Patent Publication Number: US-2018043147-A1

Title: Methods and Systems for Ultrasound Assisted Delivery of a Medicant to Tissue

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to, claims priority to, and incorporates herein by reference for all purposes U.S. patent application Ser. No. 14/637,237, filed Mar. 3, 2015, U.S. Provisional Patent Application No. 62/127,715, filed Mar. 3, 2015, and U.S. Provisional Patent Application No. 62/127,720, filed Mar. 3, 2015. 
    
    
     BACKGROUND 
     Trandermal delivery of medicants is limited primarily to the difficult-to-penetrate nature of the stratum corneum layer of skin. The stratum corneum layer forms a barrier that keeps moisture in and keeps practically everything else out. Accordingly, attempts to topically apply a medicant and deliver the medicant across the stratum corneum layer to tissue located beneath it must overcome this barrier property in order to be effect. 
     The bioavailability of topically applied medicants is typically very low. For example, the bioavailability of topically applied lidocaine is approximately 3%. See, Campbell, et al. J. Pharm. Sci. 91(5), pp. 1343-50 (May 2002). In other words, more than 30 times the desired amount of lidocaine needs to be applied topically for the desired effect. In the case of an expensive medicant or a medicant having various side effects, it is undesirable to require application of such an excess of medicant in order to have the desired effect. 
     Workarounds for this limited bioavailability of topically applied medicants generally include physically puncturing the skin, which is undesirable, because some patients can have aversion to the needles associated with such procedures. 
     Low-frequency sonophoresis is a known method for enhancing transdermal drug delivery. However, these existing methods employ low-frequencies, low peak intensities, require long application times, or some combination of these to achieve improved transdermal drug delivery. 
     Accordingly, a need exists for new systems and methods that overcome the aforementioned shortcomings. 
     SUMMARY 
     The present disclosure overcomes the aforementioned drawbacks by presenting systems and methods for ultrasound assisted delivery of a medicant to tissue. 
     In one aspect, this disclosure provides an ultrasound assisted medicant delivery system. The system can include an ultrasound probe and a control system. The ultrasound probe can include an ultrasound transducer. The ultrasound probe and the ultrasound transducer can be configured for coupling to a medicant administered to a skin surface. The control system can be electronically coupled to the ultrasound trasndcuer. The control system can, in use, cause the ultrasound transducer to apply a first pulse acoustic energy field to the skin surface. The first pulsed acoustic energy field can have a frequency from 1 MHz to 30 MHz, a peak intensity from 100 W/cm 2  to 100 kW/cm 2 , and a pulse width from 33 nanoseconds to 5 seconds. The first pulsed acoustic energy field can generate inertial cavitation, acoustic streaming, or a combination thereof in the stratum corneum layer and drive the medicant through the stratum corneum layer. 
     In another aspect, this disclosure provides a method for ultrasound assisted delivery of a medicant through a stratum corneum layer of a skin surface. The method can include: administering the medicant to a skin surface; coupling an ultrasound transducer to the medicant and the skin surface; and applying a first pulse acoustic energy field from the ultrasound transducer to the skin surface. The first pulse acoustic energy field can have a frequency from 1 MHz to 30 MHz, a peak intensity from 100 W/cm 2  to 100 kW/cm 2 , and a pulse width from 33 nanoseconds to 5 seconds. The first pulsed acoustic energy field can generate inertial cavitation, acoustic streaming, or a combination thereof in the stratum corneum layer and drive the medicant through the stratum corneum layer. 
     In a further aspect, this disclosure provides a method for reducing or eliminating pain generated by ultrasound treatment. The method can include: applying a coupling medium comprising a medicant to a skin surface above a region of intere, the medicant comprising an anesthetic configured to numb a tissue in the region of interest; coupling an ultrasound energy source to the coupling medium, the skin surface, and the region of interest; directing a first acoustic energy field from the ultrasound energy source into the skin surface, thereby delivering the medicant into the tissue in the region of interest and numbing the tissue in a portion of the region of interest; and directing a second acoustic energy field to a target volume in the tissue in the region of interest, the second acoustic energy field ablating the tissue in the target volume, the medicant reducing or eliminating pain generated by the ablating of the tissue. 
     In yet another aspect, this disclosure provides a method of ultrasound assisted transdermal drug delivery. The method can include: contacting a skin surface with a coupling medium comprising a non-anesthetic medicant and an anesthetic; coupling an ultrasound energy source to the coupling medium and the skin surface; and applying a first pulsed acoustic energy field from the ultrasound transducer to the skin surface. The first pulse acoustic energy field can have a peak intensity from 100 W/cm 2  to 100 kW/cm 2 . The first pulsed acoustic energy field can drive the medicant and the anesthetic across a stratum corneum layer of the skin surface and into an epidermis layer beneath the skin surface. The anesthetic can alleviate pain or swelling associated with the application of the first pulsed acoustic energy field. 
     The foregoing and other aspects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred aspect of the disclosure. Such aspect does not necessarily represent the full scope of the disclosure, however, and reference is made therefore to the claims and herein for interpreting the scope of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates an ultrasound assisted drug delivery probe and a first stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 1B  illustrates an ultrasound assisted drug delivery probe and a second stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 1C  illustrates an ultrasound assisted drug delivery probe and a third stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 1D  illustrates an ultrasound assisted drug delivery probe and a fourth stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 2A  illustrates an ultrasound assisted drug delivery probe and a first stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 2B  illustrates an ultrasound assisted drug delivery probe and a second stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 2C  illustrates an ultrasound assisted drug delivery probe and a third stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 2D  illustrates an ultrasound assisted drug delivery probe and a fourth stage of a method of its use, according to one aspect of the present disclosure. 
         FIG. 3  illustrates a set of components for use in an ultrasound assisted drug delivery system, according to one aspect of the present disclosure. 
         FIG. 4  is a flowchart illustrating methods of ultrasound assisted drug delivery, according to one aspect of the present disclosure. 
         FIG. 5A  is a picture showing the result of applying a method according to one aspect of the present disclosure with and without a 5% lidocaine ointment, as shown in Example 1. 
         FIG. 5B  is a picture showing the result of applying a method according to one aspect of the present disclosure with and without a 5% lidocaine ointment, as shown in Example 1. 
     
    
    
     DETAILED DESCRIPTION 
     Before the present invention is described in further detail, it is to be understood that the invention is not limited to the particular embodiments described. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. The scope of the present invention will be limited only by the claims. As used herein, the singular forms “a”, “an”, and “the” include plural embodiments unless the context clearly dictates otherwise. 
     Specific structures, devices, and methods relating to improved ultrasound treatment efficiency and operation are disclosed. It should be apparent to those skilled in the art that many additional modifications beside those already described are possible without departing from the inventive concepts. In interpreting this disclosure, all terms should be interpreted in the broadest possible manner consistent with the context. Variations of the term “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, so the referenced elements, components, or steps may be combined with other elements, components, or steps that are not expressly referenced. Embodiments referenced as “comprising” certain elements are also contemplated as “consisting essentially of” and “consisting of” those elements. 
     This disclosure provides methods and systems for enhancing medicant delivery across the stratum corneum layer of skin and into the epidermis layer. The systems and methods also facilitate movement of the medicant deeper into the epidermis or into the dermis layer and subcutaneous tissue beneath the dermis layer. 
