Azulene and Its Derivatives as Potential Compounds in the Therapy of Dermatological and Anticancer Diseases: New Perspectives against the Backdrop of Current Research.

The scientific article focuses on the role of azulene and its derivatives in the therapy of dermatological diseases, presenting the latest laboratory and clinical research as well as prospects for further studies. In a synthetic literature review, various databases such as PubMed, Scopus, Web of Science, and the Database of Polish Scientific Journals were queried to select relevant articles concerning azulene. The conclusions drawn from the thematic analysis of the studies emphasize the multifaceted pharmacological actions of azulene and its derivatives including their anti-inflammatory properties, potential anticancer effects, photoprotective abilities, alleviation of itching, management of atopic dermatitis, and treatment of erectile dysfunction. However, there are certain limitations associated with the application of unmodified azulene on the skin, particularly related to photodecomposition and the generation of reactive oxygen species under UV radiation. These effects, in turn, necessitate further research on the safety of azulene and azulene-derived substances, especially regarding their long-term use and potential application in phototherapy. The authors of this work emphasize the necessity of conducting further preclinical and clinical studies to fully understand the mechanisms of action. Incorporating azulene and its derivatives into the therapy of dermatological disorders may represent an innovative approach, thereby opening new treatment avenues for patients.

Efficacy of photodynamic therapy using ALAHCl in gel with a lipid nanoemulsion and MALHCl in cream in superficial basal cell carcinoma.

INTRODUCTION AND OBJECTIVE: Photodynamic therapy (PDT) is a therapeutic option for low-risk basal cell carcinoma (BCC). The aim of the study was to assess the efficacy of topical PDT in the treatment of superficial BCC (sBCC) using two different photosensitizers: aminolevulinic acid hydrochloride (ALA-HCl) in a gel formulation with a lipid nanoemulsion (ALA-HCl in gel) and ALA methyl ester hydrochloride (MAL-HCl) in a cream formulation (MAL-HCl in cream). MATERIAL AND METHODS: 21 patients were treated twice with a one week interval between treatments. The formulations were applied onto lesions: 10 patients were treated with MAL-HCl in cream, and 11 with ALA-HCl in gel. After three hours of incubation and removing the preparations, fluorescence was assessed. The skin areas were then irradiated with red light 630 ± 5 nm. RESULTS: At the follow-up visit 12 weeks after the second treatment, complete clinical remission was found in 82% after ALA-HCl in gel and in 80% after MAL-HCl in cream. An excellent cosmetic result was found in 96% of patients after MALHCl in cream and in 100% after ALA-HCl in gel. Faster skin healing and less post-inflammatory hyperpigmentation during follow-up visits was observed after treatment with ALA-HCl in gel. CONCLUSIONS: Both formulations - ALA-HCl in gel and MAL-HCl in cream - were highly effective photosensitisers for PDT. The advantage of ALA-HCl in a gel formulation with a lipid nanoemulsion was faster skin healing, resulting in better cosmetic results.

Structure-activity relationship and cytotoxicity of the new thiosemicarbazide derivatives and their Cu(II) complexes against prostate and melanoma cancer cells.

In this study, eighteen new ligands (B1-B18) containing a thiosemicarbazide core were synthesized and characterized in terms of physicochemical properties, molecular docking and in vitro biological activity. The structures of eleven ligands were investigated using X-Ray diffraction and Hirschfeld Surface analysis. To study the structure-activity relationship, the organic ligands contained pyridin-2-ylmethyl, pyridin-3-ylmethyl or pyridin-4-ylmethyl moieties and various substituents. Their pharmakokinetic profiles and molecular docking results suggest high potential as new drug candidates. The complexing ability of the selected organic ligands was also evaluated, yielding five new Cu(II) complexes (Cu(B1)Cl2, Cu(B4)Cl2, Cu(B10)Cl2, Cu(B17)Cl2, Cu(B18)Cl2). The obtained results suggest the formation of the polymeric structures. All organic ligands and Cu(II) complexes were tested for anticancer activity against prostate and melanoma cancer cells (PC-3, DU-145, LNCaP, A375, G-361, SK-MEL-28) and normal fibroblasts (BJ), as well as antimicrobial activity against six selected bateria strains. Among B1-B18 compounds, B3, B5, B9, B10, B12 and B14 exhibited cytotoxic activity. The studied Cu(II) complexes were in general more active, with Cu(B1)Cl2 exhibiting antincancer activity agains all three prostate cancer cells and Cu(B10)Cl2 reaching the IC50 value equal to 88 µM against G-361 melanoma cells. Several compounds also exhibited antimicrobial activity against gram-positive and gram-negative bacteria. It was found that the type of specific substituents, especially the presence of -chloro and -dichloro substituents had a greated impact on the cytotoxicity than the position of the nitrogen atom in the pyridylacetyl moiety.

