Azithromycin-loaded liposomes and niosomes for the treatment of skin infections: Influence of excipients and preparative methods on the functional properties

The aim of this study was to develop azithromycin (AZT)-loaded liposomes (LP) and niosomes (NS) useful for the treatment of bacterial skin infections and acne. LP based on phosphatidylcholine from egg yolk (EPC) or from soybean lecithin (SPC), and NS composed of sorbitan monopalmitate (Span 40) or sorbitan monostearate (Span 60) were prepared through the thin film hydration (TFH) and the ethanol injection (EI) methods. The formulations were subsequently characterized for their physico-chemical and functional properties. Vesicles prepared through TFH showed higher average sizes than the corresponding formulations obtained by EI. All the vesicles presented adequate encapsulation efficiency and a negative ζ potential, which assured good stability during the storage period (except for LP-SPC). Formulations prepared with TFH showed a more prolonged AZT release than those prepared through EI, due to their lower surface area and multilamellar structure, as confirmed by atomic force microscopy nanomechanical characterization. Finally, among all the formulations, NS-Span 40-TFH and LP-EPC-TFH allowed the highest drug accumulation in the skin, retained the antimicrobial activity and did not alter fibroblast metabolism and viability. Overall, they could ensure to minimize the dosing and the administration frequency, thus representing promising candidates for the treatment of bacterial skin infections and acne.

Design and Characterization of an Ethosomal Gel Encapsulating Rosehip Extract

Rising environmental awareness drives green consumers to purchase sustainable cosmetics based on natural bioactive compounds. The aim of this study was to deliver Rosa canina L. extract as a botanical ingredient in an anti-aging gel using an eco-friendly approach. Rosehip extract was first characterized in terms of its antioxidant activity through a DPPH assay and ROS reduction test and then encapsulated in ethosomal vesicles with different percentages of ethanol. All formulations were characterized in terms of size, polydispersity, zeta potential, and entrapment efficiency. Release and skin penetration/permeation data were obtained through in vitro studies, and cell viability was assessed using an MTT assay on WS1 fibroblasts. Finally, ethosomes were incorporated in hyaluronic gels (1% or 2% w/v) to facilitate skin application, and rheological properties were studied. Rosehip extract (1 mg/mL) revealed a high antioxidant activity and was successfully encapsulated in ethosomes containing 30% ethanol, having small sizes (225.4 ± 7.0 nm), low polydispersity (0.26 ± 0.02), and good entrapment efficiency (93.41 ± 5.30%). This formulation incorporated in a hyaluronic gel 1% w/v showed an optimal pH for skin application (5.6 ± 0.2), good spreadability, and stability over 60 days at 4 °C. Considering sustainable ingredients and eco-friendly manufacturing technology, the ethosomal gel of rosehip extract could be an innovative and green anti-aging skincare product.

Drug delivery to the brain: In situ gelling formulation enhances carbamazepine diffusion through nasal mucosa models with mucin

The objective of this work was to optimize a thermosensitive in situ gelling formulation to improve intranasal and nose-to-brain delivery of the antiepileptic drug carbamazepine (CBZ). A preliminary procedure of vehicles obtained just mixing different fractions of poloxamer 407 (P407) and poloxamer 188 (P188) revealed preparations with phase transition temperatures, times to gelation and pH values suitable for nasal delivery. Subsequently, the mucoadhesive properties of the most promising formulations were tuned by adding hydroxypropylmethylcellulose types of different viscosity grades, and the effect of the adhesive polymers was evaluated by testing in vitro time and strength of mucoadhesion on specimens of sheep nasal mucosa. The formulation that showed the greatest mucoadhesive potential in vitro, with a time and force of mucoadhesion equal to 1746,75 s and 3.66 × 10-4 N, respectively, was that composed of 22% P407, 5% P188 and 0.8% HPMC low-viscous and it was further investigated for its ability to increase drug solubility and to control the release of the drug. Lastly, the capability of the candidate vehicle to ensure drug permeation across the biomimetic membrane Permeapad®, an artificial phospholipid-based barrier with a stratified architecture, and the same barrier enriched with a mucin layer was verified. The final formulation was characterized by a pH value of 6.0, underwent gelation at 32.33°C in 37.85 s, thus showing all the features required by in situ gelling thermosensitive preparations designed for nasal delivery and, more notably, it conserved the ability to favor drug permeation in the presence of mucin. These findings suggest that the optimized gelling system could be a promising and easy to realize strategy to improve CBZ delivery to the brain exploiting both a direct and indirect pathway.

