US2469957A - Dusting powder and method of making same - Google Patents

Description

Patented May 10, 1949 DUSTING POWDER AND METHOD OF MAKING SAME James E. Fenn, Baldwin, N. Y.

No Drawing. Application December 9, 1946, Serial No. 715,131

13 Claims. 1

This invention relates generally to dusting powders for use on the human body.

It has been known for a long time that the accidental introduction of foreign substances into the human body during surgical operations has been the cause of complications after an otherwise successful operation. One commonly known complication caused. in this Way is the development of adhesions within the body after an abdominal operation.

Foreign substances in the form of dusting powder are often introduced into the human body by the surgeon despite the most elaborate and careful precautions to prevent this occurrence. This dusting powder is used on the rubber gloves worn by the surgeon in order to enable the gloves to slip easily over his hands. Some of this powder enters the human body either directly from the gloves or from the fine powder which falls upon the surgical instruments during the dusting procedure. In the last twenty years, the dusting powder used by the surgeons on their rubber gloves has been talc. This talc material, known as talcum powder, however, is known to be responsible for most of the aforementioned undesired complications, and the reason for these complications attributed to this powder is the fact that talc cannot be absorbed by the human body. This talc may find its way into any part of the human body upon which the operation is performed. Talc, even in the form of the finest dusting powder, shows up under the microscope as sharp needle-like particles interspersed with thin platelets having sharp pointed corners. This tal-c has been the cause of suppurating wounds and granulomas on the tough palms of adults and is much more dangerous on the tender skins of babies.

The medical literature is replete with reports emphasizing the irritating qualities of talc when injected intr-a-peritoneally, intrapleurally, intrapericardially, or subcutaneously. In fact, in a certain type of heart disease, talc has been recommended to produce pericardial adhesions in an attempt to promote better collateral circulation. Numerous observations and experiments have definitely proven that talc is responsible for all types of adhesions ranging from a massive type of occulsion of almost the entire peritoneal cavity to less massive localized adhesions of the stomach, spleen, liver and omentum or intestinal loops (folds), or merely thin adhesive bands of fixed omental strands that not infrequently cause death from intestinal obstructions, sometimes referred to as strangulation.

The need for a substitute for talc as a dusting powder has been urgent and the search for such a substitute has been long and continuous. Such a substitute powder must satisfy the following two essential requirements: (1) It must possess such a degree of actual or potential solubility as to be disposed of rapidly and completely by some form of peritoneal or tissue absorption, and (2) It must possess such a degree of insolubility that it can withstand steam sterilization at 15 lbs. pressure without losing that dusting property which serves to prevent the surgical glove surfaces from adhering to one another or to the hands of the surgeon.

As a result of numerous tests made on diiferent powders and many different forms of starch, I have found that although many of these withstood the sterilization test successfully, none of them (until the discovery of the present invention) with the exception of potassium bitartrate, were absorbed quickly and wihout causing adhesions. Th difliculty with the starches resides in the fact that during sterilization they gel. If the gloves were already dusted before sterilization, the starch forms a hard, stiff coating on the gloves which prevents the gloves from slipping easily on the hands. All starches, however, were absorbed by the human body without any harmful effects. The potassium bitartrate was given to a number of hospitals and used by the surgeons therein successfully, but this particular material has these disadvantages: The sterilization process must be conducted very carefully and the steam pressure not raised above 15 lbs. nor must the time of sterilization be prolonged beyond 15 minutes, otherwise the bitartrate will caramelize and lose its dusting properties. It will thus be seen that the use of potassium bitartrate involves a rather critical procedure. Moreover, it was found that the surgical gloves deteriorated much more rapidly with the use of potassium bitartrate as a dusting powder than gloves dusted with talc. Furthermore, potassium bitartrate is not satisfactory for use on the human skin because this chemical may be toxic and is irritating to the skin on account of its acid nature.

