Katarzyna Sosnowska

Background/Objectives: Despite the continuous development of medicine, the treatment of dermatological fungal infections is difficult due to their chronic nature, recurrence, and resistance of some pathogens to standard therapies. In order to improve the effectiveness of treatment, not only are new active substances with antifungal activity synthesized, but new, unconventional carriers are also developed for substances already used. Methods: Therefore, the focus of this research was to evaluate the possibility of using a combination of two cross-linking techniques for sodium alginate ionic cross-linking with Zn²⁺ ions and electrostatic interaction with ε-poly-L-lysine. The pharmaceutical properties, antifungal activity against Candida strains, and compatibility with human fibroblasts of the designed hydrogels were assessed. Results: It was shown that the double cross-linking process increased the viscosity of the developed hydrogels, improved bioadhesive properties to hairless mice skin, and provided an extended release profile of the active substance. In addition, obtained formulations were characterized by improved antifungal effect against C. albicans, C. krusei, and C. parapsilosis. Prepared hydrogels expressed biocompatibility with human fibroblasts. Conclusions: Dual-cross-linked alginate hydrogels are a promising dermatological formulation that might improve the efficacy of posaconazole in the treatment of antifungal infections.

Jednymi z częściej wykonywanych w recepturze leków są preparaty zawierające w swoim składzie omeprazol. Brak substancji pro receptura wymuszał korzystanie z leku gotowego w postaci peletek. Wprowadzenie na rynek farmaceutyczny omeprazolu jako surowca farmaceutycznego ułatwia wykonywanie leków z omeprazolem, należy jednak pamiętać o możliwości rozkładu substancji w środowisku kwasowym. Celem pracy była ocena trwałości recepturowych zawiesin z omeprazolem w postaci proszku (surowca do receptury), zawierających w swoim składzie glicerol, syrop prosty lub glukozę. Jako substancję zapewniającą odpowiednie pH zastosowano wodorowęglan sodu w stężeniu 8%. Sporządzono sześć zawiesin, które badano bezpośrednio po wykonaniu oraz po 1, 2, 3 i 4 tygodniach przechowywania w temperaturze pokojowej i lodówce. Analizowano ich cechy fizykochemiczne (szybkość sedymentacji i objętość osadu, jednolitość rozproszenia po trzydziestosekundowym wstrząsaniu, ilość wstrząśnięć niezbędnych do ponownego zdyspergowania mieszaniny) oraz trwałość substancji czynnej (pH zawiesin i zawartość omeprazolu). Oznaczanie zawartości omeprazolu prowadzono z wykorzystaniem wysokosprawnej chromatografii cieczowej (HPLC). Badane preparaty podczas przechowywania w temperaturze pokojowej zmieniały barwę na żółto-brązową. Zjawiska tego nie obserwowano w zawiesinach przechowywanych w lodówce. Mieszaniny z glicerolem i syropem prostym ulegały wolniejszej sedymentacji niż mieszaniny z glukozą. Powstający osad był bardzo łatwo dyspergowalny. Aby uzyskać równomierne rozproszenie wystarczyło dziesięciosekundowe wstrząsanie. Wartość pH badanych zawiesin wynosiła ok. 8,86. Podczas ich czterotygodniowego przechowywania pH wzrosło do 9,23 – 9,45 w zawiesinach przechowywanych w temperaturze pokojowej i do 9,17 – 9,24 w preparatach przechowywanych w lodówce. Zgodnie z wymogami zamieszczonymi w USP (United States Pharmacopoeia) za trwałe uznano zawiesiny, w których zawartość omeprazolu była równa lub wyższa niż 90% zawartości początkowej. Zawartość substancji czynnej powyżej 90% wykazano w przypadku wszystkich zawiesin przechowywanych przez dwa tygodnie. Z uwagi na szybszy rozkład omeprazolu pod wpływem temperatury, zawiesiny z omeprazolem sporządzone w recepturze aptecznej powinny być przechowywane w lodówce i zostać zużyte w ciągu 14 dni.

