A Phase 1 pharmacokinetic study of a single-dose bioadhesive clindamycin 2% gel for bacterial vaginosis.

OBJECTIVES: To evaluate pharmacokinetics (PK) of a single dose of an investigational 2% clindamycin phosphate vaginal gel in healthy women by assessment of plasma and vaginal clindamycin concentrations over 7 days, and assess safety. METHODS: Single-centre, Phase 1, single-dose PK study. Blood and vaginal samples were collected daily and safety was evaluated through to Day 7. RESULTS: Twenty-one subjects were enrolled; 20 completed the study. Plasma clindamycin concentrations demonstrated quantifiable values in all subjects through to 24 h post-dose, remaining above the limits of quantification (LOQ) through to 48 h for the majority of subjects. Systemic exposure (AUC0-t) was 1179 (range 62-3822) h·ng/mL. Arithmetic mean AUC0-24 was 818 (range 51-3287) h·ng/mL. Vaginal clindamycin phosphate levels were relatively high 24 h following administration in 15/21 subjects (6 subjects had values >400 µg/g and 9 had values of 100-400 µg/g). The levels dropped in most participants to below the LOQ 2 days following dosing. In a few participants, levels remained elevated for several days. Maximal amounts of vaginal clindamycin occurred on Day 2 with a mean value of 30.3 µg. One treatment-emergent adverse event (TEAE) of moderate-severity headache not related to study drug was reported and resolved on Day 1. No TEAEs were related to physical examinations, pelvic examinations, laboratory values or vital signs. CONCLUSIONS: The vaginal concentrations of clindamycin phosphate plus the clindamycin plasma profile over time are consistent with release of drug from the investigational gel over 24 to 72 h. A single dose was well tolerated.

Pharmacokinetic and safety analyses of tenofovir and tenofovir-emtricitabine vaginal tablets in pigtailed macaques.

Vaginal rapidly disintegrating tablets (RDTs) containing tenofovir (TFV) or TFV and emtricitabine (FTC) were evaluated for safety and pharmacokinetics in pigtailed macaques. Two separate animal groups (n = 4) received TFV (10 mg) or TFV-FTC (10 mg each) RDTs, administered near the cervix. A third group (n = 4) received 1 ml TFV gel. Blood plasma, vaginal tissue biopsy specimens, and vaginal fluids were collected before and after product application at 0, 0.5, 1, 4, and 24 h. A disintegration time of <30 min following vaginal application of the RDTs was noted, with negligible effects on local inflammatory cytokines, vaginal pH, and microflora. TFV pharmacokinetics were generally similar for both RDTs and gel, with peak median concentrations in vaginal tissues and vaginal secretions being on the order of 10(4) to 10(5) ng/g (147 to 571 µM) and 10(6) ng/g (12 to 34 mM), respectively, at 1 to 4 h postdose. At 24 h, however, TFV vaginal tissue levels were more sustained after RDT dosing, with median TFV concentrations being approximately 1 log higher than those with gel dosing. FTC pharmacokinetics after combination RDT dosing were similar to those of TFV, with peak median vaginal tissue and fluid levels being on the order of 10(4) ng/g (374 µM) and 10(6) ng/g (32 mM), respectively, at 1 h postdose with levels in fluid remaining high at 24 h. RDTs are a promising alternative vaginal dosage form, delivering TFV and/or FTC at levels that would be considered inhibitory to simian-human immunodeficiency virus in the macaque vaginal microenvironment over a 24-h period.

A nine-month repeat-dose intravaginal ring (Ovaprene) irritation study in sheep.

