Selectively coated contact lenses by nanoelectrospray (nES) to fabricate drug-eluting contact lenses for treating ocular diseases.

Drug-eluting contact lenses (DECLs) incorporated with poly(lactic-co-glycolic acid) (PLGA) and various model drugs (ketotifen fumarate, bimatoprost and latanoprost) were fabricated using nanoelectrospray (nES) approach. The resulting DECLs demonstrated outstanding optical transmittance within the optical zone, indicating that the employed coating procedure did not compromise visual acuity under the prescribed spraying parameters. In vitro drug release assessments of the model drugs (ketotifen fumarate (KF), bimatoprost (BIM), and latanoprost (LN)) revealed a strong correlation between the model drug's hydrophobicity and the duration of drug release. Changing the drug loading of the more hydrophilic model drugs, BIM and KF, showed no impact on the drug release kinetics of DECLs loaded with BIM and KF. However, for the hydrophobic model drug, LN, the highest LN loading led to the most extended drug release. The conventional steam sterilisation method was found to damage the PLGA coating on the DECLs fabricated by nES. An alternative sterilisation strategy, such as radiation sterilisation may need to be investigated in the future study to minimise potential harm to the coating.

Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies.

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job's method, which was compatible with the results obtained using the Benesi-Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

Cell-based, animal and H1 receptor binding studies relative to the sedative effects of ketotifen and norketotifen atropisomers.

OBJECTIVES: Ketotifen (K) and its active metabolite norketotifen (N) exist as optically active atropisomers. They both have antihistaminic and anti-inflammatory properties but the S-atropisomer of N (SN) causes less sedation than K and RN in rodents. This study investigated whether this could be related to a lower concentration of SN in brain or a lower affinity of SN for rat brain H1 receptors. METHODS: Ketotifen and norketotifen atropisomers were quantified using a validated chiral HPLC assay. RBE4 and Caco-2 cell monolayers were used in uptake and permeability studies, respectively. Free and total brain-to-plasma (B/P) ratios were determined after injecting racemic K and N into rat tail veins. Affinity for rat brain H1 receptors (KI ) was determined using the [3 H]mepyramine binding assay. KEY FINDINGS: Uptake and permeation studies indicate no stereoselective transport for K or N. B/P ratios reveal the brain concentration of N is lower than K with no stereoselective transport into brain. Finally, the [3 H]mepyramine binding assay shows SN has the lowest affinity for rat brain H1 receptors. CONCLUSION: The lower sedative effect of SN in rodents is probably due to a combination of a lower uptake of N than K into the brain and less affinity of SN for CNS H1 receptors.

Development of a Carrier Free Dry Powder Inhalation Formulation of Ketotifen for Pulmonary Drug Delivery.

BACKGROUND: Pulmonary drug delivery route is gaining much attention because it enables to target the active ingredients directly to lung both for local and systemic treatments, which maximize the therapeutic effect and minimize unwanted systemic toxicity. Dry powder inhaler (DPI) systems for asthma therapy have shown several merits to the other pulmonary delivery systems such as nebulizers and metered dose inhalers. PURPOSE: The present study aims to develop and optimize a DPI formulation for Ketotifen fumarate through spray drying technique. METHODS: Particles size and morphology, crystallinity, and drug-excipient interaction of fabricated DPI formulations were evaluated by scanning electron microscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier Transform Infrared Spectroscopy methods, respectively. The aerosolization indexes and aerodynamic properties of dry powders were determined by next generation impactor. The powder flowability was assessed by measuring the Hausner ratio and compressibility index. RESULTS: Among solvent systems, ethanol-water mixture produced the most desirable powder property for inhalation after spray drying. Although co-spray dried formulations with ammonium bicarbonate resulted in the porous structure, it was not beneficial for DPI formulations due to the interaction with Ketotifen. DSC and XRD experiments proved the amorphous structure of prepared powders, which were stable for 12 months. CONCLUSION: The results of this study demonstrate the potential of Ketotifen DPI formulation and pave a way to use it easily in an industrial scale.

Mast cell stabilizing effect of a geranyl acetophenone in dengue virus infection using in vitro model of DENV3-induced RBL-2H3 cells.

