Abstract:
sampling device including a Near-Infrared Spectroscopy (NIRS) fiber optic probe and methods of using the device are provided. The sampling device performs both NIRS data collection and physical sample collection. The sampling device operates by inserting the device into a powder or blend to be sampled, collecting a sample within the sample chamber in the device, and performing NIRS analysis of the sample within the sample chamber.

Description:
FIELD 
       [0001]    The present invention relates generally to sampling devices and methods of using sampling devices, and more particularly, sampling devices including a NIRS fiber optic probe and methods of using such devices. 
       BACKGROUND 
       [0002]    Sampling devices are used to obtain blend samples, such as in manufacturing of pharmaceutical products. Sampling with a grain-type sampler device is typically performed by an operator (or a technician) inserting the sampler tip into the powder bed with the sample port closed. The sample port is then opened, and the sampler is agitated or pushed further into the powder bed to allow the powder sample to enter the sampler chamber. The sample port is then closed, and the sample is removed and dispensed into a suitable container. After dispensing the samples from the sampling device, the samples are often sent to a quality control laboratory to be analyzed. The quality control laboratory performs an analysis of the samples. 
         [0003]    Analysis times typically vary from 24 hours to 7 days, depending on factors such as laboratory capacity and test methods. The forward processing of a sampled blend occurs after the quality control laboratory completes and releases its analysis of the sample taken. Thus, while a manufacturing facility waits for receipt of this data from the laboratory, the sampled blends are stored for several days, which can disadvantageously lead to particle segregation and de-mixing. This limits a manufacturing facility&#39;s through-put and may result in the processing of an adulterated blend out of specification. To increase production through-put and reduce segregation and de-mixing, blends may be compressed “at risk” before laboratory results are generated. However, if a finished product was compressed at risk and found to be out of specification with regard to blend uniformity, the batch may be rejected. 
         [0004]    The present invention overcomes the major drawbacks associated with current sampling and analysis practices by way of a sampler device integrated with a NIRS fiber optic probe. An advantage of the present invention is that NIRS data acquisition can be performed immediately after sampling. Thus, the need to compress at risk or store blends for extended periods of time is eliminated. Because an external laboratory analysis is not required, an increase in laboratory capacity results from utilization of the fiber optic sampling device. 
       SUMMARY 
       [0005]    The following presents a simplified summary of the invention in order to provide a basic understanding of some example aspects of the invention. This summary is not an extensive overview of the invention. Moreover, this summary is not intended to identify critical elements of the invention nor delineate the scope of the invention. The purpose of the summary is to present some concepts of the invention in simplified form as a prelude to the more detailed description that is presented later. 
         [0006]    In one embodiment, a sampling device, such as a grain-type device, is integrated with a probe to collect data from a sample, while contained in the sample chamber of the sampling device. For example, the probe can be a NIRS fiber optic probe used to perform analytical methods such as, inter alia, direct determination of blend uniformity. 
         [0007]    In another embodiment, a sampling device includes an inner housing and an outer housing, wherein the outer housing surrounds a portion of the inner housing, a sample chamber for collecting a sample, wherein the sample chamber is a hollow cavity within the outer housing, and a probe within the inner housing configured to collect data from the sample. A portion of the internal surface of the sample chamber can have a low-reflectance finish. Further, the probe can be a NIRS fiber optic probe configured to transmit an NIR beam into the sample chamber. 
         [0008]    In yet another embodiment, a sampling device includes an inner housing and an outer housing, wherein the outer housing surrounds a portion of the inner housing, a sample chamber for collecting a sample, wherein the sample chamber is a cavity of a slug positioned within the outer housing, and a probe within the inner housing configured to collect data from the sample. The slug is not positioned within the inner housing. A portion of an internal surface of the sample chamber comprises a low-reflectance finish. Further, the probe can be a NIRS fiber optic probe configured to transmit an NIR beam into the sample chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    An example embodiment that incorporates one or more aspects of the present invention is described and illustrated in the following figures. The illustrated examples are not intended to be a limitation on the present invention. For example, one or more aspects of the present invention can be utilized in other embodiments and even other types of devices. Moreover, certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. 
           [0010]      FIG. 1  is a schematic view of a sampling device incorporated with a fiber optic probe. 
           [0011]      FIG. 2A  is a schematic view of an inner tube and a slug for use with a sampling device. 
           [0012]      FIG. 2B  is a cross-sectional view of the inner tube of  FIG. 2A . 
           [0013]      FIG. 3A  is a schematic view of a slug for insertion into the outer housing of a sampling device. 
           [0014]      FIG. 3B  is a cross-sectional view of the slug of  FIG. 3A . 
           [0015]      FIG. 4A  is a schematic view of an outer tube for use with a sampling device. 
