Patent Description:
This invention relates to a method for cryogranulating a pharmaceutical composition during manufacturing of a drug product.

Cryogranulation equipment is commercially available for the manufacture of frozen product pellets in the food industry. In particular, cryogranulation systems used in the food industry are suitable for preparing frozen foods, such as ice cream. <CIT>; <CIT>, and <CIT>, for example, disclose systems used for cryogranulation.

Cryogranulation systems may include a tray or channel carrying a flow of a cryogenic liquid, such as liquid nitrogen. A material to be cryogranulated is introduced into the flow of liquid nitrogen from a dispenser positioned above the tray. The material is frozen by the liquid nitrogen into pellets or granules. At the end of the tray, the liquid nitrogen and the frozen pellets are separated, typically using a screen. The liquid nitrogen is returned to the upper end of the tray to form a closed loop circulation of liquid nitrogen. The frozen pellets may be used as is or subjected to further processing. The terms "cryogranulating" and "cryopelletizing" are used more or less interchangeably.

Some processes, such as manufacturing of pharmaceutical formulations, require precise control and repeatable results. Prior art cryogranulation systems have not heretofore been suitable for manufacturing of pharmaceutical formulations. Accordingly, there is a need for improvements in the design and manufacture of cryogranulation systems and methods for use in manufacturing of pharmaceutical formulations.

<CIT> describes a spray-dried diketopiperazine-insulin particle formulation useful as a pharmaceutical formulation for pulmonary delivery.

<CIT> describes a method of introducing a physiologically active agent into the circulatory system of a mammal. The method utilises a rapid drug delivery system which prevents deactivation or degradation of the active agent being administered to a patient in need of treatment. In particular, the drug delivery system is designed for pulmonary drug delivery such as by inhalation, for delivery of the active agents such as proteins and peptides to the pulmonary circulation in a therapeutically effective manner avoiding degradation of the active agents in peripheral and vascular tissue before reaching the target site.

<CIT> describes a polycarbohydrate-siloxane (PCS) coating, a formulation comprising one or more active ingredient units coated with PCS and methods for producing such pharmaceutical formulations.

The present invention provides a method of cryogranulating a pharmaceutical composition comprising diketopiperazine, the steps of the method being defined in claim <NUM>.

Cryogranulation systems with an improved dispenser assembly for use in the above method for manufacturing frozen pellets of pharmaceutical substances in a fluid medium are described. Methods of cryogranulating the pharmaceutical substance in the fluid medium are also described. In particular parts of the description, the dispenser assembly is used with suspensions or slurries of pharmaceutical compositions comprising biodegradable substances, such as proteins, peptides, and nucleic acids. The pharmaceutical substance can be adsorbed to any pharmaceutically acceptable carrier particles suitable for making pharmaceutical powders. In the description, the pharmaceutical carrier is diketopiperazine-based microparticles.

A cryogranulation system for use in the above method is described. The cryogranulation system comprises at least one tray configured to carry a flow of a cooling agent; a mechanism configured to deliver the cooling agent to the at least one tray; a dispenser assembly configured to supply a pharmaceutical composition into the cooling agent, the dispenser assembly including a housing and a dispenser subassembly, the housing configured to mount the dispenser subassembly above the tray, the dispenser subassembly including an enclosure defining an interior chamber, at least one inlet port for supplying the pharmaceutical composition to the interior chamber and a plurality of dispenser ports for supplying the pharmaceutical composition to the cooling agent in the tray, the dispenser ports being configured to produce, after interaction of the pharmaceutical composition with the cooling agent, pellets of the pharmaceutical composition in a predetermined size range; and a transport assembly configured to separate the pellets from the cooling agent and to transport the pellets to a pellet receptacle.

A dispenser assembly is described for use in the above method for supplying a pharmaceutical composition into a cooling agent in a cryogranulation system. The dispenser assembly comprises a housing and a dispenser subassembly, the housing configured to mount the dispenser subassembly above the cooling agent, the dispenser subassembly including an enclosure defining an interior chamber, at least one inlet port for supplying the pharmaceutical composition to the interior chamber and a plurality of dispenser ports for supplying the pharmaceutical composition to the cooling agent, the dispenser ports being configured to produce, after interaction of the pharmaceutical composition with the cooling agent, pellets of the pharmaceutical composition in a predetermined size range.

