Researching the level of agreement among experts on terms used to describe wounds: An international study

Establishing a common language that allows univocal and objective communication in describing wounds and their healing is of utmost importance in defining the diagnostic hypothesis and proper wound management. To measure the level of agreement on the description of wounds, an international study was performed among experts of different professional backgrounds on several common terms used to describe ulcerative lesions. A panel of 27 wound care experts anonymously completed a multiple-choice questionnaire on 100 images of 50 ulcerative lesions. The participants were asked to describe each image using a set of pre-defined terms. An expert data analyst interpreted the questionnaires to map the level of agreement on the used terminology. Our findings show a very low level of agreement among experts in using the proposed terminology to describe the wound bed, the wound edge, and the surrounding skin conditions. Efforts should be planned to find a consensus on the correct use of terminology for wound description. To this aim, partnership, consensus, and agreement with educators in medicine and nursing are necessary.

Technical Evaluation of a New Medical Device Based on Rigenase in the Treatment of Chronic Skin Lesions

Chronic wound is characterized by slow healing time, persistence, and abnormal healing progress. Therefore, serious complications can lead at worst to the tissue removal. In this scenario, there is an urgent need for an ideal dressing capable of high absorbency, moisture retention and antimicrobial properties. Herein we investigate the technical properties of a novel advanced non-woven triple layer gauze imbibed with a cream containing Rigenase, an aqueous extract of Triticum vulgare used for the treatment of skin injuries. To assess the applicability of this system we analyzed the dressing properties by wettability, dehydration, absorbency, Water Vapor Transmission Rate (WVTR), lateral diffusion and microbiological tests. The dressing showed an exudate absorption up to 50%. It created a most environment allowing a proper gaseous exchange as attested by the WVTR and a controlled dehydration rate. The results candidate the new dressing as an ideal medical device for the treatment of the chronic wound repairing process. It acts as a mechanical barrier providing a good management of the bacterial load and proper absorption of abundant wound exudate. Finally, its vertical transmission minimizes horizontal diffusion and side effects on perilesional skin as maceration and bacterial infection.

Design, Evaluation and Comparison of Nanostructured Lipid Carriers and Chitosan Nanoparticles as Carriers of Poorly Soluble Drugs to Develop Oral Liquid Formulations Suitable for Pediatric Use

There is a serious need of pediatric drug formulations, whose lack causes the frequent use of extemporaneous preparations obtained from adult dosage forms, with consequent safety and quality risks. Oral solutions are the best choice for pediatric patients, due to administration ease and dosage-adaptability, but their development is challenging, particularly for poorly soluble drugs. In this work, chitosan nanoparticles (CSNPs) and nanostructured lipid carriers (NLCs) were developed and evaluated as potential nanocarriers for preparing oral pediatric solutions of cefixime (poorly soluble model drug). The selected CSNPs and NLCs showed a size around 390 nm, Zeta-potential > 30 mV, and comparable entrapment efficiency (31-36%), but CSNPs had higher loading efficiency (5.2 vs. 1.4%). CSNPs maintained an almost unchanged size, homogeneity, and Zeta-potential during storage, while NLCs exhibited a marked progressive Zeta-potential decrease. Drug release from CSNPs formulations (differently from NLCs) was poorly affected by gastric pH variations, and gave rise to a more reproducible and controlled profile. This was related to their behavior in simulated gastric conditions, where CSNPs were stable, while NLCs suffered a rapid size increase, up to micrometric dimensions. Cytotoxicity studies confirmed CSNPs as the best nanocarrier, proving their complete biocompatibility, while NLCs formulations needed 1:1 dilution to obtain acceptable cell viability values.

4-Heteroaryl Substituted Amino-3,5-Dicyanopyridines as New Adenosine Receptor Ligands: Novel Insights on Structure-Activity Relationships and Perspectives

A new set of amino-3,5-dicyanopyridines was synthesized and biologically evaluated at the adenosine receptors (ARs). This chemical class is particularly versatile, as small structural modifications can influence not only affinity and selectivity, but also the pharmacological profile. Thus, in order to deepen the structure–activity relationships (SARs) of this series, different substituents were evaluated at the diverse positions on the dicyanopyridine scaffold. In general, the herein reported compounds show nanomolar binding affinity and interact better with both the human (h) A₁ and A_2A ARs than with the other subtypes. Docking studies at hAR structure were performed to rationalize the observed affinity data. Of interest are compounds 1 and 5, which can be considered as pan ligands as binding all the ARs with comparable nanomolar binding affinity (A₁AR: 1, K_i = 9.63 nM; 5, K_i = 2.50 nM; A_2AAR: 1, K_i = 21 nM; 5, Ki = 24 nM; A₃AR: 1, Ki = 52 nM; 5, Ki = 25 nM; A_2BAR: 1, EC₅₀ = 1.4 nM; 5, EC₅₀ = 1.12 nM). Moreover, these compounds showed a partial agonist profile at all the ARs. This combined AR partial agonist activity could lead us to hypothesize a potential effect in the repair process of damaged tissue that would be beneficial in both wound healing and remodeling.

