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Transdermal Drug Delivery (transdermal + drug_delivery)

Distribution by Scientific Domains

Chemistry	33%
Polymers and Materials Science	25%
Medical Sciences	25%

Selected Abstracts

Two Photon Polymerization of Polymer,Ceramic Hybrid Materials for Transdermal Drug Delivery

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 1 2007
A. Ovsianikov
Three-dimensional microneedle devices were created by femtosecond laser two photon polymerization (2PP) of organically modified ceramic (Ormocer®) hybrid materials. Arrays of in-plane and out-of-plane hollow microneedles (microneedle length=800 ,m, microneedle base diameter=150,300 ,m) with various aspect ratios were fabricated. The fracture and penetration properties of the microneedle arrays were examined using compression load testing. In these studies, the microneedle arrays penetrated cadaveric porcine adipose tissue without fracture. Human epidermal keratinocyte viability on the Ormocer® surfaces polymerized using 2PP was similar to that on control surfaces. These results suggest that 2PP is able to create microneedle structures for transdermal drug delivery with a larger range of geometries than conventional microfabrication techniques. [source]

Transdermal drug delivery by coated microneedles: geometry effects on drug concentration in blood

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2009
Barrak Al-Qallaf
Abstract Drug administration through transdermal delivery is restricted by the top layer of skin, the stratum corneum. One possible solution to overcome the barrier function of the stratum corneum is to employ microneedle arrays. However, detailed theoretical models relating drug-coated microneedles and their geometry to the drug concentration in the blood are limited. This article aims to address this issue by examining the blood concentration profiles for a model drug, insulin, that has been administered via coated microneedles. A mathematical model is introduced and applied to predict theoretical blood concentrations. Furthermore, the insulin concentration in blood is calculated for a range of different microneedle shapes and dimensions to identify the most effective geometry. The results indicate that the optimum microneedle geometry in terms of maximizing insulin concentration was a rocket-shaped needle with a constant tip angle of 90°. Also, it has been found that the number of microneedles in an array is the most significant factor in determining maximum insulin concentration in the blood (Cb, max). Penetration depth of the microneedle, centre-to-centre spacing and microneedle thickness had a less significant effect on the maximum insulin concentration in the blood. It is envisaged that the current study will help in designing microneedles of optimum size and shape for transdermal drug delivery. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Low-Frequency Sonophoresis: A Noninvasive Method of Drug Delivery and Diagnostics

BIOTECHNOLOGY PROGRESS, Issue 3 2000
Samir Mitragotri
Transdermal drug delivery offers an attractive alternative to injections and oral medications. However, applications of transdermal drug delivery are limited to only a few drugs as a result of low skin permeability. Application of low-frequency ultrasound enhances skin permeability, a phenomenon referred to as low-frequency sonophoresis. In this method, a short application of ultrasound is used to permeabilize skin for a prolonged period of time. During this period, ultrasonically permeabilized skin may be utilized for drug delivery. In addition, a sample of interstitial fluid or its components may be extracted through permeabilized skin for diagnostic applications. In this paper, we report our in vivo studies that demonstrate the principles of both of these concepts. Detailed studies on drug delivery are performed using inulin and mannitol as model drugs. Studies on diagnostics are performed using glucose as a model analyte. Applications of this technology to drug delivery and diagnostics are discussed. [source]

Two Photon Polymerization-Micromolding of Polyethylene Glycol-Gentamicin Sulfate Microneedles

ADVANCED ENGINEERING MATERIALS, Issue 4 2010
Shaun D. Gittard
The use of microneedles for transdermal drug delivery is limited due to the risk of infection associated with formation of channels through the stratum corneum layer of the epidermis. The risk of infection associated with use of microneedles may be reduced by imparting these devices with antimicrobial properties. In this study, a photopolymerization-micromolding technique was used to fabricate microneedle arrays from a photosensitive material containing polyethylene glycol 600 diacrylate, gentamicin sulfate, and a photoinitiator. Scanning electron microscopy indicated that the photopolymerization-micromolding process produced microneedle arrays that exhibited good microneedle-to-microneedle uniformity. An agar plating assay revealed that microneedles fabricated with polyethylene glycol 600 diacrylate containing 2,mg mL,1 gentamicin sulfate inhibited growth of Staphylococcus aureus bacteria. Scanning electron microscopy revealed no platelet aggregation on the surfaces of platelet rich plasma-exposed undoped polyethylene glycol 600 diacrylate microneedles and gentamicin-doped polyethylene glycol 600 diacrylate microneedles. These efforts will enable wider adoption of microneedles for transdermal delivery of pharmacologic agents. [source]

Two Photon Polymerization of Polymer,Ceramic Hybrid Materials for Transdermal Drug Delivery

