Freeze-Dried Secretome (Lyosecretome) from Mesenchymal Stem/Stromal Cells Promotes the Osteoinductive and Osteoconductive Properties of Titanium Cages.

Titanium is one of the most frequently used materials in bone regeneration due to its good biocompatibility, excellent mechanical properties, and great osteogenic performance. However, osseointegration with host tissue is often not definite, which may cause implant failure at times. The present study investigates the capacity of the mesenchymal stem cell (MSC)-secretome, formulated as a ready-to-use and freeze-dried medicinal product (the Lyosecretome), to promote the osteoinductive and osteoconductive properties of titanium cages. In vitro tests were conducted using adipose tissue-derived MSCs seeded on titanium cages with or without Lyosecretome. After 14 days, in the presence of Lyosecretome, significant cell proliferation improvement was observed. Scanning electron microscopy revealed the cytocompatibility of titanium cages: the seeded MSCs showed a spread morphology and an initial formation of filopodia. After 7 days, in the presence of Lyosecretome, more frequent and complex cellular processes forming bridges across the porous surface of the scaffold were revealed. Also, after 14 and 28 days of culturing in osteogenic medium, the amount of mineralized matrix detected by alizarin red was significantly higher when Lyosecretome was used. Finally, improved osteogenesis with Lyosecretome was confirmed by confocal analysis after 28 and 56 days of treatment, and demonstrating the production by osteoblast-differentiated MSCs of osteocalcin, a specific bone matrix protein.

Cyto/Biocompatibility of Dopamine Combined with the Antioxidant Grape Seed-Derived Polyphenol Compounds in Solid Lipid Nanoparticles.

Background: The loss of nigrostriatal neurons containing dopamine (DA) together with the "mitochondrial dysfunction" in midbrain represent the two main causes related to the symptoms of Parkinson's disease (PD). Hence, the aim of this investigation is to co-administer the missing DA and the antioxidant grape seed-derived proanthocyanidins (grape seed extract, GSE) in order to increase the levels of the neurotransmitter (which is unable to cross the Blood Brain Barrier) and reducing the oxidative stress (OS) related to PD, respectively. Methods: For this purpose, we chose Solid Lipid Nanoparticles (SLN), because they have been already proven to increase DA uptake in the brain. DA-SLN adsorbing GSE (GSE/DA-SLN) were formulated and subjected to physico-chemical characterization, and their cytocompatibility and protection against OS were examined. Results: GSE was found on SLN surface and release studies evidenced the efficiency of GSE in preventing DA autoxidation. Furthermore, SLN showed high mucoadhesive strength and were found not cytotoxic to both primary Olfactory Ensheathing and neuroblastoma SH-SY5Y cells by MTT test. Co-administration of GSE/DA-SLN and the OS-inducing neurotoxin 6-hydroxydopamine (100 µM) resulted in an increase of SH-SY5Y cell viability. Conclusions: Hence, SLN formulations containing DA and GSE may constitute interesting candidates for non-invasive nose-to-brain delivery.

Design, synthesis and evaluation of biotin decorated inulin-based polymeric micelles as long-circulating nanocarriers for targeted drug delivery.

Here, long-circulating behaviors of Inulin-based nanomicelles are demonstrated for the first time in vivo. We show the synthesis and evaluation of biotin (BIO)-decorated polymeric INVITE micelles constituted of substances of natural origin, Inulin (INU) and Vitamin E (VITE), as long-circulating carriers for receptor-mediated targeted drug delivery. The resulting INVITE or INVITE-BIO micelles, nanometrically sized, did not reveal any cytotoxicity after 24h of incubation with Caco-2 cells. Moreover, in vitro studies on Caco-2 cells monolayers indicated that the transport of INVITE-BIO micelles was faster than surface unmodified INVITE micelles. In vivo optical imaging studies evidenced that, upon intravenous administration, INVITE-BIO micelles were quantitatively present in the body up to 48h. Instead, after oral administration, the micelles were not found in the systemic circulation but eliminated with the normal intestinal content. In conclusion, INVITE-BIO micelles may enhance drug accumulation in tumor-cells over-expressing the receptor for biotin through receptor mediated endocytosis.

