METHOD FOR SANITIZING PACKAGING CONTAINERS AND MATERIALS, PARTICULARLY FOR PHARMACEUTICAL AND COSMETICS USE, AND PLANT FOR IMPLEMENTING THE METHOD

Abstract: A method for sanitizing packaging containers and mat­ erials, particularly for pharmaceutical and cosmetics use, characterised by: - feeding an oxygen stream into an ozonising chamber, - feeding a controlled quantity of the ozone produced in said ozonising chamber into a sanitizing chamber in which the containers to be treated have been previously placed, - after the ozone has remained in the sanitizing chamber for a predetermined time, purging said chamber with sterile air until a residual ozone concentration is obtained which is less than a predetermined safety value, - passing the stream of air and ozone leaving the sanitizing chamber through an ozone decomposition device.

Description: This invention relates to a method for sanitizing packaging containers and materials, particularly for pharmaceutical and cosmetics use, and a plant for implementing the method. In the biomedical, food, pharmaceutical and cosmetics field, the various product containers have to be subjected to sanitizing processes before use, to ensure that the products remain preserved and unaltered for long time periods. The known hot-sterilization method is not always applicable because certain packaging materials cannot be exposed to dry or moist heat. Because of this, alternative methods have been proposed comprising the use of electromagnetic radiation and chemical agents such as ethylene oxide, formaldehyde etc. Although these systems have high sterilizing activity, they can modify the organoleptic characteristics of the various products, and can also produce side effects which are important from the safety aspect. The bactericide properties of ozone are well known, but because of its toxic and reactive criaracteristics it has never been considered usable for sterilizing purposes other than for conditioning water, where it can be used practically without concentration limits because of its very rapid decomposition. The object of the invention is to extend the field of application of ozone as a sanitizing agent, and to propose an industrial process and plant for sanitizing packaging material, particularly for pharmaceutical and cosmetics use. This object is attained according to the invention by a process characterised by: - feeding an oxygen stream into an ozonising chamber, - feeding a controlled quantity of the ozone produced in said ozonising chamber into a sanitizing chamber in which the containers to be treated have been previously placed, - after the ozone has remained in the sanitizing chamber for a predetermined time, purging said chamber with sterile air until a residual ozone concentration is obtained which is less than a predetermined safety value, - passing the stream of air and ozone leaving the sanitizing chamber through an ozone decomposition device. Again according to the invention, before feeding ozone into the sanitizing chamber, said chamber can be put under slight vacuum, preferably of about 100 mm Hg. Advantageously, the ozone can be fed into the sanitizing chamber through a disperser member which provides uniform ozone distribution within said chamber from the top to the bottom. The method according to the invention is implemented by a plant comprising: - an ozone generator fed with a stream of dry oxygen, - a sanitizing chamber fed by said generator, - means for purging the sanitizing chamber with sterile air on termination of each sanitizing cycle, - means for decomposing the residual ozone on termination of the purge stage, - means for monitoring the ozone concentration in the generator, in the sanitizing chamber and/or in the ozone decomposition means and/or in the surrounding aosphere. Advantageously, the sanitizing chamber according to the invention can be tunnel-shaped, with its inlet opening disposed at one end and in communication with the loading department for the containers and materials to be sanitizing, and with its outlet opening disposed at the opposite end and in communication with the packaging department. Again according to the invention, the means for monitoring the oxygen concentration can consist of a spectrophotometer with a quartz flow cell, which can be selectively connected in series with the measuring circuit of the ozone generator, the ozonising chamber, the decomposition means and the surrounding atmosphere. A preferred embodiment of the present invention is described in detail hereinafter by way of non-limiting example with reference to the accompanying drawing, which diagrammatically illustrates a plant for implementing the method according to the invention. As can be seen from the drawing, the plant according to the invention comprises essentially a sanitizing chamber 1, for example of cylindrical shape, with its inlet end located in the loading department for the containers to be sanitized, and its outlet end located in the packaging department. In the top of the sanitizing chamber there is disposed a dispersing sparger 2 connected to the outside at the inlet end by way of a valve 3, to which two separate pipes are connected, the first pipe 4 being for feeding air made sterile by a filter 5, and the second pipe 6 for connection to an ozonising chamber 7, to which there is fed a stream of oxygen or oxygen-enriched air measured by a rotameter 9 and suitably dried by passing through a dryer 8. The outflow from the sanitizing chamber 1 is connected by way of a discharge valve 10 to a container 11 in which the ozone leaving the sanitizing chamber 1 is decomposed in water. The ozone generator 7, the sanitizing chamber 1, the inlet of the decomposition device 11 and the surrounding atmosphere can be selectively connected by way of corresponding pipes 12, 13, 14 and 15 to an ozone sensor 16 of spectrophotometric type. In order to select the circuit to be measured, a change-over switch (not shown on the drawing) is provided together with shut-off valves 17 and 18 for closing the other circa is which are not to be measured. The plant is constructed of materials which are resistent to the action of ozone under