pH-triggered polymeric nanoparticles in gel for preventing vaginal transmission of HIV and unintended pregnancy

Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/ AIDS) and unplanned pregnancy affect female reproductive health globally. A single product providing a dual purpose of HIV prophylaxis and contraception may improve adherence to the therapy. Thus, we formulated a female-centric multipurpose prevention technology (MPT) comprising of nanoparticle loaded vaginal gel formulation acting as a contraceptive and microbicide. Eudragit® S100 nanoparticles of Atazanavir sulphate (ATZ; antiviral) and Fluoxetine hydrochloride (FLX; repurposed spermicide) were prepared for pH dependent drug release and loaded in carrageenan and HPMC K200M gel. The particle size of ATZ and FLX nanoparticles was 396.7 ± 20.64 nm and 226.5 ± 2.08 nm respectively. The in vitro release of the gel formulation in simulated seminal fluid (pH 7.6) showed 96.16% and 95.98% release of ATZ and FLX respectively at the end of 8 h. The in vitro anti-HIV and spermicidal activity of the formulation was above 80% for low drug concentrations. In vivo studies on murine model showed no signs of inflammation or vaginal epithelial injury. Curcumin based imaging confirmed the retention of the formulation in the reproductive tract of mice with minimal leakage. Nanoparticles in gel enabled non-invasive and localised delivery with minimal side effects and can be an effective prophylactic therapy.

Mucosal drug delivery and 3D printing technologies: A focus on special patient populations

In the last decade, additive manufacturing (AM) technologies have revolutionized how healthcare provision is envisioned. The rapid evolution of these technologies has already created a momentum in the effort to address unmet personalized needs in large patient groups, especially those belonging to sensitive subgroup populations (e.g., paediatric, geriatric, visually impaired). At the same time, AM technologies have become a salient ally to overcome defined health challenges in drug formulation development by addressing not only the requirement of personalized therapy, but also problems related to lowering non-specific drug distribution and the risk of adverse reactions, enhancing drug absorption and bioavailability, as well as ease of administration and patient compliance. To this end, mucoadhesive drug delivery systems fabricated with the support of AM technologies provide competitive advantages over conventional dosage forms, aiming to entice innovation in drug formulation with special focus on sensitive patient populations.

Enhanced mucosal penetration and efficient inhibition efficacy against cervical cancer of PEGylated docetaxel nanocrystals by TAT modification

To investigate the potential of cell penetrating peptide (CPP) modification on nanomedicine for improving mucosal penetration and effective therapy of cervical cancer, docetaxel nanocrystals modified with trans-activator of transcription (TAT) peptide were designed for treatment of cervical cancer via vaginal administration. Docetaxel nanocrystals were coated by polymerization of dopamine to form polydopamine (PDA) coating which facilitated TAT modification and PEGylation for less mucus entrapment to get PEGylated nanocrystals modified with TAT (NC@PDA-PEG-TAT). Enhanced cellular drug uptake and cytotoxicity of NC@PDA-PEG-TAT was observed in cervical cancer-related TC-1 cells than that of PEGylated nanocrystals (NC@PDA-PEG). Intravaginally administered NC@PDA-PEG-TAT dispersed in poloxamer 407-based thermosensitive gel exhibited prolonged in vivo intravaginal retention, deeper mucosal penetration and more potent inhibition on the growth of murine orthotopic cervical cancer than NC@PDA-PEG, PDA-coated nanocrystals or unmodified nanocrystals. All data suggested the significance of CPP-modification on nanocrystals in the local treatment of vaginal mucosa-related diseases by vaginal administration.

Size-dependent biodistribution of thiol-organosilica nanoparticles and F4/80 protein expression in the genital tract of female mice after intravaginal administration

Recently the vaginal route consider as an ideal route for drug delivery systems (DDS) administration. This is because, it is suitable for lower drug dosage, higher drug concentration in the genital tract tissues and lower drug concentration in pregnant women blood circulation. However, the vaginal route administration faces many challenges due to the physiology as well as the complexity of vaginal tissue histology. Here in this study, during diestrus stage (optimal condition for foreign substance internalization), single or dual size of fluorescent thiol-organosilica nanoparticles (tOS-NPs) were administrated intravaginally. The biodistribution and reactivity of tOS-NPs in different tissues of the female genital tract were investigated under the fluorescence microscope. Furthermore, using immunohistochemical staining, the expression of F4/80 protein and the role of macrophages in transport and re-location of tOS-NPs from vaginal lumen into different genital tissues or other organs were investigated. This study showed that, tOS-NPs size and type of tissue are important in biodistribution and uptake of tOS-NPs in the genital tract. Small size (100 nm) of tOS-NPs was highly accumulated in the genital tract tissues especially endometrial epithelium compared with large tOS-NPs (1000 nm). Contradictory, the large size induced the expression of F4/80 protein and the number of vaginal macrophages compared with small size. However, both small and large sizes of tOS-NPs were found co-localized with F4/80⁺ macrophages, located in the vaginal, endometrial and ovarian tissues. The tOS-NPs intravaginally administrated were found in the splenic tissues, indicating its ability to enter the blood circulation from the vaginal lumen. Additionally, the high accumulation of tOS-NPs in the endometrial epithelium indicated the endometrial first pass effect of tOS-NPs. As a result, high concentration of tOS-NPs in the endometrial epithelium may reduce the concentration of tOS-NPs-based DDS in the blood circulation and their side effects. Furthermore, during vaginal tissue optimal condition (diestrus stage), understanding the fate and biodistribution of tOS-NPs will introduce important data about the development of save and effective DDS for the pregnant women.