N-Substituted 2-(Benzenosulfonyl)-1-Carbotioamide Derivatives Exert Antimicrobial and Cytotoxic Effects via Aldehyde Dehydrogenase Pathway: Synthesis, In Silico and In Vitro Studies.

A series of N-Substituted 2-(benzenosulfonyl)-1-carbotioamide derivatives (WZ1-WZ4) were synthesized and characterized using spectral methods. A comprehensive activity study was performed for each compound. All compounds were tested for antibacterial activity. Moreover, in silico studies were carried out to determine the anticancer potential of the designed WZ1-WZ4 ligands. Based on molecular docking, aldehyde dehydrogenase was selected as a molecular target. The obtained data were compared with experimental data in vitro tests. Novel hybrids of the thiosemicarbazide scaffold and sulfonyl groups may have promising anticancer activity via the aldehyde dehydrogenase pathway. The best candidate for further studies appears to be WZ2, due to its superior selectivity in comparison to the other tested compounds.

Therapeutic Potential of Minor Cannabinoids in Dermatological Diseases-A Synthetic Review.

Dermatological diseases pose a significant burden on the quality of life of individuals and can be challenging to treat effectively. In this aspect, cannabinoids are gaining increasing importance due to their therapeutic potential in various disease entities including skin diseases. In this synthetic review, we comprehensively analyzed the existing literature in the field of potential dermatological applications of a lesser-known subgroup of cannabinoids, the so-called minor cannabinoids, such as cannabidivarin (CBDV), cannabidiforol (CBDP), cannabichromene (CBC), tetrahydrocannabivarin (THCV), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabielsoin (CBE), cannabimovone (CBM) or cannabinol (CBN), while drawing attention to their unique pharmacological properties. We systematically searched the available databases for relevant studies and analyzed the data to provide an overview of current thematic knowledge. We looked through the full-text, bibliographic and factographic databases, especially Scopus, Web of Science, PubMed, Polish Scientific Journals Database, and selected the most relevant papers. Our review highlights that minor cannabinoids exhibit diverse pharmacological activities, including anti-inflammatory, analgesic, antimicrobial, and anti-itch properties. Several studies have reported their efficacy in mitigating symptoms associated with dermatological diseases such as psoriasis, eczema, acne, and pruritus. Furthermore, minor cannabinoids have shown potential in regulating sebum production, a crucial factor in acne pathogenesis. The findings of this review suggest that minor cannabinoids hold therapeutic promise in the management of dermatological diseases. Further preclinical and clinical investigations are warranted to elucidate their mechanisms of action, determine optimal dosage regimens, and assess long-term safety profiles. Incorporating minor cannabinoids into dermatological therapies could potentially offer novel treatment options of patients and improve their overall well-being.

Polymer microspheres modified with pyrazole derivatives as potential agents in anticancer therapy - Preliminary studies.

The methods of fighting cancer are far from ideal, therefore it is necessary to search for innovative and effective drugs. In our work, we present pyrazole derivatives and their modifications with polymer microspheres as potential anticancer agents. Molecular and crystal structures of pyrazole derivatives were determined an X-ray analysis and characterized by theoretical calculations. Modifications of cross-linked polymer microspheres with pyrazole derivatives were made on the basis of divinylbenzene and glycidyl methacrylate. The in vitro antiproliferative activity of the pyrazole derivatives and their modified microspheres was assessed against a normal cell line, namely monkey epithelial renal cells (GMK) and cancer cell lines, such as human hepatocellular carcinoma cell line (HepG2), human breast adenocarcinoma cell line (MCF-7) as well as human lung adenocarcinoma cell line (A549), using the MTT assay. All the tested pyrazole derivatives and the polymer microspheres modified by them showed antiproliferative activity in vitro. Two of the modified substances showed the greatest ability to inhibit divisions of all cancer cells. In order to determine a potential target, molecular docking was performed. In silico studies carried out with the use of the human EphB1 receptor revealed that the analyzed compounds bound to the EphB1 binding site, and the compounds with the highest antiproliferative activity showed a better fit to the active site.

