News Column

Patent Issued for Injectable, Non-Aqueous Suspension with High Concentration of Therapeutic Agent

August 25, 2014

By a News Reporter-Staff News Editor at Clinical Trials Week -- A patent by the inventors Houston, Paul R. (Hayward, CA); Chen, Guohua (Sunnyvale, CA); Luk, Andrew Sheung-King (Pleasanton, CA), filed on October 26, 2011, was published online on August 12, 2014, according to news reporting originating from Alexandria, Virginia, by NewsRx correspondents (see also Durect Corporation).

Patent number 8802095 is assigned to Durect Corporation (Cupertino, CA).

The following quote was obtained by the news editors from the background information supplied by the inventors: "Proteins and peptides have become powerful therapeutic agents in the treatment of various diseases, such as cancer, inflammatory, cardiovascular, respiratory, and infectious diseases. However, formulation and delivery of these molecules are challenging due to solubility and viscosity limitations. Except for highly potent molecules, formulations of these molecules need to contain relatively high concentrations of the protein to enable efficacious dose levels by subcutaneous ('SC') or intramuscular ('IM') routes of administration.

"Commercialization strategies often involve lyophilized formulations that require reconstitution of the protein prior to being delivered by injection, which can add costs and time to the manufacturing process. Ready-to-use solution formulations of proteins and peptides, when feasible, can minimize this inconvenience. However, the requirement for a high concentration of the protein adds complexity to formulation design and promotes instability.

"It has been estimated that greater than 20% of all biopharmaceuticals currently being evaluated in clinical trials are monoclonal antibodies ('mAbs'). In general, mAb therapies require the delivery of between approximately 100 mg and approximately 1 g of protein per dose. Because the high end of formulation concentrations for mAbs is typically in the range of 50 mg/ml, such treatments commonly require the administration of 2 to 20 ml. Typically, such volumes are administered only through intravenous ('IV') infusion performed in a clinical or hospital setting, which leads to poor patient compliance.

"To achieve a high protein concentration, nonaqueous suspensions of proteins have been formulated. In these formulations, the protein is suspended in a vehicle that includes at least two of the following: a polymer, a surfactant, and a solvent. The formulation has a protein concentration of up to 500 mg/ml.

"To expand therapeutic opportunities and increase patient compliance, a method of achieving a high concentration of mAbs is needed so that large protein doses are deliverable in a small volume appropriate for SC or IM injection. One possible approach is to prepare extremely high concentration preparations of soluble mAbs, on the order of 150 to 250 mg/ml. However, achieving such highly concentrated mAb solutions is problematic due to solubility limitations and/or relatively high viscosities, which often results in protein aggregation and poor overall stability.

"Polyethoxylated castor oil (also known as polyoxyl castor oil, polyoxyl 35 castor oil, polyoxyethylated castor oil, macrogolglycerol ricinoleate, or macrogolglyceroli ricinoleas) has been used as a solvent for pharmaceutical compositions that include a hydrophobic drug, such as miconazole, echinomycin, teniposide, diazepam, althesin, or paclitaxel. The hydrophobic drug and the polyethoxylated castor oil form a solution. To further solubilize the hydrophobic drug, many of these pharmaceutical compositions also include an alcohol.

"There remains a need to develop highly concentrated protein formulations to enable delivery of a variety of therapeutic proteins in a convenient way with a small volume."

In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventors' summary information for this patent: "The present invention relates to an injectable, nonaqueous suspension that includes at least one therapeutic agent suspended in a single component vehicle.

"The present invention also relates to a dosage kit that includes a syringe and the injectable, nonaqueous suspension.

"The present invention also relates to a method of administering a therapeutic agent that includes suspending the at least one therapeutic agent in the single component vehicle and injecting the injectable, nonaqueous suspension into a patient in need thereof."

URL and more information on this patent, see: Houston, Paul R.; Chen, Guohua; Luk, Andrew Sheung-King. Injectable, Non-Aqueous Suspension with High Concentration of Therapeutic Agent. U.S. Patent Number 8802095, filed October 26, 2011, and published online on August 12, 2014. Patent URL:

Keywords for this news article include: Therapy, Durect Corporation.

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Source: Clinical Trials Week

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