OBJECTIVES: Ovaprene is a novel, investigational, intravaginal hormone-free monthly ring contraceptive designed for use in women of reproductive age to be worn over multiple weeks (one menstrual cycle). The objective of this work was to evaluate the safety of Ovaprene during a nine-month repeat-dose sheep study. STUDY DESIGN: In addition to traditional safety endpoints such as histopathological evaluation of the sheep female reproductive tract, vaginal fluids were collected and tested for released iron over time. Also, the amount of iron in the rings was assessed following removal, and serum iron levels were measured. There were four sheep in each group (Ovaprene group and sham group). RESULTS: There were no macroscopic clinical findings. There was minimal to mild, mixed or mononuclear cell infiltration present in all levels of vagina (cranial, mid, and caudal) from all animals including sham controls based on post-study necropsy. The female reproductive tract from animals treated with the Ovaprene ring was comparable to the sham controls. The concentrations of serum iron in sheep treated with Ovaprene ring were similar compared to a sham treated animal. The average amount of ferrous gluconate released from Ovaprene over the 29-day period of use was 175 mg of the approximately 512 mg nominally loaded into the rings. CONCLUSIONS: Overall, the Ovaprene devices were well-tolerated in female sheep. IMPLICATIONS: This study should support a chronic (e.g., one year) contraceptive efficacy study in women.

Preliminary Efficacy of Topical Sildenafil Cream for the Treatment of Female Sexual Arousal Disorder: A Randomized Controlled Trial.

OBJECTIVE: To assess the efficacy of topical sildenafil cream, 3.6% among healthy premenopausal women with female sexual arousal disorder. METHODS: We conducted a phase 2b, exploratory, randomized, placebo-controlled, double-blind study of sildenafil cream. Coprimary efficacy endpoints were the change from baseline to week 12 in the Arousal Sensation domain of the SFQ28 (Sexual Function Questionnaire) and question 14 of the FSDS-DAO (Female Sexual Distress Scale-Desire, Arousal, Orgasm). RESULTS: Two hundred women with female sexual arousal disorder were randomized to sildenafil cream (n=101) or placebo cream (n=99). A total of 174 participants completed the study (sildenafil 90, placebo 84). Among the intention-to-treat (ITT) population, which included women with only female sexual arousal disorder and those with female sexual arousal disorder with concomitant sexual dysfunction diagnoses or genital pain, although the sildenafil cream group demonstrated greater improvement in the SFQ28 Arousal Sensation domain scores, there were no statistically significant differences between sildenafil and placebo cream users in the coprimary and secondary efficacy endpoints. An exploratory post hoc subset of the ITT population with an enrollment diagnosis of female sexual arousal disorder with or without concomitant decreased desire randomized to sildenafil cream reported significant increases in their SFQ28 Arousal Sensation domain score (least squares mean 2.03 [SE 0.62]) compared with placebo cream (least squares mean 0.08 [SE 0.71], P=.04). This subset achieved a larger mean improvement in the SFQ28 Desire and Orgasm domain scores. This subset population also had significantly reduced sexual distress and interpersonal difficulties with sildenafil cream use as measured by FSDS-DAO questions 3, 5, and 10 (all P≤.04). CONCLUSION: Topical sildenafil cream improved outcomes among women with female sexual arousal disorder, most significantly in those who did not have concomitant orgasmic dysfunction. In particular, in an exploratory analysis of a subset of women with female sexual arousal disorder with or without concomitant decreased desire, topical sildenafil cream increased sexual arousal sensation, desire, and orgasm and reduced sexual distress. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT04948151.

Evaluation of 28-day estradiol and progesterone vaginal rings in a phase 1 clinical pharmacokinetic study.