     As will be described with respect to  FIGS. 1A, 1B, 1C, and 1D , an ultrasound assisted drug delivery probe  10  can be positioned atop and coupled to a skin surface  12 . The skin surface  12  can be located above a stratum corneum  14 , an epidermis  16 , and a dermis  18 . A region of interest  20  can be any contiguous location within the illustrated skin surface  12 , the stratum corneum  14 , the epidermis  16 , the dermis  18 , or a combination thereof. The region of interest  20  can be a region of interest as described herein. The ultrasound assisted drug delivery probe  10  can include an ultrasound source  22 , which can include one or more transducers  24 . The ultrasound source  22  can be any source described herein. The transducers  24  can be any transducers described herein. The one or more transducers  24  can each independently be a single transduction element, an array of transduction elements, or a group of arrays of transduction elements. The ultrasound assisted drug delivery probe  10  can be coupled to a power supply  26  and electronics  28  sufficient for the operation of an ultrasound system. The power supply  26  can be any power supply known to one of skill in the art to be suitable for powering an ultrasound probe, such as any power supply described herein, among others. The electronics  28  can be any electronics known to one of skill in the art to be suitable for operating an ultrasound probe, such as any electronics described herein, among others. The ultrasound assisted drug delivery probe  10  can be coupled to a control module  30  adapted to control the emission of ultrasound from the ultrasound assisted drug delivery probe  10 . The control module  30  can be any control module or controller known to one of skill in the art to be suitable for controlling the emission characteristics of an ultrasound probe, such as any control module or controller described herein, among others. 
     Examples of suitable power supplies  26  can include, but are not limited to, one or more direct current (DC) power supplies, single-use or rechargeable batteries, or other power supplies configured to provide electrical energy to the ultrasound assisted drug delivery probe  10 , including to the ultrasound source  28 , transducers  30 , electronics  28 , control modules  30 , or any other aspect of the ultrasound assisted drug delivery probe  10  that requires electrical energy. Associated sensors for monitoring the performance of the power supplies  26  are contemplated, such as current sensors, power sensors, and the like. 
     Examples of suitable electronics  28  can include, but are not limited to, amplifiers or drivers, such as multi-channel or single channel power amplifiers or drivers; power converters configured to adjust voltages; open-loop feedback systems; closed-loop feedback systems; filters, such as harmonic filters or matching filters; and the like. 
     Control modules  30  can include components suitable for controlling the emission characteristics of the ultrasound assisted drug delivery probe  10 , including but not limited to, a computing system adapted to control the ultrasound assisted drug delivery probe  10 ; timing circuits; software and algorithms to provide control and user interfacing; input controls, such as switches, buttons, touchscreens, and the like; outputs, such as lighting or audio signals or displays; storage elements, such as memory to store calibration and usage data; and the like. 
     The ultrasound assisted drug delivery probe  10  can also include sensors suitable for measuring certain aspects of the ultrasound assisted drug delivery probe  10 . Examples of sensors include, but are not limited to, temperature sensors, motion sensors, location sensors, coupling sensors, such as capacitive or acoustic coupling sensors, and the like. 
     The transducer  30  can be configured as a spherically-focused single element transducer, an annular/multi-element transducer, an annular array having an imaging region, a line-focused single-element transducer, a one-dimensional linear array, a one-dimensional curved linear array, a two-dimensional array with a mechanical focus, a convex lens focus, a concave lens focus, a compound lens focus, or a multiple lens focus, a two-dimensional planar array, or other transducer arrangements suitable for producing the ultrasound energy described herein and corresponding effects. 
     Referring to  FIG. 1A , the ultrasound assisted drug delivery probe  10  can be coupled to the skin surface  12  by way of a coupling medium  32 . The coupling medium  32  can include a medicant  34 . 
     Referring to  FIG. 1B , the arrangement illustrated in  FIG. 1A  is illustrated after the ultrasound assisted drug delivery probe  10  has begun emitting a first acoustic energy field  36  that penetrates at least through the skin surface  12  and the stratum corneum  14  and penetrates at least partially into the epidermis  16 . In response to the first acoustic energy field  36 , the medicant  34  can be driven from above the skin surface  12  through the skin surface  12 , into or through the stratum corneum  14 , and into the epidermis  16 . 
     It should be appreciated that there exist intermediate states between the state of the arrangement illustrated in  FIG. 1A  and that illustrated in  FIG. 1B , where the first acoustic energy field  36  penetrates only partially into the stratum corneum  14 , or penetrates throughout the stratum corneum  14  but not into the epidermis  16 , or penetrates throughout the stratum corneum  14  and partially into the epidermis  16  to a depth different than that illustrated. In similar intermediate states, the medicant  34  can penetrate only partially into the stratum corneum  14 , or penetrates throughout the stratum corneum  14  but not into the epidermis  16 , or penetrates throughout the stratum corneum  14  and partially into the epidermis  16  to a depth different than that illustrated. 
     Referring to  FIG. 1C , the arrangement illustrated in  FIGS. 1A and 1B  is illustrated after the ultrasound assisted drug delivery probe  10  has begun emitting a second acoustic energy field  38  that penetrates at least through the skin surface  12 , the stratum corneum  14 , and the epidermis  16 , and penetrates at least partially into the dermis  18 . In response to the second acoustic energy field  38 , the medicant  34  can be driven from the epidermis  16  to a deeper portion of the epidermis  16  or into the dermis  18 . 
     It should be appreciated that there exist intermediate states between the state of the arrangement in  FIG. 1B  and that illustrated in  FIG. 1C , where the second acoustic energy field  38  can penetrate throughout the epidermis  16  but not into the dermis  18 , or can penetrate through the epidermis  16  and partially into the dermis  18 , or can penetrate into the dermis  18  to a depth different than that illustrated. In similar intermediate states, the medicant  34  can penetrate throughout the epidermis  16  but not into the dermis  18 , or can penetrate through the epidermis  16  and partially into the dermis  18 , or can penetrate into the dermis  18  to a depth different than that illustrated. 
     Referring to  FIG. 1D , the arrangement illustrated in  FIGS. 1A, 1B, and 1C  is illustrated after the medicant  34  has been driven into the dermis  18 . In the dermis  18 , the medicant  34  can interact with tissue or enter the blood stream via capillaries. In certain applications, a third acoustic energy field  40 , optionally referred to as a therapeutic acoustic energy field  40 , can be directed to a target volume  42  within the dermis  18 . The target volume  42  can be located in a portion of the dermis  18  containing the medicant  34 . 
     A method for ultrasound-assisted delivery of a medicant through a stratum corneum layer of a skin surface can include the following steps: administering the medicant to the skin surface; coupling an ultrasound transducer to the medicant and the skin surface; and applying a first pulsed acoustic energy field from the ultrasound transducer to the skin surface, the first pulsed acoustic energy field having one or more of the properties described elsewhere herein, the first pulsed acoustic energy field generating intertial cavitation, acoustic streaming, or a combination thereof in the stratum corneum layer and driving the medicant through the stratum corneum layer. 
     As will be described with respect to  FIGS. 2A, 2B, 2C, and 2D , a delivery system  44  can include an ultrasound assisted drug delivery probe  10  and a standoff  46  comprising a medicant  34 . The ultrasound assisted drug delivery probe  10  can include features described elsewhere herein. The standoff  46  can include a plurality of pores in a bottom surface  48 , the plurality of pores being in fluid communication with the medicant  34 . The plurality of pores can be of a size and shape that are sufficient to retain the medicant  34  within the standoff  46 . In certain aspects, the medicant  34  is retained in the standoff  46  by virtue of a surface tension of the medicant  34 . In certain aspects, the standoff  46  can include a gel pack coupled to the ultrasound assisted drug delivery probe  10 . In certain aspects, the standoff  46  can be rigid or flexible. 
