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A novel drug delivery system (DDS) with sustained release properties was developed to allow ocular protein delivery. The DDS developed is aimed at overcoming stability issues during preparation such as denaturation of proteins caused by shear forces applied or due to elevated temperatures and air entrapment potentially causing oxidation of the molecule. The rod-shaped HPMC inserts were loaded with lysozyme and several HPMC types were studied and compared. An aqueous colloidal HPMC solution (hydrogel) was prepared and subsequently dried at 150°C to dehydrate the polymer solution. This partially dehydrated polymer cylinder was loaded with an aqueous glycerol/lysozyme solution at 2°C. A 2(4) full factorial design was set up to evaluate the effect of the different preparation parameters on water uptake and release properties. As a result, four out of sixteen formulations revealed homogenous distribution for lysozyme in both duplicates. The change in water uptake over time was dependent on the type of HPMC polymer used but not between the chosen HPMC percentages. After 240min, 50% of lysozyme loaded was released depending on the chosen formulation. Lysozyme molecules exhibit slower release from a K100M matrix compared to E10M inserts, albeit the overall effect is relatively limited.

A methodology was developed and optimised for the preparation of a new drug delivery system (DDS) with sustained release properties to allow ocular protein delivery and to limit destructive production steps during manufacturing. Elevated temperatures, shear forces and an oxidative environment should be avoided in order to prevent denaturation or oxidation of proteins. An aqueous HPMC solution was prepared using heat and casted into small semi-rod-shaped PVC blisters. The polymer solution was allowed to cool down and was partially dehydrated at room temperature. A drug solution containing glycerol, drug and water was subsequently added to rehydrate the partially dehydrated polymer matrix at a temperature of 2 degrees C. Several parameters of the production process were varied to determine their influence on the release kinetics from HPMC inserts from three different molecules of different molecular weight. This production method was further optimised in order to shorten the rehydration time from weeks to days, while eliminating heat and shear forces on the selected drug molecules sodium fluorescein, lysozyme and albumin. Slow release kinetics were achieved for sodium fluorescein and lysozyme as model drug molecules. The higher molecular weight of albumin prevented a good penetration into the insert during the rehydration process resulting in predominantly burst release. The biocompatibility of a viscous HPMC solution was evaluated on SV40-human corneal epithelial cells with PrestoBlue (R) and no cytotoxic effects were observed. (C) 2017 Elsevier B.V. All rights reserved.

Drug delivery systems present an opportunity to potentiate the therapeutic effect of antileishmanial drugs. Colloidal carriers are rapidly cleared by the phagocytic cells of the reticuloendothelial system (RES), rendering them ideal vehicles for passive targeting of antileishmanials. This paper describes the development of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) for the antileishmanial saponin β-aescin. NPs were prepared using the combined emulsification solvent evaporation/salting-out technique. Confocal microscopy was used to visualise the internalisation and intracellular trafficking of fluorescein- and nile red-labelled PLGA NPs in J774A.1 macrophages infected with GFP-transfected Leishmania donovani. The in vitro activity of aescin and aescin-loaded NPs on L. infantum was determined in the axenic model as well as in the ex vivo model. The developed PLGA NPs were monodispersed with Zave

Dry eye syndrome is a common disorder of the tear film caused by decreased tear production or increased evaporation. The objective of this study was to evaluate the potential effectiveness of Cyclosporine A (CsA) nanoparticles (NPs) for the treatment of inflammation of the eye surface. Topical CsA is currently the only and safe pharmacologic treatment of severe dry eye symptoms. The NPs were prepared using either poly-lactide-co-glycolide (PLGA) or a mixture of PLGA with Eudragit®RL or were coated with Carbopol®. The mean size of CsA loaded NPs was within the range from 148 to 219 nm, except for the Carbopol® coated NPs (393 nm). The drug entrapment efficiency was very high (from 83 to 95%) and production yield was found between 75 and 92% in all preparations. The zeta potential of the Eudragit® RL containing NPs was positive (1925 mV). The NPs formulations exhibited a biphasic drug release with initial burst followed by a very slow drug release and total cumulative release within 24 h ranged from 75 to 90%. Kinetically, the release profiles of CsA from NPs appeared to fit best with the Weibull model. The viability of L929 cells was decreased by increasing the concentration of the various NPs examined as well as the incubation time. The amount of NPs uptake was related to the polymer type used. The highest degree of cellular uptake (52.2%), tear film concentration of the drug (366.3 ng/g) and AUC0 → 24 (972.6 ng h/g) value were obtained from PLGA: Eudragit® RL (75:25)-CsA NPs formulations. The change of surface characteristics of NPs represents a useful approach for improvement of ocular retention and drug availability.

Objective: Ocular bioadhesive minitablets containing gentamicin and vancomycin were developed using different powder mixtures of pregelatinized starch and Carbopol (physical or cospray-dried mixtures). Methods: Drug content, antimicrobial activity, and radical formation of the powders used for tablet preparation were evaluated immediately and 30 days after gamma sterilization. Tablet properties and in vitro drug release from the sterilized minitablets were determined. Storage stability of vancomycin and gentamicin in sterilized bioadhesive mixtures was examined by LCUV/MS and a microbiological assay, respectively. A bioadhesive powder mixture containing only vancomycin was irradiated by X electron-magnetic radiation to evaluate vancomycin stability following sterilization through irradiation. Results: The antimicrobial activity of gentamicin against Staphylococcus epidermidis was not altered in comparison to nonsterilized formulations. Only after an overkill dose of 50 kGy, the concentration of vancomycin decreases to an extent that was pharmaceutically significant. No significant difference in radiation stability between drug substance and product (i.e., powder mixture) was observed. A shift in stability profile was not observed at 6 weeks after irradiation. All other degradation products were present only in small quantities not exceeding 1.0%. The in vitro drug release from the minitablets prepared with physical powder mixtures of pregelatinized starch and Carbopol® 974P NF (96 : 4) was faster compared to the cospray-dried mixtures of starch with Carbopol® 974P NF (ratio: 95:5 and 85:15). The electron paramagnetic resonance signals of the radicals formed during sterilization were still visible after storage for 30 days. The slug mucosal irritation test indicated mild irritation properties of the bioadhesive powder mixtures although no tissue damage was observed.

