Recent Patents on Drug Delivery & Formulation

ISSN: 1872-2113

Recent Patents on Drug Delivery & Formulation
Volume 2, Number 2, June 2008

Contents


Incorporation of Small Molecular Weight Active Agents into Polymeric Components Pp. 94-107
Sofia M. Iconomopoulou, Joannis K. Kallitsis and George A. Voyiatzis
[Abstract]


Mucoadhesive Polymers for Delivery of Drugs to the Oral Cavity Pp. 108-119
Boaz Mizrahi and Abraham J. Domb
[Abstract]


Recent Advances and Patents on Solid Lipid Nanoparticles Pp. 120-135
Krutika K. Sawant and Shamsunder S. Dodiya
[Abstract]


Potential of Microemulsions in Drug Delivery and Therapeutics: A Patent Review Pp. 136-144
Vikas Bali, Bhavna, Mushir Ali, Sanjula Baboota and Javed Ali
[Abstract]


Inventions Designed to Enhance Drug Delivery Across Epithelial and Endothelial Cells Through the Paracellular Pathway Pp. 145-176
Lorenza Gonzalez-Mariscal, Sandra Hernández and Jesús Vega
[Abstract]


Buccoadhesive Drug Delivery Systems - Extensive Review on Recent Patents Pp. 177-188
Shadab A. Pathan, Zeenat Iqbal, Jasjeet K. Sahani, Sushma Talegaonkar, Roop K. Khar and Farhan J. Ahmad
[Abstract]


Recent Advances on Patents in Poly(Ethylene Glycol)-Base Drug Delivery Pp. 189-195
Gian M. Bonora and Sara Drioli
[Abstract]


Patent Selections Pp. 196-199




Abstracts


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Incorporation of Small Molecular Weight Active Agents into Polymeric Components
Sofia M. Iconomopoulou, Joannis K. Kallitsis and George A. Voyiatzis

The incorporation of small molecular weight active agents into polymeric matrixes bearing controlled release characteristics represents an interesting strategy with numerous useful applications. Antimicrobials, biocides, fungicides or drugs, encapsulated into erodible or non-erodible polymeric micro-spheres, micro-capsules and micro-shells or/and embedded into continuous polymeric matrixes, are controlled released either by particular degradation routes or/and by specific stimuli. Cross-linking, curing or micro-porosity generating agents acting during polymerization impart additional controlled encapsulation characteristics to the active substances. Release modulating agents, like retardants or carrier materials used as vehicles are often encapsulated into microspheres or dispersed within polymeric compositions for the controlled introduction of an active agent into a liquid-based medium. The aim of this review is to reveal relevant strategies reported in recent patents on the encapsulation or incorporation of low molecular weight active agents into the matrix of polymers bearing controlled release characteristics. The inventions described implicate the formation of both erodible and non erodible polymer microparticles that contain active ingredients. Modification of polymer matrix and inorganic porous carriers represent pertinent major strategies that have been also developed and patented.


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Mucoadhesive Polymers for Delivery of Drugs to the Oral Cavity
Boaz Mizrahi and Abraham J. Domb

Local therapy of the oral cavity is used to treat conditions such as gingivitis, oral candidosis, oral lesions, dental caries, xerostoma and oral carcinomas. Delivery systems used include mouthwashes, aerosol sprays, chewing gums, bioadhesive tablets, films, gels and pastes. There are three major problems associated with drug therapy within the oral cavity: rapid elimination of drugs due to the flushing action of saliva or the ingestion of food, the non-uniform distribution of drugs within saliva on release from a solid or semisolid delivery system and patient compliance in terms of taste.

Prolonged contact time of a drug with body tissue can significantly improve the clinical performance of many agents used for treating oral disorders. These improvements range from better treatment of local pathologies to improved drug bioavailability and controlled release to enhanced patient compliance. There are abundant examples in the literature over the past 15 years of these improvements using bioadhesive polymers.

This manuscript summarizes the innovations pertaining to formulation and treatments as described in recent patents.


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Recent Advances and Patents on Solid Lipid Nanoparticles
Krutika K. Sawant and Shamsunder S. Dodiya

Solid Lipid Nanoparticles (SLNs) have attracted increasing scientific and commercial attention as colloidal drug carriers during the last decade. They have emerged as a potential alternative compared to other colloidal systems like polymeric nanoparticles, liposomes and fat emulsions, as they have been claimed to combine their advantages but successfully overcome their drawbacks. SLN formulations are extensively developed and characterized for their in vitro and in vivo applications by various routes like parenteral, oral, pulmonary, ocular, and dermal. SLNs are being widely investigated as carriers for delivery of macromolecules like proteins, oligonucleotides and DNA. SLNs have already been taken up for medium and large scale production using two of its reported production methods. In fact, the first SLN based product has recently been introduced in the Poland market as a topically applied moisturizer. Newer methods for production of SLNs and their applications are being reported and patented. Nanostructured lipid carriers (NLC) are mixture of solid lipid and liquid lipid while Lipid Drug Conjugates (LDC) are water insoluble lipid carrier for loading of poorly lipid soluble drugs. These new generation of lipid nanoparticles have been claimed to overcome the shortcomings of SLNs.

