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  Method and apparatus for producing dry particlesUSPTO Application #: 20080108554Title: Method and apparatus for producing dry particles Abstract: Method and apparatus for producing dry particles. Two liquid components are combined in a static mixer, atomized into droplets, and the droplets dried to form dry particles. Use of the static mixer enables incompatible liquid components to be rapidly and homogeneously combined. The present invention optimizes process conditions for increasing and controlling particle porosity. The present invention also allows for optimization of particle size in real-time during particle production. (end of abstract) Agent: Covington & Burling, LLP Attn: Patent Docketing - Washington, DC, US Inventors: Blair C. Jackson, Lloyd P. Johnston, Ernest E. Penachio, Charles D. Blizzard, Marie Chung, Jean Sung USPTO Applicaton #: 20080108554 - Class: 514003000 (USPTO) Related Patent Categories: Drug, Bio-affecting And Body Treating Compositions, Designated Organic Active Ingredient Containing (doai), Peptide Containing (e.g., Protein, Peptones, Fibrinogen, Etc.) Doai, Insulin Or Derivative The Patent Description & Claims data below is from USPTO Patent Application 20080108554. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 10/391,199, filed Mar. 19, 2003, which is a continuation-in-part of U.S. patent application Ser. No. 10/101,563, filed Mar. 20, 2002, each of which is hereby incorporated in its entirety in this patent application. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a method and apparatus for producing dry particles. More particularly, the present invention relates to a method and apparatus for producing dry particles that are suitable for inhalation into the lung, and which contain an active agent. [0004] 2. Related Art [0005] Delivery of drugs and other active agents can be accomplished through the use of dry powder compositions made from particles containing the drug or active agent. In producing such particles, it is often desirable to combine substances with significantly different physical properties to achieve the desired pharmaceutical effect in patients. Moreover, it is often desirable to produce particles that are a combination of different substances. One way to produce particles containing a combination of different substances is to dissolve the substances in suitable solvents, and then remove the solvents by, for example, evaporation or drying, to yield the desired particles. A major difficulty with this approach is that substances with differing physical properties often have very different solubilities in solvents. Consequently, co-solvents, or a larger mixture of solvents, may be needed to form the solution from which the particles are produced. However, the use of co-solvents can cause degradation of one of the components, through chemical or physical incompatibility of the components in solution. [0006] One example of the incompatibility of components is the production of particles that contain a hydrophobic component and a hydrophilic component. The production of such particles is described in U.S. Pat. No. 6,077,543 to Gordon et al. ("the Gordon patent"). As described in the Gordon patent, a hydrophobic drug solution and a hydrophilic excipient solution are spray dried together to form dry powders containing the drug and the excipient. To solve the incompatibility between the hydrophobic and hydrophilic components, the hydrophilic and hydrophobic components are separately dissolved in different solvents, and separately directed simultaneously through a nozzle into a spray dryer. In this method, the two liquid components are separately delivered to the nozzle that atomizes the two liquid components into droplets that are dried in a spray dryer to form dry particles. [0007] One of the drawbacks of the method and apparatus of the Gordon patent is that there is no complete mixing of the two liquid components before being atomized into droplets. Thus, the droplets that are produced are unlikely to be a homogeneous mixture of the two liquid components, nor is there likely to be uniformity among the droplets. Consequently, the particles that are produced are unlikely to contain a homogeneous mixture of the drug and excipients, and are unlikely to have uniformity among the particles themselves. Thus, there is a need in the art for an improved method and apparatus for producing dry particles that contain a homogenous mixture of drug and excipient components, with improved uniformity among the particles. There is a particular need in the art for such a method and apparatus where the drug component and excipient component are physically or chemically incompatible in the liquid state. [0008] One important application for dry powder compositions is pulmonary drug delivery. Several properties of the dry particles have been identified that correlate with enhanced delivery to the pulmonary system. For example, it has been found that particles having a tap density less than 0.4 g/cm.sup.3 and an aerodynamic diameter that is between about 1 and about 3 microns (.mu.m) are well suited for delivery to the alveoli or the deep lung. If delivery to the central or upper airways is desired, particles having larger aerodynamic diameters, ranging for example, from about 3 to about 5 microns are preferred. Furthermore, particles