     Referring to  FIG. 2A , the delivery system  44  is positioned above the skin surface  12 . In  FIG. 2B , the arrangement illustrated in  FIG. 2A  is illustrated after the delivery system  44  has been coupled to the skin surface  12 . The ultrasound assisted drug delivery probe  10  can emit a first acoustic energy field  36  that penetrates at least through the skin surface  12  and the stratum corneum  14  and penetrates at least partially into the epidermis  16 . In response to the first acoustic energy field  36 , the medicant  34  can be driven from above the skin surface  12  through the skin surface  12 , into or through the stratum corneum  14 , and into the epidermis. 
     It should be appreciated that there exist intermediate states between the state of the arrangement in  FIG. 2A  and that illustrated in  FIG. 2B , where the first acoustic energy field  36  can penetrate only partially into the stratum corneum  14  or can penetrate throughout the stratum corneum  14  but not into the epidermis  16 , or can penetrate through the stratum corneum  14  and partially into the epidermis  16  to a depth different than that illustrated. In similar intermediate states, the medicant  34  can penetrate only partially into the stratum corneum  14 , or can penetrate throughout the stratum corneum  14  but not into the epidermis  16 , or can penetrate throughout the stratum corneum  14  and partially into the epidermis  16  to a depth different than that illustrated. 
     Referring to  FIG. 2C , the arrangement illustrated in  FIGS. 2A and 2B  is illustrated after the ultrasound assisted drug delivery probe  10  has begun emitting a second acoustic energy field  38  that penetrates at least through the skin surface  12 , the stratum corneum  14 , and the epidermis  16 , and penetrates at least partially into the dermis  18 . In response to the second acoustic energy field  38 , the medicant  34  can be driven from the epidermis to a deeper portion of the epidermis  16 , partially into the dermis  18 , or entirely into the epidermis. 
     It should be appreciated that there exist intermediate states between the state of the arrangement in  FIG. 2B  and that illustrated in  FIG. 2C , where the second acoustic energy field  38  can penetrate throughout the epidermis  16  but not into the dermis  18 , or can penetrate through the epidermis  16  and partially into the dermis  18 , or can penetrate into the dermis  18  to a depth different than that illustrated. In similar intermediate states, the medicant  34  can penetrate throughout the epidermis  16  but not into the dermis  18 , or can penetrate through the epidermis  16  and partially into the dermis  18 , or can penetrate into the dermis  18  to a depth different than that illustrated. 
     Referring to  FIG. 2D , the arrangement illustrated in  FIGS. 2A, 2B, and 2C  is illustrated after the medicant  34  has been driven into the dermis  18 . In the dermis, the medicant  34  can interact with the tissue or enter the blood stream via capillaries. In certain applications, a third acoustic energy field  40 , optionally referred to as a therapeutic acoustic energy field  40 , can be directed to a target volume  42  within the dermis  18 . The target volume  42  can be located in a portion of the dermis  18  containing the medicant  34 . 
     In certain aspects, the delivery system  44  can be configured as a transdermal patch. For example, the delivery system  44  can be configured for off-the-shelf operation, where the delivery system  44  include the medicant  34  in appropriate dosage within the standoff  46  and a suitable portable power supply, such as battery power, to power the delivery system  44 . After removing any packaging for the delivery system  44 , the delivery system  44  can be applied to a location by a patient or a user. In certain aspects, the delivery system  44  can include an adhesive material on the bottom surface  48  of the standoff  46  or a patch that extends over the ultrasound assisted drug delivery probe  10  to facilitate retention of coupling between the probe  10  and the skin surface  12 . 
     In certain aspects, the delivery system  44  can have an on-off switch or a separate on-off device that allows a patient or user to turn the delivery system  44  on (and subsequently off) when the ultrasound assisted drug delivery probe  10  is properly located on the skin surface  12 . The delivery system  44  can utilize at least one ultrasound energy effect to move the medicant  34  from the standoff  46  to below the skin surface  12 . 
     A delivery system  44  as described herein can have significant advantages over a traditional transdermal patch. For example, the delivery system  44  can deliver medicants  34  having a higher molecular weight, for example, medicants  34  having a molecular weight of at least about 100 Da or at least about 500 Da. As another example, the delivery system  44  does not rely on mechanical diffusion, so lower doses of the medicant  34  can be deployed because more of the medicant  34  reaches areas beneath the skin surface  12 . As yet another example, the delivery system  44  is not limited to deploying medicants  34  having an affinity for both lipophilic and hydrophilic phases or medicants  34  that are non-ionic. In certain aspects, the delivery system  44  can include a solar panel, which can optionally be no bigger than the area of a patch covering the ultrasound assisted drug delivery probe  10 , to supplement power to the delivery system  44 . 
     Referring to  FIG. 3 , multiple devices, including a microchannel device  50  comprising a microchannel creation means  52 , a first ultrasound device  54 , a second ultrasound device  56 , and a third ultrasound device  58 , can be configured individually or as a part of a single system to independently or cooperatively provide delivery of a medicant  34 . The microchannel device  50  comprising the microchannel creation means  52  is configured to create a microchannel  60  through the stratum corneum  14 . The microchannel device  50  and microchannel creation means  52  can be any of the systems or methods described herein. For example, the microchannel device  50  can be an ultrasound probe and the microchannel creation means  52  can employ one or more acoustic energy fields, such as described in the description of  FIGS. 1A, 1B, 1C, 1D, 2A, 2B, 2C, and 2D . The microchannel device  50  microchannel creation means  52  can also include one or more microneedles. The microchannel device  50  can be a photon-based energy source and the microchannel creation means  52  can include a photon-based energy field configured to generate microchannels  60  in the stratum corneum  14 . 
     The microchannel device  50 , the first ultrasound device  54 , the second ultrasound device  56 , and the third ultrasound device  58  can move from right to left across the illustrated skin surface  12 , either collectively or independently. A coupling medium  32  can be applied to the skin surface  12  before or after the microchannel creation means  52  has created a microchannel  60 . If the microchannel device  50 , the first ultrasound device  54 , the second ultrasound device  56 , and the third ultrasound device  58  are operating in series, then the coupling medium  32  is typically applied to the skin surface  12  after the microchannel creation means  52  has created the microchannel  60  to avoid loss of the medicant  34  or contamination of the medicant  34  by the microchannel creation means  52 . The microchannel device  50 , the first ultrasound device  54 , the second ultrasound device  56 , and the third ultrasound device  58  can be controlled by a control module  30 , either collectively or independently. In certain aspects, the microchannel device  50 , the first ultrasound device  54 , the second ultrasound device  56 , and the third ultrasound device  58  can each be housed in individual cylinders or spheres that are configured to roll across the skin surface  12 . 
     The first ultrasound device  54  can be configured to direct a fourth acoustic energy field  62  into the skin surface  12 . The fourth acoustic energy field  62  can be configured to drive the medicant  34  through the microchannel  60 . In certain aspect, the fourth acoustic energy field  62  can have the properties of the first acoustic energy field  36 , as described herein. 
     The second ultrasound device  56  can be configured to direct a fifth acoustic energy field  64  into the skin surface  12 . The fifth acoustic energy field  64  can be configured to drive the medicant  34  through the epidermis  16  and optionally through the dermis  18 . In certain aspects, the fifth acoustic energy field  64  can have the properties of the second acoustic energy field  38 , as described herein. 
     The third ultrasound device  58  can be configured to direct a sixth acoustic energy field  66  into the skin surface  12 . The sixth acoustic energy field  66  can be configured to interact with the medicant  34  or with tissue containing or proximate to the medicant  34 . In certain aspect, the sixth ultrasound acoustic energy field  66  can have the properties of the third acoustic energy field  40 , as described herein. 
     In addition to the first acoustic energy field  36 , the second acoustic energy field  38 , the third acoustic energy field  40 , the fourth acoustic energy field  62 , the fifth acoustic energy field  64 , or the sixth acoustic energy field  66 , the methods described herein can utilize additional acoustic energy fields configured to provide one or more effects described herein. 
