Ciprofloxacin (Cipro) is a broad-spectrum antibiotic used against both Gram (+) and Gram (-) bacteria. Its biological half-life is very short (4-5 hours) and its conventional administration forms present a limited absorption efficiency. For this reason, the aim of this work was to study other administration strategies based on topical films. Sodium alginate (SA), a naturally occurring polymer, and a recombinant elastin-like polymer (rELP) produced by advanced genetic engineering techniques were evaluated as potential carrier systems. The films were obtained by the casting technique, adding the Cipro by direct dispersion in the polymer solution - using 16.6% w/w rELP or 1.5% w/w SA. The in-vitro release assays were performed at 37°C in physiological solution and with orbital shaking at 90 rpm. Cipro concentration was determined by UV spectrophotometry at 276 nm. The release profiles were analyzed and adjusted using the Lumped model developed and validated by our research group. Pharmaceutical interest parameters were calculated and compared for both polymer-Cipro systems: the time required to reach 80% of the drug dissolved (t_80%), the Dissolution Efficiency (DE) and the Mean Dissolution Time (MDT). The SA-Cipro platform released the 80% of the drug in 35 min, while this parameter was 209 min for the rELP-Cipro system. The MDT_80% was 8.9 and 53 min for the SA-Cipro and rELP-Cipro, respectively, while the DE, evaluated at 200 min, was 66.6 and 58.8 for each platform, respectively. These parameters values demonstrate that the rELP films were able to modulate the drug release rate and for the SA ones, release can be considered immediate. Therefore, both systems are promising strategies for the topical application of Cipro.

Solid Lipid Nanoparticles (SLN) emerged in the late 20^th century as versatile nanoparticle drug delivery systems. Since then, SLNs have demonstrated to be useful for the encapsulation of a great number of actives. In particular, the role of SLN in wound healing is pretty recent, since the major part of scientific literature on this field is concentrated during 2019 and 2020 (keywords “solid lipid nanoparticle” and “wound healing”; Boolean operator “and”; databases: Web of Sciences, Science Direct and Pubmed) [1–7].

In this pilot study we propose the formulation of a semisolid system formed by SLN embedded in an inorganic hydrogel with demonstrated wound healing activity [8]. The aim is to assess the main properties and stability of SLN embedded in a wound healing hydrogel. The hot emulsification method was used to prepare the SLN. Spring water (ALI) and ultrapurified water (milliQ^®) were used as aqueous medium. Then, the clay mineral (PS9) was added and homogenized by means of an Ultraturrax^®. Granulometry, pH, rheology and TEM microscopy were used to characterize the formulations.

Granulometry showed that the use of natural spring water does not affect the SLN’s particle size. The presence of the PS9 moved the granulometry towards higher sizes and maintained stable for three months. TEM results confirm the granulometry previously reported, some coalescence of SLN found in the samples with PS9. The pH of all the samples was around 6-8 and stable for 3 months. Regarding the rheology, it was revealed that the composition of the aqueous medium significantly influenced the viscosity and time-dependent properties.

In conclusion, the proposed SLN formulations would be very versatile for the treatment of skin diseases, especially for wound healing, due to the possibility to load different actives inside the SLN together with the already demonstrated wound healing activity of the inorganic hydrogel.

Wound healing treatments continue to be a medical challenge, since complications usually lead to chronicization and comorbidities. Natural inorganic ingredients such as clays have demonstrated to exert useful activities in this regard [1–3]. Hectorite is a smectite clay with desirable rheology due to its layered structure and remarkable swelling capacity. These properties make it appropriate excipient for semisolid systems. Nonetheless, the biocompatibility of natural hectorite has been scarcely addressed, the majority of studies centred in synthetic or functionalized hectorites [4–10].

The aim of this study was to prepare and characterize a hectorite/spring water hydrogel. The hectorite clay mineral was subjected to a solid-state characterization, while the hydrogel (HTgel@10) was evaluated in terms of rheology, pH and in vitro biocompatibility and wound healing.

