JOURNAL OF COSMETIC SCIENCE 6 circular aperture of 2-mm diameter (test area of about 3 mm). Optional probes with apertures of 4, 6, and 8 mm are available on request. The measuring system inside the probe head is noncontact and consists of a light source (light-emitting diode) and a light recipient, as well as two opposing glass prisms, which project the light from the emitter to the recipient. The changes of the infrared light beam intensity during measurement are converted into millime- ters (from 0 to 3.0 mm) and calculated with a resolution equal to 2 μm. The measuring probe is connected to the main unit through an air tube and an electric cable. During measurement, it is held perpendicularly to the skin surface under constant pressure ensured (provided) by an elastic spring. The calibration data are stored in the memory of each probe, which allows fast and easy exchange of probes with different apertures. The Cutometer MPA 580 (COURAGE+KHAZAKA electronic GmbH) (Figure 1B), that is currently available, com- bines the vacuum box for the Cutometer with a built-in Sebumeter (SM) 815 and a modular multi-probe adapter system which makes possible to connect up to four additional measuring probes as well as an ambient condition sensor. MEASURING TECHNIQUE S There are two measu ring techniques available: 1. In the strain–ti m e mode, the deformation of the skin (in millimeters) is showed as a function of time (in seconds). This mode is mostly used in research studies. Figure 1. (A) Cutometer SEM 575. (B) Cutometer MPA 580.

EMULGEL FORMULATION AND IN VITRO AND IN VIVO ASSESSMENT 7 2. In the stress–st r ain mode, the deformation of the skin (in millimeters) is showed as a function of the vacuum (in millibar). IN VIVO STUDY Study design. The d uration of th is observational crossover study was two weeks. It was approved by the Institutional Review Board at An-Najah National University, Palestine. The primary objective was to assess the organoleptic properties of emulgel such as odor, feel, smoothness, emollience, cooling effect, and skin moisturization. A blank emulgel formulation was used which lacks the LG essential oil. Volunteers. A total of 50 male and female volunteers older than 20 years with normal or dry skin were enrolled in the study. Exclusion criteria were subjects characterized as oily or sensitive skin and subjects who were using other moisturizing creams or other cosmetics. Application and ass essment. All participants w ere divided into two groups. In the fi rst week, one group was asked to apply LG emulgel formulation and the other group was asked to apply the blank emulgel formulation on their hands. Each group was asked to rate the results from 1 to 5 (1: the least and 5: the best) by fi lling a specifi c questionnaire. In the second week after a 3-days washout period, the two groups were switched to com- plete the assessment of the emulgel formulations. The results were recorded and analyzed by using a paired sample T-test. RESULTS AND DISCUSS ION YIELDS OF DIFFERENT LG PLANTS The quality control of herbal or plant drug products should start with its raw material. Specifi c information on the used plants should include agricultural practices such as growing, harvesting time, collection processing, geographic area, and storage conditions (26). Accordingly, the us ed LG was collected from the north area of West Bank, Palestine. Two sources (cultivated and wild) were evaluated for 3 mo to fi nd the best yield. The yield of LG was different according to their type and their harvesting time. As shown in Table IV and Figure 2, wild LG showed the highest yield, and the suitable harvest time was May for both cultivated and wild herbs. This may be because of the maturation of the oily glands of the grass (10). Table IV Percentage Yield of LG Essential Oil from C. citratus Leaves Yield (%) Harvesting time (month) Wild March April May 0.0 0.73 1.12 Cultivated 0.0 0.0344 0.7