FIELD O 

 Column 49 



Symbol Assigned time interval Time interval range scale 



3 More frequent than hourly <45 minutes, but not continuous 



4 1 hour 45 minutes through 4 hours 



5 3 times daily > 4 hours through 10 hours 



6 2 times daily > 10 hours through 18 hours 



7 One day > 18 hours through 3 6 hours 



8 Every other day > 36 hours through 60 hours 



9 Every 3 days or less frequently ... >60 hours 



2. Double coding of two frequency schedules or of two secondary compound- test compound 

 sequences in two or more tests 



Double coding is described and defined in Division 15 of the Specific Directions and Explanations 

 Section of Fields M and N (as it applies to those fields). If the evaluations from two or more tests are 

 so alike that they are coded by the identical symbol in Field Y and if the only variations in the two or 

 more tests are the schedules of administration ( Field O ), all the schedules used for those tests may be 

 coded in Field O in a single line and all punched on the same IBM card. Similarly, if the only variation 

 between two or more such tests is the sequence of administration of test compound and secondary 

 compound, the sequences of administration may be coded in a single line and all punched on the same 

 IBM card. (See Division 5 of this section concerning the situation of variation of frequency during a 

 single test. ) 



Double coding in Field O and another field, in the same line, is seldom possible. Thus, if 

 Field O is double coded with two frequencies of administration (e. g. , hourly and 3 times daily, Symbols 

 4 and 5), the dosage size (Fields M and N) and the duration of administration (Field P) must be the 

 same for both frequencies of administration. For example, if the dosage size varies as well as the 

 frequency of administration, it is impossible to indicate which of the doses double coded in Field M 

 or N is related to either of the frequencies double coded in Field O. It is not possible, in other words, 

 to indicate in one line that a large dose given at short intervals and a smaller dose given at longer 

 intervals accomplish the same result; this can only be done by coding two lines. (See also Division 17 

 of the Specific Directions and Explanations for Fields M and N. ) 



3. Coding of ad libitum feeding 



When the test compound is administered ad libitum , the CBCC codes Field O with the same 

 symbol as for "continuous supply insured", Symbol 2. If, however, in ad libitum feeding, the total 

 quantity of test compound consumed is determined and expressed as quantity per unit time , the quantity 

 is recorded in Field N, the unit time is coded in Field O, and the total duration of treatment is expressed 

 in Field P. 



4. Distinction between use of Symbols 1 and 2 



Symbols 1 and 2 are used to specify a single application of the test compound. This application 

 technique may be designed to provide a continuous exposure of the organism to the test compound 

 (Symbol 2) or the organism may be exposed to the test compound for only a very short period of time 

 (Symbol 1). 



Symbol 1 is used for those application methods exemplified best by oral administrations and by 

 single simple injections (intravascular, intraperitoneal, etc. ) which occupy only the time needed for 

 swallowing or for puncture, injection of the test compound, and withdrawal of a syringe. Even in the 

 case of special and tedious injections (certain intra-organal injections, e. g. ), the time is considered 

 negligible. The fate of the ingested or injected material thereafter is essentially dependent on the 

 biological-chemical interaction; the compound may be quickly dispersed and eliminated, or it may be 

 only very slowly eliminated, or it may selectively accumulate in one tissue. In any case, if the pro- 

 cedure of single administration did not provide for prolonged exposure of the treated test organism (or 

 the treated anatomical part of the test organism) at the dosage level coded in Fields M and N, Field O 

 should be coded with Symbol 1 and Field P will not be coded, since there is no significant duration of 

 exposure guaranteed at the level indicated in Fields M and N . 



When the test procedure involves a single application which provides for a prolonged exposure 

 to the test compound at the dose level indicated in Fields M and N, the duration of exposure is con- 

 sidered significant and, if known, is coded in Field P. This application is indicated in Field O as 



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