Combined Use of Cyclodextrins and Amino Acids for the Development of Cefixime Oral Solutions for Pediatric Use

Cefixime (CEF) is a cephalosporin included in the WHO Model List of Essential Medicines for Children. Liquid formulations are considered the best choice for pediatric use, due to their great ease of administration and dose-adaptability. Owing to its very low aqueous solubility and poor stability, CEF is only available as a powder for oral suspensions, which can lead to reduced compliance by children, due to its unpleasant texture and taste, and possible non-homogeneous dosage. The aim of this work was to develop an oral pediatric CEF solution endowed with good palatability, exploiting the solubilizing and taste-masking properties of cyclodextrins (CDs), joined to the use of amino acids as an auxiliary third component. Solubility studies indicated sulfobutylether-β-cyclodextrin (SBEβCD) and Histidine (His) as the most effective CD and amino acid, respectively, even though no synergistic effect on drug solubility improvement by their combined use was found. Molecular Dynamic and ¹H-NMR studies provided insight into the interactions of binary CEF:His and ternary CEF:His:SBEβCD systems used to prepare CEF solutions, which resulted stable and maintained unchanged antimicrobial activity during the two-weeks-use in therapy. The ternary solution was superior in terms of more tolerable pH (5.6 vs. 4.7) and better palatability, being resulted completely odorless by a panel test.

Development of a Cyclodextrin-Based Mucoadhesive-Thermosensitive In Situ Gel for Clonazepam Intranasal Delivery

A thermosensitive, mucoadhesive in-situ gel for clonazepam (CLZ) intranasal delivery was developed, which aimed to achieve prolonged in-situ residence and controlled drug release, overcoming problems associated with its oral or parenteral administration. Poloxamer was selected as a thermosensitive polymer and chitosan glutamate and sodium hyaluronate as mucoadhesive and permeation enhancer. Moreover, randomly methylated β-Cyclodextrin (RAMEB) was used to improve the low drug solubility. A screening DoE was applied for a systematic examination of the effect of varying the formulation components proportions on gelation temperature, gelation time and pH. Drug-loaded gels at different clonazepam-RAMEB concentrations were then prepared and characterized for gelation temperature, gelation time, gel strength, mucoadhesive strength, mucoadhesion time, and drug release properties. All formulations showed suitable gelation temperature (29-30.5 °C) and time (50-65 s), but the one with the highest drug-RAMEB concentration showed the best mucoadhesive strength, longest mucoadhesion time (6 h), and greatest release rate. Therefore, it was selected for cytotoxicity and permeation studies through Caco-2 cells, compared with an analogous formulation without RAMEB and a drug solution. Both gels were significantly more effective than the solution. However, RAMEB was essential not only to promote drug release, but also to reduce drug cytotoxicity and further improve its permeability.

Improvement of Butamben Anesthetic Efficacy by the Development of Deformable Liposomes Bearing the Drug as Cyclodextrin Complex

This work was aimed at enhancing butamben (BTB) anesthetic efficacy by the "drug-in cyclodextrin (CD)-in deformable liposomes" strategy. In the study, phase-solubility studies with natural (α-, β-, γ-) and derivative (hydroxypropyl-α-and β-, sulfobutylether-β, methyl-β) CDs evidenced the highest BTB affinity for βCD and its derivatives and indicated methyl-βCD (RAMEB) as the best carrier. Drug-RAMEB complexes were prepared by different techniques and were characterized for solid-state and dissolution properties. The best BTB-RAMEB product was chosen for entrapment in the aqueous core of deformable liposomes containing stearylamine, either alone or with sodium cholate, as edge activators. Double-loaded (DL) liposomes, bearing the lipophilic drug (0.5% w/v) in the bilayer and its hydrophilic RAMEB complex (0.5% w/v) in the aqueous core, were compared to single-loaded (SL) liposomes bearing 1% w/v plain drug in the bilayer. All vesicles showed homogeneous dimensions (i.e., below 300 nm), high deformability, and excellent entrapment efficiency. DL-liposomes were more effective than SL ones in limiting drug leakage (<5% vs. >10% after a 3 months storage at 4 °C). In vivo experiments in rabbits proved that all liposomal formulations significantly (p < 0.05) increased the intensity and duration of drug anesthetic action compared to its hydroalcoholic solution; however, DL liposomes were significantly (p < 0.05) more effective than SL ones in prolonging BTB anesthetic effect, owing to the presence of the drug-RAMEB complex in the vesicle core, acting as a reservoir. DL liposomes containing both edge activators were found to have the best performance.

