Dosage Forms and Delivery Systems for Vaginal Therapy

A special issue of Pharmaceutics (ISSN 1999-4923).

Deadline for manuscript submissions: closed (30 September 2014) | Viewed by 58625

Special Issue Editor

Drug Transport and Delivery Research Group, Department of Pharmacy, University of Tromsø, Universitetsveien 57, 9037 Tromsø, Norway
Interests: drug delivery; nanomedicine; liposomes; skin therapy; vaginal therapy
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The focus of this issue is on the challenges and promises of delivery systems for the drug therapy of vaginal diseases. In spite of advancements in drug delivery technologies, the vaginal route of drug administration remains a challenge in the development of novel drug therapies. Most of the delivery systems are aimed at improving the treatment of vaginal infections, including HIV prevention. Promising new approaches in design of drug delivery systems destined both for local therapy and systemic absorption, the role of system’s mucoadhesiveness, potential for drug targeting, industrial scale up and acceptability by patients will be discussed in this issue. In addition, potential toxicity issues and use of delivery systems in pregnancy, optimization of drug delivery in pre- and post-menopausal women will also be included.

Prof. Dr. Natasa Skalko-Basnet
Guest Editor

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Keywords

  • vagina
  • mucoadhesion
  • drug delivery
  • topical vaginal therapy
  • systemic therapy via vagina
  • nanopharmaceuticals

Published Papers (6 papers)

