117 A New Alternative for Acne Treatment instrument. Separation was achieved on a GL Sciences Inertsil® (INERTSIL®, Torrance, CA, United States) ODS-3 HP (3 µm, 150 x 2.1 mm) C18 column at 25 °C by using an isocratic elution method with water: acetonitrile (15:85, v/v) at a flow rate of 200 µL/min. Photodiode-array detection was made at 225 nm. This method was validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines (24). ENCAPSULATION EFFICIENCY AND DRUG LOADING OF BPO-LOADED MICROSPONGES To determine the encapsulation efficiency (EE) and drug loading (DL), 0.01 g of BPO- loaded microsponge was dissolved in 50 mL acetone at 200 rpm for 48 hours. After filtration through 0.22 µm membrane filter, the concentration of BPO was analyzed by a validated UPLC method (n = 5). The EE and DL was determined by using Eq. 1 and Eq. 2: EE% Experimental drug content Theoretical drug content = ×100 (1) DL% Drug amount in microsponge Amount of microsponge = ×100 (2) CHARACTERIZATION OF THE BPO MICROSPONGES BPO microsponges were assessed by determining surface morphology, particle size distribution, pore structure, and Fourier transform infrared (FTIR) spectroscopy. PARTICLE SURFACE MORPHOLOGY The particle surface morphology of the BPO microsponges and the fabrics that were treated with BPO microsponges were visualized by scanning electron microscopy (SEM) (Carl Zeiss, Carl-Zeiss-Stiftung, Oberkochen, Germany, 300VP). The samples were coated with a thin layer of gold prior to the SEM analysis by using a QUORUM Q150 RES (Quorum Technologies, Lewes, United Kingdom) device. Particle size distribution analysis of the optimum microsponge formulation was performed by a Malvern Mastersizer (Malvern Instruments, Worcestershire, United Kingdom) using the wet dispersion technique. PARTICLE SIZE AND DISTRIBUTION The mean particle size and distribution were measured by laser diffraction measurements with the Mastersizer using the wet dispersion technique (25,26). Dv(50) value was expressed as the mean particle size by volume, and the size distributions (span) were calculated by using Eq. 3: Span= Dv(90)- Dv(10) Dv(50) (3)

118 JOURNAL OF COSMETIC SCIENCE FTIR SPECTROSCOPY The Nicolet™ iS50 (Thermo Fisher Scientific, Waltham, MA, United States) was used to get the FTIR spectra. The measurements took place at the room temperature in the wavelength range of 0–4,000 cm−1. PORE STRUCTURE STUDIES The pore structures of the BPO microsponges were determined by using nitrogen gas adsorption (Micromeritics 3 Flex, Micromeritics, Norcross, GA, United States). The adsorption analysis was conducted under 765 mmHg pressure. The surface area and pore diameter were calculated using the Brunauer-Emmett-Teller surface area analysis model, and the pore volume was calculated using the Barrett-Joyner-Halenda pore size analysis model. Prior to the analysis, the sample was kept under the low pressure at the degas unit for 12 hours at 30 °C. IN VITRO DRUG RELEASE OF BPO-LOADED MICROSPONGES To determine in vitro drug release profiles of the microsponges, 0.05 g of BPO-loaded microsponge was suspended in glass vessels containing 200 mL phosphate buffer solution (pH 7.4): acetone (4:1) and incubated on a shaking bath at 37 °C, 70 rpm. At the appropriate time intervals, samples were withdrawn, and the released BPO amount was determined by a validated UPLC method. Sink conditions were maintained in the receptor compartment during in vitro release studies (n = 3). APPLICATION OF BPO MICROSPONGES ONTO TEXTILE MATERIALS BPO microsponges were applied onto cotton fabric by using a spraying technique with 102% wet pickup. The solution, for which content ratios are given in Table I, was prepared and applied onto textile material with a manual spraying tool. Acrylic binder was used in the solution as a crosslinking agent. HPMC is a nonirritant and nontoxic polymer, widely used in oral and topical pharmaceutical formulations (27). HPMC can be used in textiles as binders (28). In this study, HPMC was used to keep the particles at a large size on the fabric surface, which the crosslinking agent does not hold. After the treatment, the fabric samples were dried and exposed to a fixation process for 20 minutes at 65˚C. The treated cotton fabric samples were combined with adhesive tapes. Table I Content Ratios of Spraying Solution Content Amount BPO microsponges 50 g/L Acrylic binder 40 g/L HPMC 3 g/L Water L