Application of TPX polymer membranes for the controlled release of triprolidine

Lipid Cubic Systems for Sustained and Controlled Delivery of Antihistamine Drugs

Antihistamines are capable of blocking mediator responses in allergic reactions including allergic rhinitis and dermatological reactions. By incorporating various H1 receptor antagonists into a lipid cubic phase network, these active ingredients can be delivered locally over an extended period of time owing to the mucoadhesive nature of the system. Local delivery can avoid inducing unwanted side effects, often observed after systematic delivery. Lipid-based antihistamine delivery systems are shown here to exhibit prolonged release capabilities. In vitro drug dissolution studies investigated the extent and release rate of two model first-generation and two model second-generation H1 antagonist antihistamine drugs from two monoacyglycerol-derived lipid models. To optimize the formulation approach, the systems were characterized macroscopically and microscopically by small-angle X-ray scattering and polarized light to ascertain the mesophase accessed upon an incorporation of antihistamines of varying solubilities and size. The impact of encapsulating the antihistamine molecules on the degree of mucoadhesivity of the lipid cubic systems was investigated using multiparametric surface plasmon resonance. With the ultimate goal of developing therapies for the treatment of allergic reactions, the ability of the formulations to inhibit mediator release utilizing RBL-2H3 mast cells with the propensity to release histamine upon induction was explored, demonstrating no interference from the lipid excipient on the effectiveness of the antihistamine molecules.

Highly effective photon-to-cooling thermal device

Photon-to-cooling phenomenon relies on the atmospheric transparency window to dissipate heat from the earth into outer space, which is an energy-saving cooling technique. This work demonstrates a highly effective aluminized Polymethylpentene (PMP) thin-film thermal structure. The emissivity of aluminized PMP thin films matches well to the atmospheric transparency window so as to minimize parasitic heat losses. This photon-to-cooling structure yields a temperature drop of 8.5 K in comparison to the ambient temperature and a corresponding radiative cooling power of 193 W/m2 during a one-day cycle. The easy-to-manufacture feature of an aluminized PMP thin film makes it a practically scalable radiative cooling method.

Controlled Release of Pranoprofen from the Ethylene-Vinyl Acetate Matrix Using Plasticizer

An ethylene-vinyl acetate (EVA) matrix containing pranoprofen was prepared using the casting method and the release patterns of pranoprofen were observed. The solubility of pranoprofen was determined to be a function of the volume fraction of polyethylene glycol 400. The release of the drug from the matrix was examined as a function of temperature and drug concentration. Plasticizers such as the citrates and the phthalates were added to prepare the membrane in order to increase the flexibility of the EVA matrix. The solubility of pranoprofen was the highest when the PEG 400 concentration was 20% (v/v). The rate of drug release from the EVA matrix increased with increasing temperature and drug loading dose. There was a linear relationship between the flux of pranoprofen and the square root of the loading dose. The activation energy of release (Ea), which was measured from the slope of the log P versus 1000/T plots, was estimated to be 17.44, 16.14, 14.88, and 14.78 kcal/mol for loading doses of 0.5, 1, 1.5, and 2%, respectively. Among the plasticizers used such as the citrate and the phthalate groups, diethyl phthalate had the best enhancing effects on drug release. In conclusion, the application of an EVA matrix containing a plasticizer might be useful in the development of a controlled drug delivery system.

Poly(2-hydroxy-3-phenoxypropylacrylate, 4-hydroxybutyl acrylate, dibutyl maleate) membrane controlled clonidine zero-order release

Poly(2-hydroxy-3-phenoxypropylacrylate, 4-hydroxybutyl acrylate, dibutyl maleate) membrane was synthesized by UV curing method in our laboratory for the first time. When above-mentioned monomers were in the weight ratio of 4:4:2, the membrane not only had perfect permeation property but also had excellent plasticity, so the membrane made from monomers in the ratio of 4:4:2 was chosen as an optimized membrane. The optimized membrane provided perfect linear permeation properties in clonidine transdermal drug delivery system. The permeation rate decreased in proportion to the thickness of membrane. When the concentrations of clonidine were in the range of 0.5-7.0mg/ml, the permeation rate was proportional to the square root of clonidine concentrations. The optimized membrane was characterized by FTIR, DSC and SEM.