Characterization and evaluation of the performance of different calcium and magnesium salts as excipients for direct compression

The performance of a series of inorganic salts as direct compression excipients was systematically evaluated. The physical-chemical and technological properties of the different salts were investigated in terms of crystalline/amorphous state, morphology, granulometry, apparent/tapped density, specific surface area, flowability, compressibility, dilution and distribution coefficients. To achieve a comprehensive evaluation of the performance of the different salts, the data obtained by the various analyses were normalized, giving a score to each excipient for each evaluated property/parameter. Statistical elaboration (JMP software) of the full dataset provided a final ranking of the powders based on their effectiveness as direct compression excipients. The salt emerged as the best was used to prepare direct-compression tablets, using cefixime as model drug, by modifying the composition of marketed tablets. A significant improvement of the mechanical properties of the new tablets was observed, compared to the marketed ones, with a crushing strength increase of over 30%, without variations of the drug dissolution profile. Even though the resulted ranking cannot have an absolute value, being the behavior of the different excipients susceptible to the kind of drug and other formulation excipients, the proposed approach can provide a useful model for a systematic evaluation and comparison of potentially similar excipients.

Design, characterization and in vivo evaluation of nanostructured lipid carriers (NLC) as a new drug delivery system for hydrochlorothiazide oral administration in pediatric therapy

The hydrochlorothiazide (HCT) low solubility and permeability give rise to limited and variable bioavailability; its low stability makes it difficult to develop stable aqueous liquid formulations; its low dose makes the achievement of a homogeneous drug distribution very difficult. Thus, the aim of this study was to investigate the effectiveness of a strategy based on the development of nanostructured lipid carriers (NLC) as an innovative oral pediatric formulation of HCT with improved therapeutic efficacy. The performance of various synthetic and natural liquid lipids was examined and two different preparation methods were employed, i.e. homogenization-ultrasonication (HU) and microemulsion (ME), in order to evaluate their influence on the NLC properties in terms of size, polydispersity index, ζ-potential, entrapment efficiency, gastric stability, and drug release properties. Precirol®ATO5 was used as solid lipid and Tween^®80 and Pluronic^®F68 as surfactants, formerly selected in a previous study focused on the development of HCT-solid lipid nanoparticles (SLNs). The presence of Pluronic^®F68 did not allow ME formation. On the contrary, using Tween^®80, the ME method enabled a higher entrapment efficiency than the HU. Regardless of the preparation method, NLCs exhibited great entrapment efficiency values clearly higher than previous SLNs. Moreover, NLC-ME formulations provided a prolonged release, which lasted for 6 h. In particular, NLC-ME containing Tween^®20 as Co-Surfactant showed the best performances, giving rise to a complete drug release, never achieved with previous SLN formulations, despite their successful results. In vivo studies on rats confirmed these results, displaying their best diuretic profile. Moreover, all HCT-loaded NLC formulations showed higher stability than the corresponding SLNs.

Comparison of liposomal and NLC (nanostructured lipid carrier) formulations for improving the transdermal delivery of oxaprozin: Effect of cyclodextrin complexation

The combined strategy of drug-cyclodextrin (CD) complexation and complex loading into nanocarriers (deformable liposomes or nanostructured lipid carriers (NLC)), was exploited to develop effective topical formulations for oxaprozin transdermal administration. Oxaprozin was loaded as ternary complex with randomly-methylated-ßCD and arginine, selected as the best system in improving drug solubility. The colloidal dispersions, characterized for particle size, zeta-potential and entrapment efficiency, were investigated for drug permeation properties in comparison with a plain drug aqueous suspension, a ternary complex aqueous solution and a plain drug liposomal or NLC dispersion. Experiments with artificial membranes showed that the joined use of CD and both liposomes or NLC enabled a marked increase of the drug permeability (16 and 8 times, respectively) and was significantly more effective (P<0.05) than the drug as ternary complex (3.2 times increase), and the corresponding liposomal or NLC dispersion of plain drug (5.6 and 4.3 times increase, respectively). Experiments with excised human skin confirmed the significantly (P<0.05) better performance of deformable liposomes than NLC in promoting drug permeation; moreover, they evidenced a more marked permeability increase compared to the plain drug (24 and 12 fold, respectively), attributed to a possible enhancer effect of the nanocarriers components and/or of the randomly-methylated-ßCD.