Further history of the attempt to use starch as a dusting powder will now be given as a background to the present invention. Starch, especially cereal starch (like corn or rice) has granules of very small size and would make the ideal dusting powder because the enzymes of the human body make the starch soluble and enable the body to absorb it very quickly. One

of the difiiculties hitherto experienced by research people has been in the preparation of this n1- terial which will cause it to withstand sterilization in the presence of 15 lbs. pressure of live steam. Attempts have been made, heretofore, to treat starch with formaldehyde, but the resulting product was an insoluble compound. Moreover, such prior attempts have involved treatment underheat and pressure for long periods of time, such as 24 hours. It was thought by these early experimenters, that starch treated with formaldehyde could be used for the sterilization of open wounds because it was believed that formaldehyde was an antiseptic and the resulting mass would release this formaldehyde very slowly. However, the treatment outlined above produced a mass which had to be broken up and ground before it could be used for the purpose desired, and the resulting product was found to be unsatisfactory. The formaldehyde of these previously prepared powders might injure the patient;

Other research individuals have treated starch for purposes other than for obtaining a dusting powder. For example, Messrs. Rowland and Bauer have treated starch for paper making purposes either in a water suspension or dry with a formaldehyde solution and a small amount of acetic acid in an attempt to produce a starch which will dissolve in a dilute alkaline solution and willbe precipitated when the pH of the solution is lowered. This treatment, however, did not produce a starch which could withstand sterilization at 15 lbs.

It was-also proposed to treat starch by suspendingit in water and treating it with hexamethylenetetramine which is formed instantaneously when formaldehyde solution and an ammonium salt are brought together in water, to facilitate the manufacture of glucose with this starch. Here again, the resulting product will not withstand a pressure of 15 lbs. live steam without gelatinization. This treatment produces astarch which will not dissolve in an alkaline solution while the treatment of Rowland and Bauer produces a starch which will not dissolve in an acid solution.

The present invention provides a dusting powderwhich overcomes all of the foregoing difficulties. and disadvantages or prior dusting powders and which is pure enough to be used in surgical operations, insoluble enough to withstand sterilization, and will be absorbed by body fluids very rapidly and without harmful efifects on the human body.

Briefly, I treat starch with formaldehyde in a special manner outlined in detail below, and obtain a resulting product in fine powder form which can be sterilized and is not deleterious or harmful to the tissues of the human body. Whatever formaldehyde is present in the starch particles of the powder of the invention is bound within. the molecule, and no free formaldehyde can be detected by the most sensitive presently known chemical tests. Hence, the formaldehyde cannot injure the tissues of the human body when the powder is accidently introduced within the body. The process of producing the powder of the invention has the additional important advantage of requiring only a relatively short time for.its manufacture and of avoiding critical procedural steps. Hence, it can be produced commerciallyboth quickly and economically.

Another advantage of my dusting powder is that. it is. nonirritating to the human skin be- 4 cause it lacks the highly acid nature of the potassium bitartrate.

The method of producing the dusting powder of the invention will noW be given: One thousand pounds (1000 lbs.) of commercial corn starch (which has a moisture content of about 6%) are put into a dry mixer or any other suitable equipment. Then equal amounts of water and hydrochloric acid or any other suitable volatile acid (for example, nitric acid) are sprayed into the starch until it satisfies the following test: 25 grams of starch are suspended in 50 milliliters of distilled water and the pH of the suspension is measured with an electrometric potentiometer. The acid is sprayed into the starch until the suspension reaches a pI-I of 2.2 to 1.8, preferably 2.0. The water prevents the starch particles from being strongly attacked by the acid. After this pH point has been reached, the starch is placed into a vessel which is jacketed so that steam can be introduced into the jacket, or any other container where heat can be applied to the starch inside the container without having the steam or heated gas contacting the starch. The vessel is equipped with an agitator which keeps the starch tumbling So that heating proceeds uniformly. There is added to the starch in the vessel 15 to 25 lbs., preferably 20 lbs., of paraformaldehyde (dry) before the heat is applied; This formaldehyde amounts to about 2% of the starch. The vessel is then covered and the heat applied corresponding to about lbs. of steampressure in the jacket. Within 90 to minutes the starch absorbs enough of the formaldehyde gas generated by the paraformaldehyde to with! stand boiling for 15 minutes in water and the process is finished. During the heating process, samples of the starch are removed and tests made to determine whether it will withstand the boiling for 15 minutes in water without swelling or gelling. When the starch satisfies this requirement, I know that the process is complete. The starch is withdrawn from the vessel and washed repeatedly with hot water at a temperature between to F. until all odor of formaldehyde disappears. Ihe starch is then washed with a luke warm solution of 1% hydrogen peroxide at a temperature between 110 and 120 F, The hydrogen peroxide instantaneously forms formic acid with the remaining minute quantity of formaldehyde and is washed out of the starch with another rinsing of hot water. These washing operations can be carried out in a tank, on a centrifuge or a filter, like the Oliver filters or any other suitable apparatus. After this, the starch is dried in any of the conventional driers like the tunnel or the tray-drier, and screened through the conventional dry-starch screens, after which it can be packed ready for use.