OBJECTIVE: The aim of this work is to develop a combination of 17ß-estradiol (E2) and progesterone (P4) in a single-dose intravaginal ring (IVR) for the treatment of vasomotor symptoms (VMS) and genitourinary syndrome of menopause while providing endometrial protection. The objective of this study was to evaluate DARE-HRT1, a 28-day IVR that continuously delivers E2 and P4, in a phase 1 clinical trial to assess its pharmacokinetics. METHODS: This was an open-label, three-arm (group) study. Thirty-two (32) healthy postmenopausal women were recruited at two Australian sites. The average age was 57.2 years (47-69 y). The first arm received one ring for 28 days designed to release E2 at a rate of 80 µg/d and P4 at 4 mg/d (80/4 IVR); the second arm received a ring releasing E2 at 160 µg/d and P4 at 8 mg/d (160/8 IVR). The third arm received oral Estrofem (1 mg E2) and Prometrium (100 mg P4) both daily for 29 days. Blood samples were taken predose then intensively over the first day (day 1) and periodically thereafter over the remaining 27 days. After removal of the rings on the morning of day 29, intensive samples were collected. Similar procedures were conducted with women enrolled in the oral group. The plasma samples were analyzed for E2, estrone (E1), and P4 using validated bioanalytical methods. RESULTS: The baseline-adjusted steady-state plasma levels of E2 and P4 from 80/4 IVR were 20.4 ± 17.1 pg/mL and 1.32 ± 0.19 ng/mL (n = 10), respectively. The baseline-adjusted steady-state plasma levels of E2 and P4 from 160/8 IVR were 30.9 ± 8.7 pg/mL and 2.08 ± 0.50 ng/mL (n = 10), respectively. The baseline-adjusted average plasma concentrations of E2 and P4 at day 29 of the oral group were 35.4 ± 11.2 pg/mL and 0.79 ± 0.72 ng/mL (n = 11), respectively. The baseline-adjusted steady state of E1 from the 80/4 IVR and the 160/8 IVR were 22.1 ± 16.6 pg/mL (n = 10) and 25.2 ± 12.3 pg/mL (n = 10), respectively. The baseline-adjusted concentration of E1 in the oral arm was 209 ± 67.7 ng/mL (n = 11). The IVR were well tolerated, and no serious adverse events were reported. CONCLUSIONS: The 80/4 IVR and 160/8 IVR gave similar steady-state concentrations of E2 as seen with drug products approved by the US Food and Drug Administration for treatment of VMS and genitourinary symptoms of menopause. The E2 concentrations of this study support the potential of DARE-HRT1, a promising new option for hormone therapy for treatment of VMS and vaginal symptoms associated with menopause.

Characterization of UC781-tenofovir combination gel products for HIV-1 infection prevention in an ex vivo ectocervical model.

HIV continues to be a problem worldwide. Topical vaginal microbicides represent one option being evaluated to stop the spread of HIV. With drug candidates that have a specific action against HIV now being studied, it is important that, when appropriate and based on the mechanism of action, the drug permeates the tissue so that it can be delivered to specific targets which reside there. Novel formulations of the nucleotide reverse transcriptase inhibitor tenofovir (TFV) and the nonnucleoside reverse transcriptase inhibitor UC781 have been developed and evaluated here. Gels with three distinct rheological properties were prepared. The three gels released both UC781 and TFV under in vitro conditions at concentrations equal to or above the reported 50% effective concentrations (EC(50)s). The drug concentrations in ectocervical tissues were well in excess of the reported EC(50)s. The gels maintain ectocervical viability and prevent infection of ectocervical explants after a HIV-1 challenge. This study successfully demonstrates the feasibility of using this novel combination of antiretroviral agents in an aqueous gel as an HIV infection preventative.

Simultaneous delivery of tenofovir and acyclovir via an intravaginal ring.

Vaginal microbicides may play an important role in protecting women from HIV infection. A strong synergy between HSV and HIV has been observed, and epidemiological studies demonstrate that HSV infection increases the risk of HIV acquisition. Incorporation of the antiretroviral tenofovir (TFV) along with the antiherpetic acyclovir (ACV) into combination intravaginal rings (IVRs) for sustained mucosal delivery of both compounds could lead to increased microbicide product adherence and efficacy compared with conventional vaginal formulations. A novel, dual-protection "pod IVR" platform developed in-house and delivering ACV and TFV was evaluated in rabbit and sheep models. The devices were safe and exhibited sustained release of both drugs independently and at controlled rates over the 28-day studies. Daily release rates were estimated based on residual drug content of the used devices: rabbits, 343 ± 335 µg day(-1) (ACV) and 321 ± 207 µg day(-1) (TFV); sheep, 174 ± 14 µg day(-1) (ACV) and 185 ± 34 µg day(-1) (TFV). Mean drug levels in sheep vaginal samples were as follows: secretions, 5.25 ± 7.31 µg ml(-1) (ACV) and 20.6 ± 16.2 µg ml(-1) (TFV); cervicovaginal lavage fluid, 118 ± 113 ng ml(-1) (ACV) and 191 ± 125 ng ml(-1) (TFV); tissue, 173 ng g(-1) (ACV) and 93 ng g(-1) (TFV). An in vitro-in vivo correlation was established for both drugs and will allow the development of future formulations delivering target levels for prophylaxis and therapy. These data suggest that the IVR based on the pod design has potential in the prevention of transmission of HIV-1 and other sexually transmitted pathogens.

