and lower FRT. Discussion then focuses on attributes of sol–gels that can vastly improve the treatment of gynaecological conditions. The review concludes by showcasing recent advances in vaginal formulation design, and proposes novel formulation strategies enabling the infusion of a wide range of therapeutics into sol–gels, paving the way for patient-friendly treatment regimens for acute and chronic FRT-related conditions such as bacterial/viral infection control (e.g., STDs), contraception, hormone replacement therapy (HRT), infertility, and cancer.

Estradiol softgel inserts for the treatment of VVA symptoms: an expert opinion

INTRODUCTION

Vulvar and vaginal atrophy (VVA) affects up to two thirds of postmenopausal women, with symptoms of vaginal dryness, dyspareunia, and vulvar/vaginal irritation. Despite the availability of various treatments, women express dissatisfaction with their options. An estradiol (E2; 4-µg and 10-µg) softgel vaginal insert was approved by the Food and Drug Administration (FDA) to treat moderate to severe dyspareunia, a symptom of VVA, due to menopause. These inserts were designed to treat VVA effectively and safely while avoiding some of the drawbacks of other administration methods.

AREAS COVERED

This article reviews the physical characteristics and pharmacokinetic data of the E2 softgel vaginal insert. Primary and secondary efficacy endpoints and safety data are reviewed from the pivotal REJOICE trial (NCT02253173), and substudies that explore response rates, changes in vaginal epithelium by visual assessment, efficacy in patient subgroups, effects on sexual function, and patient satisfaction compared with other treatments.

EXPERT OPINION

The E2 insert shows that vaginal drug delivery is an optimal route of administration for locally treating VVA. This E2 softgel vaginal insert is a safe and effective treatment for symptoms of postmenopausal VVA. The E2 insert's pharmacokinetic characteristics are related to its unique formulation, rapid dissolution, and minimal systemic absorption.

ABBREVIATIONS

AE: adverse event; AUC: area under the concentration-time curve; BMI: body mass index; C_avg: average concentration; CI: confidence interval; C_max: maximum concentration; C_min: minimum concentration; E2: estradiol; FDA: Food and Drug Administration; FSFI: Female Sexual Function Index; GSM: genitourinary symptoms of menopause: MBS: most bothersome symptom; NAMS: North American Menopause Society; OR: odds ratio; PI: pulsatility index; PK: pharmacokinetic; REVIVE: Real Women's Views of treatment options for menopausal Vaginal changEs; RI: resistance index; ROC: receiver operating characteristic; TEAE: treatment-emergent adverse event; t_max: time to maximum concentration; VVA: vulvar and vaginal atrophy.