     In certain aspects, a system such as an ultrasound assisted drug delivery probe  10 , a delivery device  44 , a microchannel device  50 , a first ultrasound device  40 , a second ultrasound device  56 , a third ultrasound device  58 , or any combination thereof can include various components described herein. For example, a system can include a control module  30 . As one non-limiting example, such a control module  30  can be the control module  20  described above, which can be configured to receive at least one communication and control a distribution of the acoustic energy field transmitted by the ultrasound energy source, such as, for example, an acoustic transducer  24 . The control module  30  can be configured to receive a treatment start signal and a treatment stop signal. The control module  30  can be programmed to provide treatment to the ROI  20  for a desired outcome. The control module  30  can initiate and run a treatment program (treatment function), which can include the control of spatial parameters and/or temporal parameters of the ultrasound source, to provide programmed distribution of the acoustic energy field in the ROI  20 . The control module  30  can be configured to receive feedback from one or more sensors and/or detectors, and the control module  30  can terminate the treatment program based on the feedback. 
     The control module  30  can be configured to communicate with the probe  10  via wireless interface. In some embodiments, the control module  20  can be a wireless device, which has a display and a user interface such as, for example, a keyboard. Examples of a wireless device can include but are not limited to: a personal data assistant (PDA), a cell phone, a smart phone, an iPhone, an iPad, a computer, a laptop, a netbook, a tablet, or any other such device now known or developed in the future. Examples of wireless interface include but are not limited to any wireless interface described herein and any such wireless interface now known or developed in the future. Accordingly, the probe  10  can comprise any hardware, such as, for example, electronics, antenna, and the like, as well as, any software that may be used to communicate via wireless interface. 
     The wireless device can be configured to display an image generated by the probe  10 . The wireless device can be configured to control at least a portion of the probe  10 . The wireless device can be configured to store data generated by the probe  10  and sent to the wireless device. 
     Various sensing and monitoring components may also be implemented within control module. For example, monitoring, sensing, and interface control components may be capable of operating with the motion detection system implemented within the probe  10 , to receive and process information such as acoustic or other spatial and temporal information from the ROI  20 . Sensing and monitoring components may also comprise various controls, interfacing, and switches and/or power detectors. Such sensing and monitoring components may facilitate open-loop and/or closed-loop feedback systems within the probe  10 . 
     In some aspects, sensing and monitoring components may further comprise a sensor that may be connected to an audio or visual alarm system to prevent overuse of the probe  10 . The sensor may be capable of sensing the amount of energy transferred to the skin, and/or the time that the probe  10  has been actively emitting the acoustic energy. When a certain time or temperature threshold has been reached, the alarm may sound an audible alarm, or cause a visual indicator to activate to alert the user that a threshold has been reached. This may prevent overuse of the device. In some embodiments, the sensor may be operatively connected to the control module and force the control module  30 , to stop emitting the acoustic energy from the probe  10 . In some embodiments, the control module  30  is operable to control the power supply to change an amount of power provided to the acoustic transducer  24  in the probe  10 . 
     A position sensor may be located behind a transducer, in front of a transducer, or integrated into a transducer array. The probe  18  may comprise more than one position sensor, such as, for example, a laser position sensor and a motion sensor, or a laser position sensor and a visual device, or a motion sensor and a visual device, or a laser position sensor, a motion sensor, and a visual device. In some embodiments, position sensor may determine a distance between pulses of the acoustic energy to create a plurality of treatment zones which are evenly spaced or disposed in any spatial configuration in 1-D or 2-D patterns. As the probe  18  is moved in direction, the position sensor determines distance, regardless of a speed that the ultrasound source is move, at which a pulse of acoustic energy is to be emitted in to ROI  12 . 
     In some aspects, the system can further comprise a contact sensor operable to determine if the ultrasound source is coupled to the ROI  12 . The tissue contact sensor can communicate to the control module  20  whether the ultrasound source is coupled to the ROI  12 . 
     The first acoustic energy field  36 , second acoustic energy field  38 , or third acoustic energy field  40  can be planar, focused, weakly focused, unfocused, or defocused. The first acoustic energy field  36 , second acoustic energy field  38 , or third acoustic energy field  40  can have a frequency in the range of about 1 MHz to about 30 MHz, including, but not limited to, a frequency in the range of about 5 MHz to about 15 MHz, from about 2 MHz to about 12 MHz, from about 3 MHz to about 7 MHz, from about 1 MHz to about 7 MHz, from about 2 MHz to about 5 MHz, from about 3 MHz to about 10 MHz, or from about 1 MHz to about 10 MHz, or other combinations of the lower and upper limits of these ranges not explicitly recited. The first acoustic energy field  36 , second acoustic energy field  38 , or third acoustic energy field  40  can be configured to avoid damaging the cells in the stratum corneum  14  or the epidermis  16 . 
     The first acoustic energy field  36 , second acoustic energy field  38 , or third acoustic energy field  40  can be pulsed and have a delay of from about 1 μs to about 100 seconds between pulses. The first acoustic energy field  36 , second acoustic energy field  38 , or third acoustic energy field  40  can be continuous wave. In certain aspects, the first acoustic energy field  36 , second acoustic energy field  38 , or third acoustic energy field  40  can be pulsed and have a pulse repetition rate of one pulse per 10 μs to one pulse per 100 seconds. 
     In certain applications, such as generating inertial cavitation in the stratum corneum  14  which can create microchannels having an intercellular route from the skin surface  12  to the epidermis  16 , the first acoustic energy field  36  can have a pulse width in a range from about 33 ns to about 100 s. In these certain applications, the first acoustic energy field  36  can be pulsed and can have a pulse width in the range of about 1 μs to about 1 second, or in the range of about 0.01 seconds to about 5 seconds. In these certain applications, the first acoustic energy field  36  can have a peak intensity of greater than 3 W/cm 2  and less than or equal to about 100 kW/cm 2  at the skin surface  12 . In certain aspects, the first acoustic energy field  36  can have a peak intensity of greater than 10 W/cm 2 , greater than 50 W/cm 2 , greater than 100 W/cm 2 , greater than 300 W/cm 2 , greater than 500 W/cm 2 , greater than 1 kW/cm 2 , greater than 3 kW/cm 2 , or greater than 5 kW/cm 2 . The intensity of the first acoustic energy field  36  can be below a threshold value for creating a shock wave. A person having ordinary skill in the art will appreciate that this threshold value can vary based on material properties and the specific parameters of the ultrasound being used, and can determine this threshold value for specific materials and sets of parameters experimentally or computationally. 
     In certain applications, such as generating acoustic streaming providing acoustic streaming pressure to the stratum corneum  14 , the epidermis  16 , or a combination thereof, the first acoustic energy field  36  can be pulsed and the pulses can have a pulse width in a range of about 33 ns to about 100 s, including, but not limited to, a range of about 1 μs to about 10 seconds or a range of about 0.001 seconds to about 5 seconds. In these certain applications, the first acoustic energy field  36  can have a peak intensity in the range from about 5 W/cm 2  to about 100 kW/cm 2  at the skin surface  12 . In certain aspects, the first acoustic energy field  36  can have a peak intensity of greater than 10 W/cm 2 , greater than 50 W/cm 2 , greater than 100 W/cm 2 , greater than 300 W/cm 2 , greater than 500 W/cm 2 , greater than 1 kW/cm 2 , greater than 3 kW/cm 2 , or greater than 5 kW/cm 2 . Acoustic streaming can generate microchannels having a transcellular route from the skin surface  12  to the epidermis  16 . In these certain applications, acoustic streaming generated by the first acoustic energy field  36  can create pressures ranging from about 10 kPa to about 120 MPa, including, but not limited to, pressures ranging from about 10 kPa to about 10 MPa and pressures ranging from about 10 MPa to about 120 MPa, in the stratum corneum  14 , the epidermis  16 , or a combination thereof. 