Topical Photodynamic Therapy with Different Forms of 5-Aminolevulinic Acid in the Treatment of Actinic Keratosis.

Photodynamic therapy (PDT) is safe and effective in the treatment of patients with actinic keratosis (AK). The aim of the study was to assess the efficacy, tolerability and cosmetic outcome of topical PDT in the treatment of AKs with three forms of photosensitizers: 5-Aminolevulinic acid hydrochloride (ALA-HCl), 5-Aminolevulinate methyl ester hydrochloride (MAL-HCl) and 5-Aminolevulinate phosphate (ALA-P). The formulations were applied onto selected scalp/face areas. Fluorescence was assessed with a FotoFinder Dermoscope 800 attachment. Skin areas were irradiated with Red Beam Pro+, Model APRO (MedLight GmbH, Herford, Germany). Applied treatments were assessed during the PDT as well as 7 days and 12 weeks after its completion. Ninety-four percent of patients rated obtained cosmetic effect excellent. The efficacy of applied PSs did not differ significantly. However, pain intensity during the PDT procedure was significantly lower in the area treated with ALA-P (5.8 on average) in comparison to the areas treated with ALA-HCl or MAL-HCl (7.0 on average on 0-10 scale). Obtained results show that ALA-P may undergo more selective accumulation than ALA-HCl and MAL-HCl. Our promising results suggest that PDT with the use of ALA-P in AK treatment may be an advantageous alternative to the already used ALA-HCl and MAL-HCl.

Spectroscopic Study of the Molecular Structure of the New Hybrid with a Potential Two-Way Antibacterial Effect.

Bacterial strains become resistant to almost all classes of antibiotics, which makes it necessary to look for new substitutes. The non-absorbable ciprofloxacin-biguanide bismuth complex, used locally, may be a good alternative to a conventional therapy. The purpose of this study was to study the structure of the proposed ciprofloxacin (CIP) -bismuth(III)-chlorhexidine (CHX) composite (CIP-Bi-CHX). The spectroscopic techniques such as UV-VIS (ultraviolet-visible) spectroscopy, FTIR (Fourier-transform infrared) spectroscopy and NMR (Nuclear Magnetic Resonance) spectroscopy were used for structure characterization of the hybrid compound. The performed analysis confirmed the presence of the two active components-CIP and CHX and revealed the possible coordination sites of the ligands with bismuth ion in the metallo-organic structure. Spectroscopic study showed that the complexation between Bi(III) and CIP occurs through the carboxylate and ketone groups of the quinolone ring, while CHX combines with the central ion via the biguanide moieties.

Characterization of Ciprofloxacin-Bismuth-Loaded Antibacterial Wound Dressing.

The research was focused on developing a potentially antibacterial wound dressing made of polyurethane foam and loaded with bismuth-ciprofloxacin (Cip-Bi). The Cip-Bi chemical structure was confirmed by Fourier transform infrared spectroscopic (FTIR) analysis. The sought after antibacterial wound dressing was obtained by modification of the raw dressing with an iodine or bromine solution and subsequently with a Cip-Bi hydrogel. The amount of Cip-Bi loaded into the dressing matrix was determined indirectly on the basis of the differences in Cip-Bi concentrations, before and after the modification process, and the determination was performed with the HPLC (high-performance liquid chromatography) method. The modified dressing was found to have a two-step release of Cip-Bi, a feature helpful in the treatment of locally infected wounds and prevention of secondary bacterial infection. The zone of inhibition test against the selected Gram-positive and Gram-negative bacteria confirmed the antibacterial activity of the Cip-Bi-modified dressing. Preliminary tests conducted so far have been indicative of the Cip-Bi dressing's relatively high activity against the tested organisms.

Application of FTIR Method for the Assessment of Immobilization of Active Substances in the Matrix of Biomedical Materials.