Extraction, Encapsulation into Lipid Vesicular Systems, and Biological Activity of Rosa canina L. Bioactive Compounds for Dermocosmetic Use

Valorization of wild plants to obtain botanical ingredients could be a strategy for sustainable production of cosmetics. This study aimed to select the rosehip extract containing the greatest amounts of bioactive compounds and to encapsulate it in vesicular systems capable of protecting their own antioxidant activity. Chemical analysis of Rosa canina L. extracts was performed by LC-DAD-MS/MS and ¹H-NMR and vitamins, phenolic compounds, sugars, and organic acids were detected as the main compounds of the extracts. Liposomes, prepared by the film hydration method, together with hyalurosomes and ethosomes, obtained by the ethanol injection method, were characterized in terms of vesicle size, polydispersity index, entrapment efficiency, zeta potential, in vitro release and biocompatibility on WS1 fibroblasts. Among all types of vesicular systems, ethosomes proved to be the most promising nanocarriers showing nanometric size (196 ± 1 nm), narrow polydispersity (0.20 ± 0.02), good entrapment efficiency (92.30 ± 0.02%), and negative zeta potential (−37.36 ± 0.55 mV). Moreover, ethosomes showed good stability over time, a slow release of polyphenols compared with free extract, and they were not cytotoxic. In conclusion, ethosomes could be innovative carriers for the encapsulation of rosehip extract.

Mucoadhesive and mucopenetrating chitosan nanoparticles for glycopeptide antibiotic administration

The use of nanoparticles (NPs) represents a useful strategy for peptide antibiotic delivery to mucosal membranes by either prolonging drug residence time at the target site (mucoadhesive NPs) or by enhancing diffusion across mucus layer to reach the underlying epithelium (mucopenetrating NPs). The purpose of this study was to design chitosan (CH) NPs and to evaluate their employment as mucoadhesive and/or mucopenetrating systems for vancomycin (VM) delivery. NPs were prepared by ionic gelation of CH with sodium carboxymethylcellulose (CMC), sodium alginate (ALG), sodium tripolyphosphate (TPP) or phytic acid (PA) and characterized in terms of size, zeta-potential, morphology, drug encapsulation efficiency, mucoadhesion and mucopenetrating ability. Moreover, in vitro tests were conducted to evaluate VM release and the antibacterial activity against Staphylococcus aureus and Bacillus subtilis. NPs showed sizes ranged from 150 nm to 350 nm with good polydispersity index and positive zeta-potential. The selection of the suitable crosslinker allowed to modulate the mucoadhesive/mucopenetrating properties: CH/TPP NPs showed the best mucoadhesive ability, while CH/PA and CH/CMC NPs were characterized by an improved diffusion across the mucus layer. Further, NPs allowed a fast and complete release of VM, maintaining the antibacterial activity against the tested bacteria species.

Development of Spanish Broom and Flax Dressings with Glycyrrhetinic Acid-Loaded Films for Wound Healing: Characterization and Evaluation of Biological Properties

The selection of an appropriate dressing for each type of wound is a very important procedure for a faster and more accurate healing process. So, the aim of this study was to develop innovative Spanish Broom and flax wound dressings, as alternatives to cotton used as control, with polymeric films containing glycyrrhetinic acid (GA) to promote wound-exudate absorption and the healing process. The different wound dressings were prepared by a solvent casting method, and characterized in terms of drug loading, water uptake, and in vitro release. Moreover, biological studies were performed to evaluate their biocompatibility and wound-healing efficacy. Comparing the developed wound dressings, Spanish Broom dressings with GA-loaded sodium hyaluronate film had the best functional properties, in terms of hydration ability and GA release. Moreover, they showed a good biocompatibility, determining a moderate induction of cell proliferation and no cytotoxicity. In addition, the wound-healing test revealed that the Spanish Broom dressings promoted cell migration, further facilitating the closure of the wound.

Freeze-Dried Matrices for Buccal Administration of Propranolol in Children: Physico-Chemical and Functional Characterization

Buccal matrices represent a widely accepted dosage form permitting a convenient, easy, reliable drug administration and reducing administration errors. The aim of this study was the development of mucoadhesive buccal matrices for propranolol administration in children. Matrices were obtained by freeze-drying of drug loaded polymeric solutions based on gum tragacanth (GT), pectin (PEC), hydroxypropylmethylcellulose (HPMC), sodium hyaluronate (HA), gelatin (GEL), chitosan (CH) or a mixture of CH and HPMC (CH/HPMC). Matrices were characterized for drug solid state, morphology, water-uptake, mucoadhesion ability, in vitro drug release and permeation through porcine epithelium. The most promising formulations were tested for in vitro biocompatibility in human dental pulp fibroblasts. The preparative method and the polymeric composition influenced the drug solid state, as a complete amorphization as well as different polymorphic forms were observed. GEL and PEC guaranteed a fast and complete drug release due to their rapid dissolution, while for the other matrices the release was influenced by drug diffusion through the viscous gelled matrix. Moreover, matrices based on CH and CH/HPMC showed the best mucoadhesive properties, favoured the drug permeation, in virtue of CH ability to interfere with the lipid organization of biological membrane, and were characterized by a good biocompatibility profile.