The present study investigates the effect of chitosan coating layer on the properties of poly(lactic-co-glycolic acid) nanoparticles. Two concentrations of chitosan (0.1% and 0.5%) as well as two procedures, namely coating or post-coating were developed. The size of all chitosan modified particles was larger than the size of nonmodified PLGA-nanoparticles. The surface charge of the modified nanoparticles was positive (up to +57.0 mV) compared to the negative charge of PLGA-nanoparticles (-23.6 mV). The positive charge of all types of the modified particles decreased drastically 6 hours after incubation with a mucin, suggesting the electrostatic mechanism of their interaction.

The aim of present study was to examine whether cationic Eudragit® containing poly(lactide-co-glycolide) (PLGA) nanoparticles can adhere to Pseudomonas aeruginosa and Staphylococcus aureus. In order to prepare fluorescent nanoparticles, fluorescein was covalently coupled to PLGA. Fluorescent PLGA and Eudragit®/PLGA nanoparticles were prepared by w/o/w emulsification solvent evaporation. Particle size and zeta potential of the nanoparticles were measured. Nanoparticles were incubated for a short time with P. aeruginosa and S. aureus followed by measurement of the size of nanoparticles and of P. aeruginosa and S. aureus with and without adherent nanoparticles. Flow cytometric measurements were performed to detect the attachment of particles to microorganisms. Eudragit® containing nanoparticles possessed a positive zeta potential, while PLGA nanoparticles were negatively charged. Following adsorption of Eudragit® containing nanoparticles, a size increase for P. aeruginosa was observed. Flow cytometric analyses confirmed that Eudragit® containing particles showed stronger interactions with the test organisms than PLGA nanoparticles. Adhesion of particles was more pronounced for P. aeruginosa than for S. aureus. Cationic Eudragit® containing nanoparticles showed better adhesion to microorganisms than anionic PLGA nanoparticles, which is probably due to enhanced electrostatic interactions.

Nanocarriers, such as nanoparticles, liposomes and dendrimers, are used to enhance ocular drug delivery. Easily administered as eye drops, these systems provide a prolonged residence time at the ocular surface after instillation, thus avoiding the clearance mechanisms of the eye. In combination with a controlled drug delivery, it should be possible to develop ocular formulations that provide therapeutic concentrations for a long period of time at the site of action, thereby reducing the dose administered as well as the instillation frequency. In intraocular drug delivery, the same systems can be used to protect and release the drug in a controlled way, reducing the number of injections required. Another potential advantage is the targeting of the drug to the site of action, leading to a decrease in the dose required and a decrease in side effects.

The physicochemical properties and activity of ciprofloxacin HCl-loaded Eudragit nanoparticles were compared with poly(lactide-co-glycolide) (50:50) nanoparticles coated with benzalkonium chloride or cetrimide. Particle sizes varied between 150 and 400 nm. All nanoparticles possessed positive zeta potential values in water. Drug entrapment values of 60-70% were obtained. There was no significant difference in the drug release from Eudragit and poly(lactide-co-glycolide) nanoparticles, or uncoated and coated poly(lactide-co-glycolide) nanoparticles. Ciprofloxacin HCl, encapsulated in various nanoparticle preparations, was still effective against Pseudomonas aeruginosa. Eudragit and uncoated poly(lactide-co-glycolide) nanoparticles caused no cytotoxic effects. The use of Eudragit seems to be the best alternative in the preparation of cationic nanoparticles.

Poly(lactide-co-glycolide) nanoparticles incorporating ciprofloxacin HCl were prepared by means of a W/O/W emulsification solvent evaporation method. The stabiliser selected was poly(vinylalcohol). A 2 4 full factorial design based on four independent variables was used to plan the experiments and the variable parameters were the number of homogenisation cycles, addition of boric acid to the inner water phase containing the drug, ciprofloxacin concentration in the inner water phase and oil:outer water phase ratio. The effects of these parameters on the particle size, zeta potential, drug loading efficiency and drug release were investigated. Also the effect of gamma irradiation on the particle size and drug release was evaluated and DSC and XRD analyses of the compounds and the nanoparticles were performed. The activity on two series of microorganisms, Pseudomonas aeruginosa and Staphylococcus aureus , was examined.

Pilocarpine HCI-loaded PLGA nanoparticles were prepared by emulsification solvent evaporation. Three different stabilisers, polyvinylalcohol (PVA), Carbopol and Poloxamer were used, as well as mixtures thereof. The influence of the homogenisation pressure and number of cycles on the properties of nanoparticles were studied. Particle size was shown to depend on the stabiliser used. An increase of the homogenisation pressure or the number of cycles resulted in a decrease in particle size. The zeta potential value was influenced mainly by the nature of the stabiliser. Particles stabilised with poloxamer or PVA showed a slightly negative zeta potential value, while samples stabilised with carbopol posessed a more negative zeta potential, which became less negative after homogenisation. Drug encapsulation depended strongly on the stabiliser used. The higher drug entrapment of the carbopol-stabilised particles could be explained by an electrostatic interaction between the negatively charged carboxyl groups of carbopol and the positively charged, protonated pilocarpine. The drug release patterns of the particles prepared were quite similar. Differences between the release patterns of the homogenised particles could be attributed both to differences in size as well as drug encapsulation. Turbidimetric measurements suggested an interaction between mucin and PLGA nanoparticles exclusively stabilised with Carbopol.