Results demonstrated that the hectorite possessed a remarkable purity (84% w/w of hectorite), very similar to that of similar pharmaceutical excipients [11]. HTgel@10 showed a non-Newtonian, viscoplastic to pseudoplastic profile and a stable pH for 12 months. In vitro tests reported that the hectorite and the HTgel@10 were biocompatible (cellular viability ≥ 70%). Specifically, the hectorite used in this study was more biocompatible toward fibroblasts than Veegum^® HS [12]. The in vitro wound healing test revealed that HTgel@10 was able to favour the wound closure. Therefore, hectorite/spring water hydrogels could be considered as potential wound healing formulations with remarkable stability and safety.

Drugs based on oligoribonucleotides from yeast RNA have a reasonably low solubility in the range of 0.5-3 mg/ml. Our previous studies have shown that ORN has anti-inflammatory properties, and ORN with D-mannitol has anti-inflammatory and antiviral properties. The mechanism of this phenomenon is unclear. D-mannitol itself does not have these activities, but increases the solubility by 1.5-2 times and stabilises the structure of the ORN, which probably leads to new biological effects. In the course of our research, we found that D-mannitol affects the binding of ORN to interferon and the thermodynamic and conformational parameters of this interaction .

We studied the ability of yeast RNA (ORN), yeast RNANa salt (ORN Na), and yeast ORN: D-mannitol complex (ORN: D-M) and AMP to effect on fluorescence quenching and conformational changes of Interferon α2b. To determine the energy parameters of protein-ligand interactions, we use isothermal titration nanocalorimetry Nano ITC.

It is showing that when using ORN and ORN: D-M quenching of the fluorescent INF were 25% and 28%, AMP and AMP: DM - 15 and 21%. Quenching INF fluorescence in the titration of ORNsNa and ORNsNa: DM was 16% and 17%, AMPNa and AMPNa: DM - 8% and 10%. INF has a life-time of 2.95 ns. When interacting with ORN and ORN: D-M INF has fluorescence time of 2.37 and 2.32 ns, respectively, AMP and AMP: D-M 2.01 and 1.92 ns. When interacting with ORNsNa and ORNsNa: D-M INF has a fluorescence time of 2.73 and 2.49 ns, respectively, AMPNa and AMPNa: D-M 2.31 and 2.43 ns. Thus, ORN, and especially ORN: D-M and AMP: D-M leads to a change in the conformational mobility of interferon α-2b by increasing the content of disordered regions. At the same time, salt analogues increase the number of structured secondary elements, such as α-helices, β turns and β antiparallel sheets and probably increase the conformational stiffness of interferon α-2b. The results of the study of enthalpy changes in the titration of interferon α-2b acid form of ORN and ORN: D-M was -63.28 kJ/mol and -96.61 kJ/mol, respectively, and for the ORNNa and ORNNa: D-M respectively 4,516 and 5,139 kJ/mol. The change in entropy when adding the ORN to interferon α-2b was -38.72 and in the case of the ORN: D-M -63.53 kJ/mol*K, respectively. The difference in entropy when adding the ORNNa to interferon α-2b was 17.05 kJ/mol*K, and the ORNNa: D-M, respectively, 17.58 kJ/mol*K. A similar pattern demonstrated when studying the change in Gibbs energy during titration of interferon α-2b with ORNORN and ORN: D-M, and it was -24.56 and -33.07 kJ/mol, respectively. And when titrated with ORNNa and its ORNNa: D-M, respectively -12.9 and -12.43 kJ/mol.

These results of studying the effects of thermodynamics of different forms of RNA and their complexes with D-mannitol in the titration of interferon α-2b may indicate different sites of binding of different forms of ORN to protein, as well as other modes of binding and various types of conformational changes in the protein.