BACKGROUND: The purpose of the study was to demonstrate the usefulness of the Fourier transform infrared spectroscopy (FTIR) method for the evaluation of the modification process of biomaterials with the participation of active substances. METHODS: Modified catheter samples were prepared by activating the matrix with an acid, iodine, or bromine, and then immobilizing the active molecules. To carry out the modification process, the Fourier transform infrared-attenuated total reflectance (FTIR-ATR) method was used. RESULTS: FTIR analysis indicated the presence of the immobilized substances in the catheter matrix and site-specific reactions. CONCLUSION: We surmise that the infrared spectroscopic technique is an ideal tool for the assessment of the drug immobilization and the changes occurring in the course of the modification process.

Novel thiosemicarbazide derivatives with 4-nitrophenyl group as multi-target drugs: α-glucosidase inhibitors with antibacterial and antiproliferative activity.

A series of thiosemicarbazides with 4-nitrophenyl group was obtained in the reaction of carboxylic acid hydrazides with isothiocyanates. All compounds were checked for their antibacterial and antiproliferative activity. Our results have shown that derivatives 6-8 possessed antibacterial activity against S. aureus, S. epidermidis, S. mutans and S. sanguinis, moderate cytotoxicity and good therapeutic safety in vitro. Additionally, compounds 1 and 4 significantly inhibited A549, HepG2 and MCF-7 cell division. Moreover, PASS software indicated that newly obtained compounds are potential α-glucosidase inhibitors. This was confirmed by in vitro studies. To investigate the mode of interaction with the molecular target compounds were docked to glucose binding site of the enzyme and exhibited a similar binding mode as glucose.

Biological safety evaluation of the modified urinary catheter.

The purpose of this study was to evaluate in vitro safety of the novel tosufloxacin (TOS)-treated catheters with the prolonged antimicrobial activity. The test samples of silicone latex catheter were prepared by the immobilization of TOS on chitosan (CHIT)-coated catheter by means of covalent bonds and non-covalent interactions. Each step of the modification process of catheter surface was observed using ATR-Fourier transform infrared spectroscopy. In vitro cytotoxicity of the modified and unmodified catheters was assessed by direct and indirect tests in accordance with ISO standards using green monkey kidney (GMK) cell line. The MTT, lactate dehydrogenase activity (LDH), WST-8, Sulforhodamine B (SRB) test results and microscopic observation clearly indicated that unmodified silicone latex catheters decrease cell metabolic activity, act as a cytotoxic agent causing cell lysis and induce cell death through necrotic or apoptotic process. We suggest that chitosan coat with TOS immobilized limits leaching of harmful agents from silicone latex material, which significantly enhances survivability of GMK cells and therefore is quite a good protection against the cytotoxic effect of this material.

Prevention of biofilm formation on urinary catheters: comparison of the sparfloxacin-treated long-term antimicrobial catheters with silver-coated ones.

Urinary catheters are widely used for hospitalized patients and are often associated with high risk of urinary tract infection. The agar and broth diffusion tests, visual TTC (triphenyltetrazolium chloride) method, and confocal scanning laser microscopic (CSLM) observations have shown highly satisfactory antimicrobial and antibiofilm activity of the novel sparfoxacin (SPA)-treated urinary catheters compared with the controversial effectiveness of silver(Ag)-coated catheters against a background of untreated catheters used as controls. SPA-treated catheters were significantly less likely to become colonized (less than 0.01%; inner and outer surfaces against Escherichia coli and Staphylococcus aureus) than both silver-coated (from 0.01% to 39.3 %; outer surface against E. coli and inner surface against S. aureus, resp.) and untreated catheters (from 88.43% to 99.72%; outer and inner surfaces, resp., against S. aureus), and maintained their broad spectrum of antimicrobial and antibiofilm activity during storage for at least 6 months.

The cytotoxicity assessment of the novel latex urinary catheter with prolonged antimicrobial activity.