The aim of the study was to develop a mucoadhesive ocular insert for the controlled delivery of ophthalmic drugs and to evaluate its efficacy in vivo. The inserts tested were based either on unmodified or thiolated poly(acrylic acid). Water uptake and swelling behavior of the inserts as well as the drug release rates of the model drugs fluorescein and two diclofenac salts with different solubility properties were evaluated in vitro. Fluorescein was used as fluorescent tracer to study the drug release from the insert in humans. The mean fluorescein concentration in the cornea/tearfilm compartment as a function of time was determined after application of aqueous eye drops and inserts composed of unmodified and of thiolated poly(acrylic acid). The acceptability of the inserts by the volunteers was also evaluated. Inserts based on thiolated poly(acrylic acid) were not soluble and had good cohesive properties. A controlled release was achieved for the incorporated model drugs. The in vivo study showed that inserts based on thiolated poly(acrylic acid) provide a fluorescein concentration on the eye surface for more than 8 h, whereas the fluorescein concentration rapidly decreased after application of aqueous eye drops or inserts based on unmodified poly(acrylic acid). Moreover, these inserts were well accepted by the volunteers. The present study indicates that ocular inserts based on thiolated poly(acrylic acid) are promising new solid devices for ocular drug delivery.

Various powder mixtures were used to administer insulin via the nasal route: a co-spray dried mixture of Amioca ® starch and Carbopol ® 974 P (1/3), drum dried waxy maize starch and Carbopol ® 974 P (9/1), maltodextrin DE38/Carbopol ® 974 P (9/1) and pure drum dried waxy maize starch. Oscillatory rheology is performed to study and compare the viscosity, elasticity and mucoadhesivity of these powder formulations. There was no rheological synergism detectable with the co-spray dried mixture of Amioca ® starch and Carbopol ® 974 P (1/3), drum dried waxy maize starch and Carbopol ® 974 P (9/1) and maltodextrin DE38/Carbopol ® 974 P (9/1). Interaction due to entanglements was seen with drum dried waxy maize starch (100%). The differences in nasal bioavailability between the different carriers could be explained by differences in G′ (storage modulus, elasticity) and G″ (loss modulus, viscosity) values. The formulation giving the highest bioavailability, provided also the highest G′ and G″ values.

The influence of the compression force on the physical properties, the in vitro release and the in vivo behavior of ocular minitablets is evaluated in the present study. The bioerodible minitablets (O 2 mm, 6 mg) were produced at different compression forces. The crushing strength, friability, water uptake, hydration and swelling of the minitablets both in vitro as well as in vivo after application in the cul-de-sac were evaluated. The friability remained below 1% only for the minitablets made at 0.500 and 0.750 kN. The crushing strength measured was 3.53±0.98, 12.34±1.69 and 18.64±2.37 N for minitablets made at 0.250, 0.500 and 0.750 kN, respectively. The full hydration time equalled 20 and 30 min for minitablets compressed at 0.250 kN and 0.500–0.750 kN, respectively. Increasing the compression force resulted in a decreased swelling capacity. The in vivo release was evaluated in healthy volunteers using a non-invasive method to measure the apparent sodium fluorescein concentration in the tearfilm–cornea compartment as a function of time. The longest residence time of the fluorescent tracer at the administration site was obtained by the minitablets compressed at 0.750 kN. The in vitro release was evaluated with three different dissolution methods: the reciprocating cylinder method, vials in an oscillatory shaking bath and a static method with vials. The best correlation with the in vivo behavior of the matrix minitablets was obtained with the shaking bath method.

Poly(lactic-co-glycolic-acid) nanoparticles are often produced using the w/o/w emulsification solvent evaporation method. In most cases poly(vinyl alcohol) (PVA) is used as stabilizer of the emulsion. The goal of this study was to compare a series of polymers to PVA in a 2(2) full factorial design study. The influence of the concentration of PVA and the polymers tested on particle size and zeta potential value was evaluated before and after freeze-drying of the prepared particles. Nanoparticles were obtained with most polymers when they were used in combination with PVA. Leaving PVA out of the formulation, however, increased the size of the particles over 1 microm. Two exceptions are poloxamer and carbopol, which can be considered as valuable alternatives to PVA. Zeta potential values were usually slightly negative, the most extreme zeta potential values were measured when poloxamer and carbopol were employed. The use of gelatin type A made it possible to achieve positive values. The original 2(2) full factorial design study was further expanded to a central composite design for poloxamer and carbopol, in order to fit the measured data to a quadratic model and to calculate response surfaces.

