Physcion, a novel inhibitor of 5α-reductase that promotes hair growth in vitro and in vivo.

Androgenic alopecia (AGA) has a high incidence. Excess dihydrotestosterone in blood capillaries, which is converted from testosterone by 5α-reductase, is an AGA causative factor. We identified the inhibitory activity of four Polygonum multiflorum compounds against 5α-reductase via high-performance liquid chromatography, and the results showed that Physcion was a potent 5α-reductase inhibitor. Additionally, we found that through inhibiting 5α-reductase expression, Physcion could shorten the time of dorsal skin darkening and hair growth, improve hair follicle morphology, and significantly increase hair follicle count. Eventually, through molecular docking study, we found the binding energy and molecular interactions between Physcion and 5α-reductase type II. These results suggested that Physcion is a potent 5α-reductase inhibitor, as well as a new natural medicine for treating AGA.

Three-Dimensional Proteome-Wide Scale Screening for the 5-Alpha Reductase Inhibitor Finasteride: Identification of a Novel Off-Target.

Finasteride, a 5-alpha reductase (5α-R) inhibitor, is a widely used drug for treating androgen-dependent conditions. However, its use is associated with sexual, psychological, and physical complaints, suggesting that other mechanisms, in addition to 5α-R inhibition, may be involved. Here, a multidisciplinary approach has been used to identify potential finasteride off-target proteins. SPILLO-PBSS software suggests an additional inhibitory activity of finasteride on phenylethanolamine N-methyltransferase (PNMT), the limiting enzyme in formation of the stress hormone epinephrine. The interaction of finasteride with PNMT was supported by docking and molecular dynamics analysis and by in vitro assay, confirming the inhibitory nature of the binding. Finally, this inhibition was also confirmed in an in vivo rat model. Literature data indicate that PNMT activity perturbation may be correlated with sexual and psychological side effects. Therefore, results here obtained suggest that the binding of finasteride to PNMT might have a role in producing the side effects exerted by finasteride treatment.

Protective effects of combination of Stauntonia hexaphylla and Cornus officinalis on testosterone-induced benign prostatic hyperplasia through inhibition of 5α- reductase type 2 and induced cell apoptosis.

Benign prostatic hyperplasia (BPH) is a progressive pathological condition associated with proliferation of prostatic tissues, prostate enlargement, and lower-urinary tract symptoms. However, the mechanism underlying the pathogenesis of BPH is unclear. The aim of this study was to investigate the protective effects of a combination of Stauntonia hexaphylla and Cornus officinalis (SC extract) on a testosterone propionate (TP)-induced BPH model. The effect of SC extract was examined in a TP-induced human prostate adenocarcinoma cell line. Male Sprague-Dawley rats were randomly divided into 5 groups (n = 6) for in vivo experiments. To induce BPH, all rats, except those in the control group, were administered daily with subcutaneous injections of TP (5 mg/kg) and orally treated with appropriate phosphate buffered saline/drugs (finasteride/saw palmetto/SC extract) for 4 consecutive weeks. SC extract significantly downregulated the androgen receptor (AR), prostate specific antigen (PSA), and 5α-reductase type 2 in TP-induced BPH in vitro. In in vivo experiments, SC extract significantly reduced prostate weight, size, serum testosterone, and dihydrotestosterone (DHT) levels. Histologically, SC extract markedly recovered TP-induced abnormalities and reduced prostatic hyperplasia, thereby improving the histo-architecture of TP-induced BPH rats. SC extract also significantly downregulated AR and PSA expression, as assayed using immunoblotting. Immunostaining revealed that SC extract markedly reduced the 5α-reductase type 2 and significantly downregulated the expression of proliferating cell nuclear antigen. In addition, immunoblotting of B-cell lymphoma 2 (Bcl-2) family proteins indicated that SC extract significantly downregulated anti-apoptotic Bcl-2 and markedly upregulated pro-apoptotic B cell lymphoma-associated X (Bax) expression. Furthermore, SC treatment significantly decreased the Bcl-2/Bax ratio, indicating induced prostate cell apoptosis in TP-induced BPH rats. Thus, our findings demonstrated that SC extract protects against BPH by inhibiting 5α-reductase type 2 and inducing prostate cell apoptosis. Therefore, SC extract might be useful in the clinical treatment of BPH.

