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With a dapivirine-releasing vaginal ring having successfully completed late-stage clinical testing for HIV prevention and currently undergoing regulatory review, there is now growing interest in next-generation multipurpose prevention technologies that seek to combine antiretroviral and contraceptive drugs within a single product. Here, we focus on ongoing efforts to develop a silicone elastomer vaginal ring releasing both dapivirine and levonorgestrel. Specifically, we evaluate various strategies aimed at both better understanding and reducing the tendency of levonorgestrel to bind with the elastomer, including: (i) formulation and post-manufacturing strategies aimed at reducing the extent of levonorgestrel reaction with addition-cure silicone elastomers; (ii) evaluation of a simple silicone system to model the complex elastomer; (iii) use of model compounds representing the enone and ethinyl moieties of levonorgestrel to probe the mode of addition of levonorgestrel to addition-cure silicone elastomers; and (iv) solution and solid-state C-NMR analysis to probe the structural features of the levonorgestrel-silicone system. The results demonstrate that both the enone and ethinyl groups within levonorgestrel undergo hydrosilylation reaction with hydrosiloxane groups in the silicone elastomer leading to binding. The results also highlight potential strategies for further optimising the dapivirine+levonorgestrel silicone vaginal ring formulation to ensure that the levonorgestrel is available for release.
This article was published in the following journal.
Name: International journal of pharmaceutics
To describe receptive anal intercourse (RAI) behaviors and correlates in a cohort of sub-Saharan African women, evaluate the association of RAI with HIV-1 risk, and evaluate whether the HIV-1 preventi...
Expanded HIV prevention options are needed to increase uptake of HIV prevention among women, especially in generalized epidemics. As the dapivirine vaginal ring moves forward through regulatory review...
The primary aim was to investigate post-use ring weight as a potential measure of cumulative adherence to a progesterone-releasing vaginal ring.
To evaluate endocervical and vaginal environment changes in women using a levonorgestrel-releasing intrauterine system (LNG-IUS).
Real-time PCR coupled with high resolution melting curve analysis is a practical technique that could be employed in multipurpose studies. During the recent decade, this technique has been practiced f...
Participants will be randomized to one of three study vaginal rings (VRs) in a 1:1:1 ratio, 25 mg, 100 mg or 200 mg VRs.
A Two-Cohort, Open-Label, Randomised, Three-Period Crossover Trial In Healthy HIV-Negative Women To Assess The Effect Of Menses And Tampon Use On The Pharmacokinetics Of Dapivirine, Delive...
PK and Safety Study of Vaginal Ring Containing Dapivirine and Levonorgestrel
The purpose of this study is to evaluate the maternal and infant safety of the dapivirine (DPV) vaginal ring (VR) and daily oral Truvada in HIV-uninfected pregnant women and their infants.
HIV Open-label Prevention Extension (HOPE).
The uptake of substances from the VAGINA via the vaginal epithelium/mucosa.
Collection of pooled secretions of the posterior vaginal fornix for cytologic examination.
An incision of the posterior vaginal wall and a portion of the pudenda which enlarges the vaginal introitus to facilitate delivery and prevent lacerations.
A group of two-ring heterocyclic compounds consisting of a benzene ring fused to a diazepine ring.
Compounds based on a seven-membered ring fused to a five-membered ring. Heat can rearrange them to NAPHTHALENES which have two fused six-membered rings. They are similar to guaiazulenes which are SESQUITERPENES with a six-membered ring fused to a five-membered ring.
Reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. It is mainly associated with retroviruses. RT inhibitors are widely used as antiretroviral drugs. RT activitie...