Mast cells (MCs), a type of immune effector cell, have recently become recognized for their ability to cause vascular leakage during dengue virus (DENV) infection. Although MC stabilizers have been reported to attenuate DENV induced infection in animal studies, there are limited in vitro studies on the use of MC stabilizers against DENV induced MC degranulation. 2,4,6-trihydroxy-3-geranyl acetophenone (tHGA) has been reported to be a potential MC stabilizer by inhibiting IgE-mediated MC activation in both cellular and animal models. The present study aims to establish an in vitro model of DENV3-induced RBL-2H3 cells using ketotifen fumarate as a control drug, as well as to determine the effect of tHGA on the release of MC mediators upon DENV infection. Our results demonstrated that the optimal multiplicities of infection (MOI) were 0.4 × 10-2 and 0.8 × 10-2 focus forming units (FFU)/cell. Ketotifen fumarate was proven to attenuate DENV3-induced RBL-2H3 cells degranulation in this in vitro model. In contrast, tHGA was unable to attenuate the release of both ß-hexosaminidase and tumor necrosis factor (TNF)-α. Nonetheless, our study has successfully established an in vitro model of DENV3-induced RBL-2H3 cells, which might be useful for the screening of potential MC stabilizers for anti-dengue therapies.

Mast Cells in Mammary Carcinogenesis: Host or Tumor Supporters?

BACKGROUND/AIM: The effects of mast cells on carcinogenesis is not yet fully understood. This work aimed to disclose the role of mast cells in mammary carcinogenesis in a rat model. MATERIALS AND METHODS: Mammary tumors were induced by the administration of N-methyl-N-nitrosourea (MNU) in three groups of rats. Animals from one group were treated with ketotifen immediately after MNU administration, and animals from another only received ketotifen after the development of the first mammary tumor. The biochemical profile was determined. Mammary tumors were evaluated by histopathology and immunohistochemistry. RESULTS: Animals from ketotifen-treated groups developed fewer mammary tumors, higher number of mammary lesions and had lower histamine levels when compared to non-treated animals. Animals treated with ketotifen immediately after MNU exhibited the lowest proliferative and apoptotic indexes. CONCLUSION: The mainly positive effect of the inhibition of mast cell degranulation seems to be the reduction of tumor proliferation when the mast cell degranulation was inhibited before tumor development.

Extended release of ketotifen from silica shell nanoparticle-laden hydrogel contact lenses: in vitro and in vivo evaluation.

Ketotifen an anti-allergic drug delivered via eye drops has major limitations, including poor ocular bioavailability and poor patient compliance. The objective of the research work was to fabricate ketotifen loaded microemulsion laden hydrogels and silica shell nanoparticle-laden (prepared from microemulsion using octyltrimethoxysilane) hydrogels to achieve extended ocular drug delivery. The porous silica shell membrane was synthesized at the liquid interface of microemulsion, which facilitates the prolongation of drug release duration from hydrogels. Drug encapsulated microemulsion and silica shell nanoparticles were dispersed separately in pre-monomer mixture, and fabricated to hydrogel. For comparison, hydrogel with direct drug entrapment was also fabricated. Significant loss in transmittance and physical properties was observed in hydrogels with direct drug entrapment. While, microemulsion and silica shell nanoparticle-laden hydrogels did not show significant effect on transmittance and physical properties. The in vitro drug release data showed extended release of ketotifen from hydrogels in following order: direct loading

A novel in situ gel base of deacetylase gellan gum for sustained ophthalmic drug delivery of ketotifen: in vitro and in vivo evaluation.

In this study, an ion-activated ketotifen ophthalmic delivery system was developed by using a natural polysaccharide, deacetylase gellan gum. Its rheological characteristics, stability, in vitro gelation, release in vitro, and pharmacodynamic activity in vivo were investigated. The formulation had an optimum viscosity that will allow easy drop as a liquid, which then underwent a rapid sol-gel transition due to ionic interaction. There were negligible alterations in the initial values of viscosity of the formulations over a storage period of 180 days. The in vitro release profiles indicated that the release of ketotifen from in situ gels exhibited a sustained feature. Scintigraphic studies indicated that deacetylase gellan gum could increase the residence time of the formulation. At the same dose, in situ gels demonstrated a typical sustained and prolonged drug-effects behavior compared with the common drops.

Novel delivery approach for ketotifen fumarate: dissofilms formulation using 3² experimental design: in vitro/in vivo evaluation.