Candida species are opportunistic fungi, which are primary causative agents of vulvovaginal candidiasis. The cure of candidiasis is difficult, lengthy, and associated with the fungi resistivity. Therefore, the research for novel active substances and unconventional drug delivery systems providing effective and safe treatment is still an active subject. Microparticles, as multicompartment dosage forms due to larger areas, provide short passage of drug diffusion, which might improve drug therapeutic efficiency. Sodium alginate is a natural polymer from a polysaccharide group, possessing swelling, mucoadhesive, and gelling properties. Gelatin A is a natural high-molecular-weight polypeptide obtained from porcine collagen. The purpose of this study was to prepare microparticles by the spray-drying of alginate/gelatin polyelectrolyte complex mixture, with a novel antifungal drug—luliconazole. In the next stage of research, the effect of gelatin presence on pharmaceutical properties of designed formulations was assessed. Interrelations among polymers were evaluated with thermal analysis and Fourier transform infrared spectroscopy. A valid aspect of this research was the in vitro antifungal activity estimation of designed microparticles using Candida species: C. albicans, C. krusei, and C. parapsilosis. It was shown that the gelatin addition affected the particles size, improved encapsulation efficiency and mucoadhesiveness, and prolonged the drug release. Moreover, gelatin addition to the formulations improved the antifungal effect against Candida species.

Hydrogels are semi-solid systems with high flexibility, which, due to holding large amounts of water, are similar to natural tissues and are very useful in the field of biomedical applications. Despite the wide range of polymers available to form hydrogels, novel techniques utilized to obtain hydrogels with adequate properties are still being developed. The aim of this study was to evaluate the impact of the freeze–thaw technique on the properties of cryogels based on sodium alginate and chitosan glutamate with posaconazole as a model antifungal substance. The effect of the freezing and thawing process on the physicochemical, rheological, textural and bioadhesive properties of prepared cryogels was examined. Additionally, the antifungal activity against Candida albicans, Candida parapsilosis and Candida krusei of designed formulations was examined. It was shown that the freeze–thaw technique significantly improved viscosity, bioadhesiveness, textural properties and prolonged the in vitro posaconazole release. Moreover, alginate/chitosan glutamate cryogels exhibited higher values of inhibition zone in C. parapsilosis culture than traditional hydrogel formulations.

The present study reports on the encapsulation of Elsholtzia ciliata ethanolic extract by freeze-drying method using skim milk, sodium caseinate, gum Arabic, maltodextrin, beta-maltodextrin, and resistant-maltodextrin alone or in mixtures of two or four encapsulants. The encapsulation ability of the final mixtures was evaluated based on their microencapsulating efficiency (EE) of total phenolic compounds (TPC) and the physicochemical properties of freeze-dried powders. Results showed that the freeze-dried powders produced using two encapsulants have a lower moisture content, but higher solubility, Carr index, and Hausner ratio than freeze-dried powders produced using only one encapsulant in the formulation. The microencapsulating efficiency of TPC also varied depending on encapsulants used. The lowest EE% of TPC was determined with maltodextrin (21.17%), and the highest with sodium caseinate (83.02%). Scanning electron microscopy revealed that freeze-drying resulted in the formation of different size, irregular shape glassy particles. This study demonstrated good mucoadhesive properties of freeze-dried powders, which could be incorporated in buccal or oral delivery dosage forms. In conclusion, the microencapsulation of E. ciliata ethanolic extract by freeze-drying is an effective method to produce new value-added pharmaceutical or food formulations with polyphenols.