A new copolymer membrane controlling clonidine linear release in a transdermal drug delivery system

A new type of copolymer membranes was prepared through photosynthesis of mixtures of three different monomers. The membranes present a linear permeation property in clonidine transdermal drug delivery system. Monomers used in the photosynthesis were 2-hydroxy-3-phenoxypropylacrylate, 4-hydroxybutyl acrylate and sec-butyl tiglate. Permeation property of the membranes with different monomer ratios and thickness were investigated. When clonidine concentrations were in 3.0 - 5.0 mg/ml range, membranes showed near zero order permeation rates. An optimized membrane was characterized by FTIR, DSC and SEM.

Enhanced efficacy of triprolidine by transdermal application of the EVA matrix system in rabbits and rats

The bioavailability of triprolidine from the ethylene vinyl acetate (EVA) matrix system containing polyoxyethylene-2-oleyl ether was studied to determine the feasibility of enhanced transdermal delivery of triprolidine in rabbits. The antihistamine effects were also confirmed to determine the percutaneous absorption of triprolidine from the EVA matrix system containing a penetration enhancer and plasticizer in rats. The triprolidine-EVA matrix (50mg/kg) was applied to the abdominal skin of rabbits. Blood samples were collected via the femoral artery for 36 h and the plasma concentrations of triprolidine were determined by HPLC. The pharmacokinetic parameters were calculated using the LAGRAN computer program. The area under the curve(AUC) was significantly higher in the enhancer group (4582+/-1456 ng/mL h) than that (2958+/-997 ng/mL h) in the control group (P<0.05), showing an approximate 155% increased bioavailability. The average Cmax in the enhancer group (241+/-46.5 ng/mL) was significantly higher than that in the control group (198+/-28.9 ng/mL), (P<0.05). The mean Tmax in the enhancer group (8.0+/-2.57 h) was higher than that in the control group (6.0+/-2.24 h, but this was not statistically significantly. The relative bioavailability of triprolidine in the transdermal application was 35.9% in the control group and 55.6% in the enhancer group compared comparing with that after oral administration. As the triprolidine-EVA matrix, which contains polyoxyethylene-2-oleyl ether as an enhancer and triethyl citrate as a plasticizer was administered to the rabbits via the transdermal routes, the relative bioavailability increased approximately 1.55 fold compared with that in the control group, showing a relatively constant, sustained blood concentration with minimal fluctuation. The antihistamine effect was determined using the Evans blue dye procedure by comparing the changes in the vascular permeability increase following the transdermal application. The vascular permeability increase was reduced significantly by the transdermal application of the EVA-triprolidine system containing triethyl citrate and polyoxyethylene-2-oleyl ether. These results show that the plasticizer and penetration enhancer increase the skin permeation of triprolidine and the triprolidine-EVA matrix system could be developed as a transdermal delivery system providing the increased constant plasma concentration and antihistamine effects.

Antihistamine effects of triprolidine from the transdermal administration of the TPX matrix in rats

The antihistamine effects of the triprolidine were studied in rats to determine the feasibility of their enhanced transdermal delivery from the poly (4-methyl-1-pentene) (TPX) matrix system containing penetration enhancer and plasticizer. The antihistamine effects were determined by the Evans blue dye procedure by comparing the changes in vascular permeability increase following the transdermal administration. The vascular permeability increase was significantly reduced by transdermal administration of the triprolidine-TPX system containing triethyl citrate (TEC) and polyoxyethylene-2-oleyl ether (POE). Both the plasticizer and penetration enhancer played an important role in the skin permeation of triprolidine and increased the antihistamine effects. These results showed that the triprolidine-TPX matrix system containing plasticizer and penetration enhancer could be a transdermal delivery system providing the increased antihistamine effects.

Enhanced transdermal delivery of atenolol from the ethylene–vinyl acetate matrix

To enhance transdermal delivery of atenolol, ethylene-vinyl acetate (EVA) matrix of drug containing penetration enhancer was fabricated. Effect of penetration enhancer on the permeation of atenolol through the excised rat skin was studied. Penetrating enhancers showed the increased flux probably due to the enhancing effect on the skin barrier, the stratum corneum. Among enhancers used such as glycols, fatty acids and non-ionic surfactants, polyoxyethylene 2-oleyl ether showed the best enhancement. For the controlling transdermal delivery of atenolol, the application of EVA matrix containing permeation enhancer could be useful in the development of transdermal drug delivery system.