Characterization and in vitro evaluation of a vaginal gel containing Lactobacillus crispatus for the prevention of gonorrhea

The increasing resistance of Neisseria gonorrhoeae to any current antibiotic treatment and the difficulties associated with the use of prevention means such as condom urge the need for alternative methods to prevent this sexually transmitted infection. In this work, a prevention strategy based on the use of a vaginal gel containing Lactobacilli was assessed in vitro. A Lactobacillus crispatus strain (ATCC 33197) was selected based on the published data on its ability to inhibit Neisseria gonorrhoeae. Its probiotic properties were first characterized. Then, a thermo-sensitive hydrogel containing 21.5% of poloxamer 407, 1% of sodium alginate and 9log₁₀ CFU of Lactobacillus crispatus per gel sample (5 g) was developed. The gelation temperature and the rheological characteristics of this formulation appeared suitable for a vaginal administration. Lactobacillus crispatus was viable in the gel for six months although a large amount of the bacteria was not culturable. The ability of Lactobacillus crispatus to inhibit Neisseria gonorrhoeae was still observed with the gel. Such system, thus, appeared promising for the prevention of gonorrhea.

Vaginal residence and pharmacokinetic preclinical study of topical vaginal mucoadhesive W/S emulsions containing ciprofloxacin

The aim of this work is to test the in vivo behavior of a mucoadhesive vaginal emulsion resistant to the clearance of vaginal fluids using ciprofloxacin (CPX) as an anti-infective model of drug. CPX is a broad-spectrum antibiotic used in the treatment of sexual tissues infections, as intravenous injection in a dose of 20 mg every 12 h. In this study, CPX was incorporated in water in silicone (W/S) mucoadhesive emulsions and the in vivo residence time and the CPX in vivo absorption and distribution to the sexual organs was studied using the rat as animal model. W/S emulsion shows excellent in vitro bioadhesion having high resistance to the vaginal fluids clearance. The drug release profiles show a constant release of CPX during at least 6 h according to a zero-order kinetics. In vivo computerized PET/CT Image Analysis after intravaginal administration to rats indicates that W/S emulsions remain in the vaginal area for a long time and shows a good absorption of the radiotracers used as markers through the vaginal mucosa. Ciprofloxacin pharmacokinetic studies developed after the single intravaginal administration of W/S emulsion shows a good absorption and distribution of CPX on the uterus and ovarian tissue. A significant concentration of CPX in the sexual tissues was observed after 24 h of administration of W/S emulsion. Therefore, W/S emulsions have a good in vivo residence and drug release in the vaginal mucosae showing a great potential for the treatment of sexual tissues infections, as vaginal bioadhesive delivery systems of antinfectious drugs.

Controlled-release biodegradable nanoparticles: From preparation to vaginal applications

This study aimed to prepare poly (d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) with chitosan (CTS) surface modification to be used as a vaginal delivery system for antimycotic drugs. Clotrimazole was encapsulated with entrapment efficiencies of 86.1 and 68.9% into Clotrimazole-PLGA-NPs (CLT-PLGA-NPs) and PLGA-NPs with CTS-modified surface (CLT-PLGA-CTS-NPs), respectively. The later NPs exhibited a larger size and higher positive zeta potential (Z potential) in comparison to unmodified NPs. In vitro release kinetic studies indicated that Clotrimazole was released in percentages of >98% from both nanoparticulate systems after 18days. Antifungal activity and mucoadhesive properties of NPs were enhanced when CTS was added onto the surface. In summary, these results suggested that Clotrimazole loaded into PLGA-CTS-NPs has great potential for vaginal applications in treating vaginal infections generated by Candida albicans.