A 90-day tenofovir reservoir intravaginal ring for mucosal HIV prophylaxis.

A vaginal gel containing the antiretroviral tenofovir (TFV) recently demonstrated 39% protection against HIV infection in women. We designed and evaluated a novel reservoir TFV intravaginal ring (IVR) to potentially improve product effectiveness by providing a more controlled and sustained vaginal dose to maintain cervicovaginal concentrations. Polyurethane tubing of various hydrophilicities was filled with a high-density TFV/glycerol/water semisolid paste and then end-sealed to create IVRs. In vitro, TFV release increased with polyurethane hydrophilicity, with 35 weight percent water-swelling polyurethane IVRs achieving an approximately 10-mg/day release for 90 days with mechanical stiffness similar to that of the commercially available NuvaRing. This design was evaluated in two 90-day in vivo sheep studies for TFV pharmacokinetics and safety. Overall, TFV vaginal tissue, vaginal fluid, and plasma levels were relatively time independent over the 90-day duration at approximately 10(4) ng/g, 10(6) ng/g, and 10(1) ng/ml, respectively, near or exceeding the highest observed concentrations in a TFV 1% gel control group. TFV vaginal fluid concentrations were approximately 1,000-fold greater than levels shown to provide significant protection in women using the TFV 1% gel. There were no toxicological findings following placebo and TFV IVR treatment for 28 or 90 days, although slight to moderate increases in inflammatory infiltrates in the vaginal epithelia were observed in these animals compared to naïve animals. In summary, the controlled release of TFV from this reservoir IVR provided elevated sheep vaginal concentrations for 90 days to merit its further evaluation as an HIV prophylactic.

Design of a semisolid vaginal microbicide gel by relating composition to properties and performance.

PURPOSE: Develop a preclinical in vitro algorithm enabling de novo design of semisolid vaginal drug delivery gels, by using biomechanical modeling of gel spreading in the vaginal canal and empirically relating gel composition to mechanical properties and predicted performance. METHODS: Gel performance was defined through a multivariate objective function constructed from gels' mechanical properties and selected performance criteria for gel spreading within the vaginal canal. Mixture design of experiment was used to establish a semi-empirical relationship linking composition-property and property-performance relationships for gels with varying concentrations of hydroxyethylcellulose and Carbopol 974P. This permits definition of a local optimum for gel composition and volume of administration, within a defined gel composition space. RESULTS: Rheological behavior and, consequently, the value of the objective function varied broadly with composition. The algorithm indicated a 3.0 wt% HEC gel as the near optimal composition for a 3.5 mL applied volume for gels designed to spread throughout the vagina. CONCLUSIONS: The algorithm introduced herein is a novel tool that facilitates an understanding of the composition-property-performance relationship for vaginal semisolid drug delivery gels. This approach has promise as a scientific methodology for evaluation and optimization of vaginal gels prior to in vivo investigations.

Pharmaceutical development of microbicide drug products.