Water-stable and finasteride-loaded polyvinyl alcohol nanofibrous particles with sustained drug release for improved prostatic artery embolization - In vitro and in vivo evaluation.

Prostatic artery embolization (PAE) has been a well-established treatment for benign prostatic hyperplasia (BPH). To enhance the therapeutic efficacy, a strategy is to use embolic agent preloaded with 5α-reductase inhibitors for localized drug delivery. In this study, finasteride (FNS) was encapsulated into the polyvinyl alcohol (PVA) nanofibers via co-electrospinning technique, followed by heat treatment and cryogenic grinding to convert them into nanofibrous particles as a drug-loaded embolic agent. The FNS was found to be distributed uniformly in PVA nanofibers, and the processed FNS/PVA nanofibrous particles were 272 µm in mean particle size. Besides, the studies on the composition, thermal properties, swelling ratio, and water stability of the nanofibers and drug showed that the FNS remained its crystalline state in PVA nanofibers. The heat treatment increased the crystallinity of nanofibers and rendered them water stability. Both FNS and PVA possessed excellent thermal stability at high temperature (150 °C). In addition, in vitro drug release studies suggested the FNS followed a favorable sustained release up to 744 h. Furthermore, the cell viability and hemocompatibility assays indicated the nanofibers possessed excellent cytocompatibility and with no evidence of hemolysis. More importantly, the in vivo PAE procedures on beagles demonstrated the crosslinked FNS/PVA nanofibrous particles exhibited higher embolization efficacy with more obvious prostate volume (PV) reduction compared to crosslinked PVA nanofibrous particles after embolization for 1, 3, and 6 months (P < 0.05). Therefore, such drug-loaded PVA nanofibrous particles combined physical embolization and localized medical therapy together, which offer great potential to be used as an effective embolic agent for BPH therapy.

Finasteride and Its Potential for the Treatment of Female Pattern Hair Loss: Evidence to Date.

The currently approved treatment for female pattern hair loss (FPHL) includes topical minoxidil administration; however, this treatment fails to achieve hair regrowth in some patients. Finasteride, a selective 5α-reductase inhibitor (5-ARI), may be considered as an alternative treatment. However, because of its potential teratogenic effects, clinical studies and use of finasteride for FPHL are limited. In this review, we aim to summarize the literature regarding the pharmacology, clinical efficacy, and adverse effects of oral finasteride for the treatment of FPHL and to provide novel therapeutic options including topical finasteride and dutasteride, a new generation 5-ARI, for the treatment of FPHL.

Dutasteride nanocapsules for hair follicle targeting: Effect of chitosan-coating and physical stimulus.

In general, nanometer-sized drug delivery systems have a natural tendency for accommodation in the follicular cavities, which makes them advantageous in the treatment of conditions affecting these structures. Still, follicular targeting enhancement can improve therapy outcomes. Here, we compare two strategies to further promote dutasteride follicular-targeted delivery: the chemical modulation of nanosystem surface properties by coating with the natural polymer chitosan, and the application of a massage. For this, poly-(ɛ-caprolactone)-lipid-core nanocapsules (NC) containing dutasteride were developed and had their permeation profile compared to chitosan-coated nanocapsules (NC-CS). Nanocapsules showed high drug encapsulation efficiency (>94%), and stability for up to 90 days of storage. As expected, chitosan coating increased the size and zeta potential, from 199.0 ± 0.5 nm (PdI of 0.12) and - 13.6 ± 0.6 mV to 224.9 ± 3.4 nm (PdI 0.23) and + 40.2 ± 0.8 mV, respectively. Both coated and non-coated nanoparticles targeted the hair follicles compared to a drug solution. Enhanced hair follicles targeting was observed after the massage procedure, with 5 and 2-fold increases relative to NC and NC-CS, respectively. In conclusion, this work demonstrates dutasteride nanocapsules can target the follicular casts, and a simple physical stimulation can enhance 5-times the drug amount accumulated.

