Active pharmaceutical ingredients are routinely formulated with a range of excipients in the manufacture of drug products. Excipients are considered to be inert components of the formulations, although recent research has contested its inactive behaviour. This study investigated the effect of the excipient polyethylene glycol 400 (PEG 400) on the oral bioavailability and intestinal permeability of cimetidine in male and female human volunteers. Aqueous solutions of cimetidine with pharmaceutically relevant concentrations of PEG 400 at 0% (control), 0.3%, 0.5%, 0.7% and 1.0% w/v were orally administered to both sexes. Urine samples were then collected and assayed for the determination of cimetidine which reflected oral bioavailability. This human study showed that PEG 400 at 0.3%, 0.5% and 0.7% w/v concentrations significantly increased cimetidine bioavailability by 34%, 58% and 41% respectively, although this enhancement was only demonstrated in men and not women (p < 0.05). Ussing chamber transport studies with male human jejunal tissues revealed that cimetidine permeability increased by 26%, 48% and 29% with PEG 400 at 0.3% w/v, 0.5% w/v and 0.7% w/v respectively (p < 0.05). No such enhancement was demonstrated in female tissues (p > 0.05). We have shown that PEG 400 interacts with intestinal P-glycoprotein (P-gp) expression differently in males and females. The mechanistic action of PEG 400 at gut level was further investigated on human jejunal tissues following the pre-treatment of the P-gp inhibitor valspodar on the transport of cimetidine. When intestinal P-gp was inhibited, the sex- and dose-dependent modulatory effect of PEG 400 with cimetidine was completely eradicated, thus confirming that PEG 400 has a modulatory – rather than inhibitory – effect on P-gp. In sum, the widely used excipient PEG 400 is not inert at pharmaceutically relevant concentrations and its modulatory effect is demonstrated at a human clinical level. Such pharmacological effects, however, are sex- and dose-dependent via its modulation on intestinal P-gp, as evidenced by the boost in cimetidine bioavailability only in male human volunteers.

Abstract : In situ gelling Raft forming system (GRFS), a novel sol-gel system of calcium carbonate (CC) was developed with the aim to prolong the gastric residence time and thereby the bioavailability. A simple lattice mixture design was adopted to study the effect of formulation composition (% HPMC K100 M and % Xanthan gum), on buoyancy lag times, percent of CC released at 1hr and 6hr. The mathematical models generated by analysis of variance (ANOVA) indicated that the levels of HPMC K100 M and Xanthan gum were found to significantly affect all the three responses. The optimized formulation developed by numerical optimization technique was found to display short buoyancy lag time (10.90 ± 0.56 sec), minimum burst release (20.74 ± 1.08%) in 1h and controlled yet near complete release (87.25±1.81%) in 6h. The experimental data for the optimized formulations was in agreement with that predicted by the mathematical models proving the validity of the models generated. In vivo radiographic studies in rabbits indicated that optimized batch displayed a mean gastric retention time of 5.64 ± 0.43 h that was significantly higher (P < 0.05) compared to the marketed suspension that exhibited a mean gastric retention time of less than one hour. The studies proved that the GRFS gastroretentive systems can be a promising platform to improve bioavailability of nutrients having absorption window in upper gastrointestinal tract.

Joint pain with high prevalence and yet without any specific treatment option is posing a challenge to healthcare professionals day by day. Amongst several treatment options currently utilized for arthritic joint pain are merely giving symptomatic relief rather than curative treatment. Non-steroidal Anti-inflammatory Drugs (NSAIDs) are the most widely accessed treatment option amongst all. But their adverse effects profile is a major hurdle for their use, especially in elderly patients. Present study was focused to develop a transdermal patch of a novel NSAID Loxoprofen sodium with enhanced penetration and improved patient compliance. Pluronic lecithin organogel (PLO) was selected as transdermal drug delivery platform to enhance its penetration through skin. Moreover transdermal route will bypass first pass metabolism, GI side effects and necessity to administer drug through oral route. All of these credentials ultimately improved patient compliance. Several experimental batches (PL1 to PL8) were formulated to prepare PLO of loxoprofen sodium. All the batches were evaluated for physical appearance, pH, viscosity, spreadability, drug content and in vitro drug diffusion profiles. An optimized batch was selected on the basis of obtained results. It showed sustained drug release upto 12 hrs. The study evidenced that similar transdermal formulations of other NSAIDs can significantly enhance current treatment scenario for joint pain. Moreover, conversion of such formulations in transdermal patch or other forms ensure sustained and reproducible transdermal flux which can be further fabricated as bioequivalent to the oral formulations. Further studies can be designed to evaluate the clinical applicability of the formulation.