HIV infection rates in the developing world remain a serious problem. One potential approach to reduce infection rates is to use products known as microbicides, referred to herein as microbicide drug products (MDPs). These are drugs capable of, when administered topically to the vagina (or rectum), interfering with infection by one or more mechanisms. This review article covers the latest pharmaceutical developments in the area of microbicides dosage forms and delivery systems. These products are principally designed for use in the developing world and must therefore address cultural and societal issues generally unknown in the developed world. The first-generation microbicides evaluated clinically were principally polyanions. These drugs, administered intravaginally as gels, were found to be ineffective in preventing transmission of HIV from men to women. Second-generation drugs such as tenofovir, dapivirine, and UC781 are reverse transcriptase inhibitors developed as gels formulations and intravaginal rings (IVRs). Gels are considered coitally-related products while IVRs are coitally-independent systems designed to release the drug over a four-week period or possibly longer (up to 3 or 4 months). Other dosage forms under development include fast dissolving films, tablets/capsules, and possibly vaginal sponges. Dual protection systems are also under development. These systems include formulations capable of preventing HIV infection along with a second drug capable of preventing conception or other viral infections such as HSV.

Vaginal tamoxifen for treatment of vulvar and vaginal atrophy: Pharmacokinetics and local tolerance in a rabbit model over 28 days.

Vaginally delivered tamoxifen is being developed as alternative to estrogen-based therapies for the treatment of vulvar and vaginal atrophy (VVA) symptoms in subjects at high risk for breast cancer, undergoing treatment for breast cancer with aromatase inhibitors or are breast cancer survivors. Tamoxifen (1 or 20 mg) was administered intra-vaginally to female rabbits once-daily over a 28-day period to assess its pharmacokinetics, systemic exposure and local vaginal tolerance. Plasma samples were taken to assess concentrations of tamoxifen and its metabolites 4-hydroxytamoxifen and N-desmethyltamoxifen over the first day of vaginal administration and following the last dose on Day 28. In-life observations included evaluation of the vaginal region for signs of irritation. At necropsy, vaginal irritation was assessed by the method of Eckstein which reflect collective histopathological grading of four parameters within the vagina including epithelial morphology, leukocytic infiltration, congestion, and edema. Uterine effects of vaginal tamoxifen were also assessed. Plasma concentrations of tamoxifen were higher following administration of 20 mg tamoxifen compared to 1 mg tamoxifen at both Day 1 and Day 28. The metabolite 4-hydroxytamoxifen could not be detected on Day 1 and concentrations were low at Day 28 at the 1 mg tamoxifen dose. 4-Hydroxytamoxifen concentrations were low, but detectable at Day 1 and 28 following administration of 20 mg tamoxifen. The metabolite N-desmethyltamoxifen was undetectable at the 1 mg and 20 mg doses on Day 1; it remained undetectable at the 1 mg tamoxifen dose at Day 28. N-desmethyltamoxifen was detected over the first 8 h of Day 28 then fell below the quantitation limits. There was little to no vaginal or systemic accumulation of tamoxifen following once-daily dosing for 28 days. Tamoxifen accounted for more than 85% of the total systemic exposure compared to its metabolites, 4-hydroxytamoxifen, and N-desmethyltamoxifen. There was essentially no detectable vaginal irritation evident over the course of the study. At necropsy the individual Eckstein scores (maximum score of 16) of the proximal, mid, and distal vagina of females in the 1 mg and 20 mg dose groups were generally comparable in both groups and ranged from minimal to mild magnitude (1 mg dose group: ranging from 1 to 3 in the proximal vagina, 4 to 5 in the mid vagina, and 3 to 7 in the distal vagina; 20 mg dose group: ranging from 3 to 5 in the proximal vagina, 4 to 7 in the mid vagina, and 4 to 5 in the distal vagina). Overall, tamoxifen was absorbed and metabolized following vaginal administration and vaginal irritation was minimal to none at both doses.

Pharmacokinetics and tolerability of a novel progesterone intravaginal ring in sheep.

