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Some Pharmaceutical Uses c,
A. Nationalactivate~ charcoal is official in. the Formulary IX and has constderLTHOUGH
able use, there has b~en a dearth of pharmaceutical pUblications on this drug. The purpose of this investigation was to give a better pharma- _ ce~tical underst~nding of the drug and to show some of its properties with their relationship to the compounding and dispensing of prescriptions in 'which the drug is required. Historical Review
A pparent Specific Gravity of Charcoal. - I n 1919, Cude and Hulett found that it was no easy matter to duplicate specific gravity results of activated charcoal using various solvents (1). This fact was borne out by Lamb and Collidg~ (2), and Harkins and Ewing (3). They concluded that variations in the apparent density of a porous powder might be due either to differences in the degree of penetration of the porous solid by the liquid, or to differences in the degree of comFrom the Department of Pharmacy, University of Florida, Gainesville, Florida. . PreseBted before the Section on Practical Pharmacy, A. PH. A. Convention, Buffalo, N. Y., August, 1951. This paper is based on a thesis presented to the Graduate Council of the University of Florida by Oliver M . Littlejohn. in partial fulfillment of the requirements for the degree of Master of Science in Pharmacy. Head, Department of Pharmacy, University of Florida. t Fellow of the American Foundation for Pharmaceutical Education.
*
412
Authors' Sumnlary The apparent specific gravity of charcoal is relatively difficult to obtain using the ~onventional 25-ml. pycnometer. By using different solvents the specific gravity varies. Trituration of charcoal for 10 minutes caused less of it to pack into a capsule. The quantity that could be packed into a capsule was directly proportional to the Gm./cc. ratio as determined by the graduate method.
If charcoal-pepsin is present in a prescription in a ratio of 1: 1 the charcoal loses 36% of its original adsorptive power for methylene blue. If the ratio is 2: 1 there is a loss of 18% adsorptive power. Charcoal can be packed into capsules with ease if the charcoal is previously wetted with 37.5 cc. of propylene glycol per 100 grams of charcoal.
Vol. XIII, No.6
by William 1. Rusa* and Olivel' M. Littlejohnt
Although official in the N.
r.,
thel'e
has been little published on the phal'maceutical pl'opel'ties and compounding pl'oblems of chal'coal.
pression of the liquids at the solid-liquid interface. Adsorption of Pepsin by Charcoal.-In 1920, Keefer reported that pepsin was adsorbed by charcoal but did not give any data as to what percentage of adsorption took place (4). Experimental Part
Materials Used.-Six samples of charcoal were used in the investigation. Four of the samples were U. S. P. XIII, the other two samples were not official. Data regarding the six samples are given in Table I. The two latter samples were included in the investigation for comparison with the official samples. The samples will be referred to by number. Apparent SPecific Gravities.-The apparent specific gravities of the samples were determined by placing an accurate weight of the sample in a 25-ml. pycnometer and displacing the air with distilled water. The results varied from 0.48 for Sample VI to 1.97 for Sample III. AU determinations were duplicated. Sample I was chosen to determine its specific gravity in various solvents. The results were in agreement with Cude and Hulett, as several solvents were used which differed in surface tension, viscosity and other properties. The specific gravity varied from 1.53 using a 1% aqueous solution sodium lauryl sulfate, to 1.84 using alcohol. Packing Charcoal into Capsules.- The samples were packed into a No. "0" capsule by filling both the cap and body of the capsule. It was found that the amount that could be packed varied June, 1952
TABLE I.-DATA OF SAMPLES USED
Sample No. I
II III IV V VI
Grade
Method of M a nufacture
u. S. P. XIII
Unknown Coconut Unknown Unknown Bitum inous coal Pine (not activated)
P . XIII U. S. P. XIII U. S. P. XIII Not official Not official U.S.