The development of an ocular dosage form containing xanthan gum and capable of interacting with mucin in the precorneal area is a challenge. The polymer concentration that can be applied is restricted because of the limited patient acceptability of highly viscous preparations. The precorneal mucin concentration is low and the high ionic strength of the lachrymal fluid forces xanthan gum in an ordered structure, less capable of interacting through heterotypic junctions. Intrinsic viscosity measurements and shear rheometry are used to investigate the effect of several factors (polymer concentration, additional boiling or sonication step to the preparation procedure) on the physicochemical properties of xanthan gum and the degree of interaction with a low (8%, w/v) and high (16.0%, w/v) concentrated mucin dispersion. Independent of the preparation procedure applied, a xanthan gum concentration of 1.0% (w/v) is required to obtain a measurable interaction with mucin. If an extra boiling or sonication step is added to the standard preparation procedure, the minimum mucin concentration necessary to achieve formation of heterotypic junctions is decreased. Only by sonication of the highly concentrated xanthan gum dispersion is the viscosity decreased to a level that is tolerable and comfortable to the patient. The findings of the present study clearly demonstrate that a significant interaction between a tolerable and comfortable ocular dosage form containing xanthan gum, and mucin 8% (w/v), is feasible after sonication of a highly concentrated polymer dispersion. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:1117–1127, 2002

A novel drug delivery system (DDS) with sustained release properties was developed to allow ocular protein delivery. The DDS developed is aimed at overcoming stability issues during preparation such as denaturation of proteins caused by shear forces applied or due to elevated temperatures and air entrapment potentially causing oxidation of the molecule. The rod-shaped HPMC inserts were loaded with lysozyme and several HPMC types were studied and compared. An aqueous colloidal HPMC solution (hydrogel) was prepared and subsequently dried at 150°C to dehydrate the polymer solution. This partially dehydrated polymer cylinder was loaded with an aqueous glycerol/lysozyme solution at 2°C. A 2(4) full factorial design was set up to evaluate the effect of the different preparation parameters on water uptake and release properties. As a result, four out of sixteen formulations revealed homogenous distribution for lysozyme in both duplicates. The change in water uptake over time was dependent on the type of HPMC polymer used but not between the chosen HPMC percentages. After 240min, 50% of lysozyme loaded was released depending on the chosen formulation. Lysozyme molecules exhibit slower release from a K100M matrix compared to E10M inserts, albeit the overall effect is relatively limited.

The present study investigates the use of a polymer mixture containing Carbopol 974P and drum dried waxy maize starch to obtain prolonged drug release to the anterior eye segment. Two dosage forms with this composition are compared: a hydrated polymer dispersion and a minitablet. A model fluorescent tracer is used to study the ocular release and diffusion from the two dosage forms in humans. To evaluate the prolongation in the cornea/tearfilm compartment, the Apparent Fluorescein TurnOver (%/min) is calculated. The parameters Cmax, tmax, and C9h are used to characterize the pharmacokinetics of Na-fluorescein in the anterior chamber. Furthermore, the swelling behavior of the minitablet is evaluated macroscopically, while the degree of interaction with mucin is characterized by rheological measurements. Calculation of an acceptability score and a slug irritation potential is performed to evaluate user acceptability. In contrast to the hydrated dispersion, the minitablet significantly decreases the Apparent Fluorescein TurnOver (%/min) (P

Five commercial preparations are characterised physically using creep and continuous flow shear rheometry after they were classified as low or high stress-resistant by penetrometry and extensometry. Several rheological procedures are tested. The difference between the procedures is determined by the course of the stress as a function of time. Evaluation of the shear rheological method is performed by analysing the creep and flow curves and also the parameters calculated by using the mathematical Herschel–Bulkley curve-fitting model. Since the measuring results are dependent on the procedure applied, the scope of the measurement is an important criterium in selecting a procedure.

Stearylamine, oleic acid, phosphatidylserine and dicetylphosphate have been studied to determine their capacity to induce electric charge on non-ionic submicron emulsions containing halofantrine and mefloquine. The in-vivo antimalarial activity of drug-loaded emulsions, evaluated in mice, was affected by the nature of the additives used. In particular, the electric-charge inducers markedly affected the pharmacological activity of mefloquine, but not of halofantrine. After subcutaneous administration ED50 values (the doses affording 50% protection) were 3 and 15 mg kg−1, respectively, for halofantrine and mefloquine emulsions without charge inducers. The mefloquine-loaded emulsions with charge inducers were active at 10 mg kg−1 for dicetylphosphate, 17 mg kg−1 for phosphatidylserine, 23 mg kg−1 for oleic acid and 27 mg kg−1 for stearylamine, again after subcutaneous administration. This work has enabled the formulation of stable emulsions, incorporating drugs with high antimalarial activity, which are proposed for parenteral delivery of these fairly soluble drugs.

To improve the tolerance of antazoline and tetracaine ophthalmic solutions, inclusion complexes of the free bases of both drugs with hydroxypropyl- β -cyclodextrin (HP- β -CD) were prepared. The physicochemical properties of the drug:HP- β -CD solutions were determined and the inclusion complexes were characterised by 1 H and 13 C NMR spectroscopy. The apparent complex constants were calculated from the phase-solubility diagram and were estimated at 403 M −1 and 1308 M −1 for the antazoline:HP- β -CD complex and tetracaine:HP- β -CD complex, respectively. 1 H and 13 C NMR analysis showed that in the 1:1 complexes the total antazoline fraction was present as an inclusion complex, whereas tetracaine was only partly included in spite of a similar phase solubility diagram. NMR spectroscopy also revealed the site of interaction of the drugs with the HP- β -CD molecule. A solution acceptability test was carried out on volunteers. A relationship between the surface tension of the solutions and the tolerance was observed.