The objectives of this work were to evaluate the in vitro release and in vivo pharmacokinetics and local tolerability of a novel, segmented ethylene-vinyl acetate (EVA) intravaginal ring (IVR) delivering progesterone (P) in drug-naïve ovariectomized female Dorset crossbred sheep. Following preparation and assessment of in vitro release of P, animals were randomized into one of six treatment groups: group 1 Crinone® 8% gel (90 mg); group 2 Prometrium® 200-mg capsules; group 3 placebo IVR; group 4 progesterone (P) IVR 4 mg/day; group 5 P IVR 8 mg/day; or group 6 P IVR 12 mg/day. Crinone 8% gel and Prometrium capsules were administered once daily for 28 days. IVRs were inserted vaginally on day 1 and remained in place through day 14; a new ring was administered on day 15 and was removed at day 28. Animals underwent daily examinations to confirm ring placement, and vaginal irritation was scored from 0 (none) to 4 (severe). Blood samples were taken at scheduled times for pharmacokinetic analysis. Postmortem examinations performed on all IVR groups included vaginal irritation, macroscopic, and microscopic evaluations, including irritation scoring and histopathology. Intravaginal rings were retained over 28 days in all animals. Clinical observations showed no significant abnormal findings in any group. Pharmacokinetic analysis in animals showed sustained release of P over from days 0 through 14 of ring use. Irritation scores and microscopic assessments were consistent with the IVRs being well tolerated. These results will guide future human clinical studies to ultimately develop an IVR for use in women for the prevention of preterm birth.

Pharmacokinetics and Tolerability of a Novel 17ß-Estradiol and Progesterone Intravaginal Ring in Sheep.

This study reports the preparation, in vitro release, pharmacokinetics, and local tolerability of novel ethylene-vinyl acetate intravaginal rings (IVRs) delivering 17ß-estradiol (E2) and progesterone (P), in drug-naïve ovariectomized female Dorset crossbred sheep. After preparation and assessment of in vitro release of E2 and P, animals were randomized to treatment groups 1 or 2 (comparator rings releasing 50 or 100 µg/d E2, respectively), groups 3 or 4 (ethylene-vinyl acetate IVRs, 160 µg/d E2 with 4 [160/4 IVR] or 8 mg/d P [160/8 IVR], respectively), or group 5 (160 µg E2 and 10 mg P administered intravenously). IVRs were placed on day 1 and remained in place through day 29. Animals underwent daily examinations to confirm ring placement, and vaginal irritation was scored from 0 (none) to 4 (severe). Blood samples were taken at scheduled times for pharmacokinetic analysis. Postmortem examinations performed on groups 1-4 were macroscopic and microscopic evaluations, including irritation scoring and histopathology. IVRs were retained over 28 days in all but 1 animal (group 4). In all animal groups, clinical observations showed no significant abnormal findings. Pharmacokinetic analysis in the animals showed sustained release of E2 and P over a 28-day period. Irritation scores and microscopic assessments were consistent with foreign object placement. A novel 2-drug IVR delivery system was well tolerated in a sheep model and pharmacokinetic release was as expected over a 28-day release period. These results will guide future human clinical studies.

Drug delivery for the treatment of endometriosis and uterine fibroids.

Endometriosis and uterine fibroids (also known as uterine leiomyomas) are serious medical conditions affecting large numbers of women worldwide. Many women are asymptomatic but those with symptoms require medical intervention to relieve chronic pain and dysmenorrhea and to address infertility. Drug delivery has played a role in reducing some of the symptoms associated with endometriosis and uterine fibroids. Use of drug delivery systems for both conditions can roughly be divided into two categories: (1) existing systems designed for other indications such as contraception for symptomatic relief and (2) development of novel systems aimed at addressing some of the underlying biochemical changes associated with endometriosis and uterine fibroids such as oxidative stress, angiogenesis, and matrix degradation. The latter drug delivery approaches rely heavily on nanotechnology. Existing systems that deliver estrogens and/or progestins include vaginal rings, transdermal patches, and intrauterine systems. Long-acting implantable contraceptives such as Implanon® and injectables such as Depo-Provera® have found use in treating endometriosis. Similarly, long-acting GnRH products (e.g., Lupron Depot®) are used to treat endometriosis. Other drugs formulated in long-acting formulations include intravaginal rings capable of delivering selective progesterone receptor modulators, androgens such as danazol, and aromatase inhibitors (e.g., anastrozole). Nanoparticles composed of silica, poly(lactic-co-glycolic acid), cerium oxide, dendrimers, and chitosan/polyethyleneamine have all been investigated to improve treatment of endometriosis and to a lesser extent, uterine fibroids.