TABLE II.-
ADSORPTIVE TEST USI NG METHYLENE BLUE
Sample No. I II
III IV V VI
Cc. Difference (Average) 1.310 1 . 190 1.160 1 . 220 1.425 0 . 100
from 21/ 4 grains for Sample IV to 5 1/ 2grains for Sample II. Trituration for 10 minutes in the Cooper or Wedgwood mortar decreased the amount that it was possihle to pack into a No. "0" capsule. The quantity that could be packed into a No. "0" capsule decreased to 13/ 4 grains for Sample IV and to 4 1/ . grains for Sample II. Settling in Graduate.-Five grams of each sample was placed in a 50-cc. cylindrical graduate and tapped on the laboratory desk for five minutes at a rate of 100 taps per minute. The results indicated that there is a direct ratio between the Gm./ cc. as determined by this method and the (Continued on nest pale)
JO URNAL OF TH.E AMERICAN PH:\RMACEUTICAL ASSOCIATION
Acti va ted Charcoal
••••••••••••
Discussion of Results from page 413
amount of sample which would pack into a No. "0" capsule. Adsorptive Test by the Methylene Blue Method.The National Formulary IX methylene blue adsorptive test was applied to the six samples. The results are given in Table II, the tests being
Apparent Specific Gravity.-The determinations of the apparent specific gravities of the six samples were fairly consistent when water was used as the solvent, Experimentation with various solvents confirms previous works which con cluded that duplication of results offers difficulties. Settling and Packing of the Samples.-There is a definite relationship between the packing of the sample into a capsule and the settling of that sample in a graduate. Trituration of charcoal in a mortar caused less of tht! sample to pack into capsules with the activated charcoals. Trituration of activated charcoal seems to make the particles repel each other more; therefore, less can be packed into the capsules. Adsorptive Test Using Methylene Blue.-The National Formulary adsorptive test was found to give consistent results. E.ffect of Pepsin on Adsorptive Power of Charcoal.-Since charcoal and pepsin combinations are used in pharmacy , the adsorptive test was determined by the methylene blue method. It was found that pepsin is adsorbed on charcoal to some extent. The experimentatioR shows that only a portion of the pepsin is adsorbed while the remainder passes through, leaving some of the charcoal bonds free to adsorb methylene blue. When the charcoal-pepsin mixture is in equal parts the charcoal will still meet National Formulary requirements provided the charcoal has an original adsorptive power of at least 1.14 cc. difference in titration. Charcoal Prescriptions.-With capsules it was found that the charcoal could be wetted with 37.5 cc. of propylene glycol per 100 grams of charcoal and not affect the adsorptive power of the charcoal and would not soften the capsule. If the powder is wetted with this amount of propylene glycol it was found that it could be very easily packed into a smaller capsule by the " punching" method. With liquid prescriptions the type of charcoal to use depends partially on the other ingredients of the preparation, a charcoal of density near 1.0 and an adsorpti ve power of 1.25 to 1.40 cc. difference in titration would be ideal.
REFERENCES I.
Cude, H . E. , and Hulett . G . A., J. Am. Chern. Soc., 42,
39~.(lt~~·b,
A. B. , and Collidge. A. S., J. Am. Chern. Soc., 42, 1146 ( 1920). 3. Harkins. W. D., a nd Ewing, D . T., J . Am. Clum. Soc., 43, 1787 (1921). 4 , Keefer, N. D., Am . J. Pharrn., 92,160 (1920) .
Vol. XIII, No.6
able use, there has b~en a dearth of pharmaceutical pUblications on this drug. The purpose of this investigation was to give a better pharma- _ ce~tical underst~nding of the drug and to show some of its properties with their relationship to the compounding and dispensing of prescriptions in 'which the drug is required. Historical Review
A pparent Specific Gravity of Charcoal. - I n 1919, Cude and Hulett found that it was no easy matter to duplicate specific gravity results of activated charcoal using various solvents (1). This fact was borne out by Lamb and Collidg~ (2), and Harkins and Ewing (3). They concluded that variations in the apparent density of a porous powder might be due either to differences in the degree of penetration of the porous solid by the liquid, or to differences in the degree of comFrom the Department of Pharmacy, University of Florida, Gainesville, Florida. . PreseBted before the Section on Practical Pharmacy, A. PH. A. Convention, Buffalo, N. Y., August, 1951. This paper is based on a thesis presented to the Graduate Council of the University of Florida by Oliver M . Littlejohn. in partial fulfillment of the requirements for the degree of Master of Science in Pharmacy. Head, Department of Pharmacy, University of Florida. t Fellow of the American Foundation for Pharmaceutical Education.
*
412
Authors' Sumnlary The apparent specific gravity of charcoal is relatively difficult to obtain using the ~onventional 25-ml. pycnometer. By using different solvents the specific gravity varies. Trituration of charcoal for 10 minutes caused less of it to pack into a capsule. The quantity that could be packed into a capsule was directly proportional to the Gm./cc. ratio as determined by the graduate method.
If charcoal-pepsin is present in a prescription in a ratio of 1: 1 the charcoal loses 36% of its original adsorptive power for methylene blue. If the ratio is 2: 1 there is a loss of 18% adsorptive power. Charcoal can be packed into capsules with ease if the charcoal is previously wetted with 37.5 cc. of propylene glycol per 100 grams of charcoal.
