scholarly journals Microneedles as Enhancer of Drug Absorption Through the Skin and Applications in Medicine and Cosmetology

2018 ◽  
Vol 21 ◽  
pp. 73-93 ◽  
Author(s):  
Pablo Serrano-Castañeda ◽  
Jose Juan Escobar-Chavez ◽  
Isabel Marlen Rodriguez-cruz ◽  
Luz Maria Melgoza ◽  
Jessica Martinez-Hernandez
Keyword(s):  
Lactic Acid ◽  
Drug Absorption ◽  
Glycolic Acid ◽  
Therapeutic Applications ◽  
Advantages And Disadvantages ◽  
Health Related ◽  
Titanium Nickel ◽  
Treatment Of Wounds

The microneedles technology has found applications in many health-related fields. For example, their application in drugs and vaccines delivery as well, as the determination of biomarkers, has been reported. They also have a place in the dermatology and cosmetic areas such as the treatment of wounds from burns, scars, acne, depigmentation, and alopecia will be shown. Microneedles are used in therapeutic applications and are manufactured using materials such as metal (steel, titanium, nickel), polymer (oly-glycolic acid (PGA), poly-lactide-co-glycolide acid (PLGA), poly-L-lactic acid (PLA), chitosan), glass, silicon, ceramic, carbohydrates (trehalose, sucrose, mannitol). Examples of application of microneedles and their advantages and disadvantages are discussed. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

scholarly journals Optimasi dan Validasi Metode Penentuan Kadar Asam Glikolat dan Asam Laktat Dalam Krim Menggunakan Kromatografi Cair Kinerja Tinggi

2020 ◽  
Vol 16 (1) ◽  
pp. 10
Author(s):  
Devi Wulandari ◽  
Gusrizal Gusrizal ◽  
Titin Anita Zaharah
Keyword(s):  
High Performance Liquid Chromatography ◽  
Lactic Acid ◽  
Liquid Chromatography ◽  
High Performance ◽  
Glycolic Acid ◽  
Orthophosphoric Acid ◽  
Spiked Sample ◽  
Relative Standard ◽  
Uv Visible

<p>Telah dilakukan optimasi dan validasi metode penentuan asam glikolat dan asam laktat dalam krim menggunakan kromatografi cair kinerja tinggi. Pemisahan asam glikolat dan asam laktat dilakukan pada kolom fasa balik C-8menggunakan fasa gerak asam ortofosfat 0,1% dengan pH 3,5 dan detektor <em>UV-Visible</em>. Standar asam glikolat dan asam laktat dibuat dengan melarutkannya menggunakan asam ortofosfat 0,1% pH 3,5. Hasil eksperimen menunjukkan bahwa pada rentang konsentrasi 25 – 400 μg/mL, asam glikolat dan asam laktat memiliki kurva yang linear dengan koefisien korelasi masing-masing 0,9997 dan 0,9999. Uji presisi untuk larutan standar berkonsentrasi 100 µg/mL menghasilkan simpangan baku relatif sebesar 1,49% untuk asam glikolat dan 1,72% untuk asam laktat. Metode yang telah dioptimasi memberikan akurasi yang baik yang ditunjukkan oleh nilai perolehan kembali dari pengukuran tiga <em>spiked sample</em> dengan konsentrasi berbeda (50, 100, dan 150 μg/mL). Nilai perolehan kembali untuk masing-masing konsentrasi <em>spiked sample</em> adalah 97,12% ± 0,69; 98,76% ± 0,43; 100,80% ± 0,29 untuk asam glikolat dan 97,58% ± 0,39; 96,20% ± 0,68; 98,00% ± 0,38 untuk asam laktat. Batas deteksi dan batas kuantisasi untuk asam glikolat adalah 0,05 dan 0,17 μg/mL, sedangkan untuk asam laktat adalah 1,40 dan 4,67 μg/mL. Nilai kekasaran metode untuk asam glikolat pada hari pertama dan hari kedua adalah 1,43% dan 1,67%, sedangkan untuk asam laktat adalah 1,67% dan 1,25%. Metode yang telah dioptimasi dan divalidasi berpotensi untuk digunakan secara spesifik pada penentuan kadar asam glikolat dan asam laktat dalam krim.</p><p><strong>Optimization and Validation of Determination Methods of Glycolic Acid and Lactic Acid in Cream Using High-Performance Liquid Chromatography.</strong> A high-performance liquid chromatography analytical method for the determination of glycolic acid and lactic acid in creams has been optimized and validated. The separation was performed in a reverse phase C–8 column with a mobile phase of 0.1%, orthophosphoric acid at pH 3.5, and UV-Visible detector. The standard of glycolic acid and lactic acid was dissolved in 0.1% orthophosphoric acid at pH 3.5. The experimental results showed that in the concentration range of 25–400 μg/mL, glycolic acid and lactic acid showed a linear curve with a correlation coefficient of 0.9997 and 0.9999, respectively. The precision test for standard solutions containing 100 µg/mL resulted in a relative standard deviation of 1.49% for glycolic acid and 1.72% for lactic acid. The optimized method provided good accuracy indicated by the recovery of the measurement of three spiked samples in different concentrations (50, 100, and 150 μg/mL). The recovery for each concentration of the spiked sample was 97.12% ± 0.69; 98.76% ± 0.43; 100.80% ± 0.29 for glycolic acid and 97.58% ± 0.39; 96.20% ± 0.68; 98.00% ± 0.38 for lactic acid. The limit of detection and limit of quantization for glycolic acid was 0.05 and 0.17 μg/mL, and for lactic acid was 1.40 and 4.67 μg/mL. The ruggedness of the method for glycolic acid on the first day and second day was 1.43% and 1.67%, while for lactic acid, it was 1.67% and 1.25%. The method that has been optimized and validated shows the potential to be used specifically for the determination of glycolic acid and lactic acid in the cream.</p>