           [0016]      FIG. 4B  is a cross-sectional view of the outer tube of  FIG. 4A . 
           [0017]      FIG. 5A  is a schematic view of a fiber optic probe. 
           [0018]      FIG. 5B  is a cross-sectional view of the tip of the fiber optic probe of  FIG. 5A . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    As described herein, the sampling device can be made of pharmaceutically acceptable material for use in pharmaceutical applications, for example, the pharmaceutically acceptable material can be a suitable non-reactive material such as pharmaceutical grade stainless steel or a polymeric material. The sampling device is preferably made of material that provides rigidity to the device sufficient to withstand entering a powder or blend without bending so much as to damage the data collection probe contained therein. Material thickness can be selected as desired to maintain structural integrity and rigidity. 
         [0020]    In one embodiment, the sampling device includes an inner housing and an outer housing, wherein a portion of the outer housing surrounds a portion of the inner housing. The device further includes a sample chamber for collecting a sample, wherein the sample chamber can be a hollow cavity within the outer housing, and a probe within the inner housing configured to collect data from the sample. The sample chamber can be a cavity within a removable slug that can be positioned within the outer housing. To provide access to the sample chamber, the outer housing can have an aperture and the slug can include an opening. The inner housing and the outer housing can be moveable relative to each other, for example in a rotating manner, to align the outer housing aperture and slug opening such that the sample chamber is open to an environment exterior to the outer housing through the slug opening and outer housing aperture. The outer housing can further include a handle. For example, the operator of the sampling device can utilize the handle to rotate the outer tube, align the aperture and opening, and expose the sample chamber for collecting a sample. A portion of the internal surface of the sample chamber can have a low-reflectance finish or coating and a NIRS fiber optic probe configured to transmit an NIR beam into the sample chamber for acquiring characteristic data of a sample. 
         [0021]    In one embodiment, referring now to  FIG. 1 , a sampling device  20  can include a NIRS fiber optic probe  22 . As an advantage, NIRS data collection and analysis can be performed within the sampling device  20  simultaneously with or immediately after sampling, such that the sampled powder or blend need not be removed from the sample chamber  24 . In an example, NIRS data collection can occur while the sampling device  20  is positioned in the blend or mixture being sampled. Data acquisition and blend uniformity results may be generated for each sample quickly, for example within 60 seconds or less. As such, the data acquisition and blend uniformity results may be generated for various sample locations of a powder bed within a short time frame, for example within 30 minutes or less. Various probe types and spectroscopy platforms can be used with the sampling device  20 . In one embodiment, the data collection probe is a NIRS fiber optic probe  22  configured to transmit an NIR beam into the sample chamber  24  to analyze the sample. 
         [0022]    As shown in  FIG. 1 , the sampling device  20 , such as a grain-type sampling device, can include an outer housing, such as outer tube  26 . The outer tube  26  can be open at one end and closed or capped at the opposite end, for example, a closed conical tip  34  is located at one end of the outer tube  26  which can lead the sampling device  20  as it is inserted inward to penetrate a powder or blend to be sampled. The outer tube  26  can have an open cavity section that extends uniformly from the open end to the closed end, the cavity adapted for receiving or accommodating an inner housing, such as inner tube  28  and/or a NIRS fiber optic probe  22 , and a slug  38  containing a sample chamber  24 . The closed end of the outer tube  26  provides a stop for the slug  38  to rest on, which in turn provides a stop for the inner tube  28  to rest on as the inner tube  28  is in direct contact with the slug  38 . The outer diameter of the outer tube  26  can be in the range of 1 to 3 inches. The inner tube  28  and outer tube  26  are preferably cylindrical in shape. As shown, the inner tube  28  and outer tube  26  can be positioned in a concentric tube arrangement with the inner tube  28  nested inside the outer tube  26 , wherein the tubes  26 ,  28  are movable with respect to one another. 
         [0023]    The concentric tube arrangement allows the inner and outer tubes  28 ,  26  to freely rotate independent of one another. To aid rotation by a user, as shown, the outer tube can have an external handle  36  near the open end to aid in twisting the outer tube  26  during sampling procedures. Preferably, the inner tube  28  and outer tube  26  are positioned close enough to each other so as to prevent powder blend from entering the cavity or open space between them, but far enough apart so that rotation may occur. For example, the gap between the outer diameter of the inner tube  28  and the inner diameter of the outer tube  26  can be in the range of 0.1 to 0.4 inches or about 0.25 inches. 
         [0024]    The length of the sampling device  20  can vary depending on the size of the vessel containing the powder or blend to be sampled, for example the sampling device  20  can be three to eight feet long or can be segmented in to achieve a desired length. In one embodiment, the sample is a powder. For example, the powder can comprise a pharmaceutical ingredient. Preferably, the components of the sampling device  20  are made from nonreactive material. For example, the nonreactive material can be stainless steel or a polymeric material. 