     In certain applications, such as generating inertial cavitation in the stratum corneum  14  and acoustic streaming providing acoustic streaming pressure to the stratum corneum  14 , the epidermis  16 , or a combination thereof, which can generate microchannels having both an intercellular route and a transcellular route from the skin surface  12  to the epidermis  16 , the first acoustic energy  36  can provide two or more effects, such as inertial cavitation and acoustic streaming, simultaneously or alternating. In certain aspects, generating inertial cavitation and acoustic streaming can facilitate moving a larger medicant, such as a medicant with a molecular weight greater than 500 Da, through the stratum corneum  14 . 
     In certain applications, the second acoustic energy  38  can be configured to generate inertial cavitation or acoustic streaming in the epidermis  16 , the dermis  18 , or a combination thereof. In certain aspects, the second acoustic energy  38  can be configured to increase diffusion of the medicant  34  through the epidermis  16  and the dermis  18 . In certain aspects, the second acoustic energy  38  can provide a pressure in a range from about 100 kPa to about 100 MPa to push the medicant  34  through the epidermis  16  and into the dermis  18 . 
     It should be appreciated that the effects described herein are tissue-dependent, so the ultrasound energy necessary to generate inertial cavitation or acoustic streaming in one type of tissue might be different than the ultrasound energy necessary to generate inertial cavitation or acoustic streaming in a different type of tissue. It should also be appreciated that for a certain effect to be generated, the threshold for generating that effect must be exceeded. However, the thresholds for generating the effects described herein, such as inertial cavitation and subsequent acoustic streaming, in tissues are generally unknown. 
     With respect to inertial cavitation, aside from a single experimental study regarding the frequency-dependence of the threshold for inertial cavitation in canine skeletal muscle, a recent article by Church et al. states that “too little information on the experimental threshold for inertial cavitation in other tissues is available” to make conclusions regarding frequency-dependent trends. See, Church C C, et al. “Inertial cavitation from ARFI imaging and the MI”, Ultrasound in Med. &amp; Biol., Vol. 41, No. 2, pp. 472-485 (2015). This observation is solely about the inertial cavitation threshold as it relates to frequency, and does not take into account the other spatial and temporal parameters aside from frequency. Accordingly, one of skill in the art should appreciate that the present invention is disclosed in terms of effects that have been shown to produce a specific result, i.e., transporting a medicant across the stratum corneum, and a set of general parameters that are suitable for achieving that result are set forth above. One of skill in the art should also appreciate that the presence of inertial cavitation can be identified by a characteristic broadband signal that is the result of the complex dynamics associated with inertial cavitation. 
     With respect to acoustic streaming, this effect can be generated by an effect including the aforementioned inertial cavitation or without the inertial cavitation. In instances without the inertial cavitation, acoustic streaming can be accomplished by introducing heat into a tissue, for example the stratum corneum, which expands the tissue, then applying a pressure to the medicant or a carrier containing the medicant to initiate acoustic streaming. 
     The inertial cavitation and acoustic streaming effects are described herein with respect to the discrete layers of the skin, but can penetrate to a greater depth beneath the skin surface to enhance the penetration of the medicant deeper into the skin or into subcutaneous tissue. 
     In certain aspects, the first acoustic energy  36  and the second acoustic energy  38  can be substantially the same. In certain aspects, the second acoustic energy  38  can have a frequency that concentrates the acoustic energy deeper and moves the medicant  34  into the dermis  18 . In certain aspects, the second acoustic energy  38  can be configured to cause a thermal effect in the epidermis  16  or the dermis  18 , which is non-destructive to the cells of the epidermis  16  or dermis  18 . 
     The first acoustic energy  36 , second acoustic energy  38 , or third acoustic energy  40  can be generated from one or more ultrasound sources. 
     In certain aspects, the ultrasound assisted drug delivery probe  10  can be configured to create an intensity gain from the ultrasound assisted drug delivery probe  10  to the target volume  42  of at least about 5, including, but not limited to, an intensity gain of at least about 10, at least about 25, at least about 50, or at least about 100. In aspects having a focused or a strongly focused ultrasound, the ultrasound assisted drug delivery probe  10  can be configured to create an intensity gain from the ultrasound assisted drug delivery probe  10  to the target volume  42  of at least about 50, including, but not limited to, an intensity gain of at least about 100, or at least about 500. In aspects having a weakly focused ultrasound, the ultrasound assisted drug delivery probe  10  can be configured to create an intensity gain from the ultrasound assisted drug delivery probe  10  to the target volume  42  of at least about 5. 
     In certain aspects with pulsed ultrasound, a first pulse can be ultrasound having a first type of focus, a second pulse can be ultrasound having a second type of focus, a third pulse can be ultrasound having the first type of focus or a third type of focus, and so on. Any combination of focused, defocused, or unfocused energy can be used for any of the various pulses. 
     In certain aspects, the first acoustic energy  36 , second acoustic energy  38 , or third acoustic energy  40  can create a thermal effect, a mechanical effect, or a combination thereof in the target volume  42 . A mechanical effect is a non-thermal effect within a medium that is created by acoustic energy. A mechanical effect can be one of, for example, acoustic resonance, acoustic streaming, disruptive acoustic pressure, shock waves, inertial cavitation, and non-inertial cavitation. 
     Referring to  FIG. 4 , a flowchart illustrating a method  200  of ultrasound assisted drug delivery is provided. At process block  202 , the method  200  can include administering a medicant  34  to a skin surface  12 . At process block  203 , the method  200  can include creating microchannels  60  through the stratum corneum  14 . At process block  204 , the method  200  can include applying a first acoustic energy field  36  to direct the medicant  34  through the microchannels  60 . At process block  206 , the method  200  can include applying a second acoustic energy field  38  to direct the medicant  34  through the epidermis  16  and into the dermis  18 . At process block  208 , the method  200  can include moving the medicant  34  into a target volume  42  to interact with tissue, be transported via blood vessels, or a combination thereof. At process block  210 , the method  200  can include monitoring the medicant  34  effect. At decision block  218 , the method  200  can include determining whether the treatment is complete. If the treatment is determined to be complete by answering yes  222  to decision block  218 , then the method  200  can be completed. If the treatment is determined to be incomplete by answering no  220  to decision block  218 , then the method  200  can return to process block  202  or can proceed to optional process block  212 . 
     At optional process block  212 , the method  200  can include directing a therapeutic acoustic energy field  40  into the target volume  42 . When the medicant is located in or near the target volume  42 , at optional process block  214 , the method  200  can include directing a third acoustic energy field  40  into the target volume  42  to activate the medicant  34 . 
     In certain aspects, the systems and methods disclosed herein can utilize an anesthetic coupled with a non-anesthetic medicant, where the anesthetic can reduce pain and inflammation associated with application of the ultrasound energy, including pain and inflammation associated with the transdermal delivery of the medicant or other ultrasound-generated effects described herein. 
     In certain aspects, the medicant can be at least partially transparent to ultrasound energy. In certain aspects, the medicant can be substantially transparent to ultrasound energy. 
     In certain aspects, the stratum corneum layer  14  can be substantially intact prior to the application of ultrasound energy. For example, prior to the application of ultrasound energy, the stratum corneum layer  14  can have no punctures, microchannels, wounds, other means of improving permeability of a medicant, or combinations thereof. 