scholarly journals Simultaneous HPLC-UV Determination of Lactic Acid, Glycolic Acid, Glycolide, Lactide and Ethyl Acetate in Monomers for Producing Biodegradable Polymers

2014 ◽  
Vol 10 ◽  
pp. 244-251 ◽  
Author(s):  
M.K. Zamanova ◽  
V.N. Glotova ◽  
T.N. Izhenbina ◽  
D.S. Krutas ◽  
V.T. Novikov
Keyword(s):  
Lactic Acid ◽  
Ethyl Acetate ◽  
Biodegradable Polymers ◽  
Glycolic Acid

scholarly journals Delay Equivalences in Tuning PID Control for the Double Integrator Plus Dead-Time

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 328
Author(s):  
Mikulas Huba ◽  
Damir Vrancic
Keyword(s):  
Dead Time ◽  
Pid Controllers ◽  
Noisy Environment ◽  
Advantages And Disadvantages ◽  
Implementation Problem ◽  
Low Pass ◽  
Excellent Control ◽  
Low Pass Filters ◽  
Double Integrator

The paper investigates and explains a new simple analytical tuning of proportional-integrative-derivative (PID) controllers. In combination with nth order series binomial low-pass filters, they are to be applied to the double-integrator-plus-dead-time (DIPDT) plant models. With respect to the use of derivatives, it should be understood that the design of appropriate filters is not only an implementation problem. Rather, it is also critical for the resulting performance, robustness and noise attenuation. To simplify controller commissioning, integrated tuning procedures (ITPs) based on three different concepts of filter delay equivalences are presented. For simultaneous determination of controller + filter parameters, the design uses the multiple real dominant poles method. The excellent control loop performance in a noisy environment and the specific advantages and disadvantages of the resulting equivalences are discussed. The results show that none of them is globally optimal. Each of them is advantageous only for certain noise levels and the desired degree of their filtering.

scholarly journals Mechanical Properties and Bioactivity of Poly(Lactic Acid) Composites Containing Poly(Glycolic Acid) Fiber and Hydroxyapatite Particles

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 249
Author(s):  
Han-Seung Ko ◽  
Sangwoon Lee ◽  
Doyoung Lee ◽  
Jae Young Jho
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Flexural Strength ◽  
Interfacial Adhesion ◽  
Glycolic Acid ◽  
Compact Bone ◽  
Poly Lactic Acid ◽  
Coupling Reactions ◽  
The Poor ◽  
Human Compact Bone

To enhance the mechanical strength and bioactivity of poly(lactic acid) (PLA) to the level that can be used as a material for spinal implants, poly(glycolic acid) (PGA) fibers and hydroxyapatite (HA) were introduced as fillers to PLA composites. To improve the poor interface between HA and PLA, HA was grafted by PLA to form HA-g-PLA through coupling reactions, and mixed with PLA. The size of the HA particles in the PLA matrix was observed to be reduced from several micrometers to sub-micrometer by grafting PLA onto HA. The tensile and flexural strength of PLA/HA-g-PLA composites were increased compared with those of PLA/HA, apparently due to the better dispersion of HA and stronger interfacial adhesion between the HA and PLA matrix. We also examined the effects of the length and frequency of grafted PLA chains on the tensile strength of the composites. By the addition of unidirectionally aligned PGA fibers, the flexural strength of the composites was greatly improved to a level comparable with human compact bone. In the bioactivity tests, the growth of apatite on the surface was fastest and most uniform in the PLA/PGA fiber/HA-g-PLA composite.

scholarly journals PRODUCTS OF THE OXIDATION OF GLYCOLIC ACID AND l-LACTIC ACID BY ENZYMES FROM TOBACCO LEAVES

1949 ◽  
Vol 181 (2) ◽  
pp. 905-914
Author(s):  
N.E. Tolbert ◽  
C.O. Clagett ◽  
R.H. Burris
Keyword(s):  
Lactic Acid ◽  
Glycolic Acid ◽  
Tobacco Leaves
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