         [0025]    As shown, the sample chamber  24 , when empty, can be a hollow cavity within a removable slug  38  within the outer tube  26 . The walls of the sample chamber  24  may exist in any form, for example rounded or squared. For example, the sample chamber  24  can have a rectangular cavity shape with substantially flat surfaces defining the shape (side walls and bottom). The top wall of the sample chamber  24  can be formed by the inner diameter surface of the outer tube  26 . In an alternative example, the sample chamber  24  can be rounded, such as in a cylinder cavity shape wherein the side walls are rounded with a curvature similar to the outer and/or inner diameter of the inner tube  28 . The volume of the sample chamber  24  can be adjustable. For example, the dimensions of the sample chamber  24  can vary depending on the size of the sample for which a particular sampling device is designed to obtain. For example, the operator of the sampling device  20  can select a removable slug  38  from multiple options, each containing a differently sized sample chamber  24 , and the selected slug can be inserted and removed from the outer tube  26  to modify the sample size accordingly. In another embodiment, the size of the sample chamber  24  can be adjusted by placing one or more inserts (not shown) into the sample chamber  24  in order to reduce the volume of sample which can enter the chamber. 
         [0026]    The slug  38  can be made of a suitable non-reactive material. For example, the slug  38  can be made from pharmaceutical grade stainless steel. In an alternative embodiment, the slug  38  can be made from a pharmaceutically acceptable plastic or polymer material. For example, if the slug  38  is made from a pharmaceutically acceptable plastic or polymer material, the material can be tinted or dark in color, such as blue in color to provide a non-reflective surface. In one embodiment, the plastic or polymer material is polyethylene. 
         [0027]    During use, the sample chamber  24  can be selectively opened and closed by the operator of the sampling device  20 . For example, the slug  38  can have an opening  68 , which when aligned with an aperture  58  of the outer tube  26 , creates a pass-through opening for accommodating powder flow into the sample chamber  24 . When the outer tube aperture  58  and slug opening  68  are not aligned, such that no access to the sample chamber  24  is provided, the sample chamber  24  is in the closed position and no powder can travel into the chamber. As shown in  FIG. 2A  and  FIG. 3A , the slug  38  can have a rectangular-shaped opening  68  to the sample chamber  24 . Likewise, as shown in  FIG. 4A , the outer tube  26  can have a rectangular-shaped aperture  58  in its tube wall near the closed end portion having a conical tip  34 . Referring again to  FIG. 1 , when the slug  38  is situated within the outer tube  26 , the opening in the slug is the open section of the sample chamber  24  facing the inner wall surface of the outer tube  26 . Because the outer tube aperture  58  and the slug opening  68  are not visible to the operator while the sampling device  20  is inserted into the powder bed, it can be difficult for an operator to precisely align such openings having identical dimensions. The particular dimensions of the slug opening  68 , and the outer tube aperture  58  can vary, for example, the outer tube aperture  58  and slug opening  68  can be equally sized, the aperture  58  in the outer tube can be larger than the opening  68  in the slug, or vice versa. As such, the operator of the sampling device  20  may achieve effective alignment to open the sample chamber  24  without the need for exact precision. 
         [0028]    The inner tube  28  can include a pin for rotation  56 , as shown in  FIG. 2A , which is configured to enter a slot for rotation  62 , as shown in  FIG. 4A , located on the outer tube  26 . The handle  36 , pin for rotation  56 , and slot for rotation  62  enable the operator of the sampling device  20  to rotate the outer tube  26  such that the sample chamber  24  positioned within the outer housing is opened to an exterior environment outside the outer tube  26 . The pin for rotation  56  and slot for rotation  62  can be arranged to guide the user for opening and closing the sample chamber  24  without having to view the rotating aperture in the outer tube. 
         [0029]    The sample chamber  24  can have an opening along its surface, such as in a side wall, to accommodate a NIRS fiber optic probe  22 . For example, the side wall of the sample chamber  24  facing an open end of the inner tube  28  can include an opening that connects the open cavity portion of the inner tube  28  with the sample chamber  24 . In one embodiment, an internal surface of the sample chamber  24  comprises a portion of the probe. For example, the NIRS fiber optic probe body, as shown in  FIG. 5A , can be inserted through an open cavity portion of the inner tube  28  of the grain-type sampler device such that the NIRS fiber optic probe tip  46 , in particular the surface (window)  48 , is positioned to form a wall of the sample chamber  24 . Preferably, the NIRS fiber optic probe  22  is positioned such that the collected powder or blend sample, within the sample chamber, is in contact with the surface (window)  48  of the NIRS fiber optic probe tip  46 . For example, the probe tip  46  fits in and fills the opening in the sample chamber side wall to create a sample chamber side wall surface free of open cracks or a pass through. The surface (window)  48  of the probe tip  46  can be made from NIR transparent material designed to prevent disruption of the NIRS beam. For example, the NIRS fiber optic probe tip surface (window)  48  is made from NIRS transparent material such as quartz or sapphire. 