The use of polymers for dermal and transdermal delivery

The use of polymers for skin preparations is manifold. Requirements of such polymers are dependent on the formulation types. The most applied polymers on skin belong to various classes, for example to cellulose derivatives, chitosan, carageenan, polyacrylates, polyvinylalcohol, polyvinylpyrrolidone and silicones. They are gelating agents, matrices in patches and wound dressings, anti-nucleants and penetration enhancers. Correlations between commercially available products and results of new scientific investigations are often difficult or not possible, because of the lack of comparative data especially for transdermal patches. Finally, two promising future trends of polymeric systems, gene delivery and tissue engineering, are discussed.

Enhanced transdermal delivery of triprolidine from the ethylene-vinyl acetate matrix

Triprolidine-containing matrix was fabricated with ethylene-vinyl acetate (EVA) copolymer to control the release of the drug. The permeation rate of triprolidine in the stripped skin was greatly larger than that in the whole skin. Thus it showed that the stratum corneum acts as a barrier of skin permeation. The effect of penetration enhancer and stripping of skin on the permeation of triprolidine through the excised mouse skin was studied. Penetrating enhancers showed increased flux probably due to the enhancing effect on the skin barrier, the stratum corneum. Among enhancers used such as glycols, fatty acids and non-ionic surfactants, polyoxyethylene-2-oleyl ether showed the best enhancement. The permeability of triprolidine was markedly increased with stripping of the mouse skin to remove the stratum corneum that acts as a barrier of skin permeation. For the controlling transdermal delivery of triprolidine, the application of EVA membrane containing permeation enhancer could be useful in the development of transdermal drug delivery system.

Controlled release of triprolidine using ethylene-vinyl acetate membrane and matrix systems

The studies on the permeability of triprolidine through ethylene-vinyl acetate (EVA) copolymer membrane using two-chamber diffusion cell was carried out to develop the controlled delivery system. To evaluate the effect of drug concentration in reservoir, polyethylene glycol (PEG) 400 was added to saline solution as a solubilizer and a sink condition was maintained in the receptor solution. The permeation rate of drug through EVA membrane was proportional to PEG 400 volume fraction. A linear relationship existed between the permeation rate and the reciprocal of the membrane thickness. Triprolidine-containing matrix was fabricated with EVA copolymer to control the release of the drug. The plasticizers was added for preparing the pore structure of EVA membranes to increase the drug release. The effects of PEG 400, vinyl acetate (VA) contents of EVA, membrane thickness, drug concentration, temperature, and plasticizers, on drug release were studied. The release rate of drug from the EVA matrix increased with PEG 400 volume fraction, increased temperature and drug loading doses. An increased vinyl acetate comonomer content in EVA membrane increased the drug release rate and permeability coefficient. Among the plasticizers used such as alkyl citrates and phthalates, tetra ethyl citrate showed the best enhancing effects showing the enhancement factor of 1.88. The release of triprolidine from the EVA matrix follows a diffusion controlled model, where the quantity released per unit area is proportional to the square root of time. The controlled release of triprolidine could be achieved using the EVA polymer including the plasticizer.

Transdermal delivery of triprolidine using TPX polymer membrane

Triprolidine-containing matrix was fabricated with poly(4-methyl-1-pentene) (TPX) polymer to control the release of the drug. Effect of penetration enhancer and stripping of skin on the permeation of triprolidine through the excised mouse skin was studied. Penetrating enhancers showed the increased flux probably due to the enhancing effect on the skin barrier, the stratum corneum. Among enhancers used such as glycols, fatty acids and non-ionic surfactants, polyoxyethylene-2-oleyl ether showed the best enhancement. The permeability of triprolidine was markedly increased with stripping the mouse skin to remove the stratum corneum, which acts as a barrier of skin permeation. For the controlling delivery of triprolidine, the TPX matrix containing permeation enhancer could be developed.