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Research

853 KiB  
Article
Evaluation of Rapidly Disintegrating Vaginal Tablets of Tenofovir, Emtricitabine and Their Combination for HIV-1 Prevention
by Meredith R. Clark, M. Melissa Peet, Sarah Davis, Gustavo F. Doncel and David R. Friend
Pharmaceutics 2014, 6(4), 616-631; https://0-doi-org.brum.beds.ac.uk/10.3390/pharmaceutics6040616 - 08 Dec 2014
Cited by 30 | Viewed by 9194
Abstract
Vaginal tablets are being developed as an alternative to gels as an inexpensive, discreet dosage form for the administration of microbicides. This work describes the pharmacokinetic (PK) evaluation of rapidly disintegrating vaginal tablets containing tenofovir (TFV, 10 mg), emtricitabine (FTC, 10 mg), and [...] Read more.
Vaginal tablets are being developed as an alternative to gels as an inexpensive, discreet dosage form for the administration of microbicides. This work describes the pharmacokinetic (PK) evaluation of rapidly disintegrating vaginal tablets containing tenofovir (TFV, 10 mg), emtricitabine (FTC, 10 mg), and the combination of TFV and FTC (10 mg each) under in vitro and in vivo conditions, and in direct comparison to the clinical TFV 1% gel, a microbicide product in Phase III clinical testing. The PK of TFV and FTC from tablets were also evaluated in female rabbits following intravaginal administration. Direct comparison of a single dose of TFV tablets (intact or predissolved at 10 mg/mL) and TFV 1% gel showed no differences in the vaginal PK of TFV between groups; however systemic bioavailability of TFV was significantly higher from the gel. When rabbits were dosed either once or daily for seven days with intact tablets of TFV, FTC, or the combination of TFV/FTC, vaginal and systemic concentrations of TFV and FTC were unaffected by co-formulation. Moreover, plasma PK parameters were similar following a single dose or seven once-daily doses. Tissue concentrations of TFV and FTC in the cranial vagina 4 h after administration ranged between 104 and 105 ng/g. Concentrations of TFV-diphospate (TFV-DP, the active metabolite) were also high (over 103 ng/g or about 3000 to 6000 fmol/mg) in the cranial vagina 4 h after administration and similar to those measured following administration of TFV 1% gel. These data demonstrate that rapidly disintegrating vaginal tablets may be a suitable topical microbicide dosage form providing similar vaginal TFV PK to that of TFV 1% gel. The data also support co-administration of FTC with TFV in a single vaginal tablet to create a combination microbicide in a simple and inexpensive dosage form. Full article
(This article belongs to the Special Issue Dosage Forms and Delivery Systems for Vaginal Therapy)
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930 KiB  
Article
What do Portuguese Women Prefer Regarding Vaginal Products? Results from a Cross-Sectional Web-Based Survey
by Rita Palmeira-de-Oliveira, Paulo Duarte, Ana Palmeira-de-Oliveira, José Das Neves, Maria Helena Amaral, Luiza Breitenfeld and José Martinez-de-Oliveira
Pharmaceutics 2014, 6(4), 543-556; https://0-doi-org.brum.beds.ac.uk/10.3390/pharmaceutics6040543 - 21 Oct 2014
Cited by 11 | Viewed by 6889
Abstract
Therapeutic outcomes of vaginal products depend not only on their ability to deliver drugs to or through the vagina but also on acceptability and correct use. Women’s preferences, in turn, may vary according to age and cultural backgrounds. In this work, an anonymous [...] Read more.
Therapeutic outcomes of vaginal products depend not only on their ability to deliver drugs to or through the vagina but also on acceptability and correct use. Women’s preferences, in turn, may vary according to age and cultural backgrounds. In this work, an anonymous online survey was completed by 2529 Portuguese women to assess their preferences for physical characteristics and mode of application of vaginal products, according to age. Additionally, intention to use and misconceptions about these issues were assessed. The majority of women of all age groups would use vaginal products to treat or prevent diseases, upon medical prescription. Women preferred vaginal products to be odorless and colorless gels, creams and ointments composed by natural origin drugs/excipients and applied by means of an applicator. Although the majority of women would prefer not to insert any product in the vagina, intention to use for self and recommendation to use for others was associated with previous experiences with vaginal products. General concerns and misconceptions related to use of vaginal products were rare. These data may contribute to the development of products that women are more prone to use. Full article
(This article belongs to the Special Issue Dosage Forms and Delivery Systems for Vaginal Therapy)
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Article
Characterization of Commercially Available Vaginal Lubricants: A Safety Perspective
by Ana Raquel Cunha, Rita M. Machado, Ana Palmeira-de-Oliveira, José Martinez-de-Oliveira, José Das Neves and Rita Palmeira-de-Oliveira
Pharmaceutics 2014, 6(3), 530-542; https://0-doi-org.brum.beds.ac.uk/10.3390/pharmaceutics6030530 - 22 Sep 2014
Cited by 39 | Viewed by 16592
Abstract
Vaginal lubricants are widely used by women to help solve intercourse difficulties or as enhancers, but recent reports raise questions about their safety. Twelve commercially available gel products were tested for pH value, pH buffering capacity, osmolality and cytotoxicity relevant to vaginal delivery. [...] Read more.
Vaginal lubricants are widely used by women to help solve intercourse difficulties or as enhancers, but recent reports raise questions about their safety. Twelve commercially available gel products were tested for pH value, pH buffering capacity, osmolality and cytotoxicity relevant to vaginal delivery. Obtained data were analyzed in light of the recent Advisory Note by the World Health Organization (WHO) for personal lubricants to be concomitantly used with condoms. Results showed that most products do not comply with pH and osmolality recommended standards, thus posing a potential hazard. Four products presented values of osmolality around three-times higher than the maximum acceptable limit of 1200 mOsm/kg. In vitro cell testing further identified substantial cytotoxicity even at 1:100 dilutions for three products, contrasting with no significant effect of up to at least a 1:5 dilution of a Universal Placebo gel. However, no direct correlation between these last results and pH or osmolality was found, thus suggesting that the individual toxicity of specific formulation components plays an important role in the outcome of a particular product. Although further assessment is required, these results highlight potential safety issues related to the formulation of commercially available vaginal lubricants. Full article
(This article belongs to the Special Issue Dosage Forms and Delivery Systems for Vaginal Therapy)
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Article
Firmness Perception Influences Women’s Preferences for Vaginal Suppositories
by Toral Zaveri, Rachel J. Primrose, Lahari Surapaneni, Gregory R. Ziegler and John E. Hayes
