Retinoids in Hair Disorders
Ayse Serap Karadag, Berna Aksoy, Lawrence Charles Parish in Retinoids in Dermatology, 2019
Hair growth involves complex interactions of genes, signaling factors, cell-to-cell interactions, and complex proteins and hormones. Retinoids have a direct impact on these interactions by altering the dynamic hair growth cycle. The cycle of hair growth comprises four main stages, including anagen (growth and differentiation), catagen (regression and apoptosis), telogen (inactivity), and exogen (the shedding of old hair follicles) (Figure 22.1) (3). This cycle results in the replacement of every hair on the scalp every 3–5 years, with individual follicles undergoing 10–30 such cycles in a lifetime (4). On average, a normal scalp has 100,000 hairs, with approximately 86% being in anagen, 1% in catagen, and 13% in telogen (5). The variation in hair cycle length is attributable to the length of the anagen phase, which is unique to the individual (6). As hair is produced solely in anagen, this phase also determines the physical length of the hair.
What You Need for a Trichology Consultation
Rubina Alves, Ramon Grimalt in Techniques in the Evaluation and Management of Hair Diseases, 2021
For the treatment of hair disorders, local drug infiltration may be necessary. It is especially useful to have corticosteroids ready to be infiltrated to any autoimmune alopecia. There are essentially two corticosteroids that are used for infiltration: triamcinolone acetonide and mometasone acetate. While the procedure and concentration of intralesional corticosteroid administration escapes the objective of this chapter, we must mention that we prefer the use of the corticosteroid diluted in an amide anaesthetic (usually lidocaine 5%) in an insulin syringe (30 G, 1 mL). In addition, other molecules can be administered to stimulate hair growth. In general, these drugs (e.g. dutasteride or minoxidil) must be formulated in excipients for their correct stability at the time of administration. Usually 1-mL luer-lock syringes are used, which are then attached to 30 G 0.30 × 4 mm needles (Figure 18.3). The administration of local anesthetics may be indicated prior to some procedures such as mesotherapy. It may be especially useful to have amides such as mepivacaine and lidocaine rapidly available to anesthetize the area. Both lidocaine and mepivacaine are excellent anesthetics due to their rapid action and safety. We usually inject them into syringes and needles of similar characteristics to the previously mentioned drugs.
Phytosomes as Useful Drug Delivery Systems for Cosmeceutical Application
Madhu Gupta, Durgesh Nandini Chauhan, Vikas Sharma, Nagendra Singh Chauhan in Novel Drug Delivery Systems for Phytoconstituents, 2020
Cosmeceuticals can be classified in the following ways (Figure 6.6): Skin cosmeceuticals: These are skin-care products able not only to color and enhance the skin, but they are also active compounds that can modulate the biological functions of the skin. The main functional ingredients used in these products are vitamins (A, C, D, E), ferulic acid, exfoliants (salicylic acid, lactic acid, and glycolic acid), depigmenting compounds (hydroquinone, kojic acid, and licorice extract), moisturizers, topical peptides, retinoids, sunscreen, and antioxidants (alpha-lipoic acid, vitamin C and B3, N-acetyl-glucosamine, α-tocopherol, and ubiquinone) (Wanjari and Waghmare, 2015).Hair cosmeceuticals: This category includes specific compounds that promote hair growth.Other cosmeceuticals: These include anti-wrinkle creams and products for the care of teeth, lips, and nails (Dureja et al., 2015).
Eclipta prostrata promotes the induction of anagen, sustains the anagen phase through regulation of FGF-7 and FGF-5
Published in Pharmaceutical Biology, 2019
Keun-Hyeun Lee, Dabin Choi, Seung-Il Jeong, Sang-Jun Kim, Chang Hyun Lee, Hyung-Sik Seo, Han-Sol Jeong
Hair loss can occur throughout the scalp and whole body. Numerous studies on the physiology of hair growth have been carried out. Many growth factors, cytokines and hormones revealed to be implicated in the regulation of hair growth cycle; however, the clear mechanism of the hair loss has not been clarified. The factors associated with hair loss that have been known so far include genetic background, hormonal changes, pathological conditions, aging, and side effects of a drug. The leading cause of scalp hair loss is heredity and age. Although hair loss is not a life-threatening condition, it causes significant impairment of life quality. Currently, FDA-approved drugs for the treatment of androgenetic alopecia are a 5-α reductase type II inhibitor, oral finasteride (propecia) and minoxidil, which is an external agent for hair growth by increasing blood flow (Price 1999; Rogers and Avram 2008). Corticosteroids are also used to treat alopecia caused by a destruction of hair follicles by the immune system (Garg and Messenger 2009). There is a continuing need for drugs that prevent the progression of hair loss and facilitate hair regrowth.
Microneedle mediated transdermal delivery of β-sitosterol loaded nanostructured lipid nanoparticles for androgenic alopecia
Published in Drug Delivery, 2022
Kousalya Prabahar, Ubaidulla Udhumansha, Nehal Elsherbiny, Mona Qushawy
The hair growth was observed by qualitative evaluation. After 21 days, the difference in hair growth in each group was examined visually and photographed. A quantitative analysis of hair growth was performed. After shaving the long hair, the animal skin in the dorsal area was dissected and fixed in 10% formalin (Dhanotia et al., 2011). Vertical sections of the skin were prepared after fixation and stained with hematoxylin and eosin (H&E). To evaluate hair growth, the sections were analyzed for various parameters. The follicular density (number of follicles/mm) was reported by recording the number of hair follicles in 2 mm area. Anagen/telogen ratio was determined by calculating the number of follicles in anagen phase (active growth phase) and telogen phase (resting phase) (Noubarani et al., 2014).
The “in’s and outs” of laser hair removal: a mini review
Published in Journal of Cosmetic and Laser Therapy, 2019
Mandy M. Thomas, Nicolette N. Houreld
Laser hair removal relies on three paramount parameters: the proper selection of wavelength in the recommended visible to near-infrared (NIR) region up to about 1100–1200 nm; pulse duration (in milliseconds, ms); and the energy density or fluence (in joules per square centimetre, J/cm2) administered, which is related to total exposure time (10). Thermal injury can be restricted to the target chromophore through the selection of the correct parameters. One other important concept is the thermal relaxation time (TRT). TRT is defined as the time required by an object to cool down to 50% of the initial temperature achieved (11). For targeted tissue damage to occur, photons at the correct wavelength need to be absorbed by the chromophore and not the adjacent tissue. In order to achieve this, the pulse duration should be less than the TRT of the target. If the pulse duration exceeds the TRT, not only will the target be damaged, but the heat energy will also dissipate to the adjacent tissue resulting in injury to the surrounding area. Additionally, the stage of hair growth also plays an important factor. The ideal stage in the hair growth cycle is the active anagen phase, as there is an abundance of melanin and the follicles are located deep within the skin and are still attached to the papilla for nourishment. It is estimated that a 20% reduction may be observed with each treatment if hair growth is in the anagen phase and if the correct laser/light parameters are used.
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