Ocular chitosan films were prepared in order to prolong ocular delivery of cyclosporine A. The mucoadhesive films were prepared using the solvent casting evaporation method. A 24 full factorial design was used to evaluate the effect of 4 preparation parameters on the film thickness, swelling index and mechanical properties. Moreover, uniformity of content and in vitro drug release were investigated. Possible interactions between the film excipients were studied by FTIR analysis. In vitro experiments were performed in order to evaluate the cytotoxicity and anti-inflammatory activity of the chitosan films. Film thickness, water uptake, mechanical properties and in vitro release of cyclosporine A were dependent on film composition, especially on the amount of plasticizer. Lower drug release was measured from chitosan films containing a higher amount of plasticizer as glycerol decreased the swelling of chitosan films. FTIR spectra suggest a reorganization of hydrogen bonds between chitosan chains in the presence of glycerol and cyclodextrins. None of the film formulations showed significant cytotoxicity as compared to the negative control using human epithelial cells (HaCaT). Cyclosporine A dispersed in the various film formulations remained anti-inflammatorily active as significant suppression of interleukin-2 secretion in concanavalin A stimulated Jurkat T cells was measured. (C) 2014 Elsevier B.V. All rights reserved.

This paper describes the development of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) and nanosuspensions with the polyene antibiotic amphotericin B (AmB). The nanoformulations were prepared using nanoprecipitation and were characterised with respect to size, zeta potential, morphology, drug crystallinity and content. Standard in vitro sensitivity tests were performed on MRC-5 cells, red blood cells, Leishmania infantum promastigotes and intracellular amastigotes and the fungal species Candida albicans, Aspergillus fumigatus and Trichophyton rubrum. The in vivo efficacy was assessed and compared to that of Fungizone® and AmBisome® in the acute A. fumigatus mouse model at a dose of 2.5 and 5.0 mg/kg AmB equivalents. The developed AmB nanoformulations were equivalently or more effective against the different Leishmania stages and axenic fungi in comparison with the free drug. The in vitro biological activity, and especially hemolytic activity, clearly depended on the preparation parameters of the different nanoformulations. Further, we demonstrated that the superior in vitro antifungal activity could be extrapolated to the in vivo situation. At equivalent dose, the optimal AmB-loaded PLGA NP was about two times and the AmB nanosuspension about four times more efficacious in reducing the total burden than AmBisome®. The developed AmB nanomedicines could represent potent and cost-effective alternatives to Fungizone® and AmBisome®.

The objective of this study was to enhance the encapsulation of the antileishmanial saponin aescin in poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs). We prepared the NPs by the O/W and W/O/W combined emulsification solvent evaporation/salting-out technique and investigated the influence of organic phase composition on the NPs size, zeta potential and entrapment efficiency (EE%) using mixture designs. The obtained NPs were monodispersed with Zave

Cyclosporine A loaded poly(lactide-co-glycolide) nanoparticles coated with chitosan were prepared using the o/w emulsification solvent evaporation method. A 2(3) full factorial design was used to investigate the effect of 3 preparation parameters on the particle size, polydispersity index, zeta potential and drug release. In vitro experiments were performed in order to evaluate the cytotoxicity and anti-inflammatory activity of the developed nanoparticles. Particle sizes varied from 156 nm to 314 nm, and polydispersity index values of 0.07-0.56 were obtained depending on the different preparation parameters. All nanoparticles showed positive zeta potential values. Nanoparticles prepared with the highest concentration chitosan retained a positive zeta potential after dispersion in simulated lachrymal fluid, which supports the possibility of an electrostatic interaction between these particles and the negatively charged mucus layer at the eye. The in vitro release profile of cyclosporine A from the chitosan-coated nanoparticles was strongly dependent on the release medium used. None of the cationic nanoparticle formulations showed significant cytotoxicity compared to the negative control using human epithelial cells (HaCaT). Cyclosporine A encapsulated in the various nanoparticle formulations remained anti-inflammatory active as significant suppression of interleukine-2 secretion in concanavalin A stimulated Jurkat T cells was observed. (c) 2012 Elsevier B.V. All rights reserved.

Colloidal carriers are known to improve the therapeutic index of the conventional drugs in the treatment of visceral leishmaniasis (VL) by decreasing their toxicity whilst maintaining or increasing therapeutic efficacy. This paper describes the development of poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) for the antileishmanial saponin β-aescin. NPs were prepared by the W/O/W emulsification solvent evaporation technique and the influence of five preparation parameters on the NPs' size (Z(ave)), zeta potential and entrapment efficiency (EE%) was investigated using a 2(5-2) fractional factorial design. Cytotoxicity of aescin, aescin-loaded and blank PLGA NPs was evaluated in J774 macrophages and non-phagocytic MRC-5 cells, whereas antileishmanial activity was determined in the Leishmania infantum ex vivo model. The developed PLGA NPs were monodispersed with Z(ave)

Pilocarpine loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by solvent evaporation method and coated with various mucoadhesive polymers, in particular chitosan, sodium alginate and poloxamers. The size of chitosan-coated nanoparticles was larger than the size of all the other particles obtained. Their surface charge was changed from negative (−22.8 mV) to positive (+61.0 mV). The interaction between mucin and chitosan-coated nanoparticles took place up to six hours according to turbidimetric study. The positive charge of chitosan-coated nanoparticles decreased significantly six hours after incubation in mucin dispersion, which was attributed to their electrostatic interaction. The coating with chitosan could be considered useful approach aiming to prolong nanoparticle residence time after local ocular application.

Ocular delivery of peptides requires new concepts in order to optimize the bioavailability and its therapeutic effect. The first peptide selected in present research project is Cyclosporine A (CyA) used in the treatment of the dry eye syndrome and against corneal graft rejection. The aim of the project is the development of nanoparticles with physicochemical properties for a suitable and prolonged release of CyA, using a factorial design. These drug delivery systems will be produced employing PLGA using the emulsification solvent evaporation method. Positively charged polymers as chitosan or Eudragit® will be incorporated to obtain nanoparticles with a positive particle charge. Electrostatic interactions with the negatively charged mucins lead to a prolonged residence time at the precorneal area. Nanoparticles will be evaluated on zeta potential, particle size and their in vitro drug release properties. CyA and CyA complexed with HPβCD will be compared. The most suitable preparations will be selected in a next phase of the project for an in vivo study using an animal model.