Vol. XIII, No.6
by William 1. Rusa* and Olivel' M. Littlejohnt
Although official in the N.
r.,
thel'e
has been little published on the phal'maceutical pl'opel'ties and compounding pl'oblems of chal'coal.
pression of the liquids at the solid-liquid interface. Adsorption of Pepsin by Charcoal.-In 1920, Keefer reported that pepsin was adsorbed by charcoal but did not give any data as to what percentage of adsorption took place (4). Experimental Part
Materials Used.-Six samples of charcoal were used in the investigation. Four of the samples were U. S. P. XIII, the other two samples were not official. Data regarding the six samples are given in Table I. The two latter samples were included in the investigation for comparison with the official samples. The samples will be referred to by number. Apparent SPecific Gravities.-The apparent specific gravities of the samples were determined by placing an accurate weight of the sample in a 25-ml. pycnometer and displacing the air with distilled water. The results varied from 0.48 for Sample VI to 1.97 for Sample III. AU determinations were duplicated. Sample I was chosen to determine its specific gravity in various solvents. The results were in agreement with Cude and Hulett, as several solvents were used which differed in surface tension, viscosity and other properties. The specific gravity varied from 1.53 using a 1% aqueous solution sodium lauryl sulfate, to 1.84 using alcohol. Packing Charcoal into Capsules.- The samples were packed into a No. "0" capsule by filling both the cap and body of the capsule. It was found that the amount that could be packed varied June, 1952
TABLE I.-DATA OF SAMPLES USED
Sample No. I
II III IV V VI
Grade
Method of M a nufacture
u. S. P. XIII
Unknown Coconut Unknown Unknown Bitum inous coal Pine (not activated)
P . XIII U. S. P. XIII U. S. P. XIII Not official Not official U.S.
TABLE II.-
ADSORPTIVE TEST USI NG METHYLENE BLUE
Sample No. I II
III IV V VI
Cc. Difference (Average) 1.310 1 . 190 1.160 1 . 220 1.425 0 . 100
from 21/ 4 grains for Sample IV to 5 1/ 2grains for Sample II. Trituration for 10 minutes in the Cooper or Wedgwood mortar decreased the amount that it was possihle to pack into a No. "0" capsule. The quantity that could be packed into a No. "0" capsule decreased to 13/ 4 grains for Sample IV and to 4 1/ . grains for Sample II. Settling in Graduate.-Five grams of each sample was placed in a 50-cc. cylindrical graduate and tapped on the laboratory desk for five minutes at a rate of 100 taps per minute. The results indicated that there is a direct ratio between the Gm./ cc. as determined by this method and the (Continued on nest pale)
JO URNAL OF TH.E AMERICAN PH:\RMACEUTICAL ASSOCIATION
Acti va ted Charcoal
••••••••••••
Discussion of Results from page 413
amount of sample which would pack into a No. "0" capsule. Adsorptive Test by the Methylene Blue Method.The National Formulary IX methylene blue adsorptive test was applied to the six samples. The results are given in Table II, the tests being
Apparent Specific Gravity.-The determinations of the apparent specific gravities of the six samples were fairly consistent when water was used as the solvent, Experimentation with various solvents confirms previous works which con cluded that duplication of results offers difficulties. Settling and Packing of the Samples.-There is a definite relationship between the packing of the sample into a capsule and the settling of that sample in a graduate. Trituration of charcoal in a mortar caused less of tht! sample to pack into capsules with the activated charcoals. Trituration of activated charcoal seems to make the particles repel each other more; therefore, less can be packed into the capsules. Adsorptive Test Using Methylene Blue.-The National Formulary adsorptive test was found to give consistent results. E.ffect of Pepsin on Adsorptive Power of Charcoal.-Since charcoal and pepsin combinations are used in pharmacy , the adsorptive test was determined by the methylene blue method. It was found that pepsin is adsorbed on charcoal to some extent. The experimentatioR shows that only a portion of the pepsin is adsorbed while the remainder passes through, leaving some of the charcoal bonds free to adsorb methylene blue. When the charcoal-pepsin mixture is in equal parts the charcoal will still meet National Formulary requirements provided the charcoal has an original adsorptive power of at least 1.14 cc. difference in titration. Charcoal Prescriptions.-With capsules it was found that the charcoal could be wetted with 37.5 cc. of propylene glycol per 100 grams of charcoal and not affect the adsorptive power of the charcoal and would not soften the capsule. If the powder is wetted with this amount of propylene glycol it was found that it could be very easily packed into a smaller capsule by the " punching" method. With liquid prescriptions the type of charcoal to use depends partially on the other ingredients of the preparation, a charcoal of density near 1.0 and an adsorpti ve power of 1.25 to 1.40 cc. difference in titration would be ideal.
REFERENCES I.
Cude, H . E. , and Hulett . G . A., J. Am. Chern. Soc., 42,
39~.(lt~~·b,
A. B. , and Collidge. A. S., J. Am. Chern. Soc., 42, 1146 ( 1920). 3. Harkins. W. D., a nd Ewing, D . T., J . Am. Clum. Soc., 43, 1787 (1921). 4 , Keefer, N. D., Am . J. Pharrn., 92,160 (1920) .
Vol. XIII, No.6