Inulin-D-α-tocopherol succinate (INVITE) nanomicelles as a platform for effective intravenous administration of curcumin.

The aim of this work was to evaluate the potential of INVITE-based nanomicelles, an amphiphilic polymer constituted by inulin (INU) and vitamin E (VITE), as a platform for improving the biopharmaceutical properties of hydrophobic drugs. For this purpose, curcumin was selected as a model and curcumin-INVITE nanomicelles were prepared. This drug delivery system was characterized both in vitro for what concerns the physicochemical properties, blood compatibility, and cellular uptake, and in vivo for the evaluation of the pharmacokinetic profile. It was found that these nanomicelles released curcumin in a controlled manner, and they were able to penetrate cellular membrane. Moreover, they showed an improved pharmacokinetic profile after intravenous administration. In conclusion, INVITE micelles might constitute promising nanocarriers for improving the biopharmaceutical performance of hydrophobic drugs.

Collagen/PCL electrospun fibers loaded with polyphenols: Curcumin and resveratrol comparison.

Curcumin (Cur) and resveratrol (Rsv) have already been proposed for both anti-tumor and wound healing applications and contrasting results have been published regarding their anti- or pro-angiogenic activity; depending on the final application, an anti- or a pro-angiogenic activity is required. In the present study, a comparison of Cur and Rsv loaded electrospun fibers based on collagen and polycaprolactone (PCL) mixture was performed in order to make a contribution to understanding whether the two polyphenols have anti or pro-angiogenic activity. Despite their hydrophobic character, the two polyphenols affected morphology and wettability of the fibers, and Rsv-loaded fibers resulted larger and more quickly wettable. After hydration, collagen/PCL fibers loaded with both Cur and Rsv exhibited higher elongation and better deformation with respect to the unloaded fibers. Fourier transformed infrared spectroscopy and thermal analysis showed interactions between the polyphenols and collagen. Both fiber formulations resulted biocompatible with an increase of fibroblast number during 7 days of culture; confocal microscopy analyses demonstrated that Cur released by the fibers was internalized by the cells which remained vital and adherent. Chick embryo chorioallantoic membrane assay showed that both fibers had anti-angiogenic behavior, suggesting that an anti-cancer application more than a wound healing one could be envisaged.

Statin-Sensitive Akt1/Src/Caveolin-1 Signaling Enhances Oxidative Stress Resistance in Rhabdomyosarcoma.

Identifying the molecular mechanisms underlying radioresistance is a priority for the treatment of RMS, a myogenic tumor accounting for approximately 50% of all pediatric soft tissue sarcomas. We found that irradiation (IR) transiently increased phosphorylation of Akt1, Src, and Cav1 in human RD and RH30 lines. Synthetic inhibition of Akt1 and Src phosphorylation increased ROS levels in all RMS lines, promoting cellular radiosensitization. Accordingly, the elevated activation of the Akt1/Src/Cav1 pathway, as detected in two RD lines characterized by overexpression of a myristoylated Akt1 form (myrAkt1) or Cav1 (RDCav1), was correlated with reduced levels of ROS, higher expression of catalase, and increased radioresistance. We found that treatment with cholesterol-lowering drugs such as lovastatin and simvastatin promoted cell apoptosis in all RMS lines by reducing Akt1 and Cav1 levels and increasing intracellular ROS levels. Combining statins with IR significantly increased DNA damage and cell apoptosis as assessed by γ histone 2AX (γH2AX) staining and FACS analysis. Furthermore, in combination with the chemotherapeutic agent actinomycin D, statins were effective in reducing cell survival through increased apoptosis. Taken together, our findings suggest that the molecularly linked signature formed by Akt1, Src, Cav1, and catalase may represent a prognostic determinant for identifying subgroups of RMS patients with higher probability of recurrence after radiotherapy. Furthermore, statin-induced oxidative stress could represent a treatment option to improve the success of radiotherapy.