A dispenser assembly for use in the above method is described comprising a housing having an internal volume or chamber, a cover, and a dispenser subassembly attachable to the housing. The dispenser subassembly is configured to have an outer surface and an internal surface, a top portion and bottom portion, the top portion having an inlet port configured to communicate with the internal chamber of the dispenser subassembly. The inlet port provides a conduit for delivering to the dispenser subassembly a pharmaceutical substance in a fluid medium. The dispenser subassembly is further configured with a plurality of outlet ports located at the bottom of the dispenser assembly.

A method for cryopelletizing a suspension or a slurry which is not claimed is described. The method comprises pumping a pharmaceutical composition at a rate of about <NUM> to about <NUM> liters per minute using a peristaltic pump through a dispenser assembly comprising a dispenser subassembly having two portions, a first element and a second element; the first element forming the top portion of the device and having one or more inlet ports for providing the liquid pharmaceutical composition and a second element forming the bottom portion of the dispenser subassembly and comprising channels which are provided with a plurality of conduits and dispensing ports; both first and second elements forming an enclosure for holding a volume of a fluid and capable of dispensing said fluid in droplet form.

For a better understanding of the present invention, reference is made to the accompanying drawings, in which:.

Cryogranulation equipment cannot be readily applied to the manufacturing of pharmaceutical compositions in the freeze dry step of biological drug products processing without encountering many problems. Without pelletizing a pharmaceutical composition, the freezing process agglomerates the composition and leads to increased lyophilization times of the drug product. Other problems encountered when using off the shelf cryogranulation equipment in a pharmaceutical manufacturing process, include: lack of pellet formation, streaming and freezing of the solutions and/or suspensions containing the pharmaceutical substance prior to dispensing, which leads to clogging of the dispenser apparatus, and therefore, product loss during transport due to inability to create the desired pellet sizes during pelletization. The standard cryogranulation equipment is typically used with substances of relatively high viscosity.

Disclosed herein are an apparatus and methods for cryogranulating or cryopelletizing a pharmaceutical composition. The pharmaceutical composition may have the form of a pharmaceutical substance in a fluid medium. In a particular embodiment, the cryogranulation system produces pellets with more homogeneous pellet sizes, which are suitable for transporting through a transport system, improving the efficiency of the process and drug product yield.

In one embodiment, the cryogranulation system produces a more homogenous pellet size of any diameter depending on the pharmaceutical substance and the fluid medium to be pelletized. In certain embodiments, the granules or pellets can range from about <NUM> to <NUM> in diameter. In a particular embodiment, the cryogranulation system includes an improved dispenser assembly that can be adapted to existing commercially available cryogranulation systems.

In particular embodiments, the pharmaceutical substance can be a protein or peptide which is adsorbed onto carrier particles and contained in a medium such as a buffer, a solution, a suspension or a slurry.

The pharmaceutical substance comprises a diketopiperazine and a pharmaceutically active ingredient. In this embodiment, the pharmaceutically active ingredient or active agent can be any type depending on the disease or condition to be treated. In another embodiment, the diketopiperazine can include, for example, symmetrical molecules and asymmetrical diketopiperazines having utility to form particles, microparticles and the like, which can be used as carrier systems for the delivery of active agents to a target site in the body. The term 'active agent' is referred to herein as the therapeutic agent, or molecule such as protein or peptide or biological molecule, to be encapsulated, associated, joined, complexed or entrapped within or adsorbed onto the diketopiperazine formulation. Any form of an active agent can be combined with a diketopiperazine. The drug delivery system can be used to
deliver biologically active agents having therapeutic, prophylactic or diagnostic activities.

One class of drug delivery agents that has been used to produce microparticles that overcome problems in the pharmaceutical arts such as drug instability and/or poor absorption, are the <NUM>,<NUM>-diketopiperazines. <NUM>,<NUM>-diketopiperazines are represented by the compound of the general Formula <NUM> as shown below where E=N. One or both of the nitrogens can be replaced with oxygen to create the substitution analogs diketomorpholine and diketodioxane, respectively.

