450 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS listed the effects of eight other preservatives. It may be seen that there is no significant interference, except possibly in the case of sorbic acid, by any of these common preservative substances. The interference effects of several antioxidants used as rancidity in- hibitors, were also studied, and the data are presented in Table 14. It was found that low assay results are obtained in the presence of NDGA, but there is no interference by BHA or BHT. In general, amines and quaternary ammonium compounds produce a color sufficiently intense to mask that developed in the assay, and are thus serious interferences. The effects of a few other cosmetic in- gredients are shown in Table 15, which gives the assays found after one hour heating with the substance at 60øC. The interferences do not appear to follow a pattern, and the necessity for additional study of this subject is apparent. It may well be that in some cases of low assay results the phosphatase activity is actually present, but the interference is with the phenol detection. We are con- tinuing this work and plan to make a future report. A matter of some interest is the storage stability of a once opened flask of the lyophilized placenta ex- TAm.• 15--INTEP. FEP. ENCES Additive, %* Assay None 1195 25 glycerol 1230 25 propylene glycol 985 1 "Quat" Color too intense 1 triethanolamine Color too intense 1 coco:diethanolamide Color too intense 1 Span 80 1172 5 Ethoxylated lanolin deriv. 1252 2 Glycerol monostearate S 475 1 Tween 60 0 1 Na stearate (pH 9.4) 54 5 Stearic:NaOH (10:1 moles) 387 * Heated one hour at 60øC. TAI•LE 16 STOkAGE STABILITY (Dehydrated Form) Age, •---Assay, Units/100ml.--• Weeks Under Ng Under O• 0 2058 1836 2 2022 1805 4 1865 1820 tract. This product is commonly supplied in glass under nitrogen. Studies continued up to four weeks, as shown in Table 16, indicate that replace- merit of the nitrogen by oxygen has no deleterious effect on this form of placenta extract. TABLE 17--ErrEc'r or HEATING PLACENTA EXTI•AC'r Temperatures Time, Assay, K & øC. øF. Hr. A/100 mi. 3O 86 1 1955 40 104 1 1895 5O 122 1 1890 6(} 140 1 1375 70 158 1 1320 TASLE 18--EFFECT OF HEAT Time, •--Assay, Units/100 ml.----• Hrs. 50øC. 60øC. 70øC. 0 1966 1966 1966 1 1548 1314 1250 2 1574 1273 1094 4 1394 873 552 5 1378 846 536 6 1192 77O 196 24 1164 445 0

DETERMINATION OF ALKALINE PHOSPHATASE 451 J 32OO 2800 2400 200• 1200 800 4OO 0 EFFECT OF HEAT I HOUR I I I I •L 30 40 50 60 70øC TEMP. ]7igure 2. Inasmuch as the manufacture of many cosmetic products involves moderate heating, studies were made on the extent to which the recon- stituted extract is affected by temperatures in this range. In one group of tests, reported in Table 17 and in Fig. 2, the extracts were heated for one hour periods at temperatures up to 70øC. It was found that the activity was not appreciably diminished in one hour at up to 50øC., and was re- duced by about 30 per cent at 60øC. 3200 2800 • 2400, g2000 I.• 1600 __1200 z 800 40O o o EFFECT OF HEAT 70øC 12 15 18 21 HRS. TIME Figure 3.