Quintaquinone, a Merosesquiterpene from the Yellow Sponge Verongula cf. rigida Esper.

A chemical investigation of the sponge Verongula cf. rigida led to the isolation of 13 merosesquiterpenes, among which quintaquinone (2), 5-epi-nakijiquinone L (3), and 3-farnesyl-2-hydroxy-5-methoxyquinone (4) were isolated and reported here for the first time. Particularly, compound 2 is the first member of merosesquiterpenes with a polyketide side chain substituted on C-19. All of the isolated compounds were examined for steroid 5α-reductase inhibitory activity. Cyclospongiaquinone 1 (5) showed a strong activity in the same range as that of standard finasteride.

New Potent 5α- Reductase and Aromatase Inhibitors Derived from 1,2,3-Triazole Derivative.

This work describes the utility of pyrazole-4-carbaldehyde 1 as starting material for the synthesis of a novel potent series of 5α-reductase and aromatase inhibitors derived from 1,2,3-triazole derivative. Condensation of 1 with active methylene and different amino pyrazoles produced the respective Schiff bases 2-4, 8 and 9. On the other hand, 1 was reacted with ethyl cyanoacetate and thiourea in one-pot reaction to afford the pyrazolo-6- thioxopyridin-2-[3H]-one (10). Moreover, α-ß unsaturated chalcone derivative 11 was prepared via the reaction of compound 1 with P-methoxy acetophenone, which in turn reacted with each of ethyl cyanoacetate, malononitrile, hydrazine hydrate, and thiosemicarbazide to afford the corresponding pyridine and pyrazole derivatives 13, 14, 17, and 20. The structure of newly synthesized compounds was characterized by analytical and spectroscopic data (IR, MS and NMR). All new compounds were evaluated against 5α-reductase and aromatase inhibitors and the results showed that many of these compounds inhibit 5α-reductase and aromatase activity; compound 13 was found to be the highest potency among the tested samples comparing with the reference drugs.

In-Vitro and In-Vivo Evaluation of Supersaturable Self-Nanoemulsifying Drug Delivery System (SNEDDS) of Dutasteride.

OBJECTIVE: A novel, Supersaturable Self-Nanoemulsifying Drug Delivery System (S-SNEDDS) has been prepared to improve the Dutasteride's poor aqueous solubility. METHODS: By adding Hydroxy Propyl Methyl Cellulose (HPMC) as a precipitation inhibitor to conventional SNEDDS, a supersaturable system was prepared. Firstly, the prepared SNEDDS played an important role in increasing the aqueous solubility and hence oral absorption due to nano-range size. Secondly, the S-SNEDDS found to be advantageous over SNEDDS for having a higher drug load and inhibition of dilution precipitation of Dutasteride. Formulated S-SNEDDS (F1-F9) ranged from 37.42 ± 1.02 to 68.92 ± 0.09 nm with PDI 0.219-0.34 and drug loading of over 95 percent. RESULTS: The study of in-vitro dissolution revealed higher dissolution for S-SNEDDS compared to SNEDDS and Avodart soft gelatin capsule as a commercial product. In addition, higher absorption was observed for S-SNEDDS showing approximately 1.28 and 1.27 fold AUC (0-24h) and Cmax compared to commercial products. Therefore, S-SNEDDS has proven as a novel drug delivery system with a higher drug load, higher self-emulsification efficiency, higher stability, higher dissolution and pronounced absorption. CONCLUSION: In conclusion, S-SNEDDS could be a newly emerging approach to enhance aqueous solubility in many folds for drugs belonging to BCS Class II and IV and thus absorption and oral bioavailability.

Design, synthesis, and biological evaluation of novel androst-17ß-amide structurally related compounds as dual 5α-reductase inhibitors and androgen receptor antagonists.