Anti-HER2 Super Stealth Immunoliposomes for Targeted-Chemotherapy.

Liposomes play an important role in the field of drug delivery by virtue of their biocompatibility and versatility as carriers. Stealth liposomes, obtained by surface decoration with hydrophilic polyethylene glycol (PEG) molecules, represent an important turning point in liposome technology, leading to significant improvements in the pharmacokinetic profile compared to naked liposomes. Nevertheless, the generation of effective targeted liposomes-a central issue for cancer therapy-has faced several difficulties and clinical phase failures. Active targeting remains a challenge for liposomes. In this direction, a new Super Stealth Immunoliposomes (SSIL2) composed of a PEG-bi-phospholipids derivative is designed that stabilizes the polymer shielding over the liposomes. Furthermore, its counterpart, conjugated to the fragment antigen-binding of trastuzumab (Fab'TRZ -PEG-bi-phospholipids), is firmly anchored on the liposomes surface and correctly orients outward the targeting moiety. Throughout this study, the performances of SSIL2 are evaluated and compared to classic stealth liposomes and stealth immunoliposomes in vitro in a panel of cell lines and in vivo studies in zebrafish larvae and rodent models. Overall, SSIL2 shows superior in vitro and in vivo outcomes, both in terms of safety and anticancer efficacy, thus representing a step forward in targeted cancer therapy, and valuable for future development.

Hyperactive Akt1 Signaling Increases Tumor Progression and DNA Repair in Embryonal Rhabdomyosarcoma RD Line and Confers Susceptibility to Glycolysis and Mevalonate Pathway Inhibitors.

In pediatric rhabdomyosarcoma (RMS), elevated Akt signaling is associated with increased malignancy. Here, we report that expression of a constitutively active, myristoylated form of Akt1 (myrAkt1) in human RMS RD cells led to hyperactivation of the mammalian target of rapamycin (mTOR)/70-kDa ribosomal protein S6 kinase (p70S6K) pathway, resulting in the loss of both MyoD and myogenic capacity, and an increase of Ki67 expression due to high cell mitosis. MyrAkt1 signaling increased migratory and invasive cell traits, as detected by wound healing, zymography, and xenograft zebrafish assays, and promoted repair of DNA damage after radiotherapy and doxorubicin treatments, as revealed by nuclear detection of phosphorylated H2A histone family member X (γH2AX) through activation of DNA-dependent protein kinase (DNA-PK). Treatment with synthetic inhibitors of phosphatidylinositol-3-kinase (PI3K) and Akt was sufficient to completely revert the aggressive cell phenotype, while the mTOR inhibitor rapamycin failed to block cell dissemination. Furthermore, we found that pronounced Akt1 signaling increased the susceptibility to cell apoptosis after treatments with 2-deoxy-D-glucose (2-DG) and lovastatin, enzymatic inhibitors of hexokinase, and 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR), especially in combination with radiotherapy and doxorubicin. In conclusion, these data suggest that restriction of glucose metabolism and the mevalonate pathway, in combination with standard therapy, may increase therapy success in RMS tumors characterized by a dysregulated Akt signaling.

Griseofulvin/carrier blends: application of partial least squares (PLS) regression analysis for estimating the factors affecting the dissolution efficiency.

