Recent Patents on Drug Delivery & Formulation - Volume 3, Issue 2, 2009

Protein therapeutics are used in the treatment of a broad variety of diseases, however, usually they are not available as peroral formulations. Oral delivery systems of proteins including insulin, glucagon like peptide, calcitonin or parathyroid hormone are highly demanded by patients suffering from chronic diseases such as diabetes or osteoporosis. The need for oral protein formulations has been recognized by researchers of various scientific disciplines and a number of patents have been filed that deal with technologies capable of facilitating oral protein delivery. Within the current review, patents based on approaches such as particulate delivery systems, multifunctional polymers, enzyme inhibitors, permeation enhancers and ligand-specific binding and uptake are discussed. In addition, the technology platforms of several innovative drug delivery companies are highlighted.

Transdermal drug delivery system has been accepted as potential non-invasive route of drug administration, with advantages of avoidance of the first-pass metabolism, sustained therapeutic action and better patient compliance, though, its prevalent use is restricted due to excellent impervious nature of skin. It is the greatest challenge for researchers to surmount the inherent limitations imposed by stratum corneum of skin, for enhanced transdermal drug delivery to achieve systemic therapeutic concentration. Thus, many approaches have been attempted to perturb skin barrier and enhance the transdermal delivery of drug. The major approaches for enhancing transdermal delivery are physical enhancers (ultrasound, iontophoresis, electroporation, magnetophoresis, microneedle), vesicles, particulate systems (liposome, niosome, transfersome, microemulsion, solid lipid nanoparticle) and chemical enhancers (sulphoxides, azones, glycols, alkanols, terpenes etc.). The present review explores recent patents on techniques employed to breach the skin barrier for drug permeation along with their penetration enhancement mechanisms.

Gene therapy, as therapeutic treatment to genetic or acquired diseases, is attracting much interest in the research community, leading to noteworthy developments over the past two decades. Nonviral vectors have recently received an increasing attention in order to overcome the safety problems of viral counterpart. Nanoparticles with their special characteristics such as small particle size, large surface area and the capability of changing their surface properties have numerous advantages compared with other gene delivery systems. This article reviews the advances of nanoparticles in patents for gene delivery and emphasizes methods to promote gene transfection efficiency.

Nanocarriers offer several advantages in drug delivery including increased retention time in the body, the ability to solubilize hydrophobic cargo, and the ability to target specific tissues. These attributes have led to a large volume of research being dedicated to the development of novel nanocarriers and their use in treating disease. Many advances have been made in the synthesis and formulation of nanocarriers. For instance, flash precipitation and the use of rotary evaporator provide new methods for nanocarrier synthesis. Biomolecules like heparin and sarcosine have been successfully utilized for the synthesis of unique copolymers for use in nanocarrier systems. Also, the efficacy of nanocarrier targeting has been increased by taking advantage of unique microenvironments present in specific pathologies, utilization of phage properties, and scaffold systems for multiple targeting moieties. Finally, nanocarriers have been shown to provide immunomodulatory effects. This article provides a focused review of several recent patents covering the synthesis, composition and the use of novel nanocarriers.

Transdermal drug delivery represents one of the most rapidly advancing areas of novel drug delivery. Although the concept of transdermal drug delivery has been known since 1924, it took until 1979, as FDA approved the transdermal delivery of scopolamine, that transdermal delivery systems [TDDS] received broad attention as novel tool for controlled release. These drug delivery systems are designed for controlled release of drug through the skin into systemic circulation maintaining consistent efficacy and reducing dose of the drug and its related side effects. More than 200 patents have been granted by the United State patent alone, of which more than 35 TDD products have now been approved for sale in the US, and approximately 16 active ingredients have been approved for use globally. Statistics reveal a market of $ 12.7 billion in the year 2005 which is expected to increase by $ 21.5 billion in the year 2010 and $ 31.5 billion in the year 2015. Almost all major and minor pharmaceutical companies are developing TDDS. There is not a single review article which describes patents on different types of TDDS. Thus this review is designed for patents on the different type of TDDS which would be helpful for the researcher in the field of TDDS.

In the recent years, there has been a growing interest in the development of nanoparticles based targeting agents for the tumor diagnostics and therapeutics. This is because of their potential to detect the tumor and treat the diseased tissue at the cellular and molecular level. In this respect nanoscale magnetic materials have shown a very promising therapeutic concept and offer a new perspective for the diagnostic and target drug delivery approach. The magnetic nanocarriers have the ability to accumulate at any desired pharmacological site just by the guidance of external magnetic field. But, the interactions of these magnetic nanocarriers with the biological environment are rare and depend largely upon their surface chemistry and size. To increase the interactions and achieve the desired pharmaceutically acceptable delivery system, the surface of magnetic nanocarriers is modified in various ways by coating with organic polymers and inorganic metals or oxides. On the basis of surface characteristics, a number of effective magnetically driven therapies have been proposed by many researchers and protected through patents time to time.

There are many ways to deliver drugs into the body, viz oral (through swallowing), sub mucosal (through buccal and sublingual mucosa), parenteral (through injection), transdermal (through skin), pulmonary (through inhalation) etc. Among these deliveries oral delivery (by swallowing) is widely accepted. In oral drug delivery, many scientific challenges and breakthrough technologies are required to generate novel dosage forms raising drug delivery to higher level. Some are self emulsifying systems, solid self nanoemulsion, polymeric micelles, spray freezing, pH controlled systems, time delayed system, osmotic pumps, prodrugs etc. This paper reviews recent patents, technologies and products with their importance, manufacturing and novel approaches implemented till date to overcome the challenges in oral drug delivery systems.

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