     The medicant can be mixed into or be a component of an acoustic coupling medium. In some embodiments, an acoustic coupling medium, such as an acoustic coupling gel or an acoustic coupling cream, can comprise the medicant. In some embodiments, a medicant is administered to a skin surface above the ROI. In some applications, the medicant can be the acoustic coupling medium. In some applications, the medicant can be a combination of medicants, such as any combination of those described herein. 
     The medicant can be mixed into or can be a component of a biocompatible carrier. Example of a biocompatible medicant carrier include, but are not limited to, glycerin, liposomes, nanoparticles, microbubbles, and the like. In certain aspects, the carrier can enhance and/or lower the threshold for inertial cavitation. 
     A medicant can comprise an anesthetic. In some aspects, the anesthetic can comprise lidocaine, benzocaine, prilocaine, tetracaine, novocain, butamben, dibucaine, oxybuprocaine, pramoxine, proparacaine, proxymetacaine, tetracaine, or any combination thereof. The anesthetic an eliminate or reduce the pain generated by the application of ultrasound energy to the skin, for example, the creation of the microchannels in the skin by ultrasound energy. The anesthetic can constrict blood flow, which can eliminate or reduce any blood flowing that emerges to the skin surface by way of damage from the application of ultrasound energy to the skin, for example, blood flowing up a microchannel generated by ultrasound energy and onto the skin surface. Further, the use of an anesthetic, such as lidocaine, in the acoustic coupling medium substantially eliminates skin irritation from the application of ultrasound energy, such as the ultrasound-induced creation of microchannels penetrating the skin surface. 
     A medicant can comprise a drug, a vaccine, a nutraceatical, or an active ingredient. A medicant can comprise blood or a blood component, an allergenic, a somatic cell, a recombinant therapeutic protein, or any living cells that are used as therapeutics to treat diseases or as actives to produce a cosmetic or a medical effect. A medicant can comprise a biologic, such as for example a recombinant DNA therapy, synthetic growth hormone, monoclonal antibodies, or receptor constructs. A medicant can comprise stem cells. 
     A medicant can comprise adsorbent chemicals, such as zeolites, and other hemostatic agents are used in sealing severe injuries quickly. A medicant can comprise thrombin and/or fibrin glue, which can be used surgically to treat bleeding and to thrombose aneurysms. A medicant can comprise Desmopressin, which can be used to improve platelet function by activating arginine vasopressin receptor  1 A. A medicant can comprise a coagulation factor concentrates, which can be used to treat hemophilia, to reverse the effects of anticoagulants, and to treat bleeding in patients with impaired coagulation factor synthesis or increased consumption. A medicant can comprise a Prothrombin complex concentrate, cryoprecipitate and fresh frozen plasma, which can be used as coagulation factor products. A medicant can comprise recombinant activated human factor VII, which can be used in the treatment of major bleeding. A medicant can comprise tranexamic acid and/or aminocaproic acid, which can inhibit fibrinolysis, and lead to a de facto reduced bleeding rate. A medicant can comprise platelet-rich plasma (PRP), mesenchymal stem cells, or growth factors. For example, PRP is typically a fraction of blood that has been centrifuged. The PRP is then used for stimulating healing of the injury. The PRP typically contains thrombocytes (platelets) and cytokines (growth factors). The PRP may also contain thrombin and may contain fibenogen, which when combined can form fibrin glue. 
     In addition, a medicant can comprise a steroid, such as, for example, like the glucocorticoid cortisol. A medicant can comprise an active compound, such as, for example, alpha lipoic Acid, DMAE, vitamin C ester, tocotrienols, and/or phospholipids. A medicant can comprise a pharmaceutical compound such as for example, cortisone, Etanercept, Abatacept, Adalimumab, or Infliximab. A medicant can comprise Botox. A medicant can comprise lignin peroxidase, which can be derived from fungus and can be used for skin lightening applications. A medicant can comprise hydrogen peroxide, which can be used for skin lighting applications. 
     The medicant can comprise an anti-inflammatory agent, such as, for example, a non-steroidal anti-inflammatory drug (NSAID), such as aspirin, celecoxib (Celebrex), diclofenac (Voltaren), diflunisal (Dolobid), etodolac (Lodine), ibuprofen (Motrin), indomethacin (Indocin), ketoprofen (Orudis), ketorolac (Toradol), nabumetone (Relafen), naproxen (Aleve, Naprosyn), oxaprozin (Daypro), piroxicam (Feldene), salsalate (Amigesic), sulindac (Clinoril), or tolmetin (Tolectin). 
     Still further, a medicant can comprise an active ingredient which provides a cosmetic and/or therapeutic effect to the area of application on the skin. Such active ingredients can include skin lightening agents, anti-acne agents, emollients, non-steroidal anti-inflammatory agents, topical anesthetics, artificial tanning agents, antiseptics, anti-microbial and anti-fungal actives, skin soothing agents, sunscreen agents, skin barrier repair agents, anti-wrinkle agents, anti-skin atrophy actives, lipids, sebum inhibitors, sebum inhibitors, skin sensates, protease inhibitors, skin tightening agents, anti-itch agents, hair growth inhibitors, desquamation enzyme enhancers, anti-glycation agents, compounds which stimulate collagen production, and mixtures thereof. 
     Other examples of such active ingredients can include any of panthenol, tocopheryl nicotinate, benzoyl peroxide, 3-hydroxy benzoic acid, flavonoids (e.g., flavanone, chalcone), farnesol, phytantriol, glycolic acid, lactic acid, 4-hydroxy benzoic acid, acetyl salicylic acid, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, 2-hydroxyhexanoic acid, cis-retinoic acid, trans-retinoic acid, retinol, retinyl esters (e.g., retinyl propionate), phytic acid, N-acetyl-L-cysteine, lipoic acid, tocopherol and its esters (e.g., tocopheryl acetate), azelaic acid, arachidonic acid, tetracycline, hydrocortisone, acetominophen, resorcinol, phenoxyethanol, phenoxypropanol, phenoxyisopropanol, 2,4,4′-trichloro-2′-hydroxy diphenyl ether, 3,4,4′-trichlorocarbanilide, octopirox, lidocaine hydrochloride, clotrimazole, miconazole, ketoconazole, neomycin sulfate, theophylline, and mixtures thereof. 
     A medicant can be any natural or synthetic compound or any combination of compounds, or a drug, or a biologic, as described herein, or is known to one skilled in the art, or is developed in the future. 
     A medicant can be diluted with an appropriate solvent for delivery. For example, a medicant can be diluted or mixed with a solvent to lower viscosity to improve transfer of the medicant. For example, a medicant can be diluted or mixed with a solvent that is a vehicle for transfer of the medicant, such as, for example, mixing a medicant with a formulation of polyethylene glycol (PEG). In some applications, the medicant can be mixed with a solvent to improve a tissue effect, such as uptake into the tissue, such as, for example, mixing a medicant with dimethyl sulfoxide (DMSO). In some applications, the medicant can be mixed with a solvent, which can restrict or inhibit an ultrasound energy effect. For example, a medicant can be mixed with ethanol (EtOH), which inhibits the thermal effect of ablation. In some applications, the medicant can be mixed with a solvent, which can amplify an ultrasound energy effect. For example, a medicant can be mixed with a contrast agent, which can be configured to promote higher attenuation and/or cavitation at lower acoustic pressures. 
     A medicant can be in a non-liquid state. In some applications, a medicant can be a gel or a solid, which by using a thermal effect, can melt into a liquid state suitable for delivery. For example, a medicant can be mixed into a thermally responsive hydrogel, which is configured to transform into an injectable state upon receiving a suitable amount of thermal energy emitted from a transducer. 