Development of controlled release systems over the past 50years in the area of contraception.

The field of controlled release has contributed significantly to female reproductive health and in particular the prevention of unintended pregnancy. For at least 50years, there have been significant advances in controlled release dosage forms used for contraception. These advances have been driven by the need to provide women a wide array of products that address adherence problems noted with oral contraceptives. The first long-acting injectable product (Depo-Provera®) was approved in the US in 1959. Since then, there has been an emphasis on development of long-acting reversible contraceptives. These products include implants, intrauterine systems, and vaginal rings. A shorter acting contraceptive option is the transdermal patch. Despite these advances there are still a large number of unplanned pregnancies around the world. New controlled release technologies will be needed to continue providing women safe and easy to use contraceptive products.

An update on multipurpose prevention technologies for the prevention of HIV transmission and pregnancy.

INTRODUCTION: Multipurpose Prevention Technologies (MPTs) are designed to address two or more indications from a single product. The overall goal is to prevent unintended pregnancy and transmission of one or more STIs including HIV-1. AREAS COVERED: The topics covered herein are advances in over the past three years. Advances include development of novel intravaginal rings capable of releasing microbicides to prevent transmission of HIV-1 and unintended pregnancy. These rings include the potential to prevent transmission of more than one STI and unintended pregnancy. There are also gels that can potentially accomplish the same thing. Finally, combination of a drug and barrier device are also covered. EXPERT OPINION: There has been considerable advance in this field over the past three years. There is one ring currently in a Phase I clinical trial and others are soon to follow. Some of these drug delivery systems are by necessity rather complicated and hence could be prohibitively expensive in the developing world. Conducting multiple clinical trials to support regulatory approval of two or more indications represents a significant barrier. It remains unclear that women will be more motivated to use MPT products than has been observed in recent microbicide-only clinical trials. Despite these challenges, the need for MPTs remain acute hopefully ensuring they will continue to be developed over the coming years.

Perceptibility and the "Choice Experience": User Sensory Perceptions and Experiences Inform Vaginal Prevention Product Design.

The development of pericoital (on demand) vaginal HIV prevention technologies remains a global health priority. Clinical trials to date have been challenged by nonadherence, leading to an inability to demonstrate product efficacy. The work here provides new methodology and results to begin to address this limitation. We created validated scales that allow users to characterize sensory perceptions and experiences when using vaginal gel formulations. In this study, we sought to understand the user sensory perceptions and experiences (USPEs) that characterize the preferred product experience for each participant. Two hundred four women evaluated four semisolid vaginal formulations using the USPE scales at four randomly ordered formulation evaluation visits. Women were asked to select their preferred formulation experience for HIV prevention among the four formulations evaluated. The scale scores on the Sex-associated USPE scales (e.g., Initial Penetration and Leakage) for each participant's selected formulation were used in a latent class model analysis. Four classes of preferred formulation experiences were identified. Sociodemographic and sexual history variables did not predict class membership; however, four specific scales were significantly related to class: Initial Penetration, Perceived Wetness, Messiness, and Leakage. The range of preferred user experiences represented by the scale scores creates a potential target range for product development, such that products that elicit scale scores that fall within the preferred range may be more acceptable, or tolerable, to the population under study. It is recommended that similar analyses should be conducted with other semisolid vaginal formulations, and in other cultures, to determine product property and development targets.

