FDA report on Searle's submission for NutraSweet approval 1977 - Part 8

Back to Aspartame Articles

Part: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23




was to evaluate the stability of SC-19192 (DKP) when mixed with

Rockland mouse/rat diet and held at room temperature (73 degrees

F.). Two concentrations of diet mixture were tested: 3.0%

and 6.0% DKP. A preliminary analysis was performed on

1-31-72 to test the analytical method (T.L.C.), and recovery

of DKP. Assays were performed at one-week intervals on

2-16-72, 2-23-72, 3-1-72, 3-8-72, 3-15-72, 3-23-72, and 3-29-72.

Copies of all analytical reports were obtained and are attached

to this report, along with a copy of the protocol. (see exhibits



The titration method of DKP analysis was used initially, along

with the TLC method. The titration method was discontinued

after the 1-week analysis on 2.-23-72. Thin layer chromoto-

graphy was used thereafter. It should be noted that the titra-

tion method was the only reliable quantification method for

DKP analysis.


Page #54 of the laboratory notebook #51 (See Exhibit #26) indicated

(from the photograph) that there was something in the basal diet

itself producing a spot on the TLC plate which had an Rf.

value corresponding to DKP. This would make quantification

of DKP by this method difficult.


Some of the photographs of the TLC plates approached to labor-

atory notebook #51 showed no DKP reference standards. The

analysis described on pages #69-72 did use a DKP standard

but those on pages #88-89, #106-107, #144-145, and #284-

285 showed no reference standard. (See Exhibit #26)


Only one solvent system was used for development of TLC plates

throughout the study, even though it was apparent that some

material in the basal diet was producing a spot on the TLC

plate with an Rf. value corresponding to DKP. with the

above method of analysis, only materials reacting with the

potassium iodine starch reagent would be detected. Another

solvent system was available for TLC analysis of DKP (See

Exhibit #19) but apparently was not used in the stability



It should also be noted that some of the chromatograms showed

poor separation (day 28 on pages #144-145, and day 35 on pages

#156-157 of notebook #51). See Exhibit #26)


In general, the data described in the reports of analysis

corresponded well with the laboratory notebooks, although the

poor chromatograms were not mentioned in the reports of





The level of impurities as indicated by TLC was low; the

major impurity, an unknown substance, represented about 2% of

the DKP. The remaining impurities were also low, as apparent

from the density of the TLC spots compared with the DKP spots,

but were not quantified.


A glossary of terms for aspartame and its diketopiperazine is

attached as exhibit #9 and copies of specifications for DKP

are attached as exhibits #16-18.


No homogeneity tests were performed on any batches of diet mix

used in E-77-78, and evidence exists tat homogeneity was a

problem with the DKP diet mixtures. Two of the stability

study assay reports, analytical numbers A7728 and A7739 both

dated 2-16-72, contained the statement: "These samples were

not homogeneous. They had to be reground before they could be

sampled". The assay reports were signed by Barbara Bickford,

a Searle analyst.


We examined the laboratory notebook #51 assigned to Barbara

Bickford and noted that a B & W polaroid photograph of the non-

homogeneous sample in question was attached to page #58 of the

notebook. The photograph clearly shows discrete lighter colored

particles of diverse size and shape distributed nonuniformly

throughout the mixture. These lighter colored particles appear

to be distinct from the fairly find granular nature of the

chow itself.


A copy of this photograph was made and is attached to the report

as exhibit #29. When questioned about the size of the white

square sheet of paper in the photograph (on which the diet

mixture was placed) Ms. Bickford and C. Seul both stated that

it was 6"by6", when we interviewed them on 6-2-77. When the

photograph was enlarged until the sample paper was 6"by6" (actual

size) we measured the large particles (which were identified as

DKP by Ms. Bickford) and found them to be 4 to 6mm in size.


When we interviewed Ms. Bickford on 6-1 and 6-2-77, she stated

that she had nothing to do with the preparation of the diet

mixtures. She said that the samples had probably been received

from the toxicology lab and stored at room temperature. Her

procedure was to weigh out a predetermined amount of the sample,

and if not a uniform powder she would re-grind it with a mortar

and pestle, and would make a note of this in her lab notebook.

We asked Ms. Bickford if she ever reported this lack of homo-

geneity to Dr.Rao, and she replied that she did not.




We could not determine whether the samples assayed in the

stability study were from diet mixtures actually fed to

the animals, in spite of the fact that we were told so by some



On 6-2-77, we interviewed Analyst Barbara Bickford and Clifford

Seul, who was Mrs. Bickford's supervisor at the time that the

stability samples were analyzed (Feb. 16, 1972). Clifford

Seul told us that the samples analyzed on 2-16-72 and described

on page #58 of laboratory notebook #51, were obtained from the

admixture being fed the rats on study, and not a special mix-

ture prepared for the stability study.


On 6-1-77 we interviewed Bart Tangonan, whose duties included

observing, weighing, and feeding the animals, and mixing the

diet for study E-77/78. Mr. Tangonan did not remember if there

were any written instructions for mixing the diets but thought

that it was mixed for a specified length of time. He said that

if the diet appeared to need more mixing, it was mixed longer.

He could not remember anything about the samples obtained for

the stability study.


On 6-3-77 we interviewed Tony Martinez who was a supervisor in

the Toxicology Laboratory in 1972. He told us that although

the analytical report indicated that the sample was submitted

by Dr. Rao, actually anyone in the toxicology laboratory could

have submitted the sample. According to Mr. Martinez, the

normal procedure in such cases was to collect a sample

just after mixing compound and diet and then repeat this in

four weeks. He could not specifically recall what was done

with regard to the stability study in question, and could not

remember whether the samples had been taken from the diets

being fed the animals on study P.T. 98873 (E-77/78). He did

not remember any problems with mixing, bud did say that a longer

mixing time was required at higher compound concentrations.


A point to be considered, however, is that although the

analytical report states that the material analyzed was pre-

pared to contain 3.0 and 6.0% DKP, none of the diets reported

to be fed contained these exact amounts of DKP according to

the records of food concentration calculations, which were

used to prepare the diets for study #E-77/78. (see chart

attached to Exhibit #30.) In addition, the stability study

protocol (Exhibit #24) specified that the test batches would

be 1 kg. in size. If the protocol was followed, the small

(1 kg.) test batches would not have been sufficient in size

to feed a single dose group of the animals on study. (See

Protocol, Exhibit #24)


Continue to Part 9


NEW! Splenda® Exposed
Detox Program eBook Thumbnail

Read about SweetPoison
Buy SweetPoison

Dr. Janet Starr Hull's Newsletter:


Aspartame Dangers Revealed | Disclaimer | Link to us | Contact read tab | Site Map | Search
© Copyright 2002. SweetPoison.com All rights reserved