the operating conditions prevailing during industrial application. The operation of the described plant is as follows: initially, the containers 19 to be sanitized are placed preferably randomly in stainless steel bins 20 in the chamber 1. This is then closed and put under slight vacuum. The chamber is then fed with a stream of ozone, which is drawn into it through the dispersing sparger 2 and leaves through an analogous coil structure 21 disposed in the bottom and directly connected to the discharge valve 10. Uniform diffusion of the gas takes place in this manner from the top downwards within the containers 19, independently of their shape. During this stage, the ozone concentration is continuously monitored spectrophotometrically by a quartz cell of the sensor 16. Periodically, the ozone concentration of the surrounding atmosphere is also checked in order to prevent it exceeding predetermined safety values. On termination of the sanitizing cycle, the chamber 1 is purged repeatedly with sterile air. The residual ozone is decomposed in water in the container 11, and eliminated. Finally, the chamber 1 is opened at its outlet end and the sanitized containers 19 are withdrawn directly into the packaging department. From the aforegolng it is apparent that the method according to the invention and the plant for implementing it have considerable advantages, in that they use ozone for the first time industrially for sanitizing containers, this being a gas which is easy to produce, with a short half life and thus much less risky than other chemical agents, it being also free from problems of environmental pollution by virtue of its decomposition in water, and, finally, being easy to control in spite of its toxicity by using simple safety measures such as hoods or other suction systeme. The following example will further clarify the invention. A stainless steel sanitizing chamber was constructed having a capacity of about 15.000 1. During operation, it was put under slight vacuum (about 100 mm Hg). The continuous spectrophotometric monitoring was effected with a quartz cell having an optical path of 10 cm connected in series with the plant changeover switch. It enabled ozone to be analysed accurately and reproducibly from 0,01 ppm at a flow of 1 1/mien. In order to check the behaviour of the most common materials normally used for packaging cosmetics, the containers 19, suitably painted and/or xerographed, were treated with ozone at a concentration much higher than that used in an industrial sanitizing process, and their behaviour was observed after ageing tests. More specifically, a significant sample of plastics containers normally used for cosmetics and withdrawn from the commercial production cycle was subjected to an ozone concentration of 30.000 ppm. After exposure for 5 and 10 minutes, the containers 1 G were subjected to ageing tests at ambient temperature and at 40 xC, both as such and after filling with a typical cosmetics product. They were then checked after six months and after one year. The results, given in Table 1, show that at the concentrations used, the ozone does not alter the structure and characteristics either of the containers or of the products contained in them. EMI8.1 <tb> TABLE <SEP> I: <SEP> Effects <SEP> of <SEP> ozone <SEP> on <SEP> packaging <SEP> materials <tb> <SEP> Containers <SEP> Materials <SEP> Products <tb> <SEP> Bottles <SEP> PVC <tb> <SEP> polyethylene <SEP> liquid <SEP> sop <tb> <SEP> polypropylene <tb> <SEP> Bottles <SEP> polypropylene <tb> <SEP> semifluid <SEP> emulsion <tb> <SEP> polyethylene <tb> <SEP> Tubes <SEP> aluminium <tb> <SEP> epoxy <SEP> resins <tb> <SEP> emulsions, <SEP> toothpastes <SEP> <tb> <SEP> melamine <SEP> resins <tb> <SEP> polypropylene <tb> <SEP> Jars <SEP> SAN <SEP> (styrene <tb> <SEP> acrylonitrile) <tb> <SEP> thick <SEP> emulsion <tb> <SEP> polypropylene <tb> <SEP> polyethylene <tb> Ozone concentration: G.000 ppm; Exposure time: 5 and 10 minutes; Agelng: ambient temperature and 40 xC; Cheeking: after six months and one year. i:odifications noted Containers: none Products: none. The following test was then carried out to check the effect of ozone on various bacterial strains: initially, the ozone diffusion was checked within the containers 19 randomly placed in the sanitizing chamber 1 with the aid of chemical and bioindicators: with the sanitizing chamber under slight vacuum it was found that the ozone diffused uniformly within the containers 19, independently of their shape. In order to evaluate the bactericidal activity of the ozone, tests were then carried out using various microbic species. For ease of handling, Durham tubes were placed randomly In baskests in the sanitizing chamber, the tubes containing suitable discs inoculated with suitable suspensions of various bacterial strains of different concentration and chemical indicators, for the double purpose of checking ozone diffusion and checking the actual time of initiation of the microbiological test. The time of contact of thr ozone with the containers was kept constant at one or two hours, this tinge being considered sufficient for an industrial process, and the air or oxygen throughput was varied from t to 3 1/mien and the ozone concentration at 50 to 500 ppm. Table II shows the bacterial strains considered, and the results obtained for a concentration of 100 ppm. TABLE II: Sanitization levels obtained after treatment with 100 ppm of ozone (concentration of each species 10 CFU/ml) EMI10.1 <tb> <SEP> Treatment <SEP> duration <SEP> (minutes) <tb> <SEP> Species <SEP> 60 <SEP> 120 <tb> <SEP> Na <SEP> Nb <SEP> Is <SEP> Na <SEP> Nb <SEP> Is <tb> St. <SEP> Aureus <SEP> 50 <SEP> 2 <SEP> 0,04 <SEP> 50 <SEP> 1 <SEP> 0,02 <tb> Str. <SEP> Faeclum <SEP> 50 <SEP> 2 <SEP> 0,04 <SEP> 50 <SEP> 1 <SEP> 0,02 <tb> Ps. <SEP> Aeruginosa <SEP> 50 <SEP> 1 <SEP> 0,02 <SEP> 50 <SEP> 0 <SEP> 0 <tb> Ps. <SEP> Delaphieldil <SEP> 50 <SEP> 0 <SEP> 0 <SEP> 50 <SEP> 0 <SEP> 0 <tb> = = testes samples; Nb = samples with positive growth; 15 = sanitization Index (Nb/Na). The data collected after a significant number of tests show that the vegetative forms are completely inactivated by tne ozone.