Rosuvastatin calcium (Rsv) is one of the most recent and effective statins, with a potent antihyperlipidemic effect. However; it suffers poor bioavailability owing to its poor solubility. Thus; encapsulating Rsv into a nanovesicular structure could overcome this problem. The aim of this work is to investigate the potential of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) in enhancing the solubility of Rsv, using Quality by Design (QbD) concept to develop a better quality product. A complete risk assessment study has been conducted, where the critical process parameters (CPP), material attributes (MA), and critical quality attributes have been identified using the ishikawa diagrams. Selected CPP/MA were screened and further upgraded to a 2⁴ full factorial design to develop the design space with the optimized formula. The screened CPP/MA were tested on each of the particle size, polydispersity index (PDI), zeta potential and the entrapment efficiency (EE%). A comprehensive approach for Rsv nanovesicular carriers has been conducted, where the NLC showed better results than the SLN. The optimized formula was prepared with 3 % total lipid content, 0.154% surfactant, and 9.4 mg drug. The optimized formula had a particle size 310.5 nm, with 0.243 PDI, a zeta potential of -24.7 mV and EE% of 93.87%, and showed a sustained release of the drug up to 72 hours. It successfully lowered each of the total cholesterol, low density lipoprotein, and triglycerides and elevated the level of the high density lipoprotein of high fat fructose diet-induced hyperlipidemia/hypercholesterolemia rats, with better results as compared to the standard drug. Thus, a complete QbD study was conducted to explore experimental regions for many successful nanovesicular carriers for the enhancement of the solubility of poorly soluble drugs.

Ziprasidone hydrochloride is an atypical antipsychotic agent with an anti-schizophrenic activity having less solubility and less bioavailability. The nasal route acts as a promising delivery route for CNS targeting drugs due to improved bioavailability and can reduce peripheral side effects.

The main aim of the study is to prepare an in-situ nasal gel of ziprasidone-b-cyclodextrin for improvement in the bioavailability of the drug. The in-situ gel was optimized using box-Behnken design. The optimized formulation was evaluated for homogeneity, viscosity, gelation temperature, mucoadhesive strength, in-vitro permeation studies. The pharmacodynamic activity of in-situ nasal gel was checked using the locomotor activity model.

According to the statistical analysis of the design expert software, all the models were found significant. The pharmacodynamic investigation of the cyclodextrin mediated in situ nasal gel showed improvement in drug activity compared to a drug, drug-complex given by oral route indicating the nasal delivery of antipsychotic drug improves its effect.

Nano-hybrid systems have been presented as an attractive platform for drug delivery. These systems combine organic and inorganic materials in self-assembled structures¹. Laponite (inorganic network, LAP) nanoparticles are disk-like synthetic clays, biocompatible and guest compounds have been explored for hybridization with polymers or small molecules to improve to attach drugs^2–4. Poloxamines (organic compound) are an amphiphilic four-arm (X-shape) block copolymers of poly(ethylene oxide)-poly (propylene oxide)-poly(ethylene oxide) with a pH-sensitive and thermosensitive properties, being very attractive as a drug delivery system ^5,6. In this context, this work aimed to prepare and compared nano-hybrid formulation by physical behavior assays and their ability to increase the solubility of the βLAP, a low solubility drug model. The methodology of analysis of data used in this work consisted of Multilayer Perceptron (MLP), Support Vector Machine (SVM), both machine learning (ML) models^7–9. However, response surface analysis (RMS) was also used and compared with other methods applied. The samples were prepared by mixing the components at different concentrations (1-20%, w/w) plus LAP (0-3%, w/w). The βLAP was added in excess in all formulations. The ML techniques obtained better correlation coefficients adjustment than RSM. In addition, RSM techniques use only predefined regression models. ML's response surfaces are generated from a training process based on experimental data that it is a tremendous advantage compared to RMS¹⁰. All methods (RMS, SVM, and MLP) show T1304 (over 10%) and 1.5% LAP, or systems with only LAP (1.5%), with a 50 and 100-fold increase in βLAP solubilisation, respectively. Further, the models provided a second-order polynomial equation to predict the βLAP solubility in different blends concentrations. In silico tools promoted a fine-tuning and near experimental data shown to be an excellent strategy for use in the development of news nano-hybrid platforms.

References

1. Faustini, M.; Nicole, L.; Ruiz-Hitzky, E.; Sanchez, C. History of Organic–Inorganic Hybrid Materials: Prehistory, Art, Science, and Advanced Applications. Advanced Functional Materials 2018, 28 (27), 1704158.

2. Aguzzi, C.; Cerezo, P.; Viseras, C.; Caramella, C. Use of Clays as Drug Delivery Systems: Possibilities and Limitations. Applied Clay Science 2007, 36 (1–3), 22–36.