These <NUM>,<NUM> diketopiperazines have been shown to be useful in drug delivery, particularly those bearing acidic R groups (see for example <CIT> entitled "Self Assembling Diketopiperazine Drug Delivery System;" <CIT> entitled "Method For Making Self-Assembling Diketopiperazine Drug Delivery System;" <CIT> entitled "Microparticles For Lung Delivery Comprising Diketopiperazine;" and <CIT> entitled "Carbon-Substituted Diketopiperazine Delivery System," each of which is incorporated herein by reference in its entirety for all that it teaches regarding diketopiperazines and diketopiperazine-mediated drug delivery). Diketopiperazines can be formed into drug adsorbing microparticles. This combination of a drug and a diketopiperazine can impart improved drug stability and/or absorption characteristics. These microparticles can be administered by various routes of administration. As dry powders these microparticles can be delivered by inhalation to specific areas of the respiratory system, including the lung.

The fumaryl diketopiperazine (bis-<NUM>,<NUM>-(N-fumaryl-<NUM>-aminobutyl)-<NUM>,<NUM>-diketopiperazine; FDKP) is one preferred diketopiperazine for pulmonary applications:
<CHM>.

FDKP provides a beneficial microparticle matrix because it has low solubility in acid but is readily soluble at neutral or basic pH. These properties allow FDKP to crystallize under acidic conditions and the crystals self-assemble to form particles. The particles dissolve readily under physiological conditions where the pH is neutral. In one embodiment, the microparticles disclosed herein are FDKP microparticles loaded with an active agent such as insulin.

In some embodiments, the carrier particles can comprise other diketopiperazines, including fumaryl diketopiperazine, succinyl diketopiperazine, maleyl diketopiperazine and the like. In certain embodiments, the process can generate granules or pellets that can be greater than <NUM> or greater <NUM> in diameter.

The cryogranulation system described herein includes a dispenser assembly, a reservoir for holding a source of a cooling agent such as liquid nitrogen, a pump assembly for delivering the pharmaceutical composition, a pump system for delivering the cooling agent, and a transport system for transporting formed pellets to a pellet receptacle. The dispenser assembly is configured of any size depending on the manufacturing needs and is installed proximal to the cooling agent so that the distance from the surface of the cooling agent is within a few inches from the dispensing ports forming the droplets of pharmaceutical composition to be cryogranulated. In a particular embodiment, the dispenser assembly may be placed in the cryogranulation system within about <NUM> from the liquid nitrogen flow. Other dispenser heights in a range of about <NUM> to about <NUM> can be utilized depending on the substance to be cryogranulated.

A schematic block diagram of a cryogranulation system in accordance with embodiments of the invention is shown in <FIG> and <FIG>. The supporting structure for the components of cryogranulation system <NUM> is omitted in <FIG> and <FIG>. The cryogranulation system <NUM> may be a modification of a commercially available cryogranulation system manufactured and sold by CES Inc.

A cryogranulation system <NUM> may include an upper tray <NUM>, a lower tray <NUM> and a conveyor <NUM>. Each of trays <NUM> and <NUM> may be U-shaped, as shown in <FIG>, to carry a cooling agent, such as a cryogenic liquid, preferably liquid nitrogen <NUM>. Each of trays <NUM> and <NUM> may be tilted with respect to horizontal to cause the liquid nitrogen <NUM> to flow downwardly. The angles of trays <NUM> and <NUM> may be selected to produce a desired flow rate of liquid nitrogen <NUM>. The trays <NUM> and <NUM> may be open-ended, at least at their lower ends, to permit unrestricted flow of liquid nitrogen <NUM>.

Cryogranulation system <NUM> further includes a liquid nitrogen reservoir <NUM> located under conveyor <NUM> and near the lower end of lower tray <NUM>. Liquid nitrogen reservoir <NUM> collects the liquid nitrogen <NUM> that drops from the lower end of lower tray <NUM>. The liquid nitrogen is supplied by a pump <NUM> from reservoir <NUM> to the upper end of upper tray <NUM> to provide a closed loop system for circulation of liquid nitrogen. The liquid nitrogen <NUM> flows down upper tray <NUM> and lower tray <NUM>, and then returns to liquid nitrogen reservoir <NUM>.

A dispenser assembly <NUM> dispenses a pharmaceutical composition <NUM> into the flow of liquid nitrogen <NUM> in upper tray <NUM>. The pharmaceutical composition is supplied from a source tank <NUM> by a pump <NUM> to dispenser assembly <NUM>. The pump <NUM> may be a peristaltic pump and, in some embodiments, may pump the pharmaceutical composition <NUM> at a flow rate of about <NUM> to about <NUM> liters per minute. A nitrogen gas source <NUM> may supply nitrogen gas to dispenser assembly <NUM>.

In operation, the upper tray <NUM>, the lower tray <NUM>, the liquid nitrogen reservoir <NUM> and pump <NUM> produce a continuous flow of liquid nitrogen <NUM> in trays <NUM> and <NUM>. The dispenser assembly <NUM> dispenses the pharmaceutical composition <NUM> into the flow of liquid nitrogen, as described below. The pharmaceutical composition forms frozen pellets which flow with the liquid nitrogen and drop from the lower end of lower tray <NUM> onto conveyor <NUM>.

Conveyor <NUM> performs the functions of separating the frozen pellets from the liquid nitrogen and transporting the pellets to a pellet receptacle <NUM>. Conveyor <NUM> may be in the form of a screen or mesh having openings sized to pass the liquid nitrogen <NUM> and to retain the pellets of the pharmaceutical composition. The liquid nitrogen <NUM> drops through the conveyor <NUM> into liquid nitrogen reservoir <NUM>. The frozen pellets are carried by the conveyor <NUM> and drop from conveyor <NUM> into pellet receptacle <NUM>.

An embodiment of dispenser assembly <NUM> is shown in <FIG>. <FIG> is an isometric view of dispenser assembly <NUM> with side walls of the housing partially cut away. <FIG> is an exploded isometric view of dispenser assembly <NUM>. <FIG> is a bottom view of dispenser assembly <NUM>. <FIG> is an isometric view of the dispenser subassembly. <FIG> is a cross-sectional view of the dispenser subassembly. Like elements in <FIG> have the same reference numerals.

Dispenser assembly <NUM> may include a housing <NUM> and a dispenser subassembly <NUM> mounted in housing <NUM>. Housing <NUM> may include an upper housing member <NUM>, a lower housing member <NUM> and a cover <NUM>. The housing <NUM> serves to mount dispenser subassembly <NUM> above upper tray <NUM> of cryogranulation system <NUM> (<FIG>). The dispenser assembly <NUM> can be made of, for example, stainless steel, however other materials such as metal or plastic composites can be used.

As shown in <FIG>, upper housing member <NUM> includes four side walls <NUM> that define a chamber <NUM> and a flange <NUM> at the upper end of side walls <NUM>. Flange <NUM> may be provided with mounting holes <NUM> for mounting dispenser assembly <NUM> in the cryogranulation system <NUM> and may be further provided with handles <NUM> to facilitate installation and removal of dispenser assembly <NUM>.

Cover <NUM> may be sized to cover an opening in the upper end of upper housing member <NUM>. Cover <NUM> may be provided with openings <NUM> to supply a gas, such as nitrogen gas, into chamber <NUM>.

Lower housing member <NUM> may be dimensioned for mounting at the lower end of side walls <NUM> so as to close the lower end of chamber <NUM>. In addition, lower housing member <NUM> is provided with an opening <NUM> for installation of dispenser subassembly <NUM>, with dispenser ports of dispenser subassembly <NUM> exposed for dispensing the pharmaceutical composition <NUM> into the liquid nitrogen <NUM>.

As shown in <FIG>, the dispenser subassembly <NUM> includes a top portion <NUM> and a bottom portion <NUM> forming an enclosure having an interior chamber <NUM> for holding the pharmaceutical composition to be cryogranulated. The top portion <NUM> of dispenser subassembly <NUM> may have a relatively flat configuration and includes one or more inlet ports <NUM>, <NUM> configured to communicate with the interior chamber <NUM> of the dispenser subassembly. The inlet ports <NUM>, <NUM> provide conduits for delivering the pharmaceutical composition to be cryogranulated. In some embodiments, two or more inlet ports can be provided on top portion <NUM> so that the pharmaceutical composition is distributed throughout the interior chamber <NUM> of dispenser subassembly <NUM>. The additional inlet ports can be spaced along the top portion <NUM> of dispenser subassembly <NUM> and can provide a uniform distribution of the pharmaceutical composition.

The bottom portion <NUM> of the dispenser subassembly <NUM> is configured having one or more interior channels <NUM> or depressions. Dispenser ports <NUM> provide fluid communication between the interior channels <NUM> and the exterior of the dispenser subassembly <NUM> (<FIG>) for dispensing of the pharmaceutical composition. Each of the dispenser ports <NUM> includes a conduit <NUM> between channel <NUM> and an outlet of dispenser port <NUM>. Conduits <NUM> can be of any length, depending on the solution or suspension to be cryopelletized. However, in one embodiment, the length of conduit <NUM> is from <NUM> to <NUM> and the opening of dispenser port <NUM> can be greater than about <NUM> in diameter. In other embodiments, the number of dispenser ports can vary. In some embodiments, the dispenser ports <NUM> are aligned within the channels <NUM> of the bottom portion <NUM> of the dispenser subassembly <NUM> forming rows <NUM>, <NUM> (<FIG>) of dispenser ports <NUM>. In some embodiments, the dispenser subassembly <NUM> may have at least two channels <NUM> and at least two rows <NUM>, <NUM> of dispenser ports <NUM>. In some embodiments, the dispenser ports <NUM> can be configured to form an acute angle with reference to vertical. In some embodiments, the dispenser ports <NUM> may be located about one to four inches above the liquid nitrogen <NUM> and preferably about one to two inches above the liquid nitrogen.

As shown in <FIG>, each conduit <NUM> interconnecting channel <NUM> and dispenser port <NUM> may include an upper conduit <NUM> of a first diameter and a lower conduit <NUM> of a second diameter. In some embodiments where the dispenser subassembly is used for dispensing diketopiperazine-based microparticles, the upper conduit <NUM> may have a diameter of about <NUM> and the lower conduit <NUM> may have a diameter of about <NUM>. More generally, the upper conduit <NUM> may have a diameter of about <NUM> or greater based on desired droplet size.

As further shown in <FIG>, each upper conduit <NUM> may have a vertical orientation and each lower conduit <NUM> may be oriented at an acute angle, such as a range of <NUM> degrees to less than <NUM> degrees, with respect to vertical. Also, the lower conduits <NUM> in row <NUM> and the lower conduits <NUM> in row <NUM> are oriented at opposite angles with respect to vertical.

Spaced-apart rows <NUM> and <NUM> of dispenser ports <NUM> are shown in <FIG>. The rows <NUM> and <NUM> of dispenser ports <NUM> may be perpendicular to the flow direction of liquid nitrogen <NUM> in upper tray <NUM> (<FIG>) and may extend across substantially the entire width of upper tray <NUM> (<FIG>). In some embodiments, the spacing between dispenser ports <NUM> in rows <NUM>, <NUM> is about <NUM>. Further, the dispenser ports <NUM> in row <NUM> may be offset from the dispenser ports <NUM> in row <NUM>, for example by one-half the spacing between dispenser ports <NUM>.

The configuration of dispenser ports <NUM> described above provides uniform dispensing of the pharmaceutical substance from dispenser assembly <NUM> into liquid nitrogen <NUM> with a desired droplet size. The risk of interference between droplets dispensed from different dispenser ports <NUM> is limited by the angled passages <NUM>, and uniform distribution is enhanced by the configuration of offset rows of dispenser ports <NUM>.

A securing mechanism including, but not limited to, clamps, bolts can be used to hold top portion <NUM> and bottom portion <NUM> of the dispenser subassembly <NUM> together. In one embodiment, clamps <NUM> are used to secure the parts of dispenser subassembly <NUM>. Inlet ports <NUM>, <NUM> can be connected by tubes or hoses, for example, to pump <NUM> (<FIG>) to deliver the pharmaceutical composition to the dispenser subassembly.

The dispenser assembly <NUM> can be provided with a heater, such as a resistive heater, which can be attached to the housing to prevent the solution from freezing during dispensing.

In one embodiment, the process for cryogranulating a pharmaceutical composition comprises dissolving a pharmaceutical substance in a liquid, including a solvent, buffer, water, saline; mixing the solution or suspension; pumping the suspension through a cryogenic dispenser assembly under nitrogen gas into a cooling agent such as liquid nitrogen, and collecting the granules or pellets formed in a dewar; and transporting said pellets to a container. In one aspect of this embodiment, the pharmaceutical composition comprises microparticles of a diketopiperizine, for example, particles of fumaryl diketopiperazine and a peptide, polypeptide or protein, or a nucleic acid in a suspension or slurry. For example, the diketopiperazine microparticles can comprise compounds, including but not limited to a peptide such as endocrine peptides such as insulin, GLP-<NUM>, oxyntomodulin, parathyroid hormone, and calcitonin.

The rate of flow of the liquid solution or suspension through the dispenser depends on the type of formulation used. The rate of flow through the dispenser is controlled by the pump systems settings. In particular embodiments when using a diketopiperazine-based pharmaceutical suspension, the pump is run at rpm settings ranging from about <NUM> to about <NUM> rpms, which can generate flow rates ranging from about <NUM> to about <NUM> liters per minute through the dispenser assembly.

The following example describes the process for cryogranulating a pharmaceutical substance and it is intended to be illustrative of the disclosure of the apparatus and process described herein.

Test runs were conducted to determine the uniformity of the pellets produced with the disclosed dispenser assembly. A suspension of fumaryl diketopiperazine (FDKP) microparticles with and without insulin were cryopelletized using a cryogranulator obtained from CES, Inc. The standard dispenser was removed and replaced with the dispenser assembly described herein.

FDKP suspension in a mild acetic acid solution alone or containing insulin adsorbed onto the particles in a suspension were cryopelletized in the dispenser assembly of the present invention. The peristaltic pump (Watson-Marlow) was run at <NUM> rpm and the suspension containing about <NUM> of FDKP particles or FDKP-insulin particles were pumped through the dispenser at a flow rate of about <NUM>/min. A nitrogen gas blanket is pumped into the housing chamber while the equipment is running.

Tables <NUM>, <NUM> and <NUM> show data obtained from the experiments. Pellet size and content were determined from batch product from a known amount or weight as measured by a series of sieves ranging from larger openings of <NUM> and <NUM> followed by determination of the weights from each sieve.

As seen in Tables <NUM>, <NUM> and <NUM> the percent of pellet size greater than <NUM> diameter is significantly increased with the dispenser assembly described herein.

The dispenser assembly described herein creates a more consistent pellet size distribution, minimizes the formation of pellet fines during the cryogranulation process and eliminates dispenser freezing problems that were present with commercially available cryogranulation equipment.

The preceding disclosures are illustrative embodiments. It should be appreciated by those of skill in the art that the techniques disclosed herein elucidate representative techniques that function well in the practice of the present disclosure.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about. " Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

The terms "a," "an," "the" and similar referents used in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. The use of any and all examples, or exemplary language (e.g., "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

Claim 1:
A method of cryogranulating a pharmaceutical composition comprising diketopiperazine, the method comprising the steps of:
i) providing a cryogranulation system (<NUM>) comprising:
at least one tray (<NUM>, <NUM>) configured to carry a flow of a cooling agent (<NUM>);
a mechanism configured to deliver the cooling agent to the at least one tray;
a dispenser assembly (<NUM>) configured to supply a pharmaceutical composition (<NUM>) into the cooling agent, the dispenser assembly including a housing (<NUM>) and a dispenser subassembly (<NUM>), the housing configured to mount the dispenser subassembly above the tray, the dispenser subassembly including an enclosure defining an interior chamber (<NUM>), at least on inlet port (<NUM>, <NUM>) for supplying the pharmaceutical composition to the interior chamber and a plurality of dispenser ports (<NUM>) for supplying the pharmaceutical composition to the cooling agent in the tray, the dispenser ports being configured to produce, after interaction of the pharmaceutical composition with the cooling agent, pellets of the pharmaceutical composition in a predetermined size range; and
a transport assembly configured to separate the pellets from the cooling agent and to transport the pellets to a pellet receptacle,
ii) cryogranulating diketopiperazine in suspension by establishing a flow of the cooling agent and dispensing diketopiperazine in suspension through the dispenser assembly into the flow of cooling agent to form frozen pellets, and
iii) separating the frozen pellets from the cooling agent;
wherein dispensing the diketopiperazine in suspension comprises dispensing diketopiperazine-based microparticles in a fluid medium, and
wherein the diketopiperazine in suspension is dispensed uniformly over the flow of cooling agent and with a droplet size to form pellets in a predetermined size range, and
wherein the plurality of dispenser ports includes first and second rows (<NUM>, <NUM>) of the dispenser ports, the dispenser ports of the first and second rows being angled with respect to the vertical and the dispenser ports of the first row being disposed at opposite angles with respect to the dispenser ports of the second row, the rows of dispenser ports being disposed perpendicularly with respect to the flow of the cooling agent.