Yufei Chen

Advancements in the field of intravaginal siRNA delivery

The vaginal tract is a suitable site for the administration of both local and systemic acting drugs. There are numerous vaginal products on the market such as those approved for contraception, treatment of yeast infection, hormonal replacement therapy, and feminine hygiene. Despite the potential in drug delivery, the vagina is a complex and dynamic organ that requires greater understanding. The recent discovery that injections of double stranded RNA (dsRNA) in Caenorhabditis elegans (C. elegans) results in potent gene specific silencing, was a major scientific revolution. This phenomenon known as RNA interference (RNAi), is believed to protect host genome against invasion by mobile genetic elements such as transposons and viruses. Gene silencing or RNAi has opened new potential opportunities to study the function of a gene in an organism. Furthermore, its therapeutic potential is being investigated in the field of sexually transmitted infections such as human immunodeficiency virus (HIV) and other diseases such as age-related macular degeneration (AMD), diabetes, hypercholesterolemia, respiratory disease, and cancer. This review will focus on the therapeutic potential of siRNA for the treatment and/or prevention of infectious diseases such as HIV, HPV, and HSV within the vaginal tract. Specifically, formulation design parameters to improve siRNA stability and therapeutic efficacy in the vaginal tract will be discussed along with challenges, advancements, and future directions of the field.

Novel intravaginal nanomedicine for the targeted delivery of saquinavir to CD4+ immune cells.

The goal of this study was to develop and characterize an intravaginal nanomedicine for the active targeted delivery of saquinavir (SQV) to CD4+ immune cells as a potential strategy to prevent or reduce HIV infection. The nanomedicine was formulated into a vaginal gel to provide ease in self-administration and to enhance retention within the vaginal tract. SQV-encapsulated nanoparticles (SQV-NPs) were prepared from poly(lactic-co-glycolic acid) (PLGA) and conjugated to antihuman anti-CD4 antibody. Antibody-conjugated SQV-NPs (Ab-SQV-NPs) had an encapsulation efficiency (EE%) of 74.4% + 3.7% and an antibody conjugation efficiency (ACE%) of 80.95% + 1.10%. Over 50% of total loaded SQV was released from NPs over 3 days. NPs were rapidly taken up by Sup-T1 cells, with more than a twofold increase in the intracellular levels of SQV when delivered by Ab-SQV-NPs in comparison to controls 1 hour post-treatment. No cytotoxicity was observed when vaginal epithelial cells were treated for 24 hours with drug-free Ab-NPs (1,000 μg/mL), 1% HEC placebo gel (200 mg/mL), or 1% HEC gel loaded with drug-free Ab-NPs (5 mg NPs/g gel, 200 mg/mL of gel mixture). Overall, we described an intravaginal nanomedicine that is nontoxic and can specifically deliver SQV into CD4+ immune cells. This platform may demonstrate potential utility in its application as postexposure prophylaxis for the treatment or reduction of HIV infection, but further studies are required.

Development of polyether urethane intravaginal rings for the sustained delivery of hydroxychloroquine

Hydroxychloroquine (HCQ) has been shown to demonstrate anti-inflammatory properties and direct anti-HIV activity. In this study, we describe for the first time the fabrication and in vitro evaluation of two types of intravaginal ring (IVR) devices (a surfaced-modified matrix IVR and a reservoir segmental IVR) for achieving sustained delivery (>14 days) of HCQ as a strategy for preventing male-to-female transmission of HIV. Both IVRs were fabricated by hot-melt injection molding. Surface-modified matrix IVRs with polyvinylpyrrolidone or poly(vinyl alcohol) coatings exhibited significantly reduced burst release on the first day (6.45% and 15.72% reduction, respectively). Reservoir IVR segments designed to release lower amounts of HCQ displayed near-zero-order release kinetics with an average release rate of 28.38 μg/mL per day for IVRs loaded with aqueous HCQ and 32.23 μg/mL per day for IVRs loaded with HCQ mixed with a rate-controlling excipient. Stability studies demonstrated that HCQ was stable in coated or noncoated IVRs for 30 days. The IVR segments had no significant effect on cell viability, pro-inflammatory cytokine production, or colony formation of vaginal and ectocervical epithelial cells. Both IVR systems may be suitable for the prevention of HIV transmission and other sexually transmitted infections.