New oral delivery systems for treatment of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is often localized to specific sites in the gastrointestinal tract (GIT). As a result, this disease can be treated with oral site-specific (targeted) drug delivery systems. Targeted delivery systems for treatment of IBD are designed to increase local tissue concentrations of antiinflammatory drugs from lower doses compared with systemic administration. This review addresses the impact disease has or may have on oral targeted delivery for treatment of IBD as well as a number of delivery approaches currently used in marketed products or under investigation. Delivery systems reviewed rely on temporal control, changes in pH along the GIT, the action of local enzymes to trigger drug release, and changes in intraluminal pressure. Dissolution of enteric polymer coatings due to a change in local pH and reduction of azo-bonds to release an active agent are both used in commercially marketed products. Newer approaches showing promise in treating IBD are based on polysaccharides. These materials are most effective when used as compression coatings around core tablets, which contain the active agent. More complex polymeric prodrugs systems are also under investigation. If the dose of the drug is sufficiently low, this approach may also prove useful in improving treatment of IBD.

A Pilot Study Measuring the Distribution and Permeability of a Vaginal HIV Microbicide Gel Vehicle Using Magnetic Resonance Imaging, Single Photon Emission Computed Tomography/Computed Tomography, and a Radiolabeled Small Molecule.

Vaginal microbicide gels containing tenofovir have proven effective in HIV prevention, offering the advantage of reduced systemic toxicity. We studied the vaginal distribution and effect on mucosal permeability of a gel vehicle. Six premenopausal women were enrolled. In Phase 1, a spreading gel containing (99m)technetium-DTPA ((99m)Tc) radiolabel and gadolinium contrast for magnetic resonance imaging (MRI) was dosed intravaginally. MRI was obtained at 0.5, 4, and 24 h, and single photon emission computed tomography with conventional computed tomography (SPECT/CT) at 1.5, 5, and 25 h postdosing. Pads and tissues were measured for activity to determine gel loss. In Phase 2, nonoxynol-9 (N-9), containing (99m)Tc-DTPA, was dosed as a permeability control; permeability was measured in blood and urine for both phases. SPECT/CT showed the distribution of spreading gel throughout the vagina with the highest concentration of radiosignal in the fornices and ectocervix; signal intensity diminished over 25 h. MRI showed the greatest signal accumulation in the fornices, most notably 1-4 h postdosing. The median (interquartile range) isotope signal loss from the vagina through 6 h was 29.1% (15.8-39.9%). Mucosal permeability to (99m)Tc-DTPA following spreading gel was negligible, in contrast to N-9, with detectable radiosignal in plasma, peaking at 8 h (5-12). Following spreading gel dosing, 0.004% (0.001-2.04%) of the radiosignal accumulated in urine over 12 h compared to 8.31% (7.07-11.01%) with N-9, (p=0.043). Spreading gel distributed variably throughout the vagina, persisting for 24 h, with signal concentrating in the fornices and ectocervix. The spreading gel had no significant effect on vaginal mucosal permeability.

Lack of in vitro-in vivo correlation for a UC781-releasing vaginal ring in macaques.

This study describes the preclinical development of a matrix-type silicone elastomer vaginal ring device designed to provide controlled release of UC781, a non-nucleoside reverse transcriptase inhibitor. Testing of both human- and macaque-sized rings in a sink condition in vitro release model demonstrated continuous UC781 release in quantities considered sufficient to maintain vaginal fluid concentrations at levels 82-860-fold higher than the in vitro IC50 (2.0 to 10.4 nM) and therefore potentially protect against mucosal transmission of HIV. The 100-mg UC781 rings were well tolerated in pig-tailed macaques, did not induce local inflammation as determined by cytokine analysis and maintained median concentrations in vaginal fluids of UC781 in the range of 0.27 to 5.18 mM during the course of the 28-day study. Analysis of residual UC781 content in rings after completion of both the in vitro release and macaque pharmacokinetic studies revealed that 57 and 5 mg of UC781 was released, respectively. The pharmacokinetic analysis of a 100-mg UC781 vaginal ring in pig-tailed macaques showed poor in vivo-in vitro correlation, attributed to the very poor solubility of UC781 in vaginal fluid and resulting in a dissolution-controlled drug release mechanism rather than the expected diffusion-controlled mechanism.