The main aim of the present study was to estimate the carrier characteristics affecting the dissolution efficiency of griseofulvin (Gris) containing blends (BLs) using partial least squares (PLS) regression analysis. These systems were prepared at three different drug/carrier weight ratios (1/5, 1/10, and 1/20) by the solvent evaporation method, a well-established method for preparing solid dispersions (SDs). The carriers used were structurally different including polymers, a polyol, acids, bases and sugars. The BLs were characterised at the solid-state by spectroscopic (Fourier transform infrared spectroscopy), thermoanalytical (differential scanning calorimetry) and X-ray diffraction studies and their dissolution behaviours were quantified in terms of dissolution efficiencies (log DE/DE(Gris)). The correlation between the selected descriptors, including parameters for size, lipophilicity, cohesive energy density, and hydrogen bonding capacity and log DE/DE(Gris) (i.e., DE and DE(Gris) are the dissolution efficiencies of the BLs and the pure drug, respectively) was established by PLS regression analysis. Thus two models characterised by satisfactory coefficient of determination were derived. The generated equations point out that aqueous solubility, density, lipophilic/hydrophilic character, dispersive/polar forces and hydrogen bonding acceptor/donor ability of the carrier are important features for dissolution efficiency enhancement. Finally, it could be concluded that the correlations developed may be used to predict at a semiquantitative level the dissolution behaviour of BLs of other essentially neutral drugs possessing hydrogen bonding acceptor groups only.

Crocetin as New Cross-Linker for Bioactive Sericin Nanoparticles.

The nose-to-brain delivery route is used to bypass the blood-brain barrier and deliver drugs directly into the brain. Over the years, significant signs of progress have been made in developing nano-drug delivery systems to address the very low drug transfer levels seen with conventional formulations (e.g., nasal solutions). In this paper, sericin nanoparticles were prepared using crocetin as a new bioactive natural cross-linker (NPc) and compared to sericin nanoparticles prepared with glutaraldehyde (NPg). The mean diameter of NPc and NPg was about 248 and 225 nm, respectively, and suitable for nose-to-brain delivery. The morphological investigation revealed that NPc are spherical-like particles with a smooth surface, whereas NPg seem small and rough. NPc remained stable at 4 °C for 28 days, and when freeze-dried with 0.1% w/v of trehalose, the aggregation was prevented. The use of crocetin as a natural cross-linker significantly improved the in vitro ROS-scavenging ability of NPc with respect to NPg. Both formulations were cytocompatible at all the concentrations tested on human fibroblasts and Caco-2 cells and protected them against oxidative stress damage. In detail, for NPc, the concentration of 400 µg/mL resulted in the most promising to maintain the cell metabolic activity of fibroblasts higher than 90%. Overall, the results reported in this paper support the employment of NPc as a nose-to-brain drug delivery system, as the brain targeting of antioxidants is a potential tool for the therapy of neurological diseases.

Freeze-Dried Mesenchymal Stem Cell-Secretome Pharmaceuticalization: Optimization of Formulation and Manufacturing Process Robustness.

Producing mesenchymal stem cell (MSC)-secretome for dose escalation studies and clinical practice requires scalable and good manufacturing practice (GMP)-compliant production procedures and formulation into a standardized medicinal product. Starting from a method that combines ultrafiltration and freeze-drying to transform MSC-secretome into a pharmaceutical product, the lyosecretome, this work aims to: (i) optimize the lyosecretome formulation; (ii) investigate sources of variability that can affect the robustness of the manufacturing process; (iii) modify the ultrafiltration step to obtain a more standardized final product. Design of experiments and principal component analysis of the data were used to study the influence of batch production, lyophilization, mannitol (M)/sucrose (S) binary mixture, selected as cryoprotectant excipients, and the total amount of excipients on the extracellular vesicles (EV) particle size, the protein and lipid content and the in vitro anti-elastase. The different excipients ratios did not affect residual moisture or EV particle size; simultaneously, proteins and lipids were better preserved in the freeze-dried product using the maximum total concentration of excipients (1.5% w/v) with a M:S ratio of about 60% w/w. The anti-elastase activity was instead better preserved using 0.5% w/w of M as excipient. The secretome batch showed to be the primary source of variability; therefore, the manufacturing process has been modified and then validated: the final product is now concentrated to reach a specific protein (and lipid) concentration instead of cell equivalent concentration. The new standardization approach led to a final product with more reproducible quali-quantitative composition and higher biological activity.

Paclitaxel-eluting biodegradable synthetic vascular prostheses: a step towards reduction of neointima formation?