Design of improved permeation enhancers for transdermal drug delivery

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2009
Srinivas S. Godavarthy
Abstract One promising way to breach the skin's natural barrier to drugs is by the application of chemicals called penetration enhancers. However, identifying potential enhancers is difficult and time consuming. We have developed a virtual screening algorithm for generating potential chemical penetration enhancers (CPEs) by integrating nonlinear, theory-based quantitative structure,property relationship models, genetic algorithms, and neural networks. Our newly developed algorithm was used to identify seven potential CPE molecular structures. These chemical enhancers were tested for their toxicity on (a) mouse embryonic fibroblasts (MEFs) with MTT assay, and (b) porcine abdominal skin by histology using H/E staining at the end of a 48-h exposure period to the chemicals. Further, melatonin permeability in the presence of the enhancers was tested using porcine skin and Franz diffusion cells. Careful toxicity tests showed that four of the seven "general" CPEs were nontoxic candidate enhancers (menthone, 1-(1-adamantyl)-2-pyrrolidinone, R(+)-3-amino-1-hydroxy-2-pyrrolidinone, and 1-(4-nitro-phenyl)-pyrrolidine-2,5-dione). Further testing of these four molecules as potential melatonin-specific CPEs revealed that only menthone and 1-dodecyl-2-pyrrolidinone provided sufficient enhancement of the melatonin permeation. The results from our permeability and toxicity measurements provide validation of the efficacy and ability of our virtual screening algorithm for generating potential chemical enhancer structures by virtual screening algorithms, in addition to providing additional experimental data to the body of knowledge. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:4085,4099, 2009 [source]

Elastic liposomes mediated transdermal delivery of an anti-hypertensive agent: Propranolol hydrochloride

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2007
Dinesh Mishra
Abstract One major problem encountered in transdermal drug delivery is the low permeability of drugs through the skin barrier. In the present investigation ultradeformable lipid vesicles, that is, elastic liposomes were prepared incorporating propranolol hydrochloride for enhanced transdermal delivery. Elastic liposomes bearing propranolol hydrochloride were prepared by conventional rotary evaporation method and characterized for various parameters including vesicles shape and surface morphology, size and size distribution, entrapment efficiency, elasticity, turbidity, and in vitro drug release. In vitro flux, enhancement ratio (ER), and release pattern of propranolol hydrochloride were calculated for transdermal delivery. In vivo study conducted on male albino rats (Sprague Dawley) was also taken as a measure of performance of elastic liposomal, liposomal, and plain drug solution. The better permeation through the skin was confirmed by confocal laser scanning microscopy (CLSM). Results indicate that the elastic liposomal formulation for transdermal delivery of propranolol hydrochloride provides better transdermal flux, higher entrapment efficiency, ability as a self-penetration enhancer and effectiveness for transdermal delivery as compared to liposomes. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96:145,155, 2007 [source]

Ester prodrugs of morphine improve transdermal drug delivery: a mechanistic study

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2007
Jhi-Joung Wang
Two alkyl esters of morphine, morphine propionate (MPR) and morphine enanthate (MEN), were synthesized as potential prodrugs for transdermal delivery. The ester prodrugs could enhance transdermal morphine delivery. The mechanisms of this enhancing effect were elucidated in this study. Both prodrugs were more lipophilic than their parent drug as evaluated by the skin/vehicle partition coefficient (log P) and capacity factor (log K,). The in-vitro skin permeation of morphine and its prodrugs from pH 6 buffer was in the order of MEN > MPR > morphine. MPR and MEN respectively enhanced the transdermal delivery of morphine by 2- and 5-fold. A contrary result was observed when using sesame oil as the vehicle. The prodrugs were stable against chemical hydrolysis in an aqueous solution, but were readily hydrolysed to the parent drug when exposed to skin homogenate and esterase. Approximately 98% MPR and ,75% MEN were converted to morphine in an in-vitro permeation experiment. The viable epidermis/dermis contributed to a significant resistance to the permeation of ester prodrugs. According to the data of skin permeation across ethanol-, ,-terpineol-, and oleic acid-pretreated skin, MEN was predominantly transported via lipid bilayer lamellae in the stratum corneum. The intercellular pathway was not important for either morphine or MPR permeation. [source]

Novel approach to improve permeation of ondansetron across shed snake skin as a model membrane

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2001
Koichi Takahashi
The purpose of this study was to investigate the feasibility of transdermal drug delivery of ondansetron, an antagonist of the 5-HT3 receptor, used for the treatment of chemotherapy-induced emesis. The permeability of ondansetron from an aqueous suspension through shed snake skin as a model membrane was very low and in order to improve it, several enhancers were tested. Ethanol increased the flux at a concentration of 40% or more. The solubility of ondansetron also increased as the ethanol concentration increased. The permeability coefficient increased after pretreatment of the shed snake skin with Azone, oleic acid or lauryl alcohol. Further improvement of the permeability was observed when ethanol was combined with other enhancers and was maximum for the combination of ethanol and oleic acid. Oleic acid dramatically increased the partition of ondansetron to n -hexane and shed snake skin. Oleic acid may enhance the permeation of ondansetron in two ways: by a direct effect on the stratum corneum or via counterion formation of an ion-pair. The maximum flux obtained from the combination of ethanol and other enhancers seems to be high enough to obtain a therapeutic effect. [source]

Pharmaceutical and therapeutic Potentials of essential oils and their individual volatile constituents: a review

PHYTOTHERAPY RESEARCH, Issue 4 2007
Amr E. Edris
Abstract Essential oils and their volatile constituents are used widely to prevent and treat human disease. The possible role and mode of action of these natural products is discussed with regard to the prevention and treatment of cancer, cardiovascular diseases including atherosclerosis and thrombosis, as well as their bioactivity as antibacterial, antiviral, antioxidants and antidiabetic agents. Their application as natural skin penetration enhancers for transdermal drug delivery and the therapeutic properties of essential oils in aroma and massage therapy will also be outlined. Copyright © 2007 John Wiley & Sons, Ltd. [source]