Magnetic-fluorescent bifunctional drug delivery system which possesses magnetic targeting and fluorescent tracing capabilities, effectively improves the delivery efficiency of drugs. With the in-depth study of the properties of non-spherical microparticles, it is found that the shape of the microparticles also plays a key role in drug delivery. Because of the unique shape, rod-like microparticles have exhibited great drug molecule metabolic dynamics and excellent anti-tumor effects during the process of treatment. In this study, Fe₃O₄/NaYF₄: Eu³⁺/PLGA magnetic-fluorescent bifunctional microrods were prepared via one-step electrospraying. Unlike other methods that require complicated steps or expensive equipment, one-step electrospraying is a facile and low-energy method. The prepared magnetic-fluorescent bifunctional microrods possessed uniform rod-like morphology. Compared with magnetic-fluorescent bifunctional microspheres in same volume, it was found that the microrods showed a lower water contact angle. The results of hysteresis curve and fluorescence spectrum suggested the excellent magnetic and fluorescent properties of magnetic-fluorescent bifunctional microrods. After co-cultured with A549 cells or endothelial cells, the cell viability testing results confirmed the wonderful biocompatibility of microrods. When the drug doxorubicin was loaded by the immersion method, the microrods showed a higher drug entrapment efficiency and drug-loading capacity in comprasion with microspheres. In addition, microrods loaded with the same drug in weight showed stronger cytostatic effects after two days of co-culture with A549 cells. In summary, the magnetic-fluorescent bifunctional microrods prepared via one-step electrospraying will be promising candidates for biomedical applications in drug delivery, targeting and tracking.

Liposomes are spherical vesicles composed of natural or artificial lipids and are used as drug carriers. However, their surface needs modification with ligands to target specific tissues. Cell- derived Vesicles (CVs) are bioinspired drug carriers, as they derive from whole cells by physical methods. One of their most striking characteristics is the ability to preserve the topology and composition of the molecules present in the plasma membrane of the parental cell, enabling in vivo organotropism and specific drug delivery. The aim of this study is the investigation of the mechanisms by which liposomes and autologous CVs are internalized by 3 different breast cancer cell lines. Two of the selected cell lines, 4T1 and MDA-MB-231, are triple negative breast cancer cell lines, and the third one, MCF-7, is negative only for the protein HER2. The elucidation of the mechanism is likely to result to the optimization of specific drug delivery and comprehension of their sub- cellular fate. More specifically, liposomes and CVs were produced, characterized and loaded with the fluorescent dye FITC-dextran. Uptake experiments were performed using inhibitors of the clathrin dependent or caveolin dependent endocytic pathways and after incubating the cells at 4°C, where the active processes are inactivated. The results indicate that the endocytosis of CVs is active, mainly via the caveolin pathway, whereas liposomes are internalized actively by both pathways and also passively, as their uptake at 4°C is not significantly hampered.

Acknowledgements: This research has been co‐financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE - INNOVATE (project code: MIS 5031802).

Thermosensitive nasal in situ gels are promossing formulations to administer drugs used in the management of Alzheimer's disease (AD). These formulations increase the residence time of the lipid-based nanosystems, improving drug bioavailability, and therapeutic efficacy [1-3].

The purpose of this study was to prepare thermosensitive in situ gels with optimized aqueous dispersions of nanostructured lipid carriers (NLC) and nanoemulsions to improve the residence time of an anticholinesterase drug (RVG) in the nasal cavity and, therefore, its nose-to-brain delivery. Thermosensitive in situ NLC and nanoemulsions gels were developed by the cold technique previously described by Fatouh et al. and Almeida et al. [4, 5]. Poloxamer 407 was used as gelling agent and hydroxypropyl methylcellulose as mucoadhesive polymer. Different concentrations of both polymers were added to the dispersions of NLC and nanoemulsions to optimize the gelation temperature, which was analyzed after 24h of storage at 34ºC, and a concentration of 17% of poloxamer and 0.3% of hydroxypropyl methylcellulose was selected.

The thermosensitive in situ gels of NLC and nanoemulsions were first characterized for particle size, polydispersity index (PDI), zeta potential (ZP), and pH. After that, rheological and textural analyses were performed. The results showed that the prepared formulations had a particle size, PDI, ZP, and pH of, respectively: 141.70±0.40 nm and 146.10±1.73 nm; 0.45±0.00 and 0.43±0.02; -4.06±1.03 mV and -4.09±0.71 mV, 6.60±0.01 and 7.00±0.02, which are all acceptable values for nasal application. Besides, thermosensitive in situ gels of NLC and nanoemulsions showed a non-Newtonian plastic behavior, and the texture parameters viz., compressibility, firmness, and adhesiveness presented desirable values for a nasal gel.

From these results, we conclude that thermosensitive in situ gels of NLC and nanoemulsion can be used to improve the treatment of AD through the nose-to-brain route. However, further in vitro and ex vivo studies should be performed to confirm this application.

References: [1] Zhang, L., et al. Int. J. Pharm, 2020.583:199384; [2] Adnet, T., et al. Pharmaceutics, 2020. 12(3): 251; [3] Alipour, S., et al. Trends Pharmacol Sci, 2020. 6(2): 97-104. [4] Fatouh, A.M., et al. Drug Deliv. 2017. 24(1): 1077-1085; [5] Almeida, H., et al. Curr. Drug Deliv, 2013. 10(6): 753-764.