Rupture-prone and ruptured plaques are characterized by the presence of large numbers of macrophages. N1177 is a contrast agent consisting of iodinated nanoparticles that are selectively phagocytosed by macrophages. The aim of this study was to investigate the effect of N1177 on the CT attenuation of rupture-prone and ruptured plaques in rabbits. In addition, we examined in vitro whether uptake of N1177 occurred without cytotoxic or pro-inflammatory effects on macrophages. In vitro, the viability of J774 macrophages was not affected by treatment with N1177. Moreover, N1177 had no effect on the phagocytic capacity or cytokine production of macrophages. For the in vivo experiments, 6 New Zealand White rabbits were fed a cholesterol-supplemented diet for 1215 months, resulting in the development of large atherosclerotic plaques that resembled rupture-prone plaques in humans. In three rabbits, mechanical plaque rupture was induced by retrograde pullback of an embolic protection device. N1177 had no effect on the median density of rupture-prone plaques [35 HU (range 385) before injection vs. 32 HU (range 193) 2 h after injection of N1177; P > 0.05]. However, after induction of mechanical plaque rupture, the median density of the atherosclerotic plaques increased from 40 HU (range 686) before injection to 74 HU (range 14111) 2 h after injection of N1177 (P < 0.001). Using time-of-flight static secondary ion mass spectrometry, the presence of N1177 nanoparticles was demonstrated in macrophage-rich areas of ruptured plaques, but not of non-ruptured plaques. In conclusion, our results show that N1177 is a contrast agent that can identify ruptured atherosclerotic plaques.

Dit hoofdstuk behandelt toedieningsvormen voor lokale toepassing op het mondslijmvlies, de tanden en in de keel. Toedieningsvormen met farmaca bestemd voor een systemisch effect, die via het mondslijmvlies in de algemene circulatie komen, vallen buiten het bestek van dit hoofdstuk. Voorbeelden hiervan zijn sublinguale tabletten en sprays, en de meeste buccale tabletten. Buccale tabletten met systemische werking zijn tegenwoordig vaak ontworpen om gedurende langere tijd farmaca af te geven, als zogenaamde mucoadhesieve preparaten. Deze vormen worden behandeld in hoofdstuk 26. Er zijn ook halfvaste toedieningsvormen, die na bevochtiging met speeksel aan de mondmucosa kleven. Toedieningsvormen voor lokale toepassing in de mond en de keelholte, die in de apotheek worden bereid, omvatten oplossingen (mondspoelingen, gorgeldranken, oplossingen voor oromucosaal gebruik, oplossingen voor dentaal gebruik) en halfvaste preparaten (zalven voor oromucosaal gebruik, gels voor dentaal gebruik).

Slit-lamp fluorophotometry was used to evaluate in humans the precorneal kinetics of viscous eye drops containing carbopol 940, disodium EDTA and a fluorescent tracer. The ocular retention of the tracer depends on the concentration of the polymer instilled. The addition of disodium EDTA does not improve the precorneal kinetics significantly.

The cytotoxicity and physical properties of various submicron O/W emulsions and solid lipid nanoparticles for dermal applications were investigated. Droplet size and zetapotential of submicron emulsions depended on the composition of the cosurfactant blend used. The viability of J774 macrophages, mouse 3T3 fibroblasts and HaCaT keratinocytes was significantly reduced in the presence of stearylantine. Nanoparticles consisting of stearic acid or different kinds of adeps solidus could be manufactured when formulated with lecithin, sodium taurocholate, polysorbate 80 and stearylamine. Survival of macrophages was highly affected by stearic acid and stearylamine. In general a viability of more than 90% was observed when semi-synthetic glycerides or hard fat was employed to formulate nanoparticles. (c) 2007 Elsevier B.V. All rights reserved.

The objective of present study was to prepare positively charged ciprofloxacin-loaded nanoparticles providing a controlled release formulation. The particles were prepared by water-in-oil-in-water (w/o/w) emulsification and solvent evaporation, followed by high-pressure homogenisation. Two non-biodegradable positively charged polymers, Eudragit RS100 and RL100, and the biodegradable polymer poly(lactic-co-glycolic acid) or PLGA were used alone or in combination, with varying ratios. The formulations were evaluated in terms of particle size and zeta potential. Differential scanning calorimetry measurements were carried out on the nanoparticles and on the pure polymers Eudragit and PLGA. Drug loading and release properties of the nanoparticles were examined. The antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus was determined. During solvent evaporation, the size and zeta potential of the nanoparticles did not change significantly. The mean diameter was dependent on the presence of Eudragit and on the viscosity of the organic phase. The zeta potential of all Eudragit containing nanoparticles was positive in ultrapure water (around +21/+25 mV). No burst effect but a prolonged drug release was observed from all formulations. The particles' activity against P. aeruginosa and S. aureus was comparable with an equally concentrated ciprofloxacin solution.