The purpose of this study was to evaluate the in vitro biocompatibility of the novel Sparfoxacin (SPA)-treated latex catheter with previously performed prolonged antimicrobial activity. Rectangular-shaped test samples of silicone latex catheter were fabricated according to patented procedure permitting the immobilization of SPA on heparin (HP)-coated catheter by means of mixed, covalent and non-covalent bonds. Samples subjected to cytotoxicity assay were divided into four groups: (1) the untreated catheter, (2) HP-coated catheter, (3) HP-coated catheter with SPA immobilized in low SPA concentration solution (SPA-L treated sample), and (4) high SPA concentration solution (SPA-H treated sample). Then the samples were placed directly into green monkey kidney (GMK) cell monolayer for 24 h. After the incubation period, cytotoxicity was determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The degree of cytotoxicity of each sample was evaluated according to the reference value represented by the control cells cultured without catheter sample. Statistical significance was determined by repeated t-test (P < 0.05). The cytotoxic effect of treated and untreated catheters was also estimated by microscopic observations of GMK cells morphological changes. SPA-treated catheters demonstrated high survival rates in MTT assay (>93%) on the contrary to the untreated catheters (6.13%) and HP-coated catheters (80.90%). Moreover, microscopic observation of GMK cells exposed to SPA-treated samples revealed no morphological changes and no cell growth reduction. We suggest that SPA-treated latex catheters are biofilm formation resistant (as we revealed in our previous work), considerably less toxic than untreated ones, and can be undoubtedly used in urological practice.

Characterization of the developed antimicrobial urological catheters.

Antimicrobial urological catheters were developed by the mixed, covalent and non-covalent binding of sparfloxacin (SPA) to heparin (HP) film which was first deposited on the latex surface of biomaterial. The SPA-HP modified surface was characterized by SEM analysis and ATR-Fourier transform infrared spectroscopy. For the antimicrobial prevention, SPA as an antibiotic with a broad antimicrobial spectrum was chosen. Antimicrobial activity of antibiotic-modified catheter against Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli strains was assessed using various procedures. On the basis of the inhibition zone and diffusion assays the efficacy around the modified catheters was demonstrated. The test samples clearly showed an antibacterial activity against all tested bacterial stains for a least one month. Inhibition of the bacterial colonization on the modified catheter surface was proved by the biofilm test. Antimicrobial activity of SPA-treated catheter surface was also quantitatively evaluated according to standard method of ISO based on JIS. The R-values were found to be higher than 3.8. The performed research indicated that the immobilization of SPA on the catheter surface by means of the mixed-type bonds resulted in stable antibacterial protection of the urological catheters for a long time.

Validated HPTLC methods for quantification of mexiletine hydrochloride in a pharmaceutical formulation.

Two simple, accurate, and precise HPTLC methods have been established for the determination of mexiletine hydrochloride, an antiarrhythmic agent, in Mexicord capsules. Analyses were performed in horizontal chambers on RP C18F254s and normal-phase amino (NH2) HPTLC precoated plates with the mobile phases tetrahydrofuran-citrate buffer, pH 4.45 (3 + 7, v/v) and chloroform-tetrahydrofuran-hexane-ethylamine (3 + 2 + 5 + 0.1, v/v/v/v), respectively. The plates were developed for a distance of 40 mm in both cases. Densitometric measurements were achieved in the UV mode at 217 nm based on peak areas with semilinear calibration curves (R2 > or = 0.97) in the concentration range 0.5-8.0 microg/spot for the NH2 and C18 HPTLC methods. The elaborated chromatographic methods were validated in accordance with International Conference on Harmonization guidelines in terms of linearity, accuracy (99.64% for NH2 and 99.53% for C18), precision (intraday RSD 1.16 and 2.71%, respectively), sensitivity (LOD 0.1 microg/spot for both systems), and specificity.

Covalent coating of hydroxyapatite by keratin stabilizes gentamicin release.

A novel hybrid hydroxyapatite (HAP) matrix, covalently coated with rarely applied, hardly degradable keratin and effectively modified by gentamicin immobilized in mixed-type mode (via interactions of diverse strength), was created. This hybrid showed a remarkably high drug immobilization yield and the most sustainable antibiotic release among all tested composites. It was also able to inhibit bacterial growth, both in surrounding liquid and on matrix surface, much longer (for at least 121 days of experiment) than analogous gelatin-modified and nonmodified matrices. Gentamicin-keratin-coated-HAP granules were nontoxic to human osteoblasts and enabled their proliferation with a rate similar as noncoated HAP. Presence of keratin on HAP granules seemed to slightly enhance the osteoblast proliferation. The results indicate that newly created HAP hybrid with covalently immobilized keratin and gentamicin--nontoxic and osteoblast-friendly--is a promising biomaterial of significantly prolonged antibacterial activity.

Simultaneous separation of 14 antiarrhythmic drugs and determination of mexiletine and flecainide by capillary zone electrophoresis.