Analysis of physicochemical properties of ternary systems of oxaprozin with randomly methylated-ß-cyclodextrin and l-arginine aimed to improve the drug solubility

The influence of l-arginine on the complexing and solubilizing power of randomly-methylated-β-cyclodextrin (RameβCD) towards oxaprozin, a very poorly soluble anti-inflammatory drug, was examined. The interactions between the components were investigated both in solution, by phase-solubility analysis, and in the solid state, by differential scanning calorimetry, FTIR and X-ray powder diffractometry. The morphology of the solid products was examined by Scanning Electron Microscopy. Results of phase-solubility studies indicated that addition of arginine enhanced the RameβCD complexing and solubilizing power of about 3.0 and 4.5 times, respectively, in comparison with the binary complex (both at pH≈6.8). The effect of arginine was not simply additive, but synergistic, being the ternary system solubility higher than the sum of those of the respective drug-CD and drug-arginine binary systems. Solid equimolar ternary systems were prepared by physical mixing, co-grinding, coevaporation and kneading techniques, to explore the effect of the preparation method on the physicochemical properties of the final products. The ternary co-ground product exhibited a dramatic increase in both drug dissolution efficiency and percent dissolved at 60min, whose values (83.6 and 97.1, respectively) were about 3 times higher than the sum of those given by the respective drug-CD and drug-aminoacid binary systems. Therefore, the ternary co-ground system with arginine and RameβCD appears as a very valuable product for the development of new more effective delivery systems of oxaprozin, with improved safety and bioavailability.

Development of cyclodextrin hydrogels for vaginal delivery of dehydroepiandrosterone

Objective

To develop a new vaginal delivery system for a sustained release of dehydroepiandrosterone (DHEA) in the treatment of postmenopausal symptoms, aimed to overcome the problems of poor bioavailability of the drug related to its very low water solubility.

Methods

Cyclodextrin (CD)-containing hydrogels were developed, combining in a single device the hydrogel controlled release and mucoadhesion properties, and the CD solubilizing power towards DHEA. The effect of different CDs, alone or in mixtures, on the hydrogel technological and mucoadhesion characteristics was investigated. The best formulations were loaded with DHEA and characterized for loading efficiency and release properties.

Key findings

Hydrogels based on HPβCD/γCD (15/10%w/w) or HPβCD/HP γCD (30/20%w/w) combinations proved to be the most effective, giving ovules with the desired mechanical and mucoadhesive properties. Both formulations showed high drug loading efficiency, due to the solubilizing effect of CDs, and provided a sustained in-situ release, with a rate suitably tunable by varying the drug loaded amount and/or the CD combination.

Conclusions

The proposed formulative strategy allowed to develop an intravaginal device with right consistency and elasticity, easy to apply, able to be retained in situ over 8 h, and to provide an effective DHEA loading and a tunable release rate.

Combined use of bile acids and aminoacids to improve permeation properties of acyclovir

The aim of this work was to develop a topical formulation with improved permeation properties of acyclovir. Ursodeoxycholic (UDC) and dehydrocholic (DHC) acids were tested as potential enhancers, alone or in combination with different aminoacids. Equimolar binary and ternary systems of acyclovir with cholic acids and basic, hydrophilic or hydrophobic aminoacids were prepared by co-grinding in a high vibrational micromill. Differential scanning calorimetry (DSC) was used to characterize the solid state of these systems, while their permeation properties were evaluated in vitro through a lipophilic artificial membrane. UDC was more than 2 times more effective than DHC in improving drug AUC and permeation rate. As for the ternary systems drug-UDC-aminoacid, only the combined use of l-lysine with UDC acid produced an evident synergistic effect in enhancing drug permeation properties, enabling an almost 3 and 8 times AUC increase compared to the binary UDC system or the pure drug, respectively. The best systems were selected for the development of topical cream formulations, adequately characterized and tested for in vitro drug permeation properties and stability on storage. The better performance revealed by acyclovir-UDC-l-lysine was mainly attributed to the formation of a more permeable activated system induced by the multicomponent co-grinding process.