having a geometric diameter greater than about 5 microns are believed to more successfully avoid phagocytic engulfment by alveolar macrophages and clearance from the lungs. [0009] There is a need in the art for improved methods for producing particles having selected geometric and aerodynamic sizes optimized for delivery to targeted sites of the pulmonary system. There is a particular need for an apparatus and method that allows for optimization of particle size in real-time, during the particle production process. [0010] The apparatus and method of the present invention, a description of which is fully set forth below, solve the aforementioned problems and difficulties with conventional approaches to producing dry powder compositions. SUMMARY OF THE INVENTION [0011] The present invention is directed to a method and apparatus for producing dry particles. The dry particles are advantageously formed into dry powder compositions that can be administered to a patient, such as a human patient, for therapeutic purposes. In a preferred aspect of the present invention, the dry powder compositions are formulated for inhalation by a patient for delivery of an active agent through the pulmonary system. [0012] In one aspect of the present invention, a method for preparing a dry powder composition is provided. An embodiment of the method of the present invention comprises combining a first fluid component and a second fluid component in a mixer to form a mixed fluid, wherein the first fluid component comprises an active agent that is incompatible with the second fluid component, atomizing the mixed fluid to produce droplets, and drying the droplets to form dry particles. In some embodiments, the first fluid component is hydrophilic and the second fluid component is hydrophobic and the combining step comprises adding the first fluid component to the second fluid component. In other embodiments, the second fluid component is an organic solution comprising approximately 60-70% water by volume, and the mixed fluid comprises approximately 20% organic phase by volume. In yet other embodiments, the method produces dry particles with less than about 6%, and preferably less than about 3%, high molecular weight protein ("HMWP") and more than about 90% readily extractable protein product ("RE"). [0013] In alternative embodiments of the method of the present invention, the method comprises atomizing the mixed fluid with an internal mixing nozzle, e.g., a single-hole nozzle or a six-hole nozzle. In other embodiments, other types of nozzles may be used. [0014] In some embodiments of the method of the present invention, the method further comprises adding a surfactant, for example, a non-ionic surfactant or DPPC or Tween 80, to the first fluid component, the second fluid component, or the mixed fluid. In some embodiments, at least 0.2 wt % of Tween 80 is added. In other embodiments, 0.2-2.8 wt % of Tween 80 is added. [0015] In yet other embodiments of the method of the present invention, the method comprises using a total solids concentration for the mixed fluid of about 1-60 g/L. [0016] In yet other embodiments of the method of the present invention, the method comprises adding about 5-40 g/L ammonium bicarbonate to the first fluid component, the second fluid component, or the mixed fluid. [0017] In another embodiment of the method of the present invention, the method comprises performing the drying step in a dryer with an outlet temperature of 35-70.degree. C. In alternative embodiments, a drying gas rate of approximately 80-125 kg/hr is used. [0018] Alternative embodiments of the method of the present invention comprise ascertaining the amount of solid and liquid ingredients necessary to achieve the first solution concentration and combining the liquid and solid ingredients together to form the first fluid component. [0019] In yet other alternative embodiments of the method of the present invention, the method comprises using an atomization gas rate of approximately 35-120 g/min. [0020] In other embodiments of the method of the present invention, the method comprises using a liquid feed rate of approximately 10-75 mL/min during the atomization step. [0021] In an aspect of the apparatus of the present invention, an apparatus for preparing a dry powder composition is provided. An embodiment of the apparatus of the present invention comprises a static mixer operative to combine a first fluid component with a second fluid component to form a mixed fluid, wherein the first fluid component comprises an active agent that is incompatible with the second fluid component. The apparatus further comprises an atomizer in fluid communication with the static mixer, whereby the mixed fluid is atomized to form droplets, and a dryer wherein the droplets are dried to form dry particles. In some embodiments of the apparatus of the present invention, the atomizer comprises an internal mixing nozzle, e.g., a single-hole nozzle or a six-hole nozzle. In other aspects of the invention, a sheeting action nozzle or a pressure nozzle may also be used. Continue reading... Full patent description for Method and apparatus for producing dry particles Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method and apparatus for producing dry particles patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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