BACKGROUND: Clinical small-caliber vascular prostheses are unsatisfactory. Reasons for failure are early thrombosis and late intimal hyperplasia. We thus prepared biodegradable small-caliber vascular prostheses using electrospun polycaprolactone (PCL) with slow-releasing paclitaxel (PTX), an antiproliferative drug. METHODS AND RESULTS: PCL solutions containing PTX were used to prepare nonwoven nanofibre-based 2-mm ID prostheses. Mechanical morphological properties and drug loading, distribution, and release were studied in vitro. Infrarenal abdominal aortic replacement was carried out with nondrug-loaded and drug-loaded prostheses in 18 rats and followed for 6 months. Patency, stenosis, tissue reaction, and drug effect on endothelialization, vascular remodeling, and neointima formation were studied in vivo. In vitro prostheses showed controlled morphology mimicking extracellular matrix with mechanical properties similar to those of native vessels. PTX-loaded grafts with suitable mechanical properties and controlled drug-release were obtained by factorial design. In vivo, both groups showed 100% patency, no stenosis, and no aneurysmal dilatation. Endothelial coverage and cell ingrowth were significantly reduced at 3 weeks and delayed at 12 and 24 weeks in PTX grafts, but as envisioned, neointima formation was significantly reduced in these grafts at 12 weeks and delayed at 6 months. CONCLUSIONS: Biodegradable, electrospun, nanofibre, polycaprolactone prostheses are promising because in vitro they maintain their mechanical properties (regardless of PTX loading), and in vivo show good patency, reendothelialize, and remodel with autologous cells. PTX loading delays endothelialization and cellular ingrowth. Conversely, it reduces neointima formation until the end point of our study and thus may be an interesting option for small caliber vascular grafts.

Gelatin and Glycerine-Based Bioadhesive Vaginal Hydrogel.

AIM: The work's aim was the preparation and characterization of a hydrogel based on gelatin and glycerine, useful for site-specific release of benzydamine, an anti-inflammatory drug, able to attenuate the inflammatory process typical of the vaginal infection. OBJECTIVE: The obtained hydrogel has been characterized by Electronic Scanning Microscopy (SEM) and Differential Scanning Calorimetry (DSC). In addition, due to the precursor properties, the hydrogel exhibits a relevant mucoadhesive activity. METHODS: The swelling degree was evaluated at two different pHs and at defined time intervals. In particular, phosphate buffers were used at pH 6.6, in order to mimic the typical conditions of infectious diseases at the vaginal level, particularly for HIV-seropositive pregnant women, and pH 4.6, to simulate the physiological environment. RESULTS: The obtained results revealed that the hydrogel swells up well at both pHs. CONCLUSION: Release studies conducted at both pathological and physiological pHs have shown that benzydamine is released at the level of the vaginal mucosa in a slow and gradual manner. These data support the hypothesis of the hydrogel use for the site-specific release of benzydamine in the vaginal mucosa.

Inverse Poly-High Internal Phase Emulsions Poly(HIPEs) Materials from Natural and Biocompatible Polysaccharides.

This paper shows one of the few examples in the literature on the feasibility of novel materials from natural and biocompatible polymers like inulin (INU) or glycol chitosan (GCS) templated by the formation of o/w (inverse) high internal phase emulsion (HIPE). To the best of our knowledge, this is the first example of inverse polyHIPEs obtained from glycol chitosan or inulin. The obtained polyHIPEs were specifically designed for possible wound dressing applications. The HIPE (pre-crosslinking emulsion) was obtained as inverse HIPE, i.e., by forming a cream-like 80:20 v/v o/w emulsion by using the isopropyl myristate in its oil phase, which is obtained from natural sources like palm oil or coconut oil. The surfactant amount was critical in obtaining the inverse HIPE and the pluronic F127 was effective in stabilizing the emulsion comprising up to 80% v/v as internal phase. The obtained inverse HIPEs were crosslinked by UV irradiation for methacrylated INU or by glutaraldehyde-crosslinking for GCS. In both cases, inverse poly-HIPEs were obtained, which were physicochemically characterized. This paper introduces a new concept in using hydrophilic, natural polymers for the formation of inverse poly-HIPEs.

Synthesis and characterization of novel chitosan-dopamine or chitosan-tyrosine conjugates for potential nose-to-brain delivery.

This work aims to the synthesis of novel carboxylated chitosan-dopamine (DA) and -tyrosine (Tyr) conjugates as systems for improving the brain delivery of the neurotransmitter DA following nasal administration. For this purpose, ester or amide conjugates were synthesized by N,N-dicyclohexylcarbodiimide (DCC) mediated coupling reactions between the appropriate N-tert-butyloxycarbonyl (Boc) protected starting polymers N,O-carboxymethyl chitosan and 6-carboxy chitosan and DA or O-tert-Butyl-L-tyrosine-tert-butyl ester hydrochloride. The resulting conjugates were characterized by FT-IR and 1H- and 13C NMR spectroscopies and their in vitro mucoadhesive properties in simulated nasal fluid (SNF), toxicity and uptake from Olfactory Ensheathing Cells (OECs) were assessed. Results demonstrated that N,O-carboxymethyl chitosan-DA conjugate was the most mucoadhesive polymer in the series examined and, together with the 6-carboxy chitosan-DA-conjugate were able to release the neurotransmitter in SNF. The MTT assay showed that the starting polymers as well as all the prepared conjugates in OECs resulted not toxic at any concentration tested. Likewise, the three synthesized conjugates were not cytotoxic as well. Cytofluorimetric analysis revealed that the N,O-carboxymethyl chitosan DA conjugate was internalized by OECs in a superior manner at 24 h as compared with the starting polymer. Overall, the N,O-CMCS-DA conjugate seems promising for improving the delivery of DA by nose-to-brain administration.

Combination of inulin and ß-cyclodextrin properties for colon delivery of hydrophobic drugs.

Colon drug delivery is aimed at the administration of selected drugs to act locally or even systematically. Corticosteroid drugs are often used exerting even pronounced side effects due to systemic absorption. Here a new drug delivery system (DDS) based on the chemical conjugation of ß-cyclodextrin to inulin to form the INUCD bioconjugate is described. It was designed with the aim to provide this DDS with colon degradable portions (inulin) which degradation products have direct beneficial effects on the well-being of the colon and with a carrier that can solubilize hydrophobic drugs (ß-cyclodextrin). This system was specifically designed to promote a local/topical activity with a significant reduction of the drug systemic absorption. The INUCD bioconjugate was obtained by a simple chemistry binding ß-cyclodextrin to an inulin succinate previously synthesized. The bioconjugate was then characterized in terms of physicochemical properties by ATR-FTIR, 1H NMR, DSC and TGA, DLS and SEM. Furthermore phase-solubility test by using curcumin as a model drug were performed as well as biologic evaluations for cytocompatibility and drug transport across in vitro simulated physiological barriers. Moreover enzymatic degradation studies by inulinase were performed. From the gained results a predictable local drug release of the payload could be attained so allowing a local delivery of e.g. corticosteroids thus avoiding a systemic absorption especially in prolonged therapies.

Inulin as a multifaceted (active) substance and its chemical functionalization: From plant extraction to applications in pharmacy, cosmetics and food.

This review is aimed at critically discussing a collection of research papers on Inulin (INU) in different scientific fields. The first part of this work gives an overview on the main characteristics of native INU, including production, applications in food or cosmetics industries, its benefits on human health as well as its main nutraceutical properties. A particular focus is dedicated to the extraction techniques and to the specific effects of INU on intestinal microbiota. Other than in food industry, the number of INU applications increases dramatically in the pharmaceutical field especially due to its simple chemical functionalization. Thus, aim of this review is also to give practical examples of chemical functionalization performed on INU also by including critical comments based on the direct experience of the Authors. With this aim, a full paragraph is dedicated to practical chemical experiences useful to reduce the efforts when establishing new experimental conditions. Moreover, the pharmaceutical technology is also taken in special consideration by underlining the aspects leading at the preparation of formulations based on INU. At the end of the review, a critical paragraph is intended to feed the scientists' curiosity on this versatile polysaccharide.

Drug delivery of rifampicin by natural micelles based on inulin: Physicochemical properties, antibacterial activity and human macrophages uptake.

This work aims at designing a drug delivery system for rifampicin (RIF) to be used for the therapy of infections from mycobacterium tuberculosis or other lung-colonizing bacteria. We are proposing, in particular, the delivery of RIF by micelles based on inulin functionalized with vitamin E (INVITE). We previously demonstrated that INVITE micelles are formed from the self-assembling sustained by the interaction, within the hydrophobic core, of aromatic groups belonging to vitamin E. It points on the effectiveness of these biocompatible systems in incorporating aromatic-group-bearing hydrophobic drug such as RIF. The succinilated derivative of INVITE, namely INVITESA, was further studied. Other than a full physicochemical characterization, the obtained micelles containing RIF were tested for their antibacterial activity against Gram- or Gram+bacteria including mycobacterium smegmatis. Furthermore, uptake studies on human alveolar macrophages and MTT studies were performed.

Effect of Methyl-ß-Cyclodextrin on the antimicrobial activity of a new series of poorly water-soluble benzothiazoles.

The antibacterial activity of the S-unsubstituted- and S-benzyl-substituted-2-mercapto-benzothiazoles 1-4 has been evaluated after complexation with Methyl-ß-Cyclodextrin (Me-ß-CD) or incorporation in solid dispersions based on Pluronic® F-127 and compared with that of the pure compounds. This with the aim to gain further insights on the possible mechanism(s) involved in the CD-mediated enhancement of antimicrobial effectiveness, a promising methodology to overcome the microbial resistance issue. Together with Differential Scanning Calorimetry, FT-IR spectroscopy and X-ray Powder Diffraction investigations, a molecular modeling study focused on compounds 2 and 4 showed that the S-unsubstituted compound 2/Me-ß-CD complex should be more stable than S-benzyl-substituted 4/Me-ß-CD. Only for 1/Me-ß-CD or, particularly, 2/Me-ß-CD complexes, the antibacterial effectiveness was enhanced in the presence of selected bacterial strains. The results herein presented support the mechanisms focusing on the interactions of the bacterial membrane with CD complexes more than those focusing on the improvement of dissolution properties consequent to CD complexation.

In vitro and ex vivo studies on diltiazem hydrochloride-loaded microsponges in rectal gels for chronic anal fissures treatment.

Diltiazem hydrochloride, topically applied at 2% concentration, is considered effective for the treatment of chronic anal fissures, although it involves several side effects among which anal pruritus and postural hypotension. To test the hypothesis that a sustained delivery system of diltiazem hydrochloride may be helpful for the treatment of chronic anal fissures, in the present study we evaluated the potential of gels containing diltiazem hydrochloride entrapped in microsponges. Such microsponges were based on Eudragit RS 100 and the effect of some formulation variables was assessed by a 23 full factorial screening design. An optimized formulation of diltiazem hydrochloride microsponges was dispersed in Methylcellulose 2% or Poloxamer 407 20% and the resulting gels (micro-l-diltiazem hydrochloride 2%) were subjected to in vitro drug release, ex vivo permeability and drug deposition after application on porcine rectal mucosa. The results showed a prolonged release up to 24 h from micro-l-diltiazem hydrochloride at 2% in the gels. The permeation tests revealed up to 18% higher drug retention on the mucosal tissue after 24 h by the micro-l-diltiazem hydrochloride 2% gels compared to conventional diltiazem hydrochloride gels at 2%. These results suggest that diltiazem hydrochloride-loaded microsponges dispersed in rectal gels may be useful to overcome some limitations of conventional local chronic anal fissure therapy.