Drug Delivery Module Research Articles

An overview on trends and development of niosomes as drug delivery

Niosomes or non ionic surfactant are microscopic lamellar structures which may be unilamellar or multilamellar. These are amphiphillic in nature, hence capable of entrapping both hydrophilic and lipophilic drugs for their controlled delivery. Niosomes are formulated by hydration of the lipid by the aqueous phase which may be either single surfactant or a mixture of surfactant with cholesterol. Stability of niosomes is greater as compared with other novel drug delivery techniques. Niosomes are widely used for delivery of many drugs especially in treatment of life threatening diseases, site specific targeting can be achieved with niosomes, and they are also used in diagnostic imaging purpose. This study is based upon the recent advances by which niosomes can be formulated and their application in controlled and effective delivery of variousdrugs. Niosomes represent a promising drug delivery module. They present a structure similar to liposome and hence they can represent alternative vesicular systems with respect to liposomes, due to the niosome ability to encapsulate different type of drugs within their multi environmental structure. Niosomes are thoughts to be better candidate's drug delivery as compared to liposomes due to various factors like cost, stability etc. Various types of drug deliveries can be possible using niosomes like targeting, ophthalmic, topical, parenteral, etc.

Tyloxapol niosomes as prospective drug delivery module for antiretroviral drug nevirapine.

With the aim of assuring more patient compliant pharmacotherapy for acquired immuno deficiency syndrome, a formulation of the first line anti-retroviral drug, nevirapine (NVP), has been developed by encapsulating it within niosomes. Biocompatible niosomes were fabricated using a biological surfactant, tyloxapol, with variable cholesterol concentrations. Formulation with surfactant/cholesterol molar ratio 1:0.1 exhibits maximum stability and optimum hydrophobicity. Thus, it is most suitable for the entrapment of NVP and has high entrapment efficiency of 94.3%. FTIR and DSC results indicate that NVP has sufficient compatibility with the excipients of the formulation. Photoluminescence quenching measurements were employed to elucidate the position of drug molecules in niosome bilayer along with the partition coefficient. Dissolution results indicate that the efflux of drug is sustained which creates a depot effect and decreases the fluctuations in drug release. Such a versatile and improved formulation of NVP is expected to increase its therapeutic index and alleviate toxic systemic side effects while improving the quality of life and duration of survival of the patients.

Investigation of the swelling behavior of Dome Matrix drug delivery modules by high-resolution X-ray computed tomography

The swelling behavior of novel Dome Matrix drug delivery modules was investigated using high-resolution X-ray computed tomography studies. The technique was exploited to investigate the swelling front position and the conditions of the interacting surfaces in situ without removing the sample from the medium during swelling. Surface and volume evolution of the glassy core under the gel layer were precisely described. Within the gel formed on the glassy core there were several particles not completely dissolved or swollen, transported from the core by the stresses due to the polymer swelling. The gel portion defined as partially swollen gel was evidenced on the convex and flat surfaces of tablets, where a line of fracture in the gel could be observed near the glassy core. In addition, the presence of solid particles in the gel layer confirmed that the translocation of particles in the swellable system affected the drug and polymer gradient within the system.

The disposition of free and niosomally encapsulated Rac-flurbiprofen in dairy bovines

Pharmacokinetic parameters were established for flurbiprofen (FBP) after intravenous (i.v.) administration (0.5 mg/kg) of niosomal and nonniosomal formulations in dairy cattle. Niosomes of FBP showed a drug loading of 92.0 +/- 0.7% and the intravenous administration of the FBP niosomes to dairy cattle did not produce any immunological reaction associated to niosomal components. Niosomal FBP was slowly eliminated from plasma and mean residual time (MRT) and AUC(0-->t) and t (1/2) values were significantly higher than those for non niosomal FBP formulations. The results presented in this study indicate that the long circulation of FBP niosomes offers a potential application for improving the pharmacokinetic parameters of short half-life drugs for clinical use. Niosomes offer new promising perspectives of drug delivery modules in bovine therapeutics.

