Recent Patents on Drug Delivery & Formulation - Volume 4, Issue 1, 2010

Perhaps the greatest barrier to development of the field of transmembrane drug delivery is that only a limited number of drugs are amenable to administration by this route. The highly lipophilic nature and barrier function of the uppermost layer of the skin, the stratum corneum, for example, restricts the permeation of hydrophilic, high molecular weight and charged compounds into the systemic circulation. Other membranes in the human body can also present significant barriers to drug permeation. In order to successfully deliver hydrophilic drugs, and macromolecular agents of interest, including peptides, DNA and small interfering RNA, many research groups and pharmaceutical companies Worldwide are focusing on the use of microporation methods and devices. Whilst there are a variety of microporation techniques, including the use of laser, thermal ablation, electroporation, radiofrequency, ultrasound, high pressure jets, and microneedle technology, they share the common goal of enhancing the permeability of a biological membrane through the creation of transient aqueous transport pathways of micron dimensions across that membrane. Once created, these micropores are orders of magnitude larger than molecular dimensions and, therefore, should readily permit the transport of hydrophilic macromolecules. Additionally, microporation devices also enable minimally-invasive sampling and monitoring of biological fluids. This review deals with the innovations relating to microporation-based methods and devices for drug delivery and minimally invasive monitoring, as disclosed in recent patent literature.

Ultrapure poly[bis(trifluoroethoxy)phosphazene] is a novel biocompatible, anti-inflammatory, antithrombogenic polymer which has the potential to cover stent devices without elution of a cell cycle inhibiting drug. The properties of polyphosphazene are likely to extend its use to a broad array of promising applications. This article reviews the features of the polymer and some recent patents related to use of poly[bis(trifluoroethoxy)phosphazene] in coating, its relevance as compared to other polymers, current evidence on pre-clinical and clinical performance, and future perspectives.

Although technological innovations in the area of drug delivery claim for varied benefits, increasing the drug therapeutic index for human clinical application is the main goal pursued. Drug delivery systems for local anesthetics (LA) have attracted researchers due to many biomedical advantages associated to their application. Formulation approaches to systemically deliver LA include the encapsulation in liposomes, complexation in cyclodextrins, association with biopolymers and others carrier systems. Topical delivery systems for LA are characteristically composed by a diversity of adjuvants (viscosity inducing agents, preservatives, permeation enhancers, emollients,...) and presentations such as semisolid (gel, creams, ointments), liquid (o/w and w/o emulsions, dispersions) and solid (patches) pharmaceutical forms. The proposed formulations aim to reduce the LA concentration used, increase its permeability and absorption, keep the LA at the target site for longer periods prolonging the anesthetic or analgesic effect and, finally, to decrease the clearance, local and systemic toxicity. This review deals with the innovations pertaining to formulations and techniques for drug delivery of topical and injectable local anesthetics, as described in recent patents.

The thrust for finding newer drug delivery systems for exiting therapeutic molecules has opened a wide window for colloidal systems. Due to the presence of different domains of variable polarity in the microemulsion systems, they show a huge potential to be used as drug delivery vehicles for a variety of drugs. The use of microemulsion as drug delivery vehicles through a number of routes has engaged a large number of research groups in this area. Microemulsion media finds several applications ranging from drug delivery to drug nanoparticle templating due to its ability to enhance solubility, stability and bioavailability. This review on patent articles recounts the patent literature dealing with different kind of microemulsion carriers used via different routes, solubility and permeability enhancement and its use as a template for nanoparticle synthesis.

In an effort to improve the drug solubility, stability and/or ocular bioavailability of ophthalmic formulations, various approaches have been explored in the recent past. Additionally, different formulations have been investigated in order to seek those preservative systems that are more tolerable to the ocular tissue. Over the past ten years, inventions in ophthalmic formulations directed toward front-of-eye instillations have concentrated in the areas of new excipients' applications, novel and combined use of conventional excipients, and developments of novel dosage forms. Among these areas, applications of polymeric excipients, cyclodextrins and stabilized chloride dioxide (SCD) have been the most actively studied fields. In addition, oil-in-water (O/W) emulsions have been becoming more popular as an ophthalmic dosage form due to the potentials in increasing drug solubility, stabilizing active pharmaceutical ingredients (APIs), improving ocular tolerance, and providing palliative effects. Some of these innovations from the past decade have the capability of leading to new commercial products. This patent review has a useful knowledge in the advancement for treating various ophthalmic diseases.

Modification of the surface properties of particles, which is usually achieved by coating, is desirable to maintain and enhance the utility of these particles. Saving of time, energy, number of additives, process steps and consequently, the cost of the coating process leads to development of dry coating processes using mechanical methods which exclude any liquid solvent or binder solution and are environmentally safe, and cost-effective. Mechanofusion, hybridization, magnetic assisted impaction coating, theta-composer, rotating fluidized bed coating, pressure swing granulation and high shear mixing have been extensively patented and reported in the scientific literature. These mechanical methods have found multidisciplinary applications in drug development and drug delivery. Various devices available for the dry coating process, their principle, method of working, benefits and limitations along with various applications relevant to the pharmaceutical field are discussed in the current article.

Taste has an important role in the development of oral pharmaceuticals. With respect to patient acceptability and compliance, taste is one of the prime factors determining the market penetration and commercial success of oral formulations, especially in pediatric medicine. Taste assessment is one important quality-control parameter for evaluating taste-masked formulations. Hence, pharmaceutical industries invest time, money and resources into developing palatable and pleasant-tasting products. The primary method for the taste measurement of a drug substance or a formulation is by human sensory evaluation, in which tasting a sample is relayed to inspectors. However, this method is impractical for early stage drug development because the test in humans is expensive and the taste of a drug candidate may not be important to the final product. Therefore, taste-sensing analytical devices, which can detect tastes, have been replacing the taste panelists. In the present review we are presenting different aspect of electronic tongue. The review article also discussed some useful patents and instrument with respect to E-tongue.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by therapeutic areas/targets and therapeutic agents related to drug delivery and formulations.