3. Haraguchi, K.; Farnworth, R.; Ohbayashi, A.; Takehisa, T. Compositional Effects on Mechanical Properties of Nanocomposite Hydrogels Composed of Poly (N, N-Dimethylacrylamide) and Clay. Macromolecules 2003, 36 (15), 5732–5741.

4. Chang, C.-W.; van Spreeuwel, A.; Zhang, C.; Varghese, S. PEG/Clay Nanocomposite Hydrogel: A Mechanically Robust Tissue Engineering Scaffold. Soft Matter 2010, 6 (20), 5157–5164

5. Schmolka, I. R. A Review of Block Polymer Surfactants. Journal of the American Oil Chemists’ Society 1977, 54 (3), 110–116.

6. Alexandridis, P. Poly (Ethylene Oxide)/Poly (Propylene Oxide) Block Copolymer Surfactants. Current opinion in colloid & interface science 1997, 2 (5), 478–489.

7. Pereira, A. K. V.; Barbosa, R. de M.; Fernandes, M. A. C.; Finkler, L.; Finkler, C. L. L. Comparative Analyses of Response Surface Methodology and Artificial Neural Networks on Incorporating Tetracaine into Liposomes. Brazilian Journal of Pharmaceutical Sciences 2020, 56.

8. Sun, Y.; Peng, Y.; Chen, Y.; Shukla, A. J. Application of Artificial Neural Networks in the Design of Controlled Release Drug Delivery Systems. Advanced Drug Delivery Reviews 2003, 55 (9), 1201–1215.

9. Ekins, S.; Puhl, A. C.; Zorn, K. M.; Lane, T. R.; Russo, D. P.; Klein, J. J.; Hickey, A. J.; Clark, A. M. Exploiting Machine Learning for End-to-End Drug Discovery and Development. Nature materials 2019, 18 (5), 435.

10. Che Sulaiman, I. S.; Basri, M.; Fard Masoumi, H. R.; Ashari, S. E.; Basri, H.; Ismail, M. Predicting the Optimum Compositions of a Transdermal Nanoemulsion System Containing an Extract of Clinacanthus Nutans Leaves (L.) for Skin Antiaging by Artificial Neural Network Model. Journal of Chemometrics 2017, 31 (7), e2894.

Low dissolution rates of poorly soluble drugs are the problem afflicting their bioavailability. The aim of this study is to prepare centrifugal spinning based formulation of a poorly soluble drug, oxcarbazepine for the improvement of dissolution rate and hence quick action. Sucrose based microfibers of oxcarbazepine were prepared by centrifugal melt spinning technique using a cotton candy machine. The prepared microfibers were characterized using SEM, PXRD, DSC and FTIR. The optimum formulation was molded into tablets and tested for in-vitro drug release and in-vivo pharmacokinetic studies using rabbits as test animals. The results indicated that the centrifugal spinning has produced rapidly dissolving microfibers (diameter ranges <10 µm and dissolve in few seconds). In these fibers ~20% oxcarbazepine was loaded, and both the yield and drug loading efficiency were improved by incorporating PVP in the formulations. The dissolution studies have revealed > 90% of drug was dissolved in just 2 minutes as compared with drug alone that shows only 15% dissolution at this time interval. XRD and DSC analysis have shown amorphous state of drug in the fibers while FTIR study have shown chemical stability of oxcarbazepine in the fibers. In-vivo studies have revealed a 1hr reduction in t_max of drug in the rabbits treated with microfibers as compared with controlled group which was given pure oxcarbazepine. The study concludes the potential of centrifugal spinning technique for the production of drug loaded fibers that can significantly enhance the dissolution rates of poorly soluble drugs and thus produce formulations for quick action of such drugs. Furthermore, the sucrose based formulation can enhance the palatability with the intend to attract pediatric patients.