Orally dissolving films (dissofilms) have gained increasing popularity and attention due to their ease of administration and avoidance of first pass metabolism. Ketotifen fumarate (KF) bioavailability is reported to be only ~ 50% due to hepatic first-pass metabolism. Aiming to surmount this drawback and improve patients' compliance, a 3(2) full factorial design was applied to formulate KF Orodispersible films, and to investigate the effects and interactions of the concentrations of the novel film former; Lycoat NG73® and the film modifier; maltodextrin (MDX) on the characteristics of the films prepared using solvent casting technique. The dissofilms were thoroughly evaluated regarding their weight uniformity, content uniformity, moisture uptake, in vivo mouth dissolving time (MDT) and their thermal behavior via differential scanning calorimetry. Statistical analysis revealed the significant influence of Lycoat NG73® concentration on percent elongation, percent KF dissolved after 5 min, and in vivo MDT, while MDX concentration had significant effect only on percent elongation. Further, storage of the optimal selected formula (15% Lycoat NG73 and 0% MDX) at 40 °C/75% relative humidity for 12 weeks caused no significant change in appearance, KF content or drug dissolution profile. Pharmacokinetic study revealed that the orally dissolving films showed significantly higher absorption extent than the reference marketed product, while no significant difference was observed for Cmax.

In vivo enhancement of transdermal absorption of ketotifen by supersaturation generated by amorphous form of the drug.

The enhancing effect of supersaturation generated by amorphous ketotifen in silicone pressure-sensitive adhesive matrices (PSA) on the transdermal absorption was evaluated in vivo using hairless rats, and it was compared with the increase of drug amount in skin tissues. The duration of the enhancing effect was also investigated in relation to the time how long supersaturation was maintained in PSA. PSA containing crystalline ketotifen (PSA-Crystalline) and that containing amorphous ketotifen (PSA-Amorphous) were prepared by the solvent casting method using n-hexane and dichloromethane, respectively. In vivo transdermal absorption was evaluated by measuring the amount of ketotifen in PSAs, the stratum corneum, and viable skin tissues after administration of PSAs on abdominal sites of hairless rats. The amount of ketotifen absorbed into the systemic circulation was calculated by subtracting the drug amount in whole skin tissues from the amount of the drug released from PSAs, then it was monitored for up to 23 h. In both types of PSA, a constant absorption rate was maintained for up to 23 h after 7-h lag time. The enhancement factor of PSA-Amorphous against PSA-Crystalline was approximately 7, which was in good agreement with the difference of drug amount in viable skin tissues. Time course of the drug amount in PSA-Amorphous suggested that the supersaturated level was gradually decreased after 10h, but the decline of the driving force from PSAs was supplemented by the drug release from the skin depot resulting in the constant absorption rate up to 23 h. These results suggest the usefulness of amorphous ketotifen to obtain enhanced transdermal absorption.

A nuclear magnetic resonance approach to the comparison of mucoadhesive properties of polysaccharides for ophthalmic uses.

Mucoadhesive properties of tamarind seed polysaccharide (TSP) and larch arabinogalactan (AG), which are developed for ophthalmic applications, were investigated by NMR spectroscopy. Polysaccharide to mucin affinities were compared by using ketotifen fumarate as low molecular weight interaction probe. Proton selective relaxation rate measurements revealed enhanced affinity of TSP to mucin with respect to AG.

In vitro and in vivo evaluation of ketotifen fumarate-loaded silicone hydrogel contact lenses for ocular drug delivery.

The purpose of this work was to evaluate the usefulness of silicone hydrogel contact lenses loaded with ketotifen fumarate for ocular drug delivery. First, silicone contact lenses were prepared by photopolymerization of bitelechelic methacrylated polydimethylsiloxanes macromonomer, 3-methacryloxypropyltris(trimethylsiloxy)silane, and N,N-dimethylacrylamide using ethylene glycol dimethacrylate as a cross-linker and Darocur 1173 as an initiator followed by surface plasma treatment. Then, the silicone hydrogel matrices of the contact lenses were characterized by equilibrium swelling ratio (ESR), tensile tests, ion permeability, and surface contact angle. Finally, the contact lenses were loaded with ketotifen fumarate by pre-soaking in drug solution to evaluate drug loading capacity, in vitro and in vivo release behavior of the silicone contact lenses. The results showed that ESR and ion permeability increase, and the surface contact angle and tensile strength decreased with the increase of DMA component in the silicone hydrogel. The drug loading and in vitro releases were dependent on the hydrogel composition of hydrophilic/hydrophobic phase of the contact lenses. In rabbit eyes, the pre-soaked contact lenses sustained ketotifen fumarate release for more than 24 h, which leads to a more stable drug concentration and a longer mean retention time in tear fluid than that of eye drops of 0.05%.

