Fully automated chip-based nanoelectrospray ionization-mass spectrometry as an effective tool for rapid and high-throughput screening of 5α-reductase inhibitors.

The 5α-reductase converts testosterone to dihydrotestosterone (DHT), and excess DHT could cause androgen-related diseases such as androgenetic alopecia and benign prostatic hyperplasia (BPH). To discover new 5α-reductase inhibitors, effective drug screening method with high throughput is thus essential. In this study, fully automated chip-based nanoelectrospray ionization-mass spectrometry (nano-ESI-MS) was innovatively utilized as a screening tool for 5α-reductase inhibitory assay in direct infusion mode, which simplified sample pretreatment and greatly improved experimental efficiency. The preliminary data indicated that curcumin, a natural anti-inflammatory compound, exhibited notably 5α-reductase inhibition activity. Moreover, the obtained results of the chip-based nano-ESI-MS were well consistent with those of HPLC-MS, which suggested that the chip-based nano-ESI-MS could be treated as a rapid and high-throughput drugs screening strategy in pharmaceutical development. Graphical abstract.

Identification of a new plant extract for androgenic alopecia treatment using a non-radioactive human hair dermal papilla cell-based assay.

BACKGROUND: Androgenic alopecia (AGA) is a major type of human scalp hair loss, which is caused by two androgens: testosterone (T) and 5α-dihydrotestosterone (5α-DHT). Both androgens bind to the androgen receptor (AR) and induce androgen-sensitive genes within the human hair dermal papilla cells (HHDPCs), but 5α-DHT exhibits much higher binding affinity and potency than T does in inducing the involved androgen-sensitive genes. Changes in the induction of androgen-sensitive genes during AGA are caused by the over-production of 5α-DHT by the 5α-reductase (5α-R) enzyme; therefore, one possible method to treat AGA is to inhibit this enzymatic reaction. METHODS: RT-PCR was used to identify the presence of the 5α-R and AR within HHDPCs. A newly developed AGA-relevant HHDPC-based assay combined with non-radioactive thin layer chromatography (TLC) detection was used for screening crude plant extracts for the identification of new 5α-R inhibitors. RESULTS: HHDPCs expressed both 5α-R type 1 isoform of the enzyme (5α-R1) and AR in all of the passages used in this study. Among the thirty tested extracts, Avicennia marina (AM) displayed the highest inhibitory activity at the final concentration of 10 µg/ml, as the production of 5α-DHT decreased by 52% (IC50 = 9.21 ± 0.38 µg/ml). CONCLUSIONS: Avicennia marina (AM) was identified as a potential candidate for the treatment of AGA based on its 5α-R1-inhibitory activity.

Quality evaluation of the Finasteride polymorphic forms I and II in capsules.

Finasteride (FNS) is a specific competitive inhibitor of steroid type-II 5α-reductase and is widely used for the treatment of benign prostatic hyperplasia, prostate cancer, and androgenetic alopecia. FNS has two polymorphic forms identified as Form I and Form II. It is known that polymorphism can cause significant differences in the physicochemical properties of a compound such as melting point, density, morphology, solubility, and color. Thus, proper qualitative and quantitative monitoring of the solid-state forms is crucial to ensure high-quality products. There are no published papers studying the influence of the FNS polymorphs on the physicochemical quality of capsules. Furthermore, the available analytical methods are time-consuming, expensive, use buffer or do not demonstrate stability-indicating capacity. The aim of this work was to validate a rapid high-performance liquid chromatography (HPLC) method to evaluate FNS in capsules and to study the physicochemical properties of polymorphic forms, evaluating their possible influence in the dissolution profile and stability of FNS in capsules. Capsules containing Forms I and II of FNS were prepared and subjected to quality control studies, dissolution profiles and a stability study at 50°C. A significant effect of polymorphism on the FNS solubility and dissolution properties was observed. These results suggest that changes in the effects of FNS can occur if a suitable control study is not performed on the raw material used to produce the capsules.

Development and validation of an UPLC method for determination of content uniformity in low-dose solid drugs products using the design space approach.

A simple and reproducible UPLC method was developed and validated for the quantitative analysis of finasteride in low-dose drug products. Method validation demonstrated the reliability and consistency of analytical results. Due to the regulatory requirements of pharmaceutical analysis in particular, evaluation of robustness is vital to predict how small variations in operating conditions affect the responses. Response surface methodology as an optimization technique was used to evaluate the robustness. For this, a central composite design was implemented around the nominal conditions. Statistical treatment of the responses (retention factor and drug concentrations expressed as percentage of label claim) showed that methanol content in mobile-phase and flow rate were the most influential factors. In the optimization process, the compromise decision support problem (cDSP) strategy was used. Construction of the robust domain from response-surfaces provided tolerance windows for the factors affecting the effectiveness of the method. The specified limits for the USP uniformity of dosage units assay (98.5-101.5%) and the purely experimental variations based on the repeatability test for center points (nominal conditions repetitions) were used as criteria to establish the tolerance windows, which allowed definition design space (DS) of analytical method. Thus, the acceptance criteria values (AV) proposed by the USP-uniformity of assay only depend on the sampling error. If the variation in the responses corresponded to approximately twice the repeatability standard deviation, individual values for percentage label claim (%LC) response may lie outside the specified limits; this implies the data are not centered between the specified limits, and that this term plus the sampling error affects the AV value. To avoid this fact, the limits specified by the Uniformity of Dosage Form assay (i.e., 98.5-101.5%) must be taken into consideration to fix the tolerance windows for each factor. All these results were verified by the Monte Carlo simulation. In conclusion, the level of variability for different factors must be calculated for each case, and not arbitrary way, provided a variation is found higher than the repeatability for center points and secondly, the %LC response must lie inside the specified limits i.e., 98.5-101.5%. If not the UPLC method must be re-developed.

[Establishment of an in vitro screening model for steroid 5 alpha-reductase inhibitors with the microplate reader].

OBJECTIVE: To establish an in vitro screening model for steroid 5 alpha-reductase inhibitors using the microplate reader. METHODS: Steroid 5 alpha-reductase was obtained from the liver of female rats, an in vitro screening model for steroid 5 alpha-reductase inhibitors established using the 96-well plate and microplate reader after determination of the enzymatic activity, and the reliability of the model verified with the known 5 alpha-reductase inhibitors epristeride and finasteride. Added to the 96-well plate were the final concentrations of testosterone (0-40 micromol/L), NADPH (22 micromol/L), epristeride (0-60 nmol/L) or finasteride (0-60 nmol/ L) and steroid 5 alpha-reductase (20 microl), the total volume of each well adjusted to 200 microl with Tris-Hcl buffer. The 96-well plate was placed in the microplate reader, mixed and incubated at 37 degrees C, followed by detection of the A340nm value at 0 and 10 min and analysis of the data. RESULTS: The Km value of steroid 5 alpha-reductase was 3.794 micromol/L, with a Vmax of 0.271 micromol/(L. min). The Ki of epristeride was 148.2 nmol/L, with an IC50 of 31.5 nmol/L, and the enzymatic reaction kinetic curve suggested that epristeride was an uncompetitive enzyme inhibitor. The Ki of finasteride was 158. 8 nmol/L, with an IC50 of 13.6 nmol/L. The enzymatic reaction kinetic curve showed that both epristeride and finasteride were competitive enzyme inhibitors, similar to those reported in the published literature. CONCLUSION: A screening model was successfully established, which could rapidly and effectively screen steroid 5 alpha-reductase inhibitors in vitro.