     In some aspects, a medicant can be administered to a skin surface above the ROI. The medicant can be mixed into or be a component of an acoustic coupling medium. In some applications, the medicant can be the acoustic coupling medium. In some aspects, the acoustic coupling medium can comprise a preservative and/or a preservative enhancer, such as, for example, water-soluble or solubilizable preservatives including Germall 115, methyl, ethyl, propyl and butyl esters of hydroxybenzoic acid, benzyl alcohol, sodium metabisulfite, imidazolidinyl urea, EDTA and its salts, Bronopol (2-bromo-2-nitropropane-1,3-diol) and phenoxypropanol; antifoaming agents; binders; biological additives; bulking agents; coloring agents; perfumes, essential oils, and other natural extracts. 
     In certain aspects, microchannels  60  can be long enough for fluid communication between the skin surface  12  and the epidermis  16 . The microchannels  60  can have a diameter large enough to allow the medicant to pass from the skin surface  12  to the epidermis  16 . The microchannels  60  can have a diameter small enough to prevent bleeding from subcutaneous tissue to the skin surface  12 . 
     In certain aspects, a single ultrasound pulse can provide sufficient effect to drive the medicant through the stratum corneum  14 . In some aspects, two more ultrasound pulses, including but not limited to, two, three, four, five, six, seven, eight, nine, ten, or more ultrasound pulses can provide sufficient effect to drive the medicant through the stratum corneum  14 . 
     In certain aspects, the systems and methods described herein can drive medicant through the stratum corneum  14  after application of ultrasound energy for a total length of time of less than 5 minutes, including but not limited to, less than 3 minutes, less than 1 minute, less than 50 seconds, less than 40 seconds, less than 30 seconds, less than 25 seconds, less than 20 seconds, less than 15 seconds, less than 10 seconds, less than 5 seconds, less than 4 seconds, less than 3 seconds, less than 2 seconds, or less than 1 second. 
     The systems and methods described herein can be employed in numerous clinical applications. For example, a treatment for scars can include a medicant directed by acoustic energy through microchannels to a scar location. A second acoustic energy can be directed to the scar location and be configured to interact with the medicant to remodel and/or modify the scar tissue and eventually replace the scar tissue via remodeling. The treatment can also include directing therapeutic acoustic energy into the scar tissue. In some applications, the therapeutic acoustic energy can be configured to ablate a portion of the scar tissue, thereby removing a portion of the scar tissue. In some applications, the therapeutic acoustic energy can be configured to create a lesion in or near the scar tissue, thereby facilitating skin tightening above the lesion. In some applications, the therapeutic acoustic energy can be configured to remodel and/or increase an amount of collagen around the scar tissue, thereby replacing portions of the scar tissue with newly formed collagen. 
     In another example, the systems and methods described herein can be used in the treatment of hyperpigmentation. A medicant can be a skin lightening agent, which can be any active ingredient that improves hyperpigmentation. Without being bound by theory, use of skin lightening agents can effectively stimulate the epidermis, particularly the melanocyte region, where the melanin is generated. The combined use of the skin lightening agent and ultrasound energy can provide synergistic skin lightening benefit. A medicant comprise a skin lightening agent, such as, for example, ascorbic acid compounds, vitamin B3 compounds, azelaic acid, butyl hydroxyanisole, gallic acid and its derivatives, glycyrrhizinic acid, hydroquinone, kojic acid, arbutin, mulberry extract, and mixtures thereof. Use of combinations of skin lightening agents can be advantageous as they may provide skin lightening benefit through different mechanisms. 
     In one aspect, a combination of ascorbic acid compounds and vitamin B3 compounds can be used. Examples of ascorbic acid compounds can include L-ascorbic acid, ascorbic acid salt, and derivatives thereof. Examples of ascorbic acid salts include sodium, potassium, lithium, calcium, magnesium, barium, ammonium and protamine salts. Examples of ascorbic acid derivatives include for example, esters of ascorbic acid, and ester salts of ascorbic acid. Examples of ascorbic acid compounds include 2-O-D-glucopyranosyl-L-ascorbic acid, which is an ester of ascorbic acid and glucose and usually referred to as L-ascorbic acid 2-glucoside or ascorbyl glucoside, and its metal salts, and L-ascorbic acid phosphate ester salts such as sodium ascorbyl phosphate, potassium ascorbyl phosphate, magnesium ascorbyl phosphate, and calcium ascorbyl phosphate. In addition, medicant can comprise lignin peroxidase, which can be derived from fungus used for skin lightening applications. In another example, medicant can comprise hydrogen peroxide, which can be used for skin lighting applications. 
     In an exemplary application, a coupling agent can comprise a medicant, which comprises a skin lighting agent. Ultrasound energy can direct the lightening agent into the epidermis and into contact with melanin. The lightening agent can remove excess melanin. Additional ultrasound energy can be directed to the epidermis to provide a cavitation effect to break up the excess melanin pigment. In some examples, additional ultrasound energy can be directed to the epidermis to provide a thermal effect, which can be configured to increase the effectiveness of the skin lightening agent. In one example, the skin lightening agent can be hydrogen peroxide and the ultrasound energy can increase the temperature of the hydrogen peroxide by at least 1° C. and to about 15° C., which increases the effectiveness of the skin lightening agent. 
     In another example of a clinical application, the systems and methods described herein can be used in the treatment of hypopigmentation. In an exemplary application, a coupling agent can comprise a medicant, which can comprise a corticosteroid. Ultrasound energy can direct the corticosteroid into the epidermis at the light colored areas of the skin. A second ultrasound energy can be directed to the treatment location and be configured to interact with the corticosteroid to provide a synergistic treatment to increase pigment concentration at the treatment location. A second energy, such as, a photon-based energy from a laser can be directed to the treatment location to further increase the pigment concentration in the treatment location. A third energy, such as, ultrasound energy can be directed to the treatment location to disperse the generated pigment and provide an even coloring pattern at the treatment location. 
     In another example, large molecule medicants can be delivered using the systems and methods described herein. A large molecule can be greater than 500 Da. A large molecule can be any medicinal product manufactured in or extracted from biological sources. Examples of large molecule include vaccines, blood or blood components, allergenics, somatic cells, gene therapies, tissues, recombinant therapeutic protein and living cells. In one example, a large molecule comprises stem cells. An energy effect is provided by an acoustic energy field, which is configured to drive the large molecule through the microchannels and into subcutaneous tissue. The energy effect can be acoustic streaming and/or inertial cavitation. In some applications, the energy effect is a thermal effect, which can be configured to lower the viscosity of a large molecule for improved transfer through the microchannels. 
     In another example, chemotherapy drugs can be delivered using the systems and methods described herein. Some of the advantages, of using such systems and methods, include concentrating the chemotherapy drug to the tumor site (as opposed to exposing the whole body to the drug), lower doses may be required (due to the site specific treatment), and greater effectiveness of the drug. 
     In some applications, a chemotherapy drug can be a large molecule. In some applications, the systems and methods, described herein, can deliver anti-body drug conjugates, which target cancer stem cells to destroy a tumor. In some applications, a chemotherapy drug is a liposome encapsulated chemotherapy drug, which can be delivered through the microchannels to a treatment site by an acoustic energy field, and then a second acoustic energy field can be delivered to melt the liposome and release the chemotherapy drug. In some applications, an acoustic energy field can be delivered, which is configured to provide microbubbles (cavitation) to a tumor in a treatment site without generating heat, which can lead to reduction or elimination of the tumor. These microbubbles can increase microvessel permeability of drugs, enhance drug penetration through the interstitial space, and increase tumor cell uptake of the drugs, thus enhancing the antitumor effectiveness of the drugs. 
     In some applications of chemotherapy, a drug-loaded nanoemulsion can be driven through the microchannels to a tumor site via an acoustic energy field. A second acoustic energy field can be delivered to the tumor site and can be configured to trigger drug release from nanodroplets, which can be created by microbubbles. A third acoustic energy field can be delivered to the tumor site and can be configured to produce an energy effect, for example, a thermal effect and/or cavitation, which enhances uptake of the drug by the tumor. 