Synergistic interaction between TS-polysaccharide and hyaluronic acid: implications in the formulation of eye drops.

An interaction between tamarind seed polysaccharide (TSP) and hyaluronic acid (HA) in aqueous solution has been ascertained. Various TSP/HA mixtures have been studied as the basis for the development of a potential excipient for eye drops synergistically improved over those of the separate polymers. Information about the nature of interpolymer interactions, and their dependence on TSP/HA ratios were obtained by NMR spectroscopy in solution. Superior mucin affinity of TSP/HA mixtures with respect to the single polysaccharides was assessed by NMR proton selective relaxation rate measurements. The mucoadhesivity of the TSP/HA (3/2) mixture, evaluated in vitro by NMR or viscometry, and in vivo by its mean and maximum residence time in rabbit precorneal area, is stronger than that of the component polysaccharides or the TSP/HA mixtures of different composition. TSP/HA (3/2) is little viscous and well tolerated by rabbit eyes. It stabilizes the tear film, thereby prolonging the residence of ketotifen fumarate and diclofenac sodium in tear fluid, but is unable to permeabilize the cornea. In conclusion, mucoadhesivity is responsible for the TSP/HA (3/2) synergistic enhancement of either extra- or intra-ocular drug bioavailability.

Formulation of ketotifen fumarate fast-melt granulation sublingual tablet.

The purpose of this study was to prepare sublingual tablets, containing the antiasthmatic drug ketotifen fumarate which suffers an extensive first-pass effect, using the fast-melt granulation technique. The powder mixtures containing the drug were agglomerated using a blend of polyethylene glycol 400 and 6000 as meltable hydrophilic binders. Granular mannitol or granular mannitol/sucrose mixture were used as fillers. A mechanical mixer was used to prepare the granules at 40 degrees C. The method involved no water or organic solvents, which are used in conventional granulation, and hence no drying step was included, which saved time. Twelve formulations were prepared and characterized using official and non official tests. Three formulations showed the best results and were subjected to an ex vivo permeation study using excised chicken cheek pouches. The formulation F4I possessed the highest permeation coefficient due to the presence of the permeation enhancer (polyethylene glycol) in an amount which allowed maximum drug permeation, and was subjected to a pharmacokinetic study using rabbits as an animal model. The bioavailability of F4I was significantly higher than that of a commercially available dosage form (Zaditen solution-Novartis Pharma-Egypt) (p > 0.05). Thus, fast-melt granulation allowed for rapid tablet disintegration and an enhanced permeation of the drug through the sublingual mucosa, resulting in increased bioavailabililty.

Templated hydrogels for combination devices: therapeutic contact lenses.

Molecular imprinting provides a rational design strategy for the development of controlled release drug delivery systems. We demonstrate that imprinting a network results in macromolecular memory for the template molecule, indicated by the two or more times greater partitioning into these networks as compared to non-imprinted networks. Partitioning of drug into networks synthesized from multiple functional monomers was 8 times greater than networks synthesized from single monomers. One-dimensional permeation studies showed that the gel with maximum incorporated chemical functionality had the lowest diffusion coefficient, which was at least an order of magnitude lower than all other gels studied. All imprinted networks had significantly lower diffusion coefficients than non-imprinted networks, in spite of comparable mesh sizes and equilibrium polymer volume fractions in the swollen state. This work also demonstrates molecular imprinting using a "living/controlled" polymerization strategy to enhance template loading/affinity and delay release in weakly crosslinked gels. Recognition studies revealed more than a 50% increase in template loading and dynamic template release studies showed that imprinting via "living" polymerization extends or delays the template release profile by two-fold over that of imprinting via conventional free-radical polymerization techniques and four-fold over the control network. The imprinted gel and imprinted gel prepared via "living/controlled" polymerization release profiles were less Fickian and moved toward zero-order release with profile coefficients of 0.68 and 0.70, respectively.