Development of liposomal and microemulsion formulations for transdermal delivery of clonazepam: effect of randomly methylated β-cyclodextrin

Transdermal administration of clonazepam, a poorly water-soluble benzodiazepine, is an interesting strategy for overcoming the drawbacks of its oral administration. With this aim, two nano-carrier formulations, based on ultra-deformable liposomes and microemulsions, have been developed to favour clonazepam transdermal delivery. Considering the solubilizing power of methyl-βcyclodextrin (Me-βCD) toward clonazepam and its potential positive influence on transdermal drug delivery, the effect of its addition to these formulations was investigated. Artificial lipophilic membranes simulating the skin allowed a rapid evaluation of the drug permeation properties from the systems, compared with those from an aqueous drug suspension, with or without Me-βCD. The best formulations were further characterized by permeation through excised rabbit ear skin. All the formulations increased drug permeability, ranging from 2-fold (liposomes without Me-βCD), up to over 4-fold (microemulsions containing Me-βCD). The different formulations allowed for pointing out different possible permeation enhancing mechanisms of Me-βCD: increase in drug solubility and thermodynamic activity in the vehicle, when added to the drug aqueous suspension; interactions with the vesicle bilayer, in case of liposomal formulations; interactions with the skin membrane lipids, as evidenced in experiments with excised rabbit ear for microemulsions containing Me-βCD, that were then selected for further in vivo studies.

Physico-chemical characterization in solution and in the solid state of clonazepam complexes with native and chemically-modified cyclodextrins

Clonazepam (CLZ) is a benzodiazepine derivative, whose bioavailability, limited by its very poor water-solubility, could be improved by cyclodextrin complexation. However, the choice of the most proper cyclodextrin to use to fully exploit its potential favourable effects on the drug, is a critical step. Therefore, in the present work, the performance of some amorphous cyclodextrin (CD) derivatives in terms of complexing, solubilizing and amorphizing power towards CLZ was carefully evaluated and compared with that of natural CDs. The role of CD cavity size, amorphous or crystalline nature, and presence and type of substituents on its ability in producing effective interactions with the drug has been investigated. Equimolar CLZ-CD solid systems were obtained by blending, kneading, co-grinding and coevaporation. Drug-CD interactions were investigated by phase-solubility analysis, differential scanning calorimetry and X-ray powder diffractometry. Among the natural CDs, β-CD showed the highest complexing ability, suggesting that its cavity size is the most proper to host the drug molecule. The presence of substituents had a negative effect on the performance of α-CD and γ-CD, while it improved the complexing and solubilizing power of β-CD, and the methylated derivative was more effective than the hydroxypropylated one. Solid-state studies revealed that amorphous CDs had highest amorphizing power than the corresponding natural crystalline ones, and methylated-β-CD (Me-β-CD) was the best carrier. As for the preparation method, co-grinding was the most powerful in promoting the formation of efficacious drug-CD solid-state interactions. Dissolution rate studies confirmed Me-β-CD as the best partner for CLZ and co-grinding as the best method for maximizing the drug dissolution properties. Therefore, co-ground products with Me-β-CD could be selected as the best system for future development of CLZ formulations with improved therapeutic efficacy.

Development and Characterization of Niosomal Formulations of Doxorubicin Aimed at Brain Targeting

ABSTRACT - Purpose. The aim of the present work was the development and characterization of a niosomal formulation functionalized with the glucose-derivative N-palmitoylglucosamine (NPG) to obtain a potential brain targeted delivery system for the anticancer agent doxorubicin. Methods. Five different methods have been examined for vesicle preparation. Light scattering and transmission electron microscopy were used for vesicle characterization, in terms of mean size, homogeneity and Zeta potential, and selection of the best composition and preparation conditions for developing NPG-functionalized niosomes. Drug entrapment efficiency was determined after separation of loaded from unloaded drug by size exclusion chromatography or dialysis. Preliminary in vivo studies were performed on rats, injected i.v. with 12 mg/kg of doxorubicin as commercial solution (Ebewe, 2mg/mL) or NPG-niosomal formulation. Drug amounts in the blood and in the major organs of the animals, sacrificed 60 min post injection, were determined by HPLC. Results. The selected formulation consisted in Span:cholesterol:Solulan:NPG (50:40:10:10 mol ratio) vesicles obtained by thin-layer evaporation, leading to homogeneous vesicles of less than 200 nm diameter. This formulation was used for preparation of NPG-niosomes loaded with doxorubicin (mean size 161±4 nm, encapsulation efficacy 57.8±1.8%). No significant changes (P>0.05) in vesicle dimensions, Zeta potential or entrapment efficiency were observed after six months storage at room temperature, indicative of good stability. I.v. administration to rats of the NPG-niosomal formulation allowed for reducing drug accumulation in the heart and keeping it longer in the blood circulation with respect to the commercial formulation. Moreover, a doxorubicin brain concentration of 2.9±0.4 µg/g was achieved after 60 min, while the commercial solution yielded undetectable drug brain concentrations (