Prostate cancer (PCa) is the second leading cause of death in men. Apart from androgen receptor, 5α-reductase has also been recognized as a potential target. In this study, a series of androst-17ß-amide compounds have been designed and synthesized targeting both AR and 5α-reductase. Their anti-proliferation activities were evaluated in AR + cell line 22RV1 and AR - cell line PC-3. The results indicated that most of the synthesized compounds inhibited the testosterone-stimulated cell proliferation with good selectivity and safety. Among all the compounds, androst[3,2-c]pyrazole derivatives (9a-9d) displayed the best inhibition activity comparable with flutamide. Moreover, most of the synthesized compounds displayed good 5α-reductase inhibitory activities with IC50 lower than 1 µM. The docking result of 9d-AR indicated that AR was forced to expands its binding cavity and maintain an antagonistic conformation since the steric hindrance of 9d impeded H12 transposition. Overall, compound 9d can be identified as a potential dual 5α-reductase inhibitor and AR antagonist, which might be of therapeutic importance for PCa treatment.

Gossypol inhibits 5α-reductase 1 and 3α-hydroxysteroid dehydrogenase: Its possible use for the treatment of prostate cancer.

Gossypol is a yellow polyphenol isolated from cotton seeds. It has the antitumor activity and it is being tested to treat prostate cancer. However, its underlying mechanisms are still not well understood. The present study investigated the inhibitory effects of gossypol acetate on rat 5α-reductase 1, 3α-hydroxysteroid dehydrogenase, and retinol dehydrogenase 2 for androgen metabolism. Rat 5α-reductase 1, 3α-hydroxysteroid dehydrogenase, and retinol dehydrogenase 2 were expressed in COS-1 cells. Immature Leydig cells that contain these enzymes were isolated from 35-day-old male Sprague Dawley rats. The potency and mode of action of gossypol acetate to inhibit these enzymes in both enzyme-expressed preparations and immature Leydig cells were examined. Molecular docking study of gossypol on the crystal structure of 3α-hydroxysteroid dehydrogenase was performed. Gossypol acetate inhibited 5α-reductase 1 and 3α-hydroxysteroid dehydrogenase with IC50 values of 3.33 ±â€¯0.07 and 0.52 ±â€¯0.06 × 10-6 M in the expressed enzymes as well as 8.512 ±â€¯0.079 and 1.032 ±â€¯0.068 × 10-6 M in intact rat immature Leydig cells, respectively. Gossypol acetate inhibited rat 5α-reductase 1 in a noncompetitive mode and 3α-hydroxysteroid dehydrogenase in a mixed mode when steroid substrates were supplied. Gossypol acetate weakly inhibited retinol dehydrogenase 2 with IC50 value over 1 × 10-4 M. Molecular docking analysis showed that gossypol partially bound to the steroid-binding site of the crystal structure of rat 3α-hydroxysteroid dehydrogenase. Gossypol acetate is a potent inhibitor of rat 5α-reductase 1 and 3α-hydroxysteroid dehydrogenase, possibly inhibiting the formation of androgen in the prostate cancer cells.

Discovery of Natural Steroid 5 Alpha-Reductase Inhibitors.

Human steroid 5 alpha-reductases (S5αRs) and NADPH irreversibly reduce testosterone to the more potent dihydrotestosterone (DHT). S5αR inhibitors are useful treatments for DHT-dependent diseases, including benign prostatic hyperplasia, androgenic alopecia and hair growth, and acne. There are three S5αR isozymes, and there is a need for safer and more isozyme selective inhibitors than finasteride and dutasteride currently licensed. In this study, we review the methods used to screen for S5αR inhibitory activity and describe studies that characterize the ability of herbal preparations and their constituents to inhibit S5αRs. We identified enormous variations between studies in IC50s for finasteride and dutasteride used as standards. Accordingly, we make several recommendations: Stable isozyme specific transfection systems need creating a standardized enzyme/microsome preparation and all three isozymes, as well as androgen receptor binding, should be tested; agreed reaction conditions, especially the substrate concentrations, and separation/quantitation method optimized for high throughput screening; systematic screening of herbal compounds and most extensive use of leads to develop more potent and isozyme specific inhibitors.

Activity of steroid 4 and derivatives 4a-4f as inhibitors of the enzyme 5α-reductase 1.