Alginate (ALG) cross-linking by CaCl₂ is a promising strategy to obtain modified-release drug delivery systems with mucoadhesive properties. However, current technologies to produce CaCl₂ cross-linked alginate microparticles possess major disadvantages, such as a poor encapsulation efficiency of water-soluble drugs and a difficulty in controlling the process. Hence, this study presents a novel method that streamlines microparticle production by spray drying; a rapid, continuous, reproducible, and scalable technique enabling obtainment of a product with low moisture content, high drug loading, and a high production yield. To model a freely water-soluble drug, metformin hydrochloride (MF) was selected. It was observed that MF was successfully encapsulated in alginate microparticles cross-linked by CaCl₂ using a one-step drying process. Modification of ALG provided drug release prolongation—particles obtained from 2% ALG cross-linked by 0.1% CaCl₂ with a prolonged MF rate of dissolution of up to 12 h. Cross-linking of the ALG microparticles structure by CaCl₂ decreased the swelling ratio and improved the mucoadhesive properties which were evaluated using porcine stomach mucosa.

Poor water solubility of clotrimazole (CLO) hinders development of the effective pharmaceutical dosage forms. Many different concepts and approaches, including lipid based formulations, have been undertaken to improve delivery of CLO. The purpose of this study was to design the composition of nanoemulsion with CLO for topical use, which could be processed by microfluidization method. Based on the solubility study and the results obtained from the pseudotemary phase diagrams, the optimal compositions of nanoemulsions with CLO were selected (Capryol 90/Tween 80 and oleic acid/Tween 80). The coarse emulsions were prepared by using high shear mixer and then processing by microfluidization technique. It was shown that formulation containing oleic acid and Tween 80, because of gelling properties, was not suitable for microfluidization. The stable nanoemulsion was obtained by mixing Capryol 90 as oil phase and Tween 80 as surfactant. The mean diameter of the droplets of nanoemulsion with CLO was 45.7 nm, polydispersity index was 0.27 and zeta potential -40.3 mV. The mean droplet size,of CLO nanoemulsion was significantly decreased with the increment of microfluidization passes (from 75.4 ± 3.2 nm to 63.2 ± 3.4 nm, and to 45.7 ± UR 2.8 nm after 5 and 10 passes.

In the present study, hydrogels containing the dried extract of tormentil (Potentilla erecta (L.) Raeusch., Rosaceae) were designed and qualitatively evaluated regarding their viscosity, thixotropy, and texture properties. As mucoadhesiveness is a crucial factor determining drug retention within the oral cavity, mucoadhesive properties expressed as the work of adhesion and maximum detachment force under the presence of porcine buccal mucosa and two different models of mucoadhesive layers: mucin and gelatin discs were evaluated. The fingerprints of the analyzed tormentil extract were established by using a LC-ESI-MS method. The dominating compounds of the tested extract are oligomeric proanthocyanidins and agrimoniin. This study reveals that designed hydrogels are promising semi-solid delivery systems for the dry extract of tormentil with beneficial mucoadhesive, thixotropic, and texture characteristics and may be utilized as platforms for tormentil delivery to the oral cavity in periodontal diseases. In vitro evaluation of the efficacy of the tormentil hydrogel against cariogenic Streptococcus mutans biofilms was also performed. The hydrogel significantly reduced artificial biofilm formation. For all Streptococci, complete inhibition was revealed at a final concentration of the extract of 2 mg/mL. These beneficial characteristics, as well as the anti-biofilm activity, enable its use for dental care, but further clinical studies are required.

Sodium alginate is a polymer with unique ability to gel with different cross-linking agents in result of ionic and electrostatic interactions. Chitosan cross-linked alginate provides improvement of swelling and mucoadhesive properties and might be used to design sustained release dosage forms. Therefore, the aim of this research was to develop and evaluate possibility of preparing chitosan cross-linked alginate microparticles containing metformin hydrochloride by the spray-drying method. In addition, influence of cross-linking agent on the properties of microparticles was evaluated. Formulation of microparticles prepared by the spray drying of 2% alginate solution cross-linked by 0.1% chitosan was characterized by good mucoadhesive properties, high drug loading and prolonged metformin hydrochloride release. It was shown that designed microparticles reduced rat glucose blood level, delayed absorption of metformin hydrochloride and provided stable plasma drug concentration. Additionally, histopathological studies of pancreas, liver and kidneys indicated that all prepared microparticles improved degenerative changes in organs of diabetic rats. Moreover, no toxicity effect and no changes in rats behavior after oral administration of chitosan cross-linked alginate microparticles were noted.