The purpose of this study was to evaluate different bioadhesive ocular formulations based on drum dried waxy maize starch (DDWM), Amioca starch and Carbopol 974P. The concentrations of Carbopol 974P in the mixtures varied between 5 and 25% (w/w). The rheological properties of the non-sterilized and gamma-irradiated physical blends of Carbopol 974P with either DDWM or Amioca were compared to those of the corresponding co-spray dried Amioca starch/Carbopol powders. Higher viscosity or consistency values were measured for sterilized co-spray dried powder mixtures containing an amount of Carbopol 974P equal or above 15% (w/w) compared to the physical blends. Sustained release minitablets (2 mm, 6 mg), consisting of sodium fluorescein as model drug and the bioadhesive powders, were manufactured at a compression force of 1.25 kN. Afterwards, the tablets were sterilized with gamma-irradiation. The amount of Carbopol in the co-spray dried powder mixtures on the one hand and gamma-irradiation on the other hand had no significant influence on the crushing strength and friability of the minitablets evaluated. However, these two factors affected the in vitro release properties of the minitablets. The slowest release was obtained with tablets containing 25% Carbopol 974P, which unfortunately possess mucosal irritating properties. By using co-spray dried Amioca with 15% (w/w) Carbopol 974P, a slower release can be achieved compared to the physical mixtures of DDWM or Amioca starch with Carbopol 974P. Moreover, this ocular formulation is very promising and is preferred, as it did not cause any mucosal irritation and released the model drug for at least 12 h, after application in the fornix.

In the present update on mucoadhesive ocular dosage forms, the tremendous advances in the biochemistry of mucins, the development of new polymers, the use of drug complexes and other technological advances are discussed. This review focusses on recent literature regarding mucoadhesive liquid (viscous solutions, particulate systems), semi-solid (hydrogel, in situ gelling system) and solid dosage forms, with special attention to in vivo studies. Gel-forming minitablets and inserts made of thiomers show an interesting potential for future applications in the treatment of ocular diseases.

An experimental factorial design was employed to evaluate bioadhesive granules and bioerodible ocular minitablets (6 mg and O 2 mm). The purpose of this study was to compare minitablets prepared using roller compacted granules with an optimised minitablet formulation, manufactured on laboratory scale by direct compression. The formulation consisted of drum dried waxy maize starch, Carbopol® 974P, and ciprofloxacin in a ratio of 90.5/5/3 (w/w/w). Three roller compactor parameters were varied, i.e. the roller speed, the horizontal screw speed and the compaction force, while the vertical screw speed was kept constant. Afterwards, the ribbons were milled to obtain granules suitable for compression. The friability, the flow properties, the bulk material characteristics (apparent and tap density and porosity) and the particle size distributions of two granule sieve fractions (90–125 and 125–355 μm) were investigated. The roller speed and the compaction force have the largest influence on the granule characteristics, followed by the horizontal screw speed. The physical properties of non- and gamma-irradiated minitablets were determined. From the tablet strength, friability and dissolution results, a low compaction force and a high roller speed were shown to be preferable to prepare granules which can be further tabletted into adequate ocular minitablets.

In the present study, the influence of freeze-drying with several cryoprotective agents and gamma (γ)-irradiation sterilization on the physicochemical characteristics of ciprofloxacin HCl-loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles was evaluated. Nanoparticles were prepared by W/O/W emulsification solvent evaporation followed by high-pressure homogenization. They were freeze-dried in the presence of 5.0% (w/v) mannitol, trehalose or glucose, with 5.0% (w/v) or 15.0% (w/v) dextran as cryoprotectants. The nanoparticles were irradiated at a dose of 25 kGy using a 60Co source. The following physicochemical properties of the formulations were investigated: the ratio of particle size before (initial) and after freeze-drying, the ease of reconstitution of the nanoparticle suspensions and the drug-release profiles of irradiated and non-irradiated nanoparticles. The anti-bacterial activity against Pseudomonas aeruginosa was measured. The freeze-drying process induced a significant increase in particle size when no cryoprotectant was employed. Similar results were observed when cryoprotectants were added to the formulation. Only when mannitol was used was no significant size increase measured. Moreover, for formulations with dextran, reconstitution after freeze-drying was difficult by manual agitation and particle size could not be determined because of aggregation. After γ-sterilization no significant difference in mean particle size was observed, but reconstitution was more difficult and drug release was influenced negatively. Ciprofloxacin HCl incorporated in the nanoparticles was still effective against the micro-organism selected after freeze-drying and γ-sterilization.

PURPOSE Evaluation in volunteers of ciprofloxacin-containing ocular gelling minitablets with prolonged release properties. METHODS The irritation potential of ciprofloxacin-containing bioadhesive powder mixtures, used to prepare ocular bioerodible minitablets, was evaluated with a slug mucosal-irritation test. The tear pharmacokinetic profiles of ciprofloxacin were determined in six healthy volunteers after topical administration of a minitablet and a single eye drop in the lower fornix. The drug concentrations in the tear samples collected were measured by using a validated HPLC METHOD: Each volunteer was asked to give an evaluation of the preparations applied by answering a standard questionnaire. RESULTS The results of the mucosal-irritation test demonstrated the nonirritating properties of the bioadhesive powder mixtures. The ocular minitablet, applied in the fornix was in general well tolerated by the healthy volunteers. The mean tear concentration of ciprofloxacin was 33.0, 135.2, and 33.7 microg/g at 30, 300, and 480 minutes after application of the minitablet. Mean tear levels of 84.7, 45.6, and 8.4 microg/g were obtained at 5, 30, and 60 minutes after application of an eye drop. CONCLUSIONS Due to their prolonged drug release properties, the ocular minitablets containing ciprofloxacin can be considered as a promising drug delivery system to be used in the treatment of ulcerative bacterial keratitis.

