246 JOURNAL OF COSMETIC SCIENCE
samples were exposed at room temperature for 3 months. During this time, organoleptic
properties, pH, viscosity, and spreadability were assessed. All measurements were taken at
0, 15, 30, 60, and 90 days.21
RESULTS AND DISCUSSION
PREFORMULATION STUDIES OF MAGNESIUM MYRISTATE POWDER
The determined bulk density, tapped density, Carr’s index, Hausner’s ratio, and angle of
repose all showed excellent flow properties in accordance with IP.8 Loss on drying was
found to be 0.019 ± 0.0002%, confirming less moisture content. The results have been
tabulated in Table VI.12
QUANTITATIVE ASSESSMENT OF RESPONSES FOR VARIABLES.
Liquid foundation using conventional excipients and magnesium myristate was prepared as
per Table IV and V and was assessed for viscosity and spreadability.
Viscosity. Viscosity was determined to assess the flowability of the formulated product. An
excellent topical formulation has a viscosity of 2,000–50,000 cps.14 Liquid foundation using
Table IV
Composition of Liquid Foundation Using Conventional Excipient (25% w/w)
Ingredients (%w/w) F1 F2 F3 F4 F5 F6 F7 F8
Stearic acid 0.5 0.5 0.75 0.75 0.5 0.75 0.5 0.75
Propylene glycol monostearate 0.25 0.25 0.25 0.25 0.5 0.5 0.5 0.5
Dimethicone 1.25 1.75 1.75 1.25 1.25 1.25 1.75 1.75
Cetyl alcohol 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21
Liquid paraffin 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21
Iron oxides 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90
Titanium dioxides 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30
Tween 80 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10
Methyl paraben 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
Propylene glycol 1.51 1.51 1.51 1.51 1.51 1.51 1.51 1.51
Xanthan gum 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09
Distilled water 16.63 16.13 15.88 16.38 16.38 16.13 15.88 15.63
Table V
Composition of Liquid Foundation Using Magnesium Myristate (25% w/w)
Ingredients (%w/w) F1 F2 F3 F4 F5 F6 F7 F8 F9
Magnesium myristate 0.625 0.625 0.25 1.25 1.25 0.625 0.25 0.25 1.25
Liquid paraffin 1.75 1.25 1.75 1.25 1.75 1.5 1.25 1.5 1.5
Cetyl alcohol 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21 1.21
Iron oxides 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90
Titanium dioxides 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30
Tween 80 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10
Methyl paraben 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
Propylene glycol 1.51 1.51 1.51 1.51 1.51 1.51 1.51 1.51 1.51
Xanthan gum 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09
Distilled water 17.40 17.96 17.84 17.34 16.84 17.71 18.34 18.09 17.09

247 Magnesium Myristate
conventional excipients showed viscosity in the range from 2,608 ± 6.50 to 2,880 ± 23.06
cps, while liquid foundation using magnesium myristate showed viscosity in the range
from 2,618 ± 6.55 to 3,304 ± 15.04 cps. The results have been depicted in Figure 1.
Spreadability. The spreadability of the formulated product was determined to assess if it
spreads well when applied to the skin. Good topical preparation has a spreadability of 7–31
gm.cm./sec. The spreadability of liquid foundation using conventional excipients was found
from 6.33 ± 0.14 to 7.12 ± 0.12 gm.cm./sec, while the spreadability of liquid foundation
using magnesium myristate was found in the range from 6.41 ± 0.144 to 8.18 ± 0.288
gm.cm./sec. The results have been depicted in Figure 2.
OPTIMIZATION OF LIQUID FOUNDATION USING CONVENTIONAL EXCIPIENTS
Design-Expert® software (Stat-Ease, Inc., Minnesota, USA) projected a total eight
experimental runs from the 23 factorial design for the three components: stearic acid (X1),
Table VI
Preformulation Parameters of Magnesium Myristate Powder
Parameters Result Flow property
Bulk density (g/ml) 0.436 ± 0.011 Excellent Flow
Tapped density (g/ml) 0.573 ± 0.025
Carr’s index (%)10.88 ± 2.671
Hausner ratio 1.13 ± 0.036
Angle of repose (°) 24.204° ± 1.645
Loss on drying (%)0.019 ± 0.000
Figure 1. Viscosity of liquid foundation using magnesium myristate and conventional excipients.