It is known that the growth of prostate metastatic bone tumor depends on androgens, and tumor formation can start from migratory malignant cells produced in that organ. These cells exhibit grater type 1 5α-reductase (5α-R1) activity than type 2 5α-reductase. Noteworthy, both isozymes convert testosterone (T) to the more active androgen dihydrotestosterone (DHT) in the target tissues. Thus, in order to potentially improve the prognosis of this disease, in this work, seven derivatives of 17-(1H-benzimidazol-1-yl)-16-formillandrosta-5,16-dien-3ß-yl benzoate (4a-f) and 17-(1H-benzimidazol-1-yl)-3-hydroxy-16-formylandrost-5,16-diene (4) were synthesized, characterized and identified as inhibitors of type 1 5α-reductase (5αR1). These derivatives having the advantage of improved plasma half-life. The inhibitory activity of the compounds towards 5α-R1 isoenzyme was determined by conversion of T into DHT in the presence or absence of compounds 4, 4a-f. Further, in vivo experiments were also carried out, treating gonadectomized hamsters with T and/or 4, 4a-f and evaluating their effect on the diameter of hamster flank organs and on the weight of the prostatic and seminal vesicles. Results indicated that compounds 4, 4b, 4c, served as in vitro inhibitors of the enzyme 5α-R1 and pharmacological experiments showed that 4 and derivatives 4a-f decreased the diameter of the flank glands, the weight of the prostate and seminal vesicles of treated hamsters without any appreciable toxicity during observation. Noteworthy the fact that compound 4 is the product, in all cases, of the hydrolysis of the series of esters 4a-f, thus they can serve as precursors (prodrugs) of the active form 4.

Effect of Dose and 5α-Reductase Inhibition on the Circulating Testosterone Metabolite Profile of Men Administered Oral Testosterone.

Development of an oral testosterone therapy has proven extremely challenging because of extensive and variable first-pass metabolism. We investigated the in vivo metabolism of testosterone with increasing oral doses of testosterone, both alone and with the co-administration of dutasteride (5α-reductase inhibitor) by liquid-chromatography tandem mass spectrometry (LC-MS/MS). In eugonadal men prior to dosing, the circulating concentration of testosterone, androstenedione, etiocholanolone-glucuronide, and androsterone-glucuronide was 8.6, 20.9, 9.1, and 55.3%, respectively, of the total testosterone-related species, whereas testosterone-glucuronide was ∼1%. When testosterone was dosed orally to men with experimental hypogonadism, a proportion of testosterone-glucuronide increased to 13%. Dutasteride treatment significantly decreased levels of androsterone and its metabolites. This work reveals extensive metabolism of orally dosed testosterone to androsterone glucuronide via androstenedione, with testosterone-glucuronide appearing to be the second most important metabolite. This information is of importance in the development of an effective oral testosterone therapy and may have implications for testosterone doping research.

Recent Progress of Novel Steroid Derivatives and Their Potential Biological Properties.

Steroid and its derivatives have been proved to have important and diverse biological functions, which present the wide spectrum of biological activities such as antitumor, antiviral, antibacterial, antimicrobial, antifungal, antioxidant, insecticidal, aromatase inhibitors, 5α-reductase inhibitors and neuromuscular blocking agents etc. Versatile features of steroid-derived compounds have emerged, so the aim of the present paper is to review the recent advances of steroid-based derivatives mainly focused on their structures and biological applications, which can be employed for further development to discover potential drug candidates.

Exploration of Novel 5α-Reductase Inhibitors for Benign Prostatic Hyperplasia by 2D/3D QSAR, Cytotoxicity Pre-ADME and Docking Studies.