Pharmaceutics 2014, 6(3), 512-529; https://0-doi-org.brum.beds.ac.uk/10.3390/pharmaceutics6030512 - 10 Sep 2014
Cited by 17 | Viewed by 7908
Abstract
Microbicides are being actively researched and developed as woman-initiated means to prevent HIV transmission during unprotected coitus. Along with safety and efficacy, assessing and improving compliance is a major area of research in microbicide development. We have developed carrageenan-based semisoft vaginal suppositories and [...] Read more.
Microbicides are being actively researched and developed as woman-initiated means to prevent HIV transmission during unprotected coitus. Along with safety and efficacy, assessing and improving compliance is a major area of research in microbicide development. We have developed carrageenan-based semisoft vaginal suppositories and have previously evaluated how physical properties such as firmness, size and shape influence women’s willingness to try them. Firmness has previously been quantified in terms of small-strain storage modulus, G’, however large-strain properties of the gels may also play a role in the firmness perception. In the current study we prepared two sets of suppositories with the same G’ but different elongation properties at four different G’ values (250, 2500, 12,500, 25,000 Pa): For convenience we refer to these as “brittle” and “elastic”, although these terms were never provided to study participants. In the first of two tests conducted to assess preference, women compared pairs of brittle and elastic suppositories and indicated their preference. We observed an interaction, as women preferred brittle suppositories at lower G’ (250, 2500 Pa) and elastic ones at a higher G’ (25,000 Pa). In the second test, women evaluated samples across different G’, rated the ease-of-insertion and willingness-to-try and ranked the samples in order of preference. Brittle suppositories at G’ of 12,500 Pa were most preferred. In vitro studies were also conducted to measure the softening of the suppositories in contact with vaginal simulant fluid (VSF). Release of antiretroviral drug tenofovir in VSF was quantified for the brittle and elastic suppositories at G’ of 12,500 Pa to determine the effect of suppository type on release. The initial rate of release was 20% slower with elastic suppositories as compared to brittle suppositories. Understanding how different physical properties simultaneously affect women’s preferences and pharmacological efficacy in terms of drug release is required for the optimization of highly acceptable and efficacious microbicides. Full article
(This article belongs to the Special Issue Dosage Forms and Delivery Systems for Vaginal Therapy)
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863 KiB  
Article
Bioadhesive Mini-Tablets for Vaginal Drug Delivery
by Marianne Hiorth, Susanne Nilsen and Ingunn Tho
Pharmaceutics 2014, 6(3), 494-511; https://0-doi-org.brum.beds.ac.uk/10.3390/pharmaceutics6030494 - 27 Aug 2014
Cited by 43 | Viewed by 8278
Abstract
Different non-ionic cellulose ethers (methyl cellulose, MC; hydroxyethyl cellulose, HEC; hydroxypropyl cellulose, HPC; hydroxypropylmethyl cellulose, HPMC) and microcrystalline cellulose (MCC) were investigated as matrix formers for preparation of mini-tablets targeting vaginal drug delivery. Hexyl aminolevulinat hydrochloridum (HAL) was used as a model drug. [...] Read more.
Different non-ionic cellulose ethers (methyl cellulose, MC; hydroxyethyl cellulose, HEC; hydroxypropyl cellulose, HPC; hydroxypropylmethyl cellulose, HPMC) and microcrystalline cellulose (MCC) were investigated as matrix formers for preparation of mini-tablets targeting vaginal drug delivery. Hexyl aminolevulinat hydrochloridum (HAL) was used as a model drug. The mini-tablets were characterized with respect to their mechanical strength, bioadhesion towards cow vaginal tissue in two independent tests (rotating cylinder test, detachment test using texture analyzer), and dissolution rate in two media mimicking the pH levels of fertile, healthy and post-menopausal women (vaginal fluid simulant pH 4.5, phosphate buffer pH 6.8). Mini-tablets with a matrix of either HPMC or HPC were found to possess adequate mechanical strength, superior bioadhesive behavior towards vaginal tissue, and pH independent controlled release of the model drug, suggesting that both systems would be suited for the treatment of women regardless of age, i.e., respective of their vaginal pH levels. Bioadhesive mini-tablets offer a potential for improved residence time in the vaginal cavity targeting contact with mucosal tissue and prolonged release of the drug. Full article
(This article belongs to the Special Issue Dosage Forms and Delivery Systems for Vaginal Therapy)
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845 KiB  
Article
Release of Tenofovir from Carrageenan-Based Vaginal Suppositories
by Toral Zaveri, John E. Hayes and Gregory R. Ziegler
Pharmaceutics 2014, 6(3), 366-377; https://0-doi-org.brum.beds.ac.uk/10.3390/pharmaceutics6030366 - 04 Jul 2014
Cited by 22 | Viewed by 7469
Abstract
Microbicides are an active area of research for HIV prevention, being developed as a woman-initiated method of prevention during unprotected coitus. Along with safety and efficacy, assessing and improving compliance is a major area of research in microbicide development. We have produced microbicide [...] Read more.
Microbicides are an active area of research for HIV prevention, being developed as a woman-initiated method of prevention during unprotected coitus. Along with safety and efficacy, assessing and improving compliance is a major area of research in microbicide development. We have produced microbicide prototypes in the form of semisoft vaginal suppositories prepared from carrageenan and conducted both qualitative and quantitative studies using these prototypes to determine the physical properties that drive acceptability and possibly adherence. In order to ensure that the suppositories function as effective drug delivery vehicles, we have conducted in vitro dissolution studies in water, vaginal simulant fluid (VSF) and semen simulant fluid (SSF) with suppositories loaded with the antiretroviral drug, tenofovir (TFV). TFV was released via diffusion and matrix erosion in water or by diffusion out of the matrix in VSF and SSF. Diffusion studies were conducted in two different volumes of VSF and SSF. The volume of VSF/SSF into which TFV diffused and the size of the suppositories determined the rate of diffusion from the suppositories. About 45%–50% of the encapsulated TFV diffused out of the suppositories within the first two hours, irrespective of suppository size, diffusion medium (VSF/SSF) and the volume of medium. Prior work indicates that a short waiting period between insertion and coitus is highly desired by women; present data suggest our microbicide prototypes have rapid initial release followed by a slow release curve over the first 24 h. Full article
(This article belongs to the Special Issue Dosage Forms and Delivery Systems for Vaginal Therapy)
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