Development of a new delivery system consisting in "drug--in cyclodextrin--in nanostructured lipid carriers" for ketoprofen topical delivery

A new delivery system based on drug cyclodextrin (Cd) complexation and loading into nanostructured lipid carriers (NLC) has been developed to improve ketoprofen therapeutic efficacy. The proposed strategy exploits both the solubilizing and stabilizing properties of Cds and the prolonged release, high tolerability and percutaneous absorption enhancer properties of NLC. Two different polymeric Cds, i.e. β-Cd-epichlorohydrin polymer (EPI-βCd) and carboxymethylathed-β-Cd-epichlorohydrin polymer (EPI-CMβCd) were tested and two different techniques to obtain solid ketoprofen-polymeric Cd complexes (i.e. co-grinding and co-lyophilization) were compared, to investigate the influence of the preparation method on the physicochemical properties of the end product. EPI-βCd was more effective than EPI-CMβCd in enhancing the solubility and dissolution properties of ketoprofen. Co-grinding in dry conditions was the best preparation technique of solid drug-Cd systems, allowing obtainment of homogeneous amorphous particles of nanometric range. NLC consisting in a mixture of Compritol® 888 ATO (glyceryl behenate) and Labrafac Lipophile were obtained by ultrasonication. Both empty and loaded NLC were suitably characterized for particle size, pH, entrapment efficiency and drug release behavior. The best (drug-Cd)-loaded NLC system, formulated into a xanthan hydrogel, exhibited drug permeation properties clearly better than those of the plain drug suspension or the plain drug-loaded NLC, in virtue of the simultaneous exploitation of the solubilizing effect of cyclodextrin and the penetration enhancer properties of NLC.

Improvement of oxaprozin solubility and permeability by the combined use of cyclodextrin, chitosan, and bile components

The effect of the combined use of randomly methylated β-cyclodextrin (RAMEB), chitosan (CS), and bile components (dehydrocholic (DHCA) or ursodeoxycholic (UDCA) acids and their sodium salts) on solubility and permeability through Caco-2 cells of oxaprozin (a very poorly water-soluble non-steroidal anti-inflammatory drug) has been investigated. Addition of CS, bile acids, and their sodium salts increased the RAMEB solubilizing power of 4, 2, and 5 times, respectively. Drug-RAMEB-CS co-ground systems showed very higher dissolution rate than corresponding drug-RAMEB systems. Addition of bile components further improved drug dissolution rate. The CS presence enabled a significant increase in drug permeability through Caco-2 cells with respect to drug-RAMEB systems. Moreover, CS and NaDHC showed a synergistic enhancer effect, enabling a 1.4-fold permeability increase in comparison with systems without bile salt. However, unexpectedly, no significant differences were found between physical mixtures and co-ground products, indicating that drug permeation improvement was due to the intrinsic enhancer effect of the carriers and not to drug-carrier interactions brought about by co-grinding, as instead found in dissolution rate studies. The combined use of RAMEB, CS, and NaDHC could be exploited to develop effective oral dosage forms of oxaprozin, with increased drug solubility and permeability, and then improved bioavailability.

Development of mucoadhesive films for buccal administration of flufenamic acid: Effect of cyclodextrin complexation

A new mucoadhesive film for topical administration in the oral cavity of flufenamic acid, a poorly soluble anti-inflammatory drug, has been developed, using complexation with hydroxypropyl-beta-cyclodextrin (HPbetaCD) to improve drug dissolution and release rate. Buccal films were prepared utilising chitosan as mucoadhesive polymer, KollicoatIR as film-forming polymer and glycerol as plasticiser. Different combinations of these components were used and the obtained films were characterised for weight, thickness, swelling, mucoadhesive and mechanical properties. The film containing chitosan 2%, glycerol 7.5% and KollicoatIR 1% showed the best properties for the development of the film formulation. The selected film was loaded with the plain drug and its colyophilised and coground products with HPbetaCD, and in vitro release studies in simulated saliva were performed. The improved drug dissolution properties, obtained by complexation with HPbetaCD, were critical to achieve complete release from film formulation during 4-5 h. On the contrary, film loaded with the plain drug showed incomplete release, not exceeding 70% release after 5 h. The developed film formulation containing the drug as complex with HPbetaCD can assure a prolonged drug release directly at the inflammation site and can be proposed as a new therapeutic tool in the treatment of oral mucosa inflammations.