Impact of Hydroxychloroquine-Loaded Polyurethane Intravaginal Rings on Lactobacilli

ABSTRACT The use of polymeric devices for controlled sustained delivery of drugs is a promising approach for the prevention of HIV-1 infection. Unfortunately, certain microbicides, when topically applied vaginally, may be cytotoxic to vaginal epithelial cells and the protective microflora present within the female genital tract. In this study, we evaluated the impact of hydroxychloroquine (HCQ)-loaded, reservoir-type, polyurethane intravaginal rings (IVRs) on the growth of Lactobacillus crispatus and Lactobacillus jensenii and on the viability of vaginal and ectocervical epithelial cells. The IVRs were fabricated using hot-melt injection molding and were capable of providing controlled release of HCQ for 24 days, with mean daily release rates of 17.01 ± 3.6 μg/ml in sodium acetate buffer (pH 4) and 29.45 ± 4.84 μg/ml in MRS broth (pH 6.2). Drug-free IVRs and the released HCQ had no significant effects on bacterial growth or the viability of vaginal or ectocervical epithelial cells. Furthermore, there was no significant impact on the integrity of vaginal epithelial cell monolayers, in comparison with controls, as measured by transepithelial electrical resistance. Overall, this is the first study to evaluate the effects of HCQ-loaded IVRs on the growth of vaginal flora and the integrity of vaginal epithelial cell monolayers.

Implant delivering hydroxychloroquine attenuates vaginal T lymphocyte activation and inflammation

&NA; Evidence suggests that women who are naturally resistant to HIV infection exhibit low baseline immune activation at the female genital tract (FGT). This “immune quiescent” state is associated with lower expression of T‐cell activation markers, reduced levels of gene transcription and pro‐inflammatory cytokine or chemokine production involved in HIV infection while maintaining an intact immune response against pathogens. Therefore, if this unique immune quiescent state can be pharmacologically induced locally, it will provide an excellent women‐oriented strategy against HIV infection To our knowledge, this is the first research article evaluating in vivo, an innovative trackable implant that can provide controlled delivery of hydroxychloroquine (HCQ) to successfully attenuate vaginal T lymphocyte activation and inflammation in a rabbit model as a potential strategy to induce an “immune quiescent” state within the FGT for the prevention of HIV infection. This biocompatible implant can deliver HCQ above therapeutic concentrations in a controlled manner, reduce submucosal immune cell recruitment, improve mucosal epithelium integrity, decrease protein and gene expression of T‐cell activation markers, and attenuate the induction of key pro‐inflammatory mediators. Our results suggest that microbicides designed to maintain a low level of immune activation at the FGT may offer a promising new strategy for reducing HIV infection.

Disposition, Metabolism and Histone Deacetylase and Acetyltransferase Inhibition Activity of Tetrahydrocurcumin and Other Curcuminoids

Tetrahydrocurcumin (THC), curcumin and calebin-A are curcuminoids found in turmeric (Curcuma longa). Curcuminoids have been established to have a variety of pharmacological activities and are used as natural health supplements. The purpose of this study was to identify the metabolism, excretion, antioxidant, anti-inflammatory and anticancer properties of these curcuminoids and to determine disposition of THC in rats after oral administration. We developed a UHPLC–MS/MS assay for THC in rat serum and urine. THC shows multiple redistribution phases with corresponding increases in urinary excretion rate. In-vitro antioxidant activity, histone deacetylase (HDAC) activity, histone acetyltransferase (HAT) activity and anti-inflammatory inhibitory activity were examined using commercial assay kits. Anticancer activity was determined in Sup-T1 lymphoma cells. Our results indicate THC was poorly absorbed after oral administration and primarily excreted via non-renal routes. All curcuminoids exhibited multiple pharmacological effects in vitro, including potent antioxidant activity as well as inhibition of CYP2C9, CYP3A4 and lipoxygenase activity without affecting the release of TNF-α. Unlike curcumin and calebin-A, THC did not inhibit HDAC1 and PCAF and displayed a weaker growth inhibition activity against Sup-T1 cells. We show evidence for the first time that curcumin and calebin-A inhibit HAT and PCAF, possibly through a Michael-addition mechanism.