Mucoadhesive Buccal Films for Local Delivery of Lactobacillus brevis

The aim of this work was to prepare mucoadhesive buccal films for local release of Lactobacillus brevis CD2, which shows interesting anti-inflammatory properties due to its high levels of arginine deiminase. Hydroxypropylmethylcellulose-based films were prepared by means of a modified casting method, which allowed L. brevis CD2 loading on one side of the film, before its complete drying. Three batches of films were prepared, stored at +2-8 °C and +23-25 °C for 48 weeks and characterized in terms of physico-chemical and functional properties. For each batch, the L. brevis viable count and arginine deiminase activity were evaluated at different time points in order to assess functional property maintenance over time. Moreover, the mucoadhesive properties and ability of the films to release L. brevis CD2 were evaluated. A good survival of L. brevis CD2 was observed, particularly at the storage temperature of +2-8 °C, while the activity of arginine deiminase was maintained at both temperature values. Films showed good mucoadhesive properties and guaranteed a prolonged release of viable lactobacilli, which can be directed towards the whole buccal cavity or specific mucosa lesions. In conclusion, the proposed preparative method can be successfully employed for the production of buccal films able to release viable L. brevis CD2 cells that maintain the anti-inflammatory enzymatic activity.

Transdermal Delivery of Antipsychotics: Rationale and Current Status

The aim of this article is to provide the rationale for the development of transdermal formulations of antipsychotics by highlighting their main advantages, starting with an overview of the antipsychotic formulations that are currently available on the market. Progress regarding transdermal antipsychotic formulations was investigated by performing a search of papers, patents and clinical trials published in the last 10 years. Available data on antipsychotic transdermal formulations are reported and discussed, focusing on the characteristics of the dosage forms and their ability to promote drug absorption. Despite the current availability of a large number of antipsychotics, only a few of these drugs (e.g. aripiprazole, asenapine, blonanserin, chlorpromazine, haloperidol, olanzapine, prochlorperazine, quetiapine, and risperidone) have been developed as transdermal delivery systems. Several papers and patents show that transdermal formulations, such as creams, films, gels, nanosystems, patches, solutions, and sprays, have been evaluated with the aim of expanding the clinical utility of antipsychotic drugs. In particular, the employment of different strategies, such as the use of nanoparticles/vesicles, or permeation enhancers as well as microneedles with iontophoresis, may improve the absorption of antipsychotic drugs through the skin. However, few clinical trials on transdermal delivery of antipsychotic drugs are available and only delivery systems containing asenapine and blonanserin have shown interesting clinical results in terms of pharmacokinetic data, efficacy, and tolerability. Recently, the transdermal patch formulation of blonanserin was approved in Japan for the treatment of schizophrenia.

Liposomes containing biosurfactants isolated from Lactobacillus gasseri exert antibiofilm activity against methicillin resistant Staphylococcus aureus strains

Staphylococcus aureus is the major causative agent of skin and soft tissue infections, whose prevention and treatment have become more difficult due to the emergence of antibiotic-resistant strains. In this regard, the development of an effective treatment represents a challenge that can be overcome by delivering new antibiofilm agents with appropriate nanocarriers. In this study, a biosurfactant (BS) isolated from Lactobacillus gasseri BC9 and subsequently loaded in liposomes (LP), was evaluated for its ability to prevent the development and to eradicate the biofilm of different methicillin resistant S. aureus (MRSA) strains. BS from L. gasseri BC9 was not cytotoxic and was able to prevent formation and to eradicate the biofilm of different MRSA strains. BS loaded liposomes (BS-LP) presented a mean diameter (lower than 200 nm) suitable for topical administration and a low polydispersity index (lower than 0.2) that were maintained over time for up 28 days. Notably, BS-LP showed higher ability than free BS to inhibit S. aureus biofilm formation and eradication. BS-LP were loaded in lyophilized matrices able to quickly dissolve (dissolution time lower than 5 s) upon contact with exudate, thus allowing vesicle reconstitution. In conclusion, in this work, we demonstrated the antibiofilm activity of Lactobacillus-derived BS and BS-LP against clinically relevant MRSA strains. Furthermore, the affordable production of lyophilized matrices containing BS-LP for local prevention of cutaneous infections was established.

Cromolyn-crosslinked chitosan nanoparticles for the treatment of allergic rhinitis

The aim of this work was to prepare new mucoadhesive nasal decongestant nanoparticles obtained by direct crosslinking between the cationic polymer chitosan and the anionic drug cromolyn. Different chitosan/cromolyn molar ratios were used in order to obtain nanoparticles of suitable size, encapsulation efficiency/drug loading and mucoadhesion. Moreover, the ability of the nanoparticles to deliver cromolyn into and through the nasal mucosa was evaluated. The obtained positively charged nanoparticles, sized 180-400 nm, showed interesting properties in terms of yield, mucoadhesion, encapsulation efficiency and drug loading. Release and permeation/penetration data indicated the ability of the nanoparticles to retain a high amount of cromolyn inside the mucosa, which is rich in mast cells. These findings suggest developing decongestant nanoparticles for potential treatment of allergic rhinitis.

Novel mixed vesicles containing lactobacilli biosurfactant for vaginal delivery of an anti-Candida agent

The purpose of this work was to prepare and characterize an innovative formulation for vaginal delivery of econazole nitrate, commonly used for the treatment of Candida infections. A novel biosurfactant isolated from a vaginal Lactobacillus strain was used to prepare phosphatidylcholine based mixed vesicles. Biosurfactant was produced by Lactobacillus gasseri BC9, isolated from the vagina of a healthy premenopausal woman, and was chemically characterized by FT-IR and ESI-MS. Mixed vesicles, obtained through film rehydration and extrusion method, were characterized in terms of size, zeta potential, encapsulation efficiency, mucoadhesion properties and econazole release. Moreover, the antimicrobial activity of the mixed vesicles was tested towards both planktonic cultures and biofilms of Candida albicans. Biosurfactant produced by L. gasseri BC9 was composed by peptide-like molecules containing hydrocarbon chains and possessed a high surface activity together with a low critical micelle concentration. All the mixed vesicles presented optimal diameter range (226-337nm) for topical vaginal administration. Econazole-loaded mixed vesicles containing biosurfactant showed higher encapsulation efficiency and mucoadhesion ability with respect to vesicles containing Tween 80. Further, they allowed a sustained release of econazole nitrate, maintaining the antifungal activity against C. albicans planktonic culture. Notably, biosurfactant-based vesicles were significantly more active than free econazole in the eradication of Candida biofilm. In conclusion, mixed vesicles are promising new vaginal delivery systems for the potential employment in the treatment of chronic infections.

Bilayered buccal films as child-appropriate dosage form for systemic administration of propranolol

Buccal mucosa has emerged as an attractive site for systemic administration of drug in paediatric patients. This route is simple and non-invasive, even if the saliva wash-out effect and the relative permeability of the mucosa can reduce drug absorption. Mucoadhesive polymers represent a common employed strategy to increase the contact time of the formulation at the application site and to improve drug absorption. Among the different mucoadhesive dosage forms, buccal films are particularly addressed for paediatric population since they are thin, adaptable to the mucosal surface and able to offer an exact and flexible dose. The objective of the present study was to develop bilayered buccal films for the release of propranolol hydrochloride. A primary polymeric layer was prepared by casting and drying of solutions of film-forming polymers, such as polyvinylpyrrolidone (PVP) or polyvinylalcohol (PVA), added with different weight ratios of gelatin (GEL) or chitosan (CH). In order to achieve unidirectional drug delivery towards buccal mucosa, a secondary ethylcellulose layer was applied onto the primary layer. Bilayered films were characterized for their physico-chemical (morphology, thickness, drug content and solid state) and functional (water uptake, mucoadhesion, drug release and permeation) properties. The inclusion of CH into PVP and PVA primary layer provided the best mucoadhesion ability. Films containing CH provided a lower drug release with respect to films containing GEL and increased the amount of permeated drug through buccal mucosa, thanks to its ability of interfering with the lipid organization. The secondary ethylcellulose layer did not interfere with drug permeation, but it could limit drug release in the buccal cavity.

Spanish Broom (Spartium junceum L.) fibers impregnated with vancomycin-loaded chitosan nanoparticles as new antibacterial wound dressing: Preparation, characterization and antibacterial activity

In this work, we propose as new wound dressing, the Spanish Broom fibers impregnated with vancomycin (VM) loaded chitosan nanoparticles. Spanish Broom fibers were extracted by patented method DiCoDe and the morphological, physical and mechanical properties were investigated. Chitosan nanoparticles were prepared by ionic gelation using different weight ratios between chitosan (CH) and tripolyphosphate (TPP). Nanoparticles were characterized in terms of size, zeta potential, yield, encapsulation efficiency, stability and drug release. Finally, the antibacterial activity against Staphylococcus aureus as well as in vitro cytotoxicity on HaCaT cells were evaluated. The best formulation CH/TPP 4:1 was selected based on the encapsulation efficiency and yield. Spanish Broom fibers impregnated with loaded nanoparticles showed an increased antibacterial activity against S. aureus compared to the same fibers containing VM without nanoparticles. Moreover, these fibers were not toxic to HaCaT keratinocytes cells. In conclusion, Spanish Broom fibers impregnated with VM loaded CH/TPP nanoparticles would appear to be a promising candidate for wound dressing application.

Chitosan nanoparticles for lipophilic anticancer drug delivery: Development, characterization and in vitro studies on HT29 cancer cells

The aim of this study was to develop chitosan-based nanoparticles that could encapsulate lipophilic molecules and deliver them to cancer cells. Nanoparticles were prepared with different molar ratios of chitosan, hyaluronic acid and sulphobutyl-ether-β-cyclodextrin and with or without curcumin. The nanosystems were characterized in terms of their size, zeta potential, morphology, encapsulation efficiency and stability in different media. Intestinal epithelial and colorectal cancer cells were treated with unloaded nanoparticles in order to study their effect on cellular membrane organization and ROS production. Finally, in vitro assays on both cellular lines were performed in order to evaluate the ability of nanoparticles to promote curcumin internalization and to study their effect on cell proliferation and cell cycle. Results show that nanoparticles were positively charged and their size increased with the increasing amounts of the anionic excipient. Nanoparticles showed good encapsulation efficiency and stability in water. Unloaded nanoparticles led to a change in lipid organization in the cellular membrane of both cell lines, without inducing ROS generation. Confocal microscopy, cell proliferation and cell cycle studies allowed the selection of the best formulation to limit curcumin cytotoxicity in normal intestinal epithelial cells and to reduce cancer cell proliferation. The latter was the result of the increase of expression for genes involved in apoptosis.

Antiproliferative effect of linalool on RPMI 7932 human melanoma cell line: ultrastructural studies

Linalool, a small monoterpene molecule, is used widely for its flavoring and fragrant properties in many cosmetic products. In this work, we investigated the antiproliferative effect of two different linalool solutions on RPMI 7932 human melanoma and NCTC 2544 normal keratinocites cell lines using the trypan blue method. Morphological changes in cells were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, apoptosis was evaluated using caspase 3-antibody. Linalool showed a selective inhibitory effect on the growth of melanoma cells in a concentrationdependent manner, inducing several morphological changes, as revealed by SEM and TEM analysis. Moreover, the labelling for caspase-3 is abundant in the melanoma cells and almost absent in the normal keratinocites cells. The results suggest that linalool could be used as drug and/or as model drug for developing potential therapeutic agents for melanoma.

Antiproliferative Effect of Linalool on RPMI 7932 Human Melanoma Cell Line: Ultrastructural Studies

Linalool, a small monoterpene molecule, is used widely for its flavoring and fragrant properties in many cosmetic products. In this work, we investigated the antiproliferative effect of two different linalool solutions on RPMI 7932 human melanoma and NCTC 2544 normal keratinocites cell lines using the trypan blue method. Morphological changes in cells were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, apoptosis was evaluated using caspase 3-antibody. Linalool showed a selective inhibitory effect on the growth of melanoma cells in a concentration-dependent manner, inducing several morphological changes, as revealed by SEM and TEM analysis. Moreover, the labelling for caspase-3 is abundant in the melanoma cells and almost absent in the normal keratinocites cells. The results suggest that linalool could be used as drug and/or as model drug for developing potential therapeutic agents for melanoma.

Spartium Junceum Aromatic Water: Chemical Composition and Antitumor Activity

The purpose of this study was to analyse the chemical composition of Spartium junceum L. (also known as Spanish Broom) aromatic water and to evaluate its cytotoxic activity against a series of human cancer cell lines (melanoma: RPMI 7932; leukemia: K562; breast cancer cell: MCF7-Bart and MCF7-ICLC, colon adenocarcinoma: SW480). The results show that the aromatic water was cytotoxic toward the tumor cell lines analyzed (RPMI 7932, K562, MCF7-Bart, MCF7-ICLC, SW480), while it did not appreciably alter the viability of normal keratinocytes (NCTC 2544) suggesting its potential use as an antitumor agent for cancer treatment and/or prevention.

Spartium junceum aromatic water: chemical composition and antitumor activity

The purpose of this study was to analyse the chemical composition of Spartium junceum L. (also known as Spanish Broom) aromatic water and to evaluate its cytotoxic activity against a series of human cancer cell lines (melanoma: RPMI 7932; leukemia: K562; breast cancer cell: MCF7-Bart and MCF7-ICLC, colon adenocarcinoma: SW480). The results show that the aromatic water was cytotoxic toward the tumor cell lines analyzed (RPMI 7932, K562, MCF7-Bart, MCF7-ICLC, SW480), while it did not appreciably alter the viability of normal keratinocytes (NCTC 2544) suggesting its potential use as an antitumor agent for cancer treatment and/or prevention.

Hydroxypropylmethylcellulose films for prolonged delivery of the antipsychotic drug chlorpromazine

OBJECTIVES

The aim of this study was to develop transdermal films based on hydroxypropylmethylcellulose with the purpose of improving transdermal permeation of chlorpromazine hydrochloride, an antipsychotic drug used to alleviate the symptoms and signs of psychosis.

METHODS

Hydroxypropylmethylcellulose films were prepared and evaluated for their drug content, film thickness, residual water content and bioadhesive properties. In-vitro permeation experiments were performed in the absence and in the presence of permeation enhancers (oleic acid, polysorbate 80, or both) with the purpose of improving drug availability. Other formulative parameters, such as drug and plasticizer concentration and hydroxypropylmethylcellulose type, were investigated.

KEY FINDINGS

Both oleic acid and polysorbate 80 had significant effect on drug permeation with respect to the control formulation. In particular films containing a mixture of oleic acid and polysorbate 80 provided the best enhancement activity for chlorpromazine. Moreover, a decrease in propylene glycol or chlorpromazine content or an increase of hydroxypropylmethylcellulose viscosity provided lower cumulative amounts of drug permeated.

CONCLUSIONS

The results obtained confirm that chlorpromazine permeation can be easily modulated by varying the composition of hydroxypropylmethylcellulose-based films. These formulations could serve as candidates for transdermal delivery of antipsychotic drugs.

Chitosan salts as nasal sustained delivery systems for peptidic drugs

The aim of this study was to describe a sustained drug release system based on chitosan salts for vancomycin hydrochloride delivery. Chitosan lactate, chitosan aspartate, chitosan glutamate and chitosan hydrochloride were prepared by spray-drying technique. Vancomycin hydrochloride was used as a model peptidic drug, the nasal sustained release of which should avoid first-pass metabolism in the liver. This in-vitro study evaluated the influence of chitosan salts on the release behaviour of vancomycin hydrochloride from the physical mixtures at pH 5.5 and 7.4. In-vitro release of vancomycin was retarded by chitosan salts and, in particular, chitosan hydrochloride provided the lowest release of vancomycin.

Pectin-based microspheres for colon-specific delivery of vancomycin

Objectives

The aim of this study was to describe a colon-specific delivery system based on pectin hydrogels formed by complexation with chitosan.

Methods

Hydrogels were prepared at different weight ratios (4: 1, 7: 1, 10: 1; pectin/chitosan), loaded with vancomycin hydrochloride (2: 1, 4: 1; polymer/drug weight ratio) and collected by spray-drying. The microspheres obtained were characterized in terms of morphology, swelling behaviour, mucoadhesive properties and drug loading efficiency. The influence of different pectin/chitosan hydrogels on the release behaviour of microspheres at pH 2.0, 5.5 and 7.4 were evaluated in vitro with and without pectinolytic enzyme.

Key findings

The results showed that water uptake was increased by raising the environmental pH (from 2.0 to 7.4) and the pectin/chitosan weight ratio, while drug availability was increased by raising the environmental pH (from 2.0 to 7.4) and decreased by raising the pectin/chitosan weight ratio. In the presence of pectinase, the glycoside bonds of pectin were degraded and a considerable amount of drug was released in a short time.

Conclusions

This study suggested that pectin/chitosan microspheres were able to limit the release of vancomycin under acidic conditions and release it under simulated colonic conditions, confirming their potential for a colon-specific drug delivery system.

A new physical-chemical process for the efficient production of cellulose fibers from Spanish broom (Spartium junceum L.)

A novel and efficient method for the extraction of cellulose fibers from Spanish broom (Spartium junceum L.) is presented. The method is based on the sequential combination between an initial chemical stage (alkaline digestion) and a subsequent physical-chemical stage, consisting of compression with hot air in an autoclave followed by rapid decompression (DiCoDe process, digestion-compression-decompression). The alkaline mother liquor deriving from the initial digestion step can be conveniently recycled after centrifugation followed by ultrafiltration. The process is characterized by the production of fibers with excellent physical-chemical properties, such as high mechanical resistance and high elasticity, and rapid production times. The fibers obtained after the DiCoDe process can be further softened and whitened by means of enzymatic digestion. Fibers were morphologically characterized by scanning electron microscopy (SEM), while their composition and physical-chemical properties were determined by conventional methods, including colorimetry, TAPPI protocols, IR spectroscopy, and X-ray diffractometry.

Pectin-based microspheres for colon-specific delivery of vancomycin

OBJECTIVES

The aim of this study was to describe a colon-specific delivery system based on pectin hydrogels formed by complexation with chitosan.

METHODS

Hydrogels were prepared at different weight ratios (4:1, 7:1, 10:1; pectin/chitosan), loaded with vancomycin hydrochloride (2:1, 4:1; polymer/drug weight ratio) and collected by spray-drying. The microspheres obtained were characterized in terms of morphology, swelling behaviour, mucoadhesive properties and drug loading efficiency. The influence of different pectin/chitosan hydrogels on the release behaviour of microspheres at pH 2.0, 5.5 and 7.4 were evaluated in vitro with and without pectinolytic enzyme.

KEY FINDINGS

The results showed that water uptake was increased by raising the environmental pH (from 2.0 to 7.4) and the pectin/chitosan weight ratio, while drug availability was increased by raising the environmental pH (from 2.0 to 7.4) and decreased by raising the pectin/chitosan weight ratio. In the presence of pectinase, the glycoside bonds of pectin were degraded and a considerable amount of drug was released in a short time.

CONCLUSIONS

This study suggested that pectin/chitosan microspheres were able to limit the release of vancomycin under acidic conditions and release it under simulated colonic conditions, confirming their potential for a colon-specific drug delivery system.

Micelles Based on Polyvinyl Alcohol Substituted with Oleic Acid for Targeting of Lipophilic Drugs

Polymeric micelles based on polyvinyl alcohol substituted with oleic acid were used as vehicles for progesterone and folic acid. The ability of this amphiphilic polymer to entrap lipophilic drugs and to generate stable micelles in aqueous neutral medium makes it a good candidate for drug delivery. The release of the loaded drugs in acidic environments represents another important property of these systems. Size of micelles, their stability, and their drug-loading capacity were evaluated, as well as the in vitro controlled-release profiles at pH 7.4 and 5.5.

Bovine serum albumin nanospheres carrying progesterone inclusion complexes

Bovine serum albumin nanospheres carrying cyclodextrin complexes for the delivery of progesterone were produced. Inclusion complexes composed of progesterone and hydroxypropyl-beta-cyclodextrin or dimethyl-beta-cyclodextrin were prepared by spray-drying or freeze-drying methods. Prog alone and its inclusion complexes were incorporated into bovine serum albumin nanospheres using a coacervation method and cross-linking with heating. The nanosphere suspensions were essicated by spray-drying or freeze-drying. The inclusion complexes and the nanospheres were characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). Phase-solubility diagrams and stability constants were determined in distilled water at different temperatures (10, 25, and 37 degrees C). Size of nanospheres, their drug loading capacity and swelling ability were evaluated, as well as the in vitro controlled release profiles at pH 5.5 and 7.4.

Chitosan and poly(methyl vinyl ether-co-maleic anhydride) microparticles as nasal sustained delivery systems

An original dosage form for nasal delivery based on the encapsulation of hydrophilic drug in chitosan-poly(methyl vinyl ether-co-maleic anhydride) (CH-PVM/MA) microparticles prepared by spray-drying technique was developed. Microparticles were characterized in terms of morphology, size, swelling properties, encapsulation efficiency and drug release. The physical state of the drug and the polymer was determined by scanning electron microscopy (SEM) and infrared spectroscopy (IR). Propranolol hydrochloride (PH) was a beta-blocker, used for the treatment of hypertension and was chosen as a model of hydrophilic drug. SEM studies showed spherical particles with smooth surfaces for chitosan hydrochloride (CH-HCl), whereas rather gross surface defects resulted from the incorporation of poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA). In vitro release studies revealed a sustained release of propranolol HCl from microparticles and in particular chitosan hydrochloride provided the lowest release of drug.

Crosslinked poly(methyl vinyl ether-co-maleic anhydride) as topical vehicles for hydrophilic and lipophilic drugs

Poly(methyl vinyl ether-co-maleic anhydride) crosslinked with ethylene glycol (GZ-ET), 1,4-butanediol (GZ-BUT), 1,6-exandiol (GZ-EX), 1,8-octanediol (GZ-OCT), 1,10-decanediol (GZ-DEC) or 1,12-dodecanediol (GZ-DOD) was prepared and employed as a supporting material for aqueous topical gels containing pyridoxine hydrochloride (PYCL) chosen as a hydrophilic model molecule or for O/A emulsion containing beta-carotene chosen as a hydrophobic model molecule. We analyzed the effect of the nature of the crosslinker on the permeation of hydrophilic and lipophilic vitamins through porcine skin by in vitro permeation studies. The vehicles formed by crosslinked poly(methyl vinyl ether-co-maleic anhydride) showed enhanced vitamins permeation with respect to the same vehicles formed by noncrosslinked poly(methyl vinyl ether-co-maleic anhydride) (GZ). The decrease in the crosslinker acyl chain length provides vehicles accelerating the drug permeability through the skin.

Polymeric nanoparticles composed of fatty acids and polyvinylalcohol for topical application of sunscreens

Benzophenone-3 (BZP) or oxybenzone is widely used in many cosmetic formulations, such as sunscreen lotions or emulsions, shampoos and hair sprays. The nature of the vehicle used can enhance or block the percutaneous absorption of UV filter. In this work, we hydrophobically modified polyvinylalcohol 10 000 (PVA) with fatty acids (FAs) to obtain PVA-FA derivatives for the preparation of lipophilic polymeric nanoparticles able to prevent BZP movement towards the skin. Synthesized PVA-FA derivatives were confirmed by H1 NMR. Nanoparticles loaded with BZP were prepared using a solvent extraction method. The particle size was monitored by means of dynamic light scattering measurements. In-vitro skin permeation studies were performed.

Substituted polyvinylalcohol as a drug carrier for β-carotene

The objective of this study was to evaluate the in vitro characteristics of polyvinylalcohol 10,000 (PVA10,000) and polyvinylalcohol 15,000 (PVA15,000) substituted with different alkyl chains (Iodododecane, Bromotetradecane) and crosslinked with Bis-chloro-ethoxy-ethane as an injectable drug carrier. beta-carotene was used as a lipophilic model drug. Physical mixtures of the drug and the spray-dried polymers were prepared and the release of the drug from the mixtures was evaluated in vitro at pH 7.4. The results indicated that the substituted PVA10,000 and PVA15,000 provided faster drug release with respect to the pure drug at pH 7.4. In particular, among the substituted PVA used, PVA10,000 and PVA15,000 substituted with Iodododecane and crosslinked with Bis-chloro-ethoxy-ethane improved drug release.

Analytical methods for the determination of folic acid in a polymeric micellar carrier

Amphiphilic copolymers have been the object of growing scientific interest due to their ability to form polymeric micelles in aqueous environments entrapping lipophilic drugs in their inner core. In this study, polyvinylalcohol substituted with oleic acid was employed as an amphiphilic micellar carrier for folic acid (FA), a model drug similar for its chemical-physical characteristics to methotrexate. In order to investigate the stability of the polymeric micelles, the drug incorporation and the kinetic aspects of drug release from these systems, selective analytical methods are required. The development of three analytical methods suitable for selectively identifying and reliably determining FA contained in the micelles and in the delivery systems is reported. UV derivative (first and second order) spectrophotometry was first applied to the aqueous solution of the FA containing micelles obtained at pH 9.0 and provided a characteristic spectral profiling with sharp peaks, related to the analyte, whose amplitude was used for quantitative application. A second approach involved a solid phase extraction (strong anion exchanger), which provided an effective clean up of the FA micelles solution, allowing accurate analysis to be performed also by a conventional spectrophotometric method. A RP-HPLC method, selectively supplying the FA separation from the micelles' components, was then used as a reference method to determine the accuracy of the spectrophotometric methods. These methods were applied to various micelle composition and to the delivery system study.

Controlled release of vancomycin from freeze-dried chitosan salts coated with different fatty acids by spray-drying

The aim of this study was to describe a controlled drug release system based on chitosan salts for vancomycin hydrochloride delivery. Chitosan aspartate (CH-Asp), chitosan glutamate (CH-Glu) and chitosan hydrochloride (CH-HCl) were prepared by freeze-drying and coated with stearic, palmitic, myristic and lauric acids by spray-drying technique. Vancomycin hydrochloride was used as a peptidic model drug whose sustained release should minimize its inactivation in the upper part of the gastrointestinal tract. This study evaluated, in vitro, the influence of chitosan salts on the release behaviour of vancomycin hydrochloride from the freeze-dried and spray-dried systems at pH 2.0 and 7.4.

Effect of chitosan on progesterone release from hydroxypropyl-beta-cyclodextrin complexes

An inclusion complex composed of progesterone (Prog) and hydroxypropyl-beta-cyclodextrin (HPbetaCD) was prepared by the spray-drying and freeze-drying methods. Prog alone and its inclusion complex with HPbetaCD were incorporated into chitosan by spray-drying and freeze-drying. The inclusion complex was characterized by IR and DSC. The inclusion complex was investigated in solution by phase solubility diagrams and stability constant was determined at pH 7.4 and at different temperatures (10, 25 and 37 degrees C) to obtain the thermodynamic parameters of inclusion. The results indicate that the Prog-HPbetaCD inclusion complex is more water soluble than Prog alone. Release data from all samples showed significant improvement of the dissolution rate of Prog and a controlled release is obtained in the presence of chitosan.