According to the European Pharmacopoeia, Tormentillae rhizoma is the dried rhizome of tormentil (Potentilla erecta (L.) Raeusch, Rosaceae), freed from the roots. Tormentillae rhizoma is a traditional herbal medicinal product for symptomatic treatment of unspecified diarrhoea, mild inflammation of the oral and pharyngeal mucosa [1]. Dental plaque is a highly diverse biofilm, with an important function in maintenance of oral and systemic health. In some conditions the biofilm becomes a cause of oral diseases (e.g. periodontal disease) [2]. Current methods of dental plaque control involve the use of chemical agents against biofilm pathogens. This is not sufficiently effective [3]. Prevention and control of dental plaque might be achieved by using hydrogels containing compounds that hinder glucosyltransferase activity and extracellular polysaccharides synthesis. In this study, we formulated and performed quality evaluation of new hydrogel formulations containing dry extract of tormentil. Components of dry extract were identified and tracked by LC-TOF-MS method. The dominant compounds of tormentil rhizomes are ellagitannins (agrimoniin) and oligomeric proanthocyanidins. During preliminary studies using different types of polymers, it was shown that carmellose natrium – based hydrogel did not interact with tormentil extract and was provided optimal physico-chemical and rheological properties. Designed hydrogels containing 5 or 10 mg/g of the dry extract possessed significant mucoadhesive properties evaluated by TA.XT. Plus Texture Analyzer and three different models of adhesive layers (porcine buccal mucosa, mucin and gelatine) [4]. Their mucoadhesive properties were determined to be better than commercially available product used as a control. Hydrogels at concentrations 5 and 10 mg/g, exhibited no anti-microbial activity, but strongly inhibited extracellular polysaccharides and artificial biofilm formation. Based on viscosity and thixotropy measurements using a programmable viscometer with cone-plate device [5]., it can be concluded that hydrogels were characterized by desirable thixotropic properties both at 25^°C and 37^°C. This study reveals that designed hydrogels seem to be promising vehicles which can be used for drug delivery in periodontal disease. Acknowledgements: The study was conducted with the use of equipment by Medical University of Bialystok as part of the OP DEP 2007 – 2013, Priority Axis I.3, contract No. POPW.01.03.00 – 20 – 001/12. Keywords: Potentilla erecta, hydrogel, mucoadhesive properties, periodontal disease. References: [1] Tomczyk M, Latté KP. Potentilla - a review of its phytochemical and pharmacological profile. J Ethnopharmacol 2009; 122: 184 – 204 [2] Pleszczynska M, Wiater A, Janczarek M, Szczodrak J. (1→3)-α-D-Glucan hydrolases in dental biofilm prevention and control: A review. Int J Biol Macromol 2015; 79: 761 – 778 [3] Beikler T, Flemming TF. Oral biofilm-associated diseases: trends and implications for quality of life, systemic health and expenditures. Periodontology 2011; 55: 87 – 103 [4] [4] Szymanska E, Winnicka K, Amelian A, Cwalina U. Vaginal chitosan tablets with clotrimazole – design and evaluation of mucoadhesive properties using porcine vaginal mucosa, mucin and gelatine. Chem Pharm Bull 2014; 62: 160 – 167 [5] [5] Wroblewska M, Winnicka K. The effect of cationic polyamidoamine dendrimers on physicochemical characteristics of hydrogels with erythromycin. Int J Mol Sci 2015; 16: 20277 – 20289