Ophthalmic In Situ Gels with Balsam Poplar Buds Extract: Formulation, Rheological Characterization, and Quality Evaluation.

Balsam poplar buds are a raw material with a high content of polyphenols. Various polyphenols are known for their anti-inflammatory and antioxidant properties. In this study, an aqueous extract of balsam poplar buds was prepared in order to use environmentally friendly and non-aggressive solvents. The aqueous extract was lyophilized, and a 1% aqueous solution of lyophilized balsam poplar buds extract (L1) was prepared. L1 solution was used as a source of polyphenols for the production of ophthalmic in situ gels, so as to develop a product featuring antioxidant properties. Poloxamer 407 (P407) and hydroxypropyl methylcellulose (HPMC) were selected as gelling agents for the in situ gels. In order to select the formulations with the best conditions of use, formulations of different polymer concentrations (P407-10%, 12%, 15%; HPMC-0.5%, 0.75%) were prepared, choosing the same amount of the active polyphenol source L1. The physicochemical properties, rheological parameters, stability, and irritant effect on the rabbit corneal cell line (SIRC) were evaluated. Formulations in which P407 and HMPC concentrations were 10/0.75% and 12%/0.75% reached a gelation point close to the ocular surface temperature; the gels remained stable for 30 days and did not cause an irritant effect on the SIRC cell line.

Formulation of Ocular In Situ Gels with Lithuanian Royal Jelly and Their Biopharmaceutical Evaluation In Vitro.

Royal jelly is a natural substance produced by worker bees that possesses a variety of biological activities, including antioxidant, anti-inflammatory, antibacterial, and protective. Although fresh royal jelly is kept at low temperatures, to increase its stability, it needs to be incorporated into pharmaceutical formulations, such as in situ gels. The aim of this study was to formulate in situ ocular gels containing Lithuanian royal jelly for topical corneal use in order to increase the retention time of the formulation on the ocular surface and bioavailability. Gels were evaluated for physicochemical characteristics (pH, rheological properties, refractive index) and in vitro drug release measuring the amount of 10-hydroxy-2-decenoic acid (10-HDA). An ocular irritation test and cell viability tests were performed using the SIRC (Statens Seruminstitut Rabbit Cornea) cell culture line. Results indicated that all the in situ gels were within an acceptable pH and refractive index range close to corneal properties. Rheology studies have shown that the gelation temperature varies between 25 and 32 °C, depending on the amount of poloxamers. The release studies have shown that the release of 10-HDA from in situ gels is more sustained than royal jelly suspension. All gel formulations were non-irritant according to the short-time exposure test (STE) using the SIRC cell culture line, and long-term cell viability studies indicated that the formulations used in small concentrations did not induce cell death. Prepared in situ gels containing royal jelly have potential for ocular drug delivery, and they may improve the bioavailability, stability of royal jelly, and formation of non-irritant ocular formulations.

Formulation of Liposomes Containing Royal Jelly and Their Quality Assessment.

Royal jelly, a gelatinuous consistency bee product produced and secreted by the hypopharyngeal and mandibular glands of worker honeybees, is beneficial in the treatment of dermatological conditions, likely through its content of the fatty acid 10-hydroxy-2-decenoic acid (10-HDA). However, 10-HAD poorly penetrates into skin. Thus, in this work, we produced royal jelly incorporated liposomes with the aim of increasing skin penetration of 10-HDA. Lipid nanocarriers were prepared by the thin lipid-film hydration method. Size and polydispersity index of the nanocarrier particles, and their stability over 30 days were measured. The effects of royal jelly and 10-HDA liposomal formulations on the viability of immortalized human keratinocyte cells were tested with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The skin penetration of 10-HDA from liposomal formulations and royal jelly solution was studied in vitro with Franz type vertical diffusion cells using porcine skin as limiting membrane. As result, small liposomes were achieved, and the efficacy of the obtained nanoformulations was examined by means of in vitro cell assays with a HaCaT immortalized human keratinocyte cell culture line. Finally, the skin penetration experiments showed that liposomal incorporation greatly increased 10-HDA penetration into skin layers.

Propolis - quality analysis and use in topical formulations.

The aim of this study was to produce propolis extracts, assess their quality and effect on skin cells and determine the penetration of active ingredients from designed semi-solid topical formulations. The use of higher-concentration ethanol and a larger amount of raw material allows extracting a larger quantity of active ingredients from raw propolis. Ultrasound extraction is an effective method for the production of aqueous extracts of propolis. The results show that depending on concentration, propolis extracts reduce the viability of keratinocytes. The phenolic compounds under observation penetrated the epidermis and dermis from designed formulations. The base of semi-solid formulation influences the efficacy of propolis preparations. The overall quantity of phenolic compounds that penetrated the skin was around 2 % from the ointment and 1.5 % from the cream.