Instead of or in addition to the washing with hydrogen peroxide, the starch can be washed with sodium .bisulfite in hot water which forms. sodium sulfoxylate with the formaldehyde, and this sodium sulfoxylate can be washed out readily from the starch. I prefer the washing with water and. hydrogen peroxide only because I believe that there is obtained a purer product. Tins washing: with hydrogen peroxide in addition to the hot water removes the last traces of unbound formaldee hyde and makes the product usable asv av dusting powder for surgical gloves.

Although the procedure mentioned above describes the use of 1900 lbs. of commercial-pom: starch, it will be understood that a lesser or larger amount can be used and the-same proev cedural steps carried out, in the event a difierent amount of the resulting product is desired. If an amount of starch smaller than 1000 lbs. is used, the heating interval will be correspondingly shorter, while if a quantity larger than 1000 lbs. is used, the required heating interval will be longer than the 90 to 120 minutes previously specified. Moreover, the range of pH values of 2.2 to 1.8 (preferably 2.0) has been mentioned in order to minimize the length of time necessary to obtain the resultant final product of the invention. The method of the invention, however, is not limited to this pH range, since other values of pH can be used, for example, a pH of 3 or 4, but this will require a longer time for the heat treatment to obtain the same result. The lower the pH value, the greater will be the danger of the starch being unduly attacked by the heat treatment. Also, other heating temperatures can be employed with the understanding that a lower temperature will prolong the treatment while a higher temperature will increase the danger of burning the starch.

Moreover, the temperature of the water used in the washing process may vary anywhere from tap water temperature to boiling, it being understood that the hotter the water the easier it is to remove the free formaldehyde and the fewer washings are necessary. Any higher percentages of formaldehyde than the approximately 2% can also be used in the practice of the invention.

The dusting powder of the invention is not only useful on the gloves of surgeons, but can also be used as a dusting powder for bedridden patients and babies and as a face powder. It does not cause localized inflammation (as talcum powder often does), can be dyed with harmless dyes, and absorbs and holds perfume much better than talc and provides a much smoother, finer face or dusting powder than presently used dusting powders.

The process of the present invention functions most efficiently with starch having as little moisture content as it is commercially practicable, because higher percentages of moisture will undoubtedly prolong the time of conversion of the starch which can gelatinize in water (and with which I start out) to the desired starch of the invention which will not gelatinize in water and which is the end product of the invention.

The term dry in the appended claims is used in the sense well known to those versed in the starch industry as designating a starch having less than the 25% moisture as contrasted to the wet starch having an appreciably larger percentage of moisture by virtue of being suspended in water.

I claim:

1. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH in a range of approximately 1.8 to 4, introducing formaldehyde into the acidified dry starch in such concentration as to prevent gelatinization of starch granules, applying heat and continuous agitation until a sample withdrawn from said acidified-heated starch will Withstand boiling in water for at least 15 minutes without swelling or gelling, and removing the last traces of free formaldehyde.

2. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH in a range of approximately 1.8 to 4, introducing formaldehyde into the acidified dry starch in such concentration as to prevent gelatinization of starch granules, then applying heat and continuous agitation until a sample withdrawn from said acidified-heated starch will Withstand boiling in water for at least 15 minutes without swelling or gelling, then washing the resultant product until the last traces of free formaldehyde are removed.

3. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH in range of approximately 1.8 to 4, introducing formaldehyde into the acidified dry starch in such concentration as to prevent g-elatinization of starch granules, then applying heat and continuous agitation until a sample withdrawn from said acidified-heated starch will withstand boiling in water for at least 15 minutes Without swelling or gelling, then washing the resultant product first with water and then with a dilute solution of hydrogen peroxide and again washing with water to remove the products of hydrogen peroxide and formaldehyde.

4. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH of approximately 2.0, introducing into the acidified dry starch paraformaldehyde, and applying heat and continuous agitation until a sample withdrawn from said heat treated acidified starch will withstand boiling in water for at least 15 minutes without swelling or gelling, then removing the last traces of free formaldehyde.

5. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH of approximately 2.0, introducing into the acidified dry starch paraformaldehyde, and applying heat and continuous agitation until a sample withdrawn from said heat treated acidified starch will withstand boiling in water for at least 15 minutes without swelling or gelling, then washing it first with hot water and then with a dilute solution of hydrogen peroxide and finally again with water to remove the products of the hydrogen peroxide and formaldehyde.

6. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH in a range of approximately 1.8 to 4, introducing formaldehyde into the acidified dry starch in such concentration as to prevent gelatinization of starch granules, then applying heat and continuous agitation until a sample withdrawn from said heat treated acidified starch will withstand boiling in water for at least 15 minutes without swelling or gelling; removing the last traces of free formaldehyde, then drying and screening the resultant product.

'7. A dusting powder comprising a starch which is in fine powder-like particles and non-irritating when used on the human skin, said starch being capable of being absorbed by the human body without harmful effects and without causing irritation to the tissues when introduced therein, said starch being characterized by non-swelling and non-gelling properties under pressure of 15 lbs. live steam applied for 15 minutes, said starch being produced by the steps of first being acidified while dry with a volatile acid admixed with a minimum amount of water which will give a pH in a range of the order of 1.8 to 4, then treated with formaldehyde in such concentration as to prevent gelatinization of starch granules, then heated while being continuously agitated, and finally treated to remove the last traces of formaldehyde.

8. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed. with a minimum amount of water which will give a pH of approximately 2.0, introducing into the acidified dry starch paraformaldehyde, and applying heat until a sample withdrawn from said heat and continuous agitation treated acidified starch will withstand boiling. in water for at least 15 minutes without swelling or gelling, then washing it first with hot Water and then with a dilute solution of sodium bisulfite, and finally again with water to remove the products of the sodium bisulfite and formaldehyde.

9. The method of treating starch which includes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH of approximately 2.0, agitating the acidified dry starch, introducing paraformaldehyde of approximately 2% based on the weight of the starch, applying heat corresponding to approximately 100 lbs. of steam pressure to the jacket of the vessel containing the acidified-formaldehyde treated starch while continuing the agitation until a sample withdrawn will withstand boiling in water for at least 15 minutes without swelling or gelling, then removing the last traces of free formaldehyde.

10. The method of treating starch which in eludes the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH of approximately 2.0, agitating the acidified dry starch, introducing formaldehyde of approximately 2% based on the weight of the starch in such concentration as to prevent gelatinization of starch granules, applying heat and continuing the agitation until a sample withdrawn from the acidified-formaldehyde treat-ed starch will withstand boiling in water for at least 15 minutes without swelling or gelling, and then removing the last traces of free formaldehyde.

11. A dusting powder comprising starch produced by the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of water which will give a pH in the range of approximately 1.8 to 4.0, introducing formaldehyde into the acidified dry starch in such concentration as to prevent gelatinization of starch granules, applying heat and continuous agitation until a, sample withdrawn from said acidifiedheated starch will withstand boiling in water for at least 15 minutes without swelling or gelling, and removing the last traces of free formaldehyde.

1.2. A dusting powder comprising starch produced by the steps of acidifying dry starch with a volatile acid admixed with a minimum amount of Water which will give a pH of approximately 2.0, introducing into the acidified dry starch aldehyde of approximately 2% based on the weight of the starch and in such concentration as to prevent gelatinization of starch granules, and applying heat and continuous agitation until a sample withdrawn from said heat treated acidified starch will withstand boiling in water for at least 15 minutes without swelling or gelling, then removing the last traces of free formaldehyde.

13. A dusting powder made from starch and characterized by non-swelling and non-gelling erties being capable of absorption by the human body without harmful efiects and without causing irritation to the tissues when introduc d therein and produced by the steps of acidify y starch with a volatile acid admixed with a liinium amount of water which will give a pH in a range of the general order of 1.8 to 1, treating the acidified dry starch with a small per centage of formaldehyde in such concentration as to prevent the gelatinizatien of starch granules, heating and agitating the acidified-formaldehyde treated dry starch until it will withstand boiling for ,least 15 inonutes without swelling or gelling, removing the last traces of free formaldehyde, then drying and screening the resultant product.

JAMES E. FENN.

REFERENCES CETED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,507,624 Pollak Sept. 9, 1924 2,113,034 Rowland Apr. 5, 1938 2,246,635 Moller June 24, 1941 2,397,018 Kioeger Mar. 19, 1946 2.417511 Pierson Mar. 18, 1947 2,438,855 Kerr et a1 Mar. 30, 19- 18