The development of novel antibiotics did not present significant progress over the last years due to low returns, in particular regarding clinical trials. The majority of antibiotics display low permeability across biological membranes and/or reduced solubility in water, as well as polymorphic structures with different pharmaceutical activities. Ultimately, these disadvantages lead to low efficiency of the antibacterial drugs. Several strategies have been devised by Pharma in order to address these issues, namely prodrugs, solid dispersions, micelles, organic salts, among others.

The development of Organic Salts and Ionic Liquids (OSILs) from Active Pharmaceutical Ingredients (API-OSILs) has risen in the academia, and has recently reached Pharma, as an alternative to improve the properties of current drugs, in particular bioavailability, chemical and thermal stability, safety and therapeutic efficiency.

In our lab, we have successfully combined β-lactam, carbapenems, cephalosporins and fluoroquinolones as anions with biocompatible organic cations such as choline, alkylpyridiniums and alkylimidazoliums. Additional API-OSILs based on fluoroquinolones as cations were also synthesized by direct protonation with organic carboxylic and sulfonic acids. Overall, very interesting chemical and biological improvements have been observed.

In this communication we present our continuing work on fluoroquinolone-based OSILs, aiming at further improving the physicochemical and pharmaceutical properties of these promising salts. Water solubility, permeability and also in vitro cytotoxicity and antimicrobial activity of these compounds will be presented and discussed.

Intramuscular delivery is one of the main route for DNA vaccines administration. However, it requires large amounts of the DNA administered and external stimulation to encourage the internalization of the DNA. In this work we consider routes for less invasive administration route, and develop drug delivery systems (DDS) for intranasal administration. Chitosan polyplexes using sodium tripolyphosphate (TPP) as a crosslinker were prepared using the ionic gelation method. Our method allowed preparation of nanoparticles with the size bellow 50nm that is at least two times lower than previously reported. Moreover, despite small size, we obtained DNA encapsulation efficiencies about 70%. Parameters that may affect the encapsulation efficiency were investigated, including different chitosan-TPP ratios and concentrations of DNA. We found that encapsulation efficiency of DNA inside the particles increases with the increasing TPP-chitosan ratio. Moreover, increasing the DNA concentration also leads to a higher encapsulation efficiency. Small (<50nm) chitosan nanoparticles hold enormous potential as DNA carriers through physiological barriers and subsequent internalization.

To tackle one of the biggest global health problems, the resistance of microorganisms to antibiotics, a collective effort in the search for more effective agents against bacteria was required. Peptides with antimicrobial activity have been rasing much attention as a promising alternative for antibiotics. Peptaibols, for instance, are a family of antimicrobial peptides (AMPs) with great biomedical potential, in which the Peptaibolin can be highlighted. Indeed, this peptide has gained relevance due to its small amino acids content, only four, and its acetyl group and a phenylalaninol residue (Phol) at the N-terminal and C-terminal, respectively. Here, we report the synthesis of Peptaibolin through Solid Phase Peptide Synthesis assisted by Microwave heating (MW-SPPS), in a pre-loaded Phe-Wang resin. Starting from a loading of 0.51 mmol/g, two syntheses were made, using two different combinations of coupling reagents. The best option was DIC/Oxima achieving a yield of 50.0%. Proton Nuclear Magnetic Resonance (¹H NMR) studies confirmed the peptide structure, while the High Performance Liquid Chromatography (HPLC) technique verified the peptide purity. To test the solubility of the peptide several combinations of solvents were used and it was found that the peptide was not soluble in water, only in organic solvents or in the combination of both. Antimicrobial testing has been conducted using both Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Minimum inhibitory concentration studies demonstrated the resistance of bacteria to the peptide action and the peptide instability in bacterial growth conditions.

Interest has developed in natural molecules due to their clinically proven effects on skin deseases. Flavanones display several biological activities, and recently have been the focus of studies due to their anti-inflammatory effect. To improve their pharmacological profile four flavanones (A, B, C and D), were synthesized by structural modification of one flavanone natural 1 (semi-systematic name: (2S)-5,7-dihydroxy-6-prenylflavanone) extracted from Eysenhardtia platycarpa. The hydroalcoholic flavanone solutions (FS) were assayed to investigated their anti-inflammatory effect on two in vivo cutaneous inflammation models. Materials and methods: the topical anti-inflammatory effect of FS were evaluated against models of 12-O-tetradecanoylphorbol acetate (TPA) induced mouse ear edema and arachidonic acid (AA) in rat ear edema. Results: The vinylogous cyclized derivative (flavanone D) caused edema inhibition in the TPA- induced models with an inhibition of 96.27 ± 1.93 %; equally effective and potent in inhibiting the mouse ear edema as Indometacine had been. In addition, the AA-induced increase in ear thickness was reduced the most by the topical application of modulated ether (flavanone B). Conclusions: The in vivo and histology results suggest that flavanones B and D are effective as a topical anti-inflammatory agents in inflammatory processes. Thus, this new compounds represents a promising agent for the management of skin diseases with an inflammatory component.