Using safe, affordable and accessible non-steroidal anti-inflammatory drugs to reduce the number of HIV target cells in the blood and at the female genital tract

At its basic level, HIV infection requires a replication‐competent virus and a susceptible target cell. Elevated levels of vaginal inflammation has been associated with the increased risk of HIV infection as it brings highly activated HIV target cells (CCR5+CD4+ T cells; CCR5+CD4+CD161+ Th17 T cells) to the female genital tract (FGT) where they interact with HIV. Decreased HIV risk has been associated with a phenotype of decreased immune activation, called immune quiescence, described among Kenyan female sex workers who were intensely exposed to HIV yet remain uninfected. Current prevention approaches focus on limiting viral access. We took the novel HIV prevention approach of trying to limit the number of HIV target cells in the genital tract by reducing inflammation using safe, affordable and globally accessible anti‐inflammatory drugs.

Current State of Microbicide Development

Efforts in developing an effective vaccine for human immunodeficiency virus (HIV) has been challenging as HIV strains are highly variable and exhibit extraordinary mutability. Despite condom usage and pre‐exposure prophylaxis as excellent prevention strategies, lack of accessibility in some developing countries and low adherence due to sociocultural factors continue to act as barriers in reducing the HIV epidemic. Microbicides are topical therapies developed to prevent HIV and other sexually transmitted infections during intercourse. Microbicides applied vaginally or rectally are intended to prevent HIV infection at the site of transmission by either inhibiting its entry into immune cells or prevent viral replication. This review will summarize some of the current state‐of‐the‐art microbicide formulations that are in preclinical and clinical stages of development and discuss some of the challenges associated with microbicide development.

pH responsive polymer brushes grafted from the surface of intravaginal rings for reversible switch on/off on-demand drug delivery

The preparation of various samples of ebonite vulcanizates and their physico-mechanical properties have been investigated using standard methods. This work explores the production of ebonite dust, production of ebonite vulcanizates and investigation of the characterization of the ebonite. Five different ebonite materials-labeled A, B, C, D, and E with sulphur content in parts per hundred grams of rubber (Phr) of 32, 34, 36, 38 and 40 respectively were produced. The physico-mechanical properties carried out were tensile strength, hardness and abrasion resistance. The tensile strength (MPa) for sample A, B, C, D and E were 5.6, 3.5, 4.7, 1.7 and 2.0 respectively while the abrasion (%mass loss) were 8.49, 4.24, 2.59, 1.08 and 1.05 respectively and the hardness (IRHD) being 63, 64, 65, 70 and 82.The results show that the preparation of ebonite from natural rubber as a base polymer is feasible considering the results of characterization obtained.T caffeic cid-derived polyether, namely poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl) ethylene] or poly[3-(3,4-dihydroxyphenyl) glyceric acid] (PDPGA) was isolated and identified in the water-soluble, high-molecular weight fractions obtained from extracts of different species of Boraginaceae family. According to data of 13C, 1H NMR, APT, 2D 1H/13C HSQC, 1D NOE and 2D DOSY experiments the polyoxyethylene chain is the backbone of the polymer molecule. 3,4-Dihydroxyphenyl and carboxyl groups are regular substituents at two carbon atoms in the chain. The repeating unit of this regular polymer is 3-(3, 4-dihydroxyphenyl) glyceric acid residue. Most of the carboxylic groups of PDPGA from Anchusa italica and Symphytum grandiflorum unlike the polymer of S. asperum, S. caucasicum and S. officinale are methylated. The 2D DOSY experiment gave the similar diffusion coefficient for the methylated and non-methylated signals of PDPGA. Both sets of signals fell in the same horizontal. This would imply a similar molecular weight for methylated and non-methylated polymers.Then basic monomeric moiety of this polymer, 3-(3, 4-dihydroxyphenyl) glyceric acid (DPGA) was synthesized via Sharpless asymmetric dihydroxylation of trans-caffeic acid derivatives using an osmium catalyst. Besides, it is well known that epoxides are valuable synthons in organic synthesis and have been introduced into pharmaceutical applications. Subsequently, the building block for the production of derivatives of PDPGA, methyl 3-(3,4-dimethoxyphenyl)glycidate was synthesized based on the Darzen reaction or by oxidation of trans-caffeic acid with oxone in order to produce in future derivatives of synthetic analogue of natural polymer through ring-opening polymerization of 2,3-disubstituted oxirane. PDPGA is endowed with intriguing pharmacological properties as anti-complementary, antioxidant, anti-inflammatory, burn and wound healing and anticancer properties. S. caucasicum PDPGA and DPGA exerted anti-cancer efficacy in vitro and in vivo. However, our results showed that anticancer efficacy of PDPGA is more effective compared to its synthetic monomer. Overall, this study identifies S. caucasicum PDPGA as a potent agent against PCA without any toxicity, and supports its clinical application.