     In another example, photodynamic therapy can be delivered using the systems and methods described herein. As known to one skilled in the art, photodynamic therapy is a medical treatment that utilizes a medicant, which comprises a photosensitizing agent and a photon-emission source to activate the administered medicant. In some applications, the medicant comprising a photosensitizing agent is delivered through the microchannels into tissue via an acoustic energy field. After the medicant has been delivered, a second acoustic energy field can be delivered to enhance permeability and/or uptake of the medicant by the tissue. After the medicant has been delivered, a photon energy field at a specific wavelength is delivered from the photon-emission source to the tissue, which activates the medicant. The photon-emission source can include, but are not limited to: laser, LED or intense pulsed light. The optimal photon-emission source is determined by the ideal wavelength for activation of the medicant and the location of the target tissue. The photon energy field is directly applied to the target tissue for a specific amount of time. The medicant can be Levulan, which is used for the treatment of skin cancer. The medicant can be Metvix, which is used for the treatment of skin cancer. The medicant can be Photofin, which is used for the treatment of bladder cancer, lung cancer and esophagus cancer. The medicant can be aminolevulinic acid, which has been used in the treatment of various skin conditions, such as, for example, acne, rosacea, sun damage, enlarged sebaceous glands, wrinkles, warts, hidradenitis suppurativa, and psoriasis. 
     In another example, injuries to muscles can be treated using the systems and methods described herein. For treating an injury to a muscle, ligament, or tendon, a medicant can comprise platelet-rich plasma (PRP), mesenchymal stem cells, or growth factors. For example, PRP is typically a fraction of blood that has been centrifuged. The PRP is then used for stimulating healing of the injury. The PRP typically contains thrombocytes (platelets) and cytokines (growth factors). The PRP may also contain thrombin and may contain fibenogen, which when combined can form fibrin glue. The medicant is directed through a microchannels to the injury, such as, for example a tear in the tissue. An acoustic energy field can then be directed to the injury to activate the medicant and/or disperse the medicant. The acoustic energy field can create a thermal effect to heat the injury location which can initiate interaction of the medicant with the tissue at the injury location and/or increase blood perfusion in the injury location. The acoustic energy field can ablate a portion of tissue in the injury location, which can peak inflammation and increase the speed of the healing process. The acoustic energy field can be directed to the injury location and weld together the tear using both an ablative thermal effect and various mechanical effects. 
     In an example, acne can be treated using the systems and methods described herein. A medicant can comprise any one or more of cis-retinoic acid, trans-retinoic acid, retinol, retinyl esters (e.g., retinyl propionate), phytic acid, N-acetyl-L-cysteine, lipoic acid, tocopherol and its esters (e.g., tocopheryl acetate), azelaic acid, arachidonic acid, tetracycline, ibuprofen, naproxen, ketoprofen, hydrocortisone, acetominophen, resorcinol, phenoxyethanol, phenoxypropanol, phenoxyisopropanol, 2,4,4′-trichloro-2′-hydroxy diphenyl ether, 3,4,4′-trichlorocarbanilide, octopirox, lidocaine hydrochloride, clotrimazole, miconazole, ketoconazole, neomycin sulfate, theophylline. The medicant is directed through the microchannels to a ROI comprising a sebaceous gland. The medicant interacts with bacteria in the sebaceous gland to reduce or eliminate the bacteria responsible for acne. An acoustic energy field can provide a mechanical effect to disperse the medicant into one or more sebaceous gland. An acoustic energy field can provide a thermal effect to accelerate the reaction of the medicant to eliminate or reduce the amount of bacteria in the sebaceous gland. An acoustic energy field can provide a thermal effect to injure or destroy at least a portion of the sebaceous gland. A photon based energy field can be directed to the medicant in the ROI to initiate a photodymanic effect to activate the medicant. A photon based energy field can be directed to the medicant in the ROI to reduce photosensitivity of the tissue in the ROI from sunlight. 
     As used herein, pulse width is the time from the start of the pulse to the end of the pulse measured at a −3 dB or −6 dB power point. 
     As used herein, “acoustic streaming” refers to a force of acoustic energy which displaces a material through a tissue environment. 
     Example 1 
     An ultrasound transducer was coupled to a forearm of two human patients with a standard acoustic coupling gel in one location and a 5% topical solution of lidocaine as an acoustic coupling gel in a second location. The 5% topical solution of lidocaine had negligible acoustic attenuation of less than 1 dB/cm/MHz. The ultrasound transducer transmitted ultrasound energy at 10 MHz, a pulse width of 25 ms, and an energy of 0.5 J. The ultrasound energy was focused to a depth of 1.5 mm beneath the surface of human skin. The presence of the 5% topical solution of lidocaine reduced pain from the application of the ultrasound energy by approximately 2 points on a 10-point pain scale when compared with the application of the ultrasound energy in the absence of the lidocaine. Referring to  FIG. 5A , the ultrasound energy was applied in treatment lines to an area on the left with only the standard acoustic coupling gel present and the same ultrasound energy was applied to an area on the right with the 5% lidocaine solution present on the skin surface. Referring to  FIG. 5B , the ultrasound energy was applied in treatment lines to an area on the right with only the standard acoustic coupling gel present and the same ultrasound energy was applied to an area on the left with a 5% lidocaine ointment present on the skin surface. FIGS. SA and SB show evidence of the treatment effect of lidocaine in this disclosure. After the application of the ultrasound energy, the treatment areas that did not have lidocaine applied to them were irritated, red, and welt-like, whereas the treatment areas that did have lidocaine applied to them were smooth and contained barely visible remnants. The ultrasound energy that was utilized exhibited broadband spectral properties when applied to water, gel, and tissue, which is evidence of an inertial cavitation effect. 
     Example 2 
     An ultrasound transducer was coupled to an ex-vivo sample of pig skin with dyed water as a coupling agent. The water was dyed with a green food dye. The ultrasound transducer transmitted ultrasound energy in treatment lines of high intensity ultrasound point exposures at a frequency of 2.87 MHz, a pulse width of 170 ms, and a pulse power of 10 W. The ultrasound energy was focused to a depth of approximately 1.5 mm beneath the surface of the pig skin. Locations that were not treated with the ultrasound energy showed penetration of the dye ranging from 1.0 mm to 1.5 mm. Locations that were treated with the ultrasound energy showed penetration of the dye ranging from 2.0 mm to 2.8 mm, thereby showing that the application of the ultrasound energy enhanced the transdermal transport of the water containing the dye. The ultrasound energy that was utilized exhibited broadband spectral properties when applied to water, gel, and tissue, which is evidence of an inertial cavitation effect. 
     The present disclosure has been described above with reference to various exemplary configurations. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary configurations without departing from the scope of the present invention. For example, the various operational steps, as well as the components for carrying out the operational steps, may be implemented in alternate ways depending upon the particular application or in consideration of any number of cost functions associated with the operation of the system, e.g., various of the steps may be deleted, modified, or combined with other steps. Further, it should be noted that while the method and system for ultrasound treatment as described above is suitable for use by a medical practitioner proximate the patient, the system can also be accessed remotely, i.e., the medical practitioner can view through a remote display having imaging information transmitted in various manners of communication, such as by satellite/wireless or by wired connections such as IP or digital cable networks and the like, and can direct a local practitioner as to the suitable placement for the transducer. Moreover, while the various exemplary embodiments may comprise non-invasive configurations, system can also be configured for at least some level of invasive treatment application. These and other changes or modifications are intended to be included within the scope of the present invention, as set forth in the following claims.