This article reviews the formulation, characterization, applications, and patents on the advances and research on SLNs, NLC and LDC.


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Potential of Microemulsions in Drug Delivery and Therapeutics: A Patent Review
Vikas Bali, Bhavna, Mushir Ali, Sanjula Baboota and Javed Ali

The recent success of cyclosporin marketed formulation - Sandimmune Neoral^® by Sandoz in Europe has invigorated the gaining interest in microemulsions as potential drug delivery systems. These thermodynamically stable, transparent (or translucent) dispersions of oil and water stabilized by an interfacial film of surfactant molecules have potential applications whenever it is necessary to mix oil and water and where a large oil-water interface is required. Thus, microemulsions have drawn considerable interest. Until now excellent reviews covering aspects of bioavailability, theories, physical properties, formulation design, physical characterization, drug release and delivery potential have been cited in literature but there is no review that discusses the intellectual (patent) aspect of these delivery systems. In order to appreciate the intellectual potential of these delivery systems, this review summarizes the patents governing various applications of these delivery systems.


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Inventions Designed to Enhance Drug Delivery Across Epithelial and Endothelial Cells Through the Paracellular Pathway
Lorenza Gonzalez-Mariscal, Sandra Hernández and Jesús Vega

Epithelia in multicellular organisms constitute the frontier with the environment. Hence, epithelial cells are specialized in regulating the transit of ions and molecules from and into the organism. Therapeutic agents in order to reach their targets frequently need to cross epithelial sheets. Two routes are available for such purpose: the transcellular and the paracellular pathways. The former is employed by lipophilic drugs and by molecules selectively transported by channels, pumps and carriers present in the plasma membrane. Hydrophilic molecules cannot cross biological membranes. Therefore their transepithelial transport is significantly enhanced if they move through the paracellular pathway. Transit through this route is regulated by tight junctions (TJs). This review focuses on patented inventions designed to open the paracellular route in a reversible manner in order to enhance drug delivery across epithelial and endothelial barriers. In these patents, the paracellular route is opened by altering the TJ with peptides homologous to the external loops of integral proteins of the TJ, antisense oligonucleotides and siRNA for TJ proteins, toxins and proteins derived from microorganisms that target TJ proteins, and with other molecules such as peptides, lipids, heparins, chitosan derivatives, phospholipase inhibitors and kinase activators.


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Buccoadhesive Drug Delivery Systems - Extensive Review on Recent Patents
Shadab A. Pathan, Zeenat Iqbal, Jasjeet K. Sahani, Sushma Talegaonkar, Roop K. Khar and Farhan J. Ahmad

Peroral administration of drugs, although most preferred by both clinicians and patients has several disadvantages such as hepatic first pass metabolism and enzymatic degradation within the GI tract, that prohibit oral administration of certain classes of drugs especially peptides and proteins. Consequently, other absorptive mucosae are considered as potential sites for administration of these drugs. Among the various transmucosal routes studied the buccal mucosa offers several advantages for controlled drug delivery for extended period of time. The mucosa is well supplied with both vascular and lymphatic drainage and first-pass metabolism in the liver and pre-systemic elimination in the gastrointestinal tract is avoided. The area is well suited for a retentive device and appears to be acceptable to the patient. With the right dosage form, design and formulation, the permeability and the local environment of the mucosa can be controlled and manipulated in order to accommodate drug permeation. Buccal drug delivery is thus a promising area for continued research with the aim of systemic and local delivery of orally inefficient drugs as well as feasible and attractive alternative for non-invasive delivery of potent protein and peptide drug molecules. Extensive review pertaining specifically to the patents relating to buccal drug delivery is currently available. However, many patents e.g. US patents 6, 585,997; US20030059376A1 etc. have been mentioned in few articles. It is the objective of this article to extensively review buccal drug delivery by discussing the recent patents available. Buccal dosage forms will also be reviewed with an emphasis on bioadhesive polymeric based delivery systems.


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Recent Advances on Patents in Poly(Ethylene Glycol)-Base Drug Delivery
Gian M. Bonora and Sara Drioli

Taking advantage of the peculiar features of poly(ethylene glycol), a wide range of applications in the field of drug delivery has been devised. In these last years, a series of patents have been applied on the use of this polymer in delivering of biopolymers, as peptides, proteins and nucleic acid derivatives, as well as of low molecular weight drugs. Moreover, several related strategies have been outlined for the modification of biocompatible materials employed in the field of drug delivery. In this review we focused our attention on the patents appeared in the last years; the description is not exhaustive but the reported citations have been selected as examples of the aforementioned applications.