Liposomal formulations of prilocaine: effect of complexation with hydroxypropyl-ß-cyclodextrin on drug anesthetic efficacy

A combined strategy, based on cyclodextrin complexation and loading in liposomes, has been investigated to develop a new delivery system with improved therapeutic activity of the local anesthetic, prilocaine (PRL). In order to evaluate the actual effectiveness and advantages of this approach compared to the traditional drug-in-liposome one, four different liposomal formulations were prepared: (1) liposomes loaded with PRL base as complex with hydroxypropyl-β-cyclodextrin (HP CD) in the aqueous phase; (2) liposomes loaded with PRL hydrochloride in the aqueous phase; (3) liposomes loaded with PRL base in the lipophilic phase; and (4) "double-loaded" liposomes, containing free PRL base in the membrane bilayer and its HP CD complex in the aqueous compartment. All batches were characterized for particle size, charge, deformability, and entrapment efficiency from using, respectively, light scattering, extrusion, and dialysis techniques, while the anesthetic effect was evaluated in vivo on Guinea pigs, according to the test of dorsal muscle contraction. All drug liposomal dispersions showed enhanced analgesic duration with respect to the corresponding aqueous solutions, but significant differences were observed between the different formulations. In particular, cyclodextrin complexation not only allowed an efficient encapsulation of PRL base in the aqueous vesicle core, but also increased the anesthetic effect duration and reduced the initial lag time, in comparison with the corresponding formulations containing, respectively, free PRL in the lipophilic phase or PRL hydrochloride in the aqueous vesicle core. The technique of double loading was the most effective, giving rise to the shortest onset time and longest duration of anesthetic effect.

Physical-chemical characterization of binary and ternary systems of ketoprofen with cyclodextrins and phospholipids

Binary and ternary interaction products of ketoprofen (an anti-inflammatory drug very poorly water soluble) with phospholipids (phosphatidylcholine (EPC3) and phosphatidylglycerol (EPG)) and cyclodextrins (beta-cyclodextrin and its methylated derivative (MebetaCd)), were prepared to evaluate their ability in improving drug dissolution properties. The different binary and ternary drug-carrier(s) systems were obtained by microwave irradiation, in order to investigate the effectiveness of such a newly proposed preparation technology in bringing about effective solid-state interactions among the components. The effect of different experimental conditions such as microwave irradiation power (500 and 750 W) and treatment time (5, 10 and 15 min) on the physicochemical properties of the products has been also assessed. All solid systems were characterized by differential scanning calorimetry (DSC) analysis, supported by X-ray powder diffractometry, and examined for dissolution properties. The study pointed out the better performance of ternary systems than the binary ones and allowed selection of the best drug-phospholipid-Cd combination and of the most effective preparation conditions. In particular drug-EPC3-MebetaCd ternary systems obtained by using the greatest microwave irradiation energy and the longest treatment time exhibited complete drug amorphization and allowed achievement after 60 min of almost 80% dissolved drug, with an increase in dissolution efficiency of 10.7 and 1.4 times in comparison with drug alone and the corresponding drug-Cd binary system, respectively. The synergistic effect between cyclodextrin and phospholipid in enhancing the drug dissolution properties has been attributed to the combination of the surfactant properties of phospholipids and the wetting and solubilizing power of cyclodextrins and/or the possible formation of a "multicomponent" complex.

Response surface methodology in the optimization of chitosan-Ca pectinate bead formulations

This study describes the application of a multi-varied experimental design methodology to the optimization of a bead formulation based on a mixed network of Ca pectinate and chitosan. The effect of varying the relative percent of the three components used for the bead production, i.e. pectin, chitosan and CaCl(2), has been systematically investigated with the aim of identifying their best levels to optimize drug encapsulation efficiency (considered as the experimental response to be maximized), as well as to highlight possible interactions among the components. The study was applied to two different drugs, i.e. prednisone and theophylline, selected, respectively, as model insoluble and relatively soluble drugs, in order to evaluate the influence of this parameter as well. Different bead batches were prepared according to Doehlert and D-optimal design and randomly evaluated for drug encapsulation efficiency. Analysis of response surface plots allowed identification of the best combination of the three bead components in order to maximize drug encapsulation efficiency. The most effective compositions were chitosan 3% (w/v), pectin 9% (w/v), CaCl(2) 4% (w/v) for the theophylline-loaded beads and chitosan 0.75% (w/v), pectin 6% (w/v), CaCl(2) 7.9% (w/v) for the prednisone-loaded ones. The good correspondence between calculated and experimental values indicated in both cases the validity of the generated statistical models for the prediction of microsphere encapsulation efficiency. The different results obtained for the two drugs indicated the importance of the greater or lesser drug lipophilicity in determining the optimal bead composition with the highest encapsulation efficiency.