Claims: 1. A method for sanitizing packaging containers and materials1 particularly for pharmaceutical and cosmetics use, characterised by: - feeding an oxygen stream into an ozonising chamber, - feeding a controlled quantity of the ozone produced in said ozonising chamber into a sanitizing chamber in which the containers to be treated have been previously placed, - after the ozone has remained in the sanitizing chamber for a predetermined time, purging said chamber with sterile air untIl a residual ozone concentration is obtained which is less than a predetermined safety value, - passing the stream of air and ozone leaving the sanitizing chamber through an ozone decomposition device. 2. A method as claimed in claim 1, characterised by putting the sanitizing chamber under slight vacuum before feeding ozone into said chamber. 3. A method as claimed in claim 2, characterised by stating with the sanitizing chamber under a vacuum of about 100 mm Hg. 4. A method as claimed in claim 1 characterised by feeding ozone into the sanitizing chamber through a disperser member which provides uniform ozone distribution within said chamber from tne top to the bottom. 5. A method as claimed in claim 1, characterised by continuously measuring the ozone concentration during the purging with sterile air. 6. A method as claimed in claim 1, characterised by passing the air and ozone stream leaving the sanitizing chamber through ware. 7. A plant for implementing the method claimed in one or more of claims 1 to 6, characterised by comprising: - an ozone generator (7) fed with a stream of dry oxygen, - a sanitizing chamber (1) fed by said generator (7), - means fo purging the sanitizing chamber (1) with sterile al on termination of each sanitizing cycle, reans (11 ) for decomposIng the residual ozone on tendnation of purging, - means (16i for monitoring the ozone concentration in the generator (7), in the sanitizing chamber (1) and/or in the ozone decomposition means (11 ) and/or in the surrounding atmosphere. t. A plant as claimed in claim 7, characterised in that the sanitizing chamber (1) is provided with an inlet opening and an outlet opening which are separate from each other and are in communication with the loading department for the containers and materials to be sanitized (19) and with the packaging department respectively. 9. A plant as claimed in claims 7 and 8, characterised in that the sanitizing chamber (1) is tunnel-shaped with its inlet and outlet opening provided at its ends. 10. A plant as claimed in claim 7, characterised in that the interior of the sanitizing chamber (1) is provided at its top with an ozone disperser (2) and at its bottom with an ozone collection coil (21), this latter disosed below the containers (19) to be sanitized and being of such dimensions as to generate, in combination with the dispenser (2), a uniform flow of ozone from the top downwards. 11. A plant as claimed in claim 8, characterised in that the oxygen concentration monitoring means (16) consist of a spectrophotometer with a quartz flow cell connected in series with the measuring circuit. 12. A plant as claimed in claim 8, characterised by comprising a multi-position switching device for selectively connecting the ozone concentration monitoring means (16) to the ozone generator (7), to the sanitizing chamber (1), to the decoinposition means (11) and to the surrounding atmosphere. 13. A plant as claimed in claim 7, characterised in that the means (11 ) for decomposing the ozone leaving the sanitizing chamber (1) consist of a water container into which the outlet pipe from said sanitizing chamber (1) opens.

Inventors: AVERSA, GRAZIANA, BENASSI, CARLO ALBERTO, BETTERO, ANTONIO, CERINI, ROBERTO, GIACOMIN, RENATA, LUCCHIARI, MAURO, SCALABRIN, MARIO, SEMENZATO, ALESSANDRA
Applicants: CONSIGLIO NAZIONALE DELLE RICERCHE, IDIM S.P.A. - ISTITUTO DERMATOLOGICO ITALIANO
Application year: 1986
Main classification: B65B55
IPC codes: B65B55, A61L2