Abstract: 1) Background: The aim of the study was to develop and validate a HPLC-ESI-MS method to determine simultaneously silymarin (Sil) and glibenclamide (Gly) in aqueous solutions, from chitosan-based microparticles. 2) Methods: Sil and Gly, in different concentrations, were loaded into chitosan microparticles using ionic gelation method [1]. Briefly, the drugs were dissolved in the minimum volume (0.5 mL) of proper solvent and then was added into 3 mL of 1% chitosan acetic acid solution. The mixture was stirred at room temperature for 2 h and then was dropped through a syringe needle into 20 mL of 2% TPP solution. After 12 h of stirring at room temperature, the formed beads were separated from the TPP solution and washed with distilled water and then dried at room temperature [2]. For identification and quantification of the loaded drugs, a HPLC-ESI-MS method using an Agilent 1200 Series HPLC system coupled to an Agilent 6520 accurate-mass quadrupole time-of-flight (Q-TOF) mass spectrometer, was developed. The separation was made on a Hypersil C18 column with 0.1% formic acid in MiliQ water (A) and acetonitrile (B) applied in gradient (% B: 0’-25; 5’-55; 9’-70; 12’-30; 15’-25). The DAD separation was monitored at 230, 280, 298, 300 nm, 0.1 mL/min of elute was directed to ESI/Q-TOF MS, operated at an ionization voltage of -4000 V, 325 °C, with ions’ scan 50-1000 m/z in negative ion mode. The method was validated using recommended parameters [3] and Sil:Gly (1:1) standard solutions. 3) Results: By using M8 method, the SilA Rt was registered at 5.41 min, SilB at 5.66 min and Gly at 10.54 min. The loaded drugs were identified using MS-MS spectra and m/z characteristics for all compounds were found in the higher intensity for Rt presented above. The selectivity and precision of the methods are absolute because Rt for sample and standard have the same value, and blank solution proved no interference. The linearity of the answer function is absolute for SilA (R²=1), and almost absolute for SilB (R²=0.9998), and Gly (R²=0.9991). S/N values for all compounds at all studied concentrations maintain similar values. For SilA we obtained a LOD=0.285 mg/mL and LOQ=0.95 mg/mL; for SilB we obtained a LOD=0.045 mg/mL and LOQ=0.15 mg/mL; and for Gly we obtained a LOD=0.038 mg/mL and LOQ=1.275 mg/mL. 4) Conclusion: We developed a high resolution HPLC-ESI-MS method to determine simultaneously Sil and Gly in a concentration range of 0.025-1 mg/mL.

In recent years, the Zika virus (ZIKV) has emerged from a neglected flavivirus to a health-threating pathogen that causes malformations and microcephaly in neonates as well as neurologic complications in adults. ZIKV is transmitted by mosquitoes of the Aedes species, which is also a vector for several other viruses, including yellow fever virus, Chikungunya virus and dengue virus. There is neither vaccine nor drugs available to prevent or treat ZIKV infections. Recently, we have demonstrated that poly(sodium 4-styrenesulfonate) (PSSNa) inhibits ZIKV replication in vitro both in animal and human cells, while no cytotoxicity is observed. Our mechanistic studies indicated that PSSNa acted mostly through direct binding to ZIKV particle and blocking its attachment to the host cells.¹ The anionic macromolecules of PSSNa efficiently interact electrostatically with the ZIKV fusion loop of E protein dimer and the region adjacent to the fusion loop which are positively charged.² In a current paper we have concentrated on the synthesis and studies of the antiviral activity of novel polymeric curcumin-PSSNa conjugate. Curcumin (Cur) is the active component of dried root of Curcuma longa_, an herb belonging to ginger family, with wide antimicrobial activity. Its practical application is, however, strongly limited by its low solubility/bioavailability and instability. We have demonstrated that these problems can be eliminated by using the Cur-PSSNa conjugate instead of Cur itself. More importantly, we have observed that Cur-PSSNa shows much stronger anti-ZIKV activity than PSSNa polymer of similar average molecular weight. That can be explained considering the synergistic effect of both conjugate components involving targeted Cur delivery by the active polymeric delivery agent.

Acknowledgements: This research was operated within the National Science Center (NCN), Project No. 2017/27/B/ST5/01108.

1. P. Botwina, M. Obłoza, A. Szczepański, K. Szczubiałka, M. Nowakowska, K. Pyrć; Viruses 2020, 12, 926.
2. L. Dai, J. Song, X. Lu, Y.Q. Deng, A.M. Musyoki, H. Cheng, Y. Zhang, Y. Yuan, H. Song, J. Haywood, et al.; Cell Host Microbe 2016, 19, 696