A method using capillary zone electrophoresis was developed for the simultaneous separation of 14 antiarrhythmic drugs belonging to various classes. The drugs are separated on a fused-silica capillary, 90 cm x 75 microm (72 cm effective length), with phosphate and acetate buffers as background electrolytes and UV detection at 217 nm. The effects of buffer pH, temperature, and applied voltage on the migration of the drugs were studied. The pH was found to be the most significant factor determining effective separation. The antiarrhythmic compounds are completely separated within a relatively short time (< 7 min) by using 70 mM phosphate buffer at pH 7.91, an applied voltage of 28 kV, and a temperature of 32 degrees C. Mexiletine (MEX) and flecainide (FLE) were quantified under conditions of the optimum separation. The calibration graphs were constructed over the concentration range of 4.0-14.0 microg/mL for both drugs with good correlation (r > or = 0.9999). Detection and quantitation limits were found to be 0.5 and 1.5 microg/mL for FLE and 0.7 and 2.1 microg/mL for MEX, respectively. The proposed method was used for the determination of both drugs in their commercial forms with satisfactory precision (relative standard deviations of 0.36-1.21% for FLE and 0.78-1.66% for MEX) and accuracy (relative standard errors of 0.13-1.17% for FLE and 0.35-1.18% for MEX).

Amikacin-loaded vascular prosthesis as an effective drug carrier.

Strong covalent immobilization of amikacin on Uni-Graft((R)) DV straight vascular prostheses made of gelatine-sealed poly(ethylene terephthalate) fibres was performed according to procedure described in the Polish Patent No. P-358934. The concentrations of amikacin in sample solutions were estimated either by HPLC or by UV spectroscopy method previously optimized for amikacin measurements. A high correlation was found between these two methods. It was found that the antibiotic was bound in mixed-type way via three types of interactions: strong covalent bonds (dominating amount: 81.84%) and weak interactions: physical adsorption and ionic bonds (18.19%). Even when total amount of physically and ionically attached drug has been released, the remaining covalently bound amount still locally protected the prostheses in vitro against bacteria. The release test was conducted in PBS at pH 7.4 at 37 degrees C and showed that about 15% of total drug amount was eluted from the matrix during the first 7 days of shaking, then no more antibiotic was released. It suggested that about 85% of amikacin attached to prosthesis modified in mixed-type mode was bound via covalent interactions. A bacterial inhibition test on Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 showed inhibition of growth for all strains at low inoculum concentrations up to 30 days as well as high inoculum concentration for E. coli. At high concentrations of S. aureus and P. aeruginosa, the modified prostheses showed slight bacteriostatic effect since 10th day of experiment. Amikacin-modified vascular prostheses might therefore be protected against bacterial infection locally, without long-lasting drug release to human system.

Determination of nifedipine in serum of women in preterm labor by high-performance liquid chromatography with diode array detection.

Nifedipine (Nif) is widely used in treating cardiovascular disorders (especially hypertension) and for inhibiting preterm labor. A fully validated selective high-performance liquid chromatographic method with diode array detection, using solid-phase extraction, was developed for the determination of Nif in human serum. To assess specificity, Nif and its degradation products were separated on a Purospher RP-18 (5 microm, 125 x 4 mm) column plus a LiChrospher 100 RP-18 (5 microm, 4 x 4 mm) precolumn with a mobile phase of methanol-10 mM aqueous trifluoroacetic acid, pH 7.3 (57 + 43, v/v); chromatographic separation was followed by UV detection at 238 nm. For toxicological analysis, Nif in the presence of other calcium-channel antagonist drugs was identified under optimum chromatographic conditions. The calibration graph was constructed over the concentration range of 12.5-400 ng/mL in serum with good correlation (r = 0.9956). This method was not subject to interference by other plasma components and was successfully applied to the assay of Nif in spiked human serum and in serum of women in preterm labor after sublingual administration of 30 mg Nif per day divided into 3 equal doses. The mean recovery based on the ratio of the slopes of serum and mobile phase standard curves was 96.5%. The detection and quantification limits of the drug in spiked human serum were found to be 6 and 17.5 ng/mL, respectively. Validation of the method demonstrated good intraday and interday precision, which ranged from 2.18 to 6.67% and from 6.52 to 11.93%, respectively.