A Microneedle Patch for Measles and Rubella Vaccination Is Immunogenic and Protective in Infant Rhesus Macaques.

Background: New methods to increase measles and rubella (MR) vaccination coverage are needed to achieve global and regional MR elimination goals. Methods: Here, we developed microneedle (MN) patches designed to administer MR vaccine by minimally trained personnel, leave no biohazardous sharps waste, remove the need for vaccine reconstitution, and provide thermostability outside the cold chain. This study evaluated the immunogenicity of MN patches delivering MR vaccine to infant rhesus macaques. Results: Protective titers of measles neutralizing antibodies (>120 mIU/mL) were detected in 100% of macaques in the MN group and 75% of macaques in the subcutaneous (SC) injection group. Rubella neutralizing antibody titers were >10 IU/mL for all groups. All macaques in the MN group were protected from challenge with wild-type measles virus, whereas 75% were protected in the SC group. However, vaccination by the MN or SC route was unable to generate protective immune responses to measles in infant macaques pretreated with measles immunoglobulin to simulate maternal antibody. Conclusions: These results show, for the first time, that MR vaccine delivered by MN patch generated protective titers of neutralizing antibodies to both measles and rubella in infant rhesus macaques and afforded complete protection from measles virus challenge.

Thermostability of Measles and Rubella Vaccines in a Microneedle Patch.

Measles and rubella vaccinations are highly effective at reducing disease prevalence; however, logistic issues related to subcutaneous administration and vaccine wastage limit the extent of vaccination coverage. Microneedle (MN) patches can increase coverage by easing logistics through simplified administration and improved stability. This study demonstrates the thermostability of a bivalent measles and rubella vaccine MN patch. Rubella vaccine stability required pH buffering during drying; potassium phosphate buffer at neutral pH was optimal for both vaccines. Screening 43 excipients for their ability to retain potency during drying and storage yielded sucrose-threonine-potassium phosphate buffer formulation at pH 7.5 as an optimal formulation. MN patches made with this formulation had no significant loss of vaccine titer after one month and remained within a one log10 titer loss cutoff after 3 - 4 months at 5°C, 25°C and 40°C. Finally, these patches were shown to be immunogenic in juvenile rhesus macaques. This work demonstrates the potential for MN patches for measles and rubella vaccination to be removed from the cold chain, which is expected to decrease vaccine cost and wastage, and increase vaccination coverage.

Fabrication of microneedle patches with lyophilized influenza vaccine suspended in organic solvent.

Skin vaccination by microneedle (MN) patch simplifies the immunization process to increase access to vaccines for global health. Lyophilization has been widely used to stabilize vaccines and other biologics during storage, but is generally not compatible with the MN patch manufacturing processes. In this study, our goal was to develop a method to incorporate lyophilized inactivated H1N1 influenza vaccine into MN patches during manufacturing by suspending freeze-dried vaccine in anhydrous organic solvent during the casting process. Using a casting formulation containing chloroform and polyvinylpyrrolidone, lyophilized influenza vaccine maintained activity during manufacturing and subsequent storage for 3 months at 40 °C. Influenza vaccination using these MN patches generated strong immune responses in a murine model. This manufacturing process may enable vaccines and other biologics to be stabilized by lyophilization and administered via a MN patch.

Extended delivery of vaccines to the skin improves immune responses.

Vaccines prevent 2-3 million childhood deaths annually; however, low vaccine efficacy and the resulting need for booster doses create gaps in immunization coverage. In this translational study, we explore the benefits of extended release of licensed vaccine antigens into skin to increase immune responses after a single dose in order to design improved vaccine delivery systems. By administering daily intradermal injections of inactivated polio vaccine according to six different delivery profiles, zeroth-order release over 28 days resulted in neutralizing antibody titers equivalent to two bolus vaccinations administered one month apart. Vaccinations following this profile also improved immune responses to tetanus toxoid and subunit influenza vaccine but not a live-attenuated viral vaccine, measles vaccine. Finally, using subunit influenza vaccine, we demonstrated that daily vaccination by microneedle patch induced a potent, balanced humoral immunity with an increased memory response compared to bolus vaccination. We conclude that extended presentation of antigen in skin via intradermal injection or microneedle patch can enhance immune responses and reduce the number of vaccine doses, thereby enabling increased vaccination efficacy.

Dihydroergotamine mesylate-loaded dissolving microneedle patch made of polyvinylpyrrolidone for management of acute migraine therapy.

Migraine is a widespread neurological disease with negative effects on quality of life and productivity. Moderate to severe acute migraine attacks can be treated with dihydroergotamine mesylate (DHE), an ergot derivative that is especially effective in non-responders to triptan derivatives. To overcome limitations of current DHE formulations in subcutaneous injection and nasal spray such as pain, adverse side effects and poor bioavailability, a new approach is needed for DHE delivery enabling painless self-administration, quick onset of action, and high bioavailability. In this study, we developed a dissolving microneedle patch (MNP) made of polyvinylpyrrolidone, due to its high aqueous solubility and solubility enhancement properties, using a MNP design previously shown to be painless and simple to administer. DHE-loaded MNPs were shown to have a content uniformity of 108±9% with sufficient mechanical strength for insertion to pig skin ex vivo and dissolution within 2min. In vivo pharmacokinetic studies were carried out on hairless rats, and DHE plasma levels were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The area under curve (AUC) value after DHE delivery by MNP (1259±917ng/mL min) was not significantly different (p>0.05) as compared to subcutaneous injection, with a relative bioavailability of 97%. Also, appreciable plasma levels of DHE were seen within 5min for both delivery methods and tmax value of MNPs (38±23min) showed no significant difference (p>0.05) compared to subcutaneous injection (24±13min). These results suggest that DHE-loaded MNPs have promise as an alternative DHE delivery method that can be painlessly self-administered with rapid onset and high bioavailability.

Long-term stability of influenza vaccine in a dissolving microneedle patch.

This study tested the hypothesis that optimized microneedle patch formulations can stabilize trivalent subunit influenza vaccine during long-term storage outside the cold chain and when exposed to potential stresses found during manufacturing and storage. Formulations containing combinations of trehalose/sucrose, sucrose/arginine, and arginine/heptagluconate were successful at retaining most or all vaccine activity during storage at 25 °C for up to 24 months as determined by ELISA assay. The best formulation of microneedle patches contained arginine/heptagluconate, which showed no significant loss of vaccine activity during the study. To validate these in vitro findings, mice were immunized using trivalent influenza vaccine stored in microneedle patches for more than 1 year at 25 °C, which elicited antibody titers greater than or equal to fresh liquid vaccine delivered by intradermal injection, indicating the retention of immunogenicity during storage. Finally, influenza vaccine in microneedle patches lost no significant activity during exposure to 60 °C for 4 months, multiple freeze-thaw cycles, or electron beam irradiation. We conclude that optimally formulated microneedle patches can retain influenza vaccine activity during extended storage outside the cold chain and during other environmental stresses, which suggests the possibility of microneedle patch storage on pharmacy shelves without refrigeration.