BACKGROUND: 5α-Reductase (5AR), an NADPH dependent enzyme, is expressed in most of the prostate epithelial cells. By converting testosterone (T) into more potent androgen dihydrotestosterone (DHT), it plays an important role in men physiology and represents an efficient therapeutic target for androgen-dependent diseases. Over the last few years, significant efforts have been made in order to develop 5AR inhibitors (5ARI) to treat Benign Prostatic Hyperplasia because of excessive production of DHT. METHODS: In the present study, 2D and 3D QSAR pharmacophore models have been generated for 5ARI based on known IC50 values with extensive validations. The four featured 2D pharmacophore based PLS model correlated the topological interactions (SsOHE-index); semi empirical (Quadrupole2) and physicochemical descriptors (Mol. Wt, Bromines Count, Chlorines Count) with 5AR inhibitory activity, and has the highest correlation coefficient (r2 = 0.98, q2 =0.84; F = 57.87, pred r2 = 0.88). Internal and external validation was carried out using test and proposed set of compounds. The contribution plot of electrostatic field effects and steric interactions generated by 3D-QSAR showed interesting results in terms of internal and external predictability. The well-validated 2D PLS, and 3D kNN models were used to search novel 5AR inhibitors with different chemical scaffold. The compounds were further sorted by applying ADMET properties and in vitro cytotoxicity studies against prostate cancer cell lines PC-3. Molecular docking studies have also been employed to investigate the binding interactions and to study the stability of docked conformation in detail. RESULTS: Several important hydrophobic and hydrogen bond interactions with 5AR lead to the identification of active binding sites of 4AT0 protein in the docked complex, which include the gatekeeper residues ALA 63A (Chain A: ALA63), THR 60 A (Chain A: THR60), and ARG 456 A (Chain A: ARG456), at the hinge region. CONCLUSION: Overall, this study suggests that the proposed compounds have the potential as effective inhibitors for 5AR.

Inhibition of 5α-Reductase, IL-6 Secretion, and Oxidation Process of Equisetum debile Roxb. ex Vaucher Extract as Functional Food and Nutraceuticals Ingredients.

This study aims to investigate the biological activities related to hair loss of Equisetum debile extracts, including 5α-reductase inhibition, interleukin-6 (IL-6) secretion reduction, and anti-oxidation. E. debile extracts were obtained by maceration in various solvents. Crude extract (CE) was obtained by maceration in 95% ethanol. Chlorophyll-free extract (CF) was the CE which of the chlorophyll has been removed by electrocoagulation. Hexane extract (HE), ethyl acetate extract (EA), and ethanolic extract (ET) were fraction extracts obtained from maceration in hexane, ethyl acetate, and 95% ethanol, respectively. The extracts were investigated for inhibitory activity against 5α-reductase and IL-6 secretion. Total phenolic contents (TPC) were investigated and antioxidant activities were determined by means of 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. The inhibition of lipid peroxidation was determined by the ferric thiocyanate method. The cytotoxicity of the extracts on dermal papilla cells and irritation test by hen's egg test chorioallantoic membrane assay were also investigated. All extracts could inhibit 5α-reductase and decrease IL-6 secretion in lipopolysaccharide-stimulated macrophage. The antioxidant activity of E. debile extracts was directly related to their TPC. ET which contained the highest TPC (68.8 ± 6.7 mg GA/g) showed the highest equivalent concentration (EC1) of 289.1 ± 26.4 mM FeSO4/g, TEAC of 156.6 ± 34.6 mM Trolox/g, and 20.0 ± 6.0% DPPH inhibition. However, EA exhibited the highest inhibition against lipid peroxidation (57.2 ± 0.4%). In addition, EA showed no cytotoxicity on dermal papilla cell line and no irritation on chorioallantoic membrane of hen's eggs. In conclusion, EA was suggested as the most attractive ingredients for functional food and nutraceuticals because of the high inhibitory activity against 5α-reductase, IL-6 secretion, and lipid peroxidation inhibition.

Design, synthesis and biological evaluation of novel 3-oxo-4-oxa-5α-androst-17ß-amide derivatives as dual 5α-reductase inhibitors and androgen receptor antagonists.