MDR1 (ABCB1) G1199A (Ser400Asn) polymorphism alters transepithelial permeability and sensitivity to anticancer agents

P-glycoprotein (P-gp), encoded by MDR1 (or ABCB1), is important in anticancer drug delivery and resistance. We evaluated alterations in P-gp-mediated transport of anticancer agents due to the MDR1 G1199A polymorphism. Using stable recombinant epithelial cells expressing wild-type (MDR1 (wt)) or G1199A (MDR1 (1199A)), anticancer drug sensitivity and transepithelial permeability were evaluated. The recombinant cells MDR1 (wt) and MDR1 ( 1199A ) displayed comparable doxorubicin resistance. However, MDR1 (1199A) cells displayed greater resistance to vinblastine, vincristine, paclitaxel, and VP-16 (11-, 2.9-, 1.9-, and 2.9-fold, respectively). Alterations in transepithelial permeability paralleled these changes. Efflux of doxorubicin was similar between MDR1 wt - and MDR1 (1199A)-expressing cells, while P-gp-mediated transport was greater for vinblastine and vincristine in MDR1 (1199A) cells (2.9- and 2.0-fold, respectively). The occurrence and magnitude of the MDR1 G1199A effect is drug specific. Overall, the MDR1 G1199A polymorphism may impact anticancer efficacy through modulation of drug distribution and delivery to target tumor cells.

Dendrimers - reflections on host-guest interaction mechanism towards solubility enhancement

Hydrophobicity of a bioactive is one area of major concern that poses as a great hindrance in the development of a therapeutically effective dosage form and prevents sufficient delivery of the drug to the target site. Since the last decade, dendrimers have emerged as highly promising drug delivery modules because of their unique structure and properties. Solubility enhancement is an important aspect of dendrimers and this is a synergy with site-specific drug delivery. The hydrophobic guests when entrapped in the hydrophobic channels of dendrimers are solubilized in the aqueous solution. The present article explores the various complex interaction mechanisms between the dendrimer and a bioactive. Hence the objective of this review is to reflect the host-guest interactions with the potential role of the proposed system, to enhance drug solubility and bioavailability.

Characterization of in Vitro Transdermal Iontophoretic Delivery of Insulin

In-vitro studies were conducted to characterize the transdermal iontophoretic delivery of insulin, thus avoiding potential complications from various biological variations, which may be encountered during in-vivo studies. The proteolytic degradation of insulin in skin homogenates and degradation under the experimental conditions used was investigated. Appropriate adjuvants were incorporated to minimize the potential degradation problems of insulin. 125I-Insulin was observed to penetrate into and accumulate in the skin during the iontophoresis period. It was then released gradually from this depot, as a mixture of intact and 125-I labelled fragments, into the receptor medium. Drug desorption studies supported the theory of skin depot or reservoir formation. It was found that an electric field could be used to facilitate the desorption of drug from the depot. The post-application flux of insulin (or its fragments) from the skin depot formed during iontophoresis was monitored to study the factors affecting the iontophoretic delivery of insulin. Stripping and delipidization of the skin were noted to increase the skin permeation rate of insulin. The cumulative radioactivity permeated and accumulated in the skin was higher at pH 3.6 than at pH 7.4. The iontophoresis-facilitated transdermal delivery was observed to increase with increasing duration of current application and increasing donor concentration of insulin. Modulation of drug delivery by multiple applications was also found to be feasible.

Drug Delivery Systems 5A. Oral Drug Delivery

The two main advantages of controlled drug delivery systems are: maintenance of therapeutically optimum drug concentrations in the plasma through zero-order release without significant fluctuations; and elimination of the need for frequent single dose administrations. The oral and other therapeutic systems in human use have validated the concept that controlled continuous drug release can minimize the daily dose of a drug required to maintain the required therapeutic effect, while minimizing unwanted pharmacological effects. By minimizing patient intervention, a design feature of therapeutic systems, compliance is automatically enhanced. Oral drug delivery systems, in particular, have required innovation in materials science to provide materials biocompatible during prolonged contact with body tissues, bioengineering to develop drug delivery modules, and clinical pharmacology for elucidation of drug action under conditions of continuous controlled drug administration. Recent work in advanced oral delivery has been primarily focused on liposome technology and the concept that substances that are normally destroyed by the stomach can be protected long enough before they could be absorbed downstream. For cost and patient convenience, oral delivery certainly would be an attractive method. The nature of biologic substances, however, with their unique technical problems, will probably limit greatly those that can be delivered orally. Besides, where delivery rate control is critical, oral delivery, even when possible, would probably be insufficiently precise. Oral delivery would also limit the substance to bloodstream delivery to the disease site. Even so, oral controlled drug delivery systems will likely find primary usefulness in specific carefully controlled therapies and prophylactic situations with due regard for drug interactions. This system represents a potentially very significant therapeutic modality. These delivery systems will find usefulness primarily in certain well-defined and well-controllable areas with due regard for individual patient variations. The purpose of the present article is to review oral controlled-release drug delivery systems, with particular emphasis on the practical aspects of testing and fabricating these systems and the underlying mechanisms by which control over drug release rate is accomplished.