# US 11,026,865 B2 · Accelerated drying of soft capsules in a controlled environment

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- Number: US 11,026,865 B2
- Document ID: US11026865B2
- Status: Granted
- Kind: B2
- Application number: 16/467,436
- Filed: 2017-12-08
- Published: 2020-03-05
- Granted: 2021-06-08
- Earliest claimed: 2016-12-08
- Assignees: R.P. Scherer Technologies, LLC
- Applicants: R.P. Scherer Technologies, LLC
- Inventors: Norton Richard Hart; Lester David Fulper
- Web page: https://patentgrep.com/patent/US11026865B2

## CPC

- A61J 3/077: {Manufacturing capsule shells}
- A61J 3/07: into the form of capsules or similar small containers for oral use
- F26B 3/06: the gas or vapour flowing through the materials or objects to be dried (F26B3/14 takes precedence)
- F26B 11/04: rotating about a horizontal or slightly-inclined axis {(F26B11/022, F26B11/024, F26B11/026, F26B11/028 take precedence)}
- F26B 21/25: partly outside the drying enclosure
- F26B 21/33: Humidity
- F26B 21/35: Temperature; Pressure
- F26B 21/37: Velocity of flow; Quantity of flow
- F26B 21/50: Ducting arrangements from the source of air or other gases to the materials or objects being dried
- A61K 9/4825: {Proteins, e.g. gelatin (gelatin capsule shells with substantial amounts of other macromolecular substances A61K9/4816)}
- F26B 3/02: by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air {(F26B3/283 and F26B3/343 take precedence)}
- A61J: CONTAINERS SPECIALLY ADAPTED FOR MEDICAL OR PHARMACEUTICAL PURPOSES; DEVICES OR METHODS SPECIALLY ADAPTED FOR BRINGING PHARMACEUTICAL PRODUCTS INTO PARTICULAR PHYSICAL OR ADMINISTERING FORMS; DEVICES FOR ADMINISTERING FOOD OR MEDICINES ORALLY; BABY COMFORTERS; DEVICES FOR RECEIVING SPITTLE
- F26B: DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM (drying devices for combines A01D41/133; racks for drying fruit or vegetables A01F25/12; drying foodstuffs A23; drying hair A45D20/00; body-drying implements A47K10/00; drying household articles A47L; drying gases or vapours B01D; chemical or physical processes for dewatering or like separating liquids from solids B01D43/00; centrifugal apparatus B04; drying ceramics C04B33/30; drying yarns or fabrics in association with some other form of treatment D06C; drying frames for laundry without heating or positive air circulation, domestic laundry-or spin-driers, wringing or hot pressing laundry D06F; furnaces, kilns, ovens F27)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)

## Abstract

A method of drying soft capsules including steps of: a) supplying a flow of air to said soft capsules at a velocity of the air across the soft capsules of from about 0.15 m/s to about 13 m/s; b) increasing, over time, a drying temperature to which said soft capsules are exposed while ensuring that the drying temperature remains below a melting temperature of a capsule shell of the soft capsules; c) exposing said soft capsules to an initial relative humidity of from about 49% RH to about 79% RH; d) decreasing the relative humidity to which the soft capsules are exposed as the capsules dry until an equilibrium relative humidity of the soft capsules reaches a desired relative humidity; and e) exposing the soft capsules from step d) to a temperature of from 20-25° C. Also disclosed is a drying system for carrying out the method.

## Claims

### Claim 1

A method of drying soft capsules comprising steps of:
a) supplying an airflow to said soft capsules at a velocity of the air across the soft capsules of from about 0.15 m/s to about 13 m/s;
b) increasing, over time, a drying temperature to which said soft capsules are exposed while ensuring that the drying temperature remains below a melting temperature of a capsule shell of the soft capsules;
c) exposing said soft capsules to an initial relative humidity of from about 49% RH to about 79% RH;
d) decreasing the relative humidity to which the soft capsules are exposed as the capsules dry until an equilibrium relative humidity of the soft capsules reaches a desired relative humidity; and
e) exposing the soft capsules from step d) to a temperature of from 20-25° C.