Poly(lactide-co-glycolide) nanoparticles incorporating ciprofloxacin HCl were prepared by means of a W/O/W emulsification solvent evaporation method. The physicochemical properties of these particles were evaluated by measuring particle size, zeta potential and drug loading efficiency. Gamma-sterilised nanoparticles were dispersed in different isoviscous polymer solutions, commonly used as vehicles in eye drops. The influence of γ-irradiation of the viscosifying agents on the drug release properties of the dispersed nanoparticles was evaluated with respect to release in mannitol solution. The viscosity of the polymer solutions prepared was measured by flow rheometry and thereby the influence of temperature and sterilisation by autoclaving on viscosity was examined. Before and after freeze-drying and subsequent sterilisation by gamma-irradiation, the polymer solutions were also characterised by dynamic stress sweep and dynamic frequency sweep oscillation measurements to deduce possible structural changes. A possible relationship between the differences in ciprofloxacin release from the nanoparticles suspended in the various media and the network structure or rheological behaviour of the polymers was investigated.

Ophthalmic solutions are available for multidose or single-dose administration in a wide variety of glass and plastic dropper bottles which deliver drops with a volume between 25 and 70 microl. From a biopharmaceutical and economic point of view, however, smaller volumes of 5 to 15 microl should be instilled. In this review, the technical, pharmaceutical, and therapeutic aspects of eye drop formation and delivery are presented. The different types of containers are described and the determinants of eye drop size are discussed, such as the design and physical characteristics of the dropper tip and bottle, the physico-chemical properties of the solution, and the manner in which the patient dispenses the drops. Preferred and alternative instillation techniques and aids to facilitate the administration of eye drops by elderly patients are described.

It has been shown that 5,7,3',4'-tetrahydroxy-3-O-methylflavone (3-MQ) exhibits antipicornaviral activity. In order to explore the potential of 3-MQ as an antirhinoviral compound for nasal application, the effect of 3-MQ on the ciliary beat frequency (CBF) of human nasal epithelial cells was studied in vitro in the absence or presence of solubility/absorption enhancers (hydroxypropyl-beta-cyclodextrin (HP-beta-CD) or polysorbate 80). Nasal epithelial cells were obtained by protease digestion of surgical specimens of human nasal polyps, and used at confluency. The effect of 3-MQ (2, 10, and 20 microg/ml), HP-beta-CD (1, 3, and 10% (w/v)), polysorbate 80 (0.1, 0.3, and 1% (w/v)), and of the combination of 3-MQ with 3% HP-beta-CD or 1% polysorbate 80, on the CBF was determined by computerized microscope photometry 15 min after incubation with the test compounds; recovery was determined 35 min after rinsing. HP-beta-CD at 1 and 3% did not affect CBF; a reversible decrease (by 37%) was observed at 10%. Polysorbate 80 caused a reversible cilio-inhibitory effect of 40, 53, and 49% at 0.1, 0.3, and 1%, respectively. At 2 and 10 microg/ml, 3-MQ showed a reversible cilio-stimulatory effect of 18 and 14%, respectively. Combined with 3% HP-beta-CD, the reversible cilio-stimulatory effect of 2 microg/ml 3-MQ was preserved, while 10 and 20 microg/ml 3-MQ did not affect the CBF. The combination of polysorbate 80 (1%) and 3-MQ decreased the CBF, which could be attributed to the presence of polysorbate 80. In conclusion, no ciliotoxic effect could be observed for 3-MQ (up to 20 microg/ml) in the absence or presence of HP-beta-CD (3%). The potential of this combination as an antirhinoviral formulation for nasal application will be further explored.

Gelatin nanoparticles encapsulating pilocarpine HCl or hydrocortisone as model drugs were produced using a desolvation method. The influence of a number of preparation parameters on the particle properties was investigated. For the pilocarpine HCl-loaded spheres, an influence of the pH during particle preparation on the size was observed. Slightly negative zeta potential values were measured for all samples. In the case of pilocarpine HCl-loaded spheres, no influence of the gelatin type or the pH level was observed, which could be attributed to the shielding effect of ions present in the dispersion medium. When hydrocortisone was entrapped, a difference in zeta potential value between gelatin type A and gelatin type B particles was measured. A high pilocarpine HCl entrapment was established. Hydrocortisone was complexed with cyclodextrins in order to increase its aqueous solubility. The drug encapsulation was lower than in the case of pilocarpine HCl, but still amounted to approximately 30-40%. Compared to the aqueous drug solutions, a sustained release for both drugs was observed. The release kinetics of pilocarpine HCl are close to zero order, and no significant differences were measured between the various preparations. In the case of hydrocortisone, the release data suggests a difference in release rate depending on the type of cyclodextrin employed.

Poly(lactide-co-glycolide) nanoparticles loaded with pilocarpine hydrochloride were prepared by the high-pressure emulsification-solvent evaporation method. The nanoparticles were produced using polyvinylalcohol (PVA), carbomer (Carbopol 980) or poloxamer (Lutrol F-68) as stabilizers during emulsification. The influence of pressure and number of cycles on the nanoparticle properties was investigated. For comparison, nanoparicles without high-pressure treatment of the emulsion were made. The nanoparticle size, drug loading and release properties depended strongly on the homogenization pressure and number of cycles applied. Nanoparticles obtained without high pressure homogenization showed larger size and high values of polydispersity index, especially when carbopol and poloxamer were used as emulsifiers. Drug loading and encapsulation efficiency of all samples also decreased with pressure. The low drug loading could be due to two reasons. First, the high pressure promoted drug diffusion out of protoparticles during emulsification either by size reduction or shear forces. Secondly, the characteristics of the outer water phase of the emulsion also influenced the nanoparticle drug loading. This was proven by the different drug loadings measured when nanoparticles were made with PVA, carbopol or poloxamer at equal pressures applied. The main factor influencing the release properties of nanoparticles was the pressure used during emulsification. Faster drug release was observed from nanoparticles obtained after high-pressure emulsification compared to those prepared without homogenization of the emulsion.