In vivo retention of poloxamer-based in situ hydrogels for vaginal application in mouse and rat models

The purpose of this study is to evaluate the in vivo retention capabilities of poloxamer-based in situ hydrogels for vaginal application with nonoxinol-9 as the model drug. Two in situ hydrogel formulations, which contained 18% poloxamer 407 plus 1% poloxamer 188 (GEL1, relative hydrophobic) or 6% poloxamer 188 (GEL2, relative hydrophilic), were compared with respect to the rheological properties, in vitro hydrogel erosion and drug release. The vaginal retention capabilities of these hydrogel formulations were further determined in two small animal models, including drug quantitation of vaginal rinsing fluid in mice and isotope tracing with ^99mTc in rats. The two formulations exhibited similar phase transition temperatures ranging from 27 to 32 °C. Increasing the content of poloxamer 188 resulted in higher rheological moduli under body temperature, but slightly accelerated hydrogel erosion and drug release. When compared in vivo, GEL1 was eliminated significantly slower in rat vagina than GEL2, while the vaginal retention of these two hydrogel formulations behaved similarly in mice. In conclusion, increases in the hydrophilic content of formulations led to faster hydrogel erosion, drug release and intravaginal elimination. Rats appear to be a better animal model than mice to evaluate the in situ hydrogel for vaginal application.

PEGylation of lipoplexes: The right balance between cytotoxicity and siRNA effectiveness

The delivery of small interfering RNA (siRNA) is an attractive therapeutic approach to treat several pathologies, such as viral infections or cancers. However, the stability and the efficacy of these biotherapies are still a major obstacle to their use. Cationic liposomes (DOTAP/Chol/DOPE 1/0.75/0.5M ratio) have been complexed to siRNA (lipoplexes) in order to be administrated by the vaginal route, in the context of HPV16 induced cervical preneoplastic lesions. To overcome the constraint of the cervico-vaginal mucus, PEGylation is required to allow the diffusion of lipoplexes through it. Thereby, PEGylated lipoplexes coated with three types of polyethylene glycol (PEG) as DSPE-PEG2000, DSPE-PEG750 or C8-PEG2000-Ceramide (Ceramide-PEG2000) at different densities have been developed and characterized. PEGylated lipoplexes were successfully prepared and showed a hydrodynamic diameter around 200nm, appropriate for vaginal application. In vitro assays on HPV16 positive cell lines revealed that a positive charge of PEGylated lipoplexes allows a higher mRNA knockdown by siRNA. However, the cationic property is also associated to cytotoxicity. The addition of a high percentage of PEG prevented this toxicity but seemed also to reduce siRNA endosomal escape, probably by steric hindrance. The decreasing of PEG density of Ceramide-PEG2000 to 20% allows the release of siRNA and in consequence, biological activities, contrarily to DSPE-PEG. These results suggest that Ceramide-PEG is more appropriate for siRNA delivery compared to DSPE-PEG. In conclusion, the right balance between cytotoxicity and siRNA effectiveness has been found with the transfection of lipoplexes coated with 20% of Ceramide-PEG2000. This new nanovector could have a high potential against multiple mucosal diseases, such as human papillomavirus-induced genital lesions.

Clotrimazole-loaded nanostructured lipid carrier hydrogels: thermal analysis and in vitro studies

The aim of the present work is to design a new formulation containing clotrimazole (CTZ) loaded into nanostructured lipid carriers (NLC) for the treatment of fungal vaginal infections. In order to obtain formulations with suitable viscosity for mucosal application, NLC containing CTZ produced by the ultrasonication method were viscosized by the addition of poloxamer P407 in the NLC dispersion (CTZ-NLC-gel). These systems exhibit well-known thermogelling properties. The rheological characterization of the CTZ-NLC hydrogel using a controlled stress rheometer evidenced that the presence of NLC or CTZ did not affect gelling temperature (Tgel). Dilution with simulated vaginal fluid (SVF) increased the Tgel from 17.4 to 29.6°C. For these thermogelling systems, micro-calorimetric assays conducted by a Micro-DSC III confirmed that the hydrogel-containing CTZ-NLC was able to change its structure with a rapid passage from non-crystalline (liquid) to crystalline (semi-solid) form. Furthermore, when a local application is considered, no drug should pass through the vaginal mucosa, limiting thus the systemic diffusion and toxicity. For this purpose, Franz cell has been employed to investigate the ex vivo permeation of CTZ through pig vaginal mucosa. The results showed no CTZ diffusion. The toxicological experiments performed on HeLa cells after a 24h incubation time confirmed that CTZ-NLC-gel at a concentration of 1mg/mL showed a low toxicity profile resulting in a cell vitality of 77.2%. Interestingly, anti-candida activity studies demonstrated that CTZ-NLC gel was 4-fold more active than Fungizone(®) against Candida albicans. These encouraging results suggest that the hydrogel containing CTZ-NLC could be proposed as an innovative system to administer CTZ to treat vaginal infections.