Stability of selected chlorinated thiazide diuretics

Drug administration via feeding tubes-a procedure that carries risks: systematic identification of critical factors based on commonly administered drugs in a cohort of stroke patients

PURPOSE

Drug administration via feeding tubes is considered a process with many uncertainties. This review aimed to give a comprehensive overview of data available on feeding tube application and to carry out risk assessments for drug substances commonly administered to stroke patients.

METHODS

Drugs frequently administered via feeding tubes were identified through a retrospective analysis of discharge letters from a stroke unit. Physicochemical, pharmacokinetic, and stability properties of these drugs and data on drug-enteral nutrition interactions were systematically searched for in the European Pharmacopoeia, Hagers Handbook of Pharmaceutical Practice, Birchers clinical-pharmacological data compilation, and the Martindale Complete Drug Reference, as well as from databases including DrugBank, DrugDex, PubChem, Google Scholar, and PubMed.

RESULTS

Of the drugs most commonly administered via feeding tubes in the present stroke patient cohort, bisoprolol, candesartan, and ramipril could be considered the least critical due to their overall favourable properties. Acetylsalicylic acid, amlodipine, hydrochlorothiazide, omeprazole and esomeprazole, simvastatin, and torasemide pose risks based on pH or light-dependent instability or proposed food effects. The most critical drugs to be administered via feeding tubes are considered to be furosemide, levodopa, and levothyroxine as they show relevant instabilities under administration conditions and substantial food effects; the latter two even possess a narrow therapeutic index. However, little information is available on drug-tube and drug-formula interactions.

CONCLUSION

Feeding tube administration of medications turned out to be a highly complex process with several unmet risks. Therefore, investigations that systematically assess these risk factors using clinically relevant model systems are urgently needed.

Development of sustained-release drug-loaded intravesical inserts via semi-solid micro-extrusion 3D-printing for bladder targeting

Discontinued treatment and non-adherence are oftentimes weaknesses of common first-line drug therapy against bladder conditions due to their negative side-effects. To overcome these limitations and increase patients' quality of life, intravesical therapies are continuously being explored. 3D-printing offers the possibility of freely tailoring drug delivery systems to manufacture indwelling devices that may administer drugs locally over an extended time and avoiding frequently repeated administrations while minimizing systemic side-effects. In the present work, pressure-assisted micro syringe printing has been used to develop flexible drug-loaded inserts applicable via common urinary catheter that can remain up to several weeks inside the urinary bladder. Three APIs (lidocaine hydrochloride, trospium chloride (TrCl) and hydrochlorothiazide (HCT)) with different properties and solubilities were investigated for their applicability together with two different pharmaceutical polymers (biodegradable polycaprolactone (PCL) and non-degradable ethylene vinyl acetate copolymer (EVA)). The fastest release was thereby observed for the PCL-TrCl combination and the slowest for EVA-HCT depending on the API's solubility in the dissolution medium and formation of API clusters within the matrix. It was further demonstrated that the dissolution profile could be modified by adapting drug loads between 5 and 15 % or the geometry of the printed inserts indicating the possibility of tailoring release profiles.

Determination of Hydrochlorothiazide and Two Major Degradation Products by Stability Indicating High Performance Liquid Chromatography

Background:

Hydrochlorothiazide (HCTZ) is a thiazide diuretic which comprises two sulfonamide groups. The literature is not clear regarding the identification of the chromatographic peaks of its two major related substances: chlorothiazide and 4-amino-6-chloro-1,3-benzenedisulfonamide (DSA).

Methods:

In the present study, a simple, sensitive, and selective HPLC method was developed and validated for the assay of HCTZ, Chlorothiazide and DSA. The method was carried out on a C18 column, maintained at 40ºC. The mobile phase was composed of monobasic potassium phosphate buffer 0.02M pH 3.0/acetonitrile/methanol (82:9:9, v/v/v), run at a flow rate of 1.0 mL/min, and UV detection at 270 nm.

Results:

All related compounds including processing impurities and degradants from stressed samples were well separated from each other. The performance of this method was validated in accordance to the ICH guidelines and included specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness.

Conclusion:

Based on the results, the HCTZ degradation pathway was proposed and the validated HPLC method was successfully applied to the quantitative analysis of HCTZ in pharmaceutical formulations, contributing to improve quality control, to assure therapeutic efficacy and to clarify the literature.