### Claim 2 (depends on 1)

The method of claim 1 further comprising a step of:
decreasing the velocity of the airflow to which the soft capsules are exposed, as the soft capsules dry.

### Claim 3 (depends on 1)

The method of claim 1, wherein the relative humidity is controlled so that a differential between the relative humidity to which the soft capsules are exposed and the equilibrium relative humidity of the soft capsules is maintained at about 15% dRH to about 35% dRH.

### Claim 4 (depends on 1)

The method of claim 1, wherein the soft capsules are lipophilic.

### Claim 5 (depends on 4)

The method of claim 4, wherein the initial relative humidity is from about 49% RH to about 79% RH.

### Claim 6 (depends on 1)

The method of claim 1, wherein a lowest relative humidity to which the soft capsules are exposed is from about 10% RH to about 24% RH.

### Claim 7 (depends on 1)

The method of claim 1, wherein the soft capsules are hydrophilic.

### Claim 8 (depends on 7)

The method of claim 7, wherein the wherein the initial relative humidity is from about 49% RH to about 79% RH and a lowest relative humidity to which the soft capsules are exposed is from about 23% RH to about 57% RH.

### Claim 9

A drying system for drying soft capsules comprising:
at least one dryer;
a unit in fluid communication with the dryer to provide an airflow to the dryer;
a humidifier configured to be able to increase a relative humidity within the dryer;
a heater configured to be able to increase a temperature of air in the dryer; and
a flow control valve configured to control an amount of the airflow from the unit to the dryer;
wherein the heater is configured to increase the temperature over time according to a temperature ramp based on a melting point of a capsule shell of the soft capsules and a combination of the flow control valve and the humidifier is configured to control the relative humidity in the dryer such that the relative humidity in the dryer decreases over time from an initial relative humidity of 49% RH to 79% RH to an endpoint relative humidity of 10% RH to 24% RH, and the relative humidity is decreased in a manner whereby a differential between the relative humidity in the dryer and the equilibrium relative humidity of the soft capsules is maintained at 15% dRH to 35% dRH.

### Claim 10 (depends on 9)

The drying system of claim 9, further comprising a recirculation fan located and configured to recirculate a return air stream from an exhaust of the dryer to the unit that provides the airflow to the dryer.

### Claim 11 (depends on 10)

The drying system of claim 10, wherein the humidifier comprises the recirculation fan.

### Claim 12 (depends on 9)

The drying system of claim 9, further comprising a recirculation fan located and configured to recirculate a return air stream from an exhaust of the dryer to the unit that provides the airflow to the dryer, and wherein the flow control valve is configured such that reducing the amount of airflow from the unit to the dryer increases the relative humidity within the dryer and increasing the amount of airflow from the unit to the dryer decreases the relative humidity within the dryer.

### Claim 13 (depends on 9)

The drying system of claim 9, wherein a combination of the flow control valve and the humidifier is configured to control the relative humidity in the dryer such that the relative humidity in the dryer decreases over time from an initial relative humidity of about 49% RH to about 79% RH to an endpoint relative humidity of about 23% RH and about 57% RH.

### Claim 14

A method of drying soft capsules, said method comprising steps of:
a) supplying a flow of air to said capsules at a velocity of the air across the soft capsules of from about 0.15 m/s to about 13 m/s;
b) increasing, over time, a drying temperature to which said soft capsules are exposed while ensuring that the drying temperature remains below a melting temperature of a capsule shell;
c) maintaining a differential between a relative humidity in a dryer and an equilibrium relative humidity of the soft capsules of about 15% dRH to about 35% dRH until the equilibrium relative humidity of the soft capsules reaches a desired relative humidity; and
d) exposing the soft capsules from step c) to a temperature of from 20-25° C.