Prostate cancer (PCa) is the second leading cause of death in men. Recently, some researches have showed that 5α-reductase inhibitors were beneficial in PCa treatment as well. In this study, a series of novel 3-oxo-4-oxa-5α-androst-17ß-amide derivatives have been designed and synthesized in a more simple and convenient method. Most of the synthesized compounds displayed good 5α-reductase inhibitory activities and androgen receptor binding affinities. Their anti-proliferation activities in PC-3 and LNCaP cell lines were also evaluated and the results indicated that most of the synthesized compounds exhibited potent anti-proliferative activities. It is obvious that the androgen-dependent cell line LNCaP was much more sensitive than the androgen-independent cell line PC-3. Among all the synthesized compounds, 11d and 11k displayed the best inhibition activity with 4-fold more sensitive toward LNCaP than PC-3, which was consistent with their high affinities observed in AR binding assay. Molecular modeling studies suggested that 11k could bind to AR in a manner similar to the binding of dihydrotestosterone to AR. Compared to the finasteride, 11k showed a longer plasma half-life (4h) and a better bioavailability. Overall, based on biological activities data, compound 11d and 11k can be identified as potential dual 5α-reductase inhibitors and AR antagonists which might be of therapeutic importance for prostate cancer treatment.

Design of Finasteride-Loaded Nanoparticles for Potential Treatment of Alopecia.

BACKGROUND/AIMS: Androgenetic alopecia is an extremely common dermatological disorder affecting both men and women. Oral finasteride (FNS), a synthetic 4-aza-3-oxosteroid compound with poor aqueous solubility, blocks the peripheral conversion of testosterone to dihydrotestosterone (DHT) in a significant reduction in DHT concentration, achieving satisfactory results in alopecia treatment. However, its oral intake generally causes severe side effects. Considering that there is currently no scientifically proven treatment, new drug delivery systems able to improve alopecia therapy are urgently required. METHODS: In this study, polymeric nanoparticles have been proposed as a new carrier for topical delivery of FNS in hair follicles. RESULTS AND CONCLUSIONS: Polymeric nanoparticles, prepared by using a modified method of the emulsification/solvent diffusion, showed a mean particle size around 300 nm, which may be sufficient for reaching the dermis and hair follicles and negative zeta potential values. Scanning electron microscope measurements showed that all the polymeric nanoparticles exhibited a spherical shape and a smooth surface regardless of their composition. A high encapsulation efficiency was achieved for FNS (79.49 ± 0.47%). In vitro release assays in physiological conditions demonstrated that nanoparticles yielded a prolonged release of FNS for 3 h. Skin assays through an in vitro permeation study demonstrated that nanoparticles had low levels of penetration of FNS, improving its time residence onto the skin. All excipients used in nanoparticle composition and in 3 different vehicles were safe. These results suggest that the proposed novel formulation presents several good characteristics indicating its suitability for dermal delivery of FNS for alopecia treatment.

Experimental, molecular docking investigations and bioavailability study on the inclusion complexes of finasteride and cyclodextrins.

Finasteride (FIN) is a Class II candidate of the Biopharmaceutics Classification System (BCS). The lipophilic cavity of cyclodextrins (CyDs) enables it to construct a non-covalent inclusion complex with different insoluble drugs. Only ß-cyclodextrin (ß-CyD) and hydroxypropyl-ß-CyD (HP-ß-CyD) have been previously examined with FIN. This study aimed to investigate the consistence of FIN with different kinds of ß-CyDs, including dimethyl-ß-cyclodextrin (DM-ß-CyD), carboxymethyl-ß-cyclodextrin (CM-ß-CyD), HP-ß-CyD, sulfobutyl ether-ß-cyclodextrin (SBE-ß-CyD), and ß-CyD, by the coprecipitation method. The resultant inclusion systems were characterized by differential scanning calorimetry, infrared spectroscopy, X-ray diffractometry, and dissolution studies. Moreover, molecular docking for the selected inclusion systems was carried out to explore the suitable arrangements of FIN in the cavity of ß-CyD or its derivatives. The results suggested that the DM-ß-CyD inclusion system gave the higher complexation efficiency for improvement in solubility of FIN and hence enhancement of its bioavailability. Pharmacokinetic parameters displayed a higher absorption rate and higher area under the curve of the FIN/DM-ß-CyD inclusion complex when compared with the drug alone, which indicates an improvement in the absorption and bioavailability of FIN in the DM-ß-CyD inclusion system.