Crystal structure and Hirshfeld surface analysis of N-(2-(N-methylsulfamoyl)phenyl)formamide: Degradation product of 2-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide

The hydrolysis of 2-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide (2) during crystallization under humidity (85 %) conditions, lead to N-(2-(N-methylsulfamoyl)phenyl)formamide as second step hydrolysis product, identified in the proposed degradation mechanism. Crystal of N-(2-(N-methylsulfamoyl)phenyl)formamide C8H10N2O3S (4), was obtained and characterized. The molecular structure determination was carried out with MoKα X-ray and data measured at 100 K. The compound 4 crystallizes in triclinic P͞1 space group with unit cell parameters a = 4.8465(4) Å, b = 8.1942(9) Å, c = 11.8686(13) Å, α = 77.080(4)°, β = 82.069(4)°, γ = 80.648(4)°, V = 450.76 (8) Å3 and Z = 2. The crystal structure is stabilized by intramolecular N-H···O and intermolecular C-H···O and N-H···O hydrogen bonds that extended as infinite 1D chain along [100]. Stabilization is also ensured by oxygen-π stacking interaction between the aromatic ring and oxygen of the sulfonamide group. The analysis of intermolecular interactions through the mapping of dnorm and shape-index revel that the most significant contributions to the Hirshfeld surface 40.6 and 33.9% are from H···H and O···H contacts, respectively.

Multi-scale optimisation vs. genetic algorithms in the gradient separation of diuretics by reversed-phase liquid chromatography

Multi-linear gradients are a convenient solution to get separation of complex samples by modulating carefully the gradient slope, in order to accomplish the local selectivity needs for each particular solute cluster. These gradients can be designed by trial-and-error according to the chromatographer experience, but this strategy becomes quickly inappropriate for complex separations. More evolved solutions imply the sequential construction of multi-segmented gradients. However, this strategy discards part of the search space in each step of the construction and, again, cannot deal properly with very complex samples. When the complexity is too large, the only valid alternative for finding the best gradient is the use of global search methods, such as genetic algorithms (GAs). Recently, a new global approach where the level of detail is increased along the search has been proposed, namely Multi-scale optimisation (MSO). In this strategy, cubic splines are applied to build intermediate curves to define any arbitrary solvent variation function. Subdivision schemes are used to generate the cubic splines and control their level of detail. The search was subjected to a number of restrictions, such as avoiding long elution and favouring a balanced peak distribution. The aim of this work is evaluating and comparing the results of GAs and MSO. Both approaches were tested with a set of 14 diuretics and probenecid, eluted with acetonitrile-water mixtures using a C18 column. Satisfactory baseline resolution was obtained with an analysis time of 15-16 min. We found that GAs optimisation offered results equivalent to those provided by MSO, when the penalisation parameters were included in the cost function.

Synthesis, molecular properties and comparative docking and QSAR of new 2-(7-hydroxy-2-oxo-2H-chromen-4-yl)acetic acid derivatives as possible anticancer agents

Novel coumarin amino acid derivatives were synthesized. The structure of synthesized compounds has established on basis of different spectral data. The optimization geometry, frontier molecular orbitals (FMOs), thermodynamic parameters and chemical reactivity, were discussed using DFT\B3LYP by 6-311G* basis set, to identify a clear view for inter and intramolecular interaction of tested compounds. The molecular electrostatic potential (MEP) has plotted to investigate a recognition manner of synthesized compounds upon COX-2 receptor. All tested compounds showed a promising (NLOs) nonlinear optical properties. Bond dissociation energy (BDE) has studied to investigate a potency of these molecules against autoxidation mechanism Polynomial molecular docking logarithms have performed into the COX-2 active site for tested compounds. The docking protocol that has low RMSD has selected for discussion the binding affinity. The compounds with a high docking score 3,4,6-8,10 and 11 were selected for additional study against ADMET insilico, which showed that these compounds are a good oral bioavailability without observed carcinogenesis affect. The compounds (3,4,6-8,10 and 11) which that passed through docking and ADMET profile have examined their potency against (MCF-7) breast cancer cell in vitro. The compound 7 showed a highest potency against MCF-7 with IC₅₀ value 0.39 μM. The QSAR model has created to discover the structural necessity inhibition of MCF-7. The derived QSAR model has a statistically significant with a good predictive power.

Photocatalytic degradation of 4-amino-6-chlorobenzene-1,3-disulfonamide stable hydrolysis product of hydrochlorothiazide: Detection of intermediates and their toxicity

In this work we have investigated in details the process of degradation of the 4-amino-6-chlorobenzene-1,3-disulfonamide (ABSA), stable hydrolysis product of frequently used pharmaceutical hydrochlorothiazide (HCTZ), as one of the most ubiquitous contaminants in the sewage water. The study encompassed investigation of degradation by hydrolysis, photolysis, and photocatalