Preparation and characterization of biodegradable urea-loaded microparticles as an approach for transdermal delivery

Development and Characterization of Polymeric Microsponge as a New Vehicle to Deliver Urea Topically

BACKGROUND

Topical delivery of therapeutic agents is considered beneficial due to various advantages like ease of administration, avoidance of the first-pass effect, and improved patient compliance. Therefore, scientists around the globe are exploring this route for the delivery of drugs nowadays.

OBJECTIVE

The present patent investigation aimed to prepare, optimize, and characterize the urealoaded microsponges for efficient topical delivery in vitro.

METHODS

Urea-loaded ethylcellulose microsponges were prepared using quasi emulsion solvent diffusion technique and optimized using Box-Behnken design (BBD). Furthermore, they were characterized in-vitro using various techniques like scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction analysis (XRD). In-vitro drug release and release kinetics analysis was also performed.

RESULTS

Urea-loaded microsponges were spherical and porous. Optimized urea loaded microsponges showed a minimum size (39.78 ± 1.98 μm), high entrapment (74.56 ± 2.8%), acceptable polydispersity index (PDI) (0.224 ± 0.081) and zeta potential (-21.9 ± 2.9 mV). These microsponges were capable of sustaining the release of urea for 24 h (91.21 ± 5.20%), and the mechanism of release was the combination of diffusion and erosion.

CONCLUSION

The developed microsponge system could be beneficial for topical delivery of urea as it could reduce the dosing frequency of urea and increase patient compliance through its sustained release.

Combination of Innate Immune Modulators as Vaccine Adjuvants in Mice

The development of new, effective, and safe vaccines necessarily requires the identification of new adjuvant(s) to enhance the potency and longevity of antigen-specific immune responses. In the present study, we compare the antibody-mediated and cell-mediated immune (CMI) responses within groups of mice vaccinated subcutaneously with ovalbumin (OVA; as an experimental antigen) plus polyphosphazene (an innate immune modulator), Polyinosinic:polycytidylic acid (poly-I:C; (an RNA mimetic) and glycopeptide ARC5 (which is a Toll-like receptor (TLR), TLR2 ligand and PAM3CSK4 analogue) formulated together in a soluble vaccine. We also investigated the effect of a polymeric nanoparticle of ARC4 and ARC7 (which are a novel muramyl dipeptide analogue and a monophosophoryl lipid A (MPLA) analogue, respectively) plus OVA +/- ARC5 as a subcutaneous vaccine in mice. OVA+ARC4/ARC7 nanoparticle +/- ARC5 triggered a robust and balanced Th1/Th2-type humoral response with significant anti-OVA IgA in serum, and significant interferon (IFN)-γ and interleukin (IL)-17 production in splenocytes after 35 days relative to the controls. Formulation of OVA with ARC4/ARC7 nanoparticles should be investigated for inducing protective immunity against infectious pathogens in mice and other species.

Microparticulate based topical delivery system of clobetasol propionate

Psoriasis is a chronic, autoimmune skin disease affecting approximately 2% of the world's population. Clobetasol propionate which is a superpotent topical corticosteroid is widely used for topical treatment of psoriasis. Conventional dosage forms like creams and ointments are commonly prefered for the therapy. The purpose of this study was to develop a new topical delivery system in order to provide the prolonged release of clobetasol propionate and to reduce systemic absorption and side effects of the drug. Clobetasol propionate loaded-poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres were prepared by oil-in-water emulsion-solvent evaporation technique. Particle size analysis, morphological characterization, DSC and XRD analyses and in vitro drug release studies were performed on the microparticle formulations. Emulgel formulations were prepared as an alternative for topical delivery of clobetasol propionate. In vitro drug release studies were carried out from the emulgel formulations containing pure drug and drug-loaded microspheres. In addition, the same studies were performed to determine the drug release from the commercial cream product of clobetasol propionate. The release of clobetasol propionate from the emulgel formulations was significantly higher than the commercial product. In addition, the encapsulation of clobetasol propionate in the PLGA microspheres significantly delayed the drug release from the emulgel formulation. As a result, the decrease in the side effects of clobetasol propionate by the formulation containing PLGA microspheres is expected.