Sustained-release matrix tablets of metformin hydrochloride in combination with triacetyl-beta-cyclodextrin

The low bioavailability and short half-life of metformin hydrochloride (MH) make the development of sustained-release forms desirable. However, drug absorption is limited to the upper gastrointestinal (GI) tract, thus requiring suitable delivery systems providing complete release during stomach-to-jejunum transit. This study was undertaken to develop a MH sustained-release formulation in compliance with these requirements. The strategy proposed is based on direct-compressed matrix tablets consisting of a combination of MH with the hydrophobic triacetyl-beta-cyclodextrin (TAbetaCD), dispersed in a polymeric material. Different polymers were tested as excipients, i.e. hydroxypropylmethylcellulose, xanthan gum, chitosan, ethylcellulose, Eudragit L100-55, and Precirol. Compatibility among the formulation components was assessed by DSC analysis. All the tablets were examined for drug release pattern in simulated gastric and jejunal fluids used in sequence to mimic the GI transit. Release studies demonstrated that blends of a hydrophobic swelling polymer (hydroxypropylmethylcellulose or chitosan) with a pH-dependent one (Eudragit L100-55) were more useful than single polymers in controlling drug release. Moreover, the main role played by the MH-TAbetaCD system preparation method (i.e. grinding or spray-drying) in determining the behaviour of the final formulation was evidenced. In fact, for a given matrix-tablet composition, different sustained-release effects were obtained by varying the relative amounts of MH-TAbetaCD as ground or spray-dried product. In particular, the 1:1 (w/w) blend of such systems, dispersed in a Eudragit-chitosan polymeric matrix, fully achieved the prefixed goal, giving about 30% released drug after 2h at gastric pH, and overcoming 90% released drug within the subsequent 3h in jejunal fluid.

Comparison of the effect of chitosan and polyvinylpyrrolidone on dissolution properties and analgesic effect of naproxen

The solubilizing and absorption enhancer properties towards naproxen of chitosan and polyvinylpyrrolidone (PVP) have been investigated. Solid binary systems prepared at various drug-polymer ratios by mixing, cogrinding or kneading, were characterized by differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy, and scanning electron microscopy, and tested for dissolution behavior. Both carriers improved drug dissolution and their performance depended on the drug-polymer ratio and the system preparation method. Chitosan was more effective than PVP, despite the greater amorphizing power of PVP as revealed by solid state analyses. The 3/7 (w/w) drug-carrier coground systems with chitosan and PVP were the best products enabling, respectively, an improvement of 4.8 and 3.6 times of drug dissolution efficiency. In vivo experiments in mice demonstrated that administration of 45 mg/kg of drug coground with PVP or chitosan resulted, respectively, in a 25 and 60% reduction of acetic acid-induced writhings in comparison to pure drug, which, instead, was statistically ineffective as compared to the control group. Moreover, the 3/7 (w/w) drug-chitosan coground product demonstrated an antiwrithing potency 2.4 times higher than the coground with PVP. Thus, the direct-compression properties and antiulcerogenic activity, combined with the demonstrated solubilizing power and analgesic effect enhancer ability towards the drug, make chitosan particularly suitable for developing a reduced-dose fast-release solid oral dosage form of naproxen.

Development and characterization of naproxen-chitosan solid systems with improved drug dissolution properties

The solubilizing and amorphizing properties toward naproxen (a poorly water-soluble antiinflammatory drug) of chitosan, an emerging pharmaceutical biopolymer, have been investigated. Solid binary systems at different drug/polymer ratios have been prepared according to different techniques (mixing, cogrinding, kneading, coevaporation) using chitosan at low (CS-L(w)) and medium (CS-M(w)) molecular weight, and tested for dissolution properties. Drug-carrier interactions were investigated in both the liquid and solid state, by phase solubility analysis, differential scanning calorimetry, X-ray powder diffractometry, FT-IR spectroscopy, and scanning electron microscopy. Drug dissolution parameters improved with increasing the polymer amount in the mixture, reaching the highest values at the 1:9 (w/w) drug/polymer ratio, and CS-L(w) was more efficacious than CS-M(w). Cogrinding was the most effective technique, showing the strongest amorphizing effect toward the drug and enabling an increase of more than ten times its relative dissolution rate. Coground mixtures at 3:7 (w/w) drug/polymer ratio were able to give directly compressed tablets which maintained unchanged the improved drug dissolution properties. Enhancer dissolution properties combined with its direct compression feasibility and antiulcerogenic action make CS-L(w) an optimal carrier for developing fast-release oral solid dosage forms of naproxen.