Flow injection determination of ketotifen fumarate using PVC membrane selective electrodes.

In this study a PVC membrane electrode for determination of ketotifen fumarate is reported, where ketotifen tetraphenylborate (Keto-TPB) was used as ion exchanger. The electrode has linear range of 5.6x10(-6)-1.0x10(-2) and 1.0x10(-5)-1.0x10(-2) mol/L, with detection limits 2.37x10(-6)and 4.60x10(-6) mol/L in batch and flow injection analysis (FIA), respectively. The electrodes show a Nernstian slope value (58.40 and 61.50 mV/decade in batch and FIA, respectively), and the response time is very short (

The sorption of ketotifen fumarate by chitosan.

The purpose of this investigation was to determine the mechanism of interaction between ketotifen fumarate and chitosan at different pH values. The specific surface area of chitosan was determined using gas sorption analyzer. The sorption experiments were conducted at pH 7 and 10 using two different particle size ranges of chitosan. The solutions were prepared at constant ionic strength and buffer concentration, with only varying the pH. The rotating bottle method was used for measuring the sorption. The average specific surface areas for the two different particle size ranges of chitosan were found to be 4.56 and 0.74 m(2)/g. The Langmuir-like equation and a model independent equation were both applied to the sorption experimental data. The extent of ketotifen uptake at pH 7 for small and large particles of chitosan was found to be 1,073 and 2,204 mg/g respectively. While the extent of ketotifen uptake at pH 10 for small and large particles of chitosan was found to be 4 and 11 mg/g respectively. The aforementioned results indicated that sorption of ketotifen fumarate at pH 7 is extremely high compared to pH 10 and that the sorption increases by decreasing the specific surface area of chitosan. Based on the results obtained, the following conclusions were reached. Ketotifen might be absorbed into the bulk structure of chitosan in addition to being adsorbed on the surface and the ability of chitosan to swell at pH 7 has a significant role in increasing its uptake.

Enhanced affinity of ketotifen toward tamarind seed polysaccharide in comparison with hydroxyethylcellulose and hyaluronic acid: a nuclear magnetic resonance investigation.

Nuclear magnetic resonance (NMR) spectroscopy demonstrated that, in aqueous solution, ketotifen fumarate bound more strongly to tamarind seed polysaccharide (TSP) than to hydroxyethylcellulose or hyaluronic acid. Results were confirmed by dynamic dialysis technique.

Transport and structural analysis of molecular imprinted hydrogels for controlled drug delivery.

Molecular imprinting provides a rational design strategy for the development of controlled release drug delivery systems. We demonstrate that imprinting a hydrogel network results in macromolecular memory for the template molecule, indicated by the two or more times greater partitioning into these networks as compared to non-imprinted networks. Partitioning of drug into networks synthesized from multiple functional monomers was 8 times greater than networks synthesized from single monomers. One-dimensional permeation studies showed that the gel with maximum incorporated chemical functionality had the lowest diffusion coefficient, which was one to two orders of magnitude lower than all other gels studied. All imprinted networks had significantly lower diffusion coefficients than non-imprinted networks, in spite of comparable mesh sizes and equilibrium polymer volume fractions in the swollen state, which to our knowledge, is the first time that such a study has been conducted in the literature. We propose the "tumbling hypothesis", wherein a molecule tumbling through an imprinted network with multiple, organized functionalities and an appropriate mesh size, experiences heightened interactions with memory sites and shows delayed transport kinetics. Thus, the structural plasticity of polymer chains, i.e. the organization of functional groups into memory sites, may be responsible for enhanced loading and extended release.

Ketotifen controlled release from cellulose acetate propionate and cellulose acetate butyrate membranes.

Ketotifen was immobilised in cellulose acetate propionate (CAP) membranes and in cellulose acetate butyrate (CAB) membranes. The characteristics of each system were evaluated under a range of experimental conditions. The topography and uniformity of the membranes was assessed using scanning electron microscopy. The release characteristics associated with Ketotifen were monitored spectrophotometrically. The swelling capacity of the membranes was evaluated and attributed to the combined effects of diffusion and of complex dissociation, during swelling. The materials produced were able to provide controlled release of Ketotifen due to their controlled swelling behaviour and adequate release properties. The results showed that the release of Ketotifen from the CAB membranes is higher but the release from the CAP membranes is more uniform.