         [0030]    Securing the NIRS fiber optic probe  22 , so that the glass surface (window)  48  of the probe tip forms a wall of the sample chamber, seals one end of the chamber and maximizes contact between the probe tip surface (window)  48  and the direct blend. In one embodiment, the NIRS probe is held in place and fastened to the inner tube  28  by an appropriate fastener, for example, by a compression fitting. In one embodiment, the NIRS probe  22  can include a first collar and the inner tube  28  can include a second collar, both of which can be removably attached to one another. For example, the NIRS probe collar  52 , as shown in  FIG. 5A , and the inner tube collar  54 , as shown in  FIG. 2A , may be removably attached to one another by a tri clamp fitting (not shown). 
         [0031]    Referring again to  FIG. 5A , the NIRS fiber optic probe  22  can include optical fibers  44  within a probe housing. For example, the probe housing can be a stainless steel tube. In one embodiment, the optical fibers  44  terminate at the NIRS probe collar  52 . In this embodiment, the NIRS beam is directed through the stainless steel tube and enters the sample chamber  24  via the transparent NIRS probe tip surface (window)  48  for data collection. The remaining portion of the NIRS fiber optic probe  22 , located outside of the sampling device, can be connected to an external coupling box. For example, the coupling box can send and receive signals from the NIRS unit located within the sampling device  20 . In one embodiment, the NIRS fiber optic probe  22  is commercially available. For example, the NIRS fiber optic probe can be a Solvias fiber optic probe. 
         [0032]    A portion of the internal surface of sample chamber  24  can be coated or adapted with a low-reflectance finish. The low-reflectance finish beneficially reduces or eliminates the amount of reflection of the NIRS beam from the sample chamber surface which may otherwise interfere with NIRS data acquisition and create errors in readings. The low-reflectance finish can be, for example, an anodic oxide finish created with an anodizing process as known in the art. 
         [0033]    The sampling device  20  can be inserted into a powder bed at a point beyond the sample location with the sample chamber  24  in the closed position. Once the portion of the sampling device  20  where the sample chamber  24  is located is submerged in the bulk powder or blend, the sample chamber  24  is opened, for example by rotating the outer tube  26  and/or inner tube  28  to align the outer tube aperture  58  and slug opening  68  to expose the opening of the sample chamber  24  to the powder or blend. Opening the sample chamber  24  allows powder or blend to enter the sample chamber  24 . After the desired volume of powder or blend sample enters the sample chamber  24 , preferably the entire sample chamber  24  is filled, the operator closes the sample chamber  24  by similarly rotating the outer tube  26  and/or inner tube  28  to unalign the slug opening  68  and outer tube aperture  58  wherein the inner diameter surface of the outer tube forms the top wall of the sample chamber. NIRS data collection and analysis can be started by the operator once the sample chamber  24  is closed, either while the sample device  20  is located in the powder blend or mixture being sampled or when the device is removed from the tank or bed. In one embodiment, an operator performs both physical sample collection and NIRS data collection which allows determination of blend homogeneity of the sampled powder or blend. The sampling device  20  also provides investigational capability and the economic advantages include higher production throughput, higher laboratory capacity, reduction of out of specification batches, and compressing blends at risk. Therefore, an overall improvement in product quality can be realized. 
         [0034]    The sampling device  20  can be disassembled for cleaning purposes. As such, the sampling device can meet criteria associated with GMP cleaning validations. Another feature of the sampling device is the optional inclusion of an internal air nozzle which provides in-line cleaning capability. In an embodiment where the device has an internal air nozzle, the sample chamber contains an additional opening for adaptation of the air nozzle. For example, the air nozzle can be secured flush with a wall of the sample chamber, positioned such that the air flow is directed at the surface of the data collection probe. In a preferred arrangement, the air nozzle can be part of the probe tip such that no openings in the sample chamber walls are needed. In another arrangement, the opening for the air nozzle can be on an adjacent wall to the wall containing the probe so the air can be directed towards the probe surface, perhaps at an angle. The outlet tip of the air nozzle should fit in and fill the entire opening to seal the wall surface in order to prevent powder from entering the sampling device outside of the sample chamber. This air flow can be used to remove any powder or blend sample that is sticking to the probe surface. The gas used in the air nozzle can be a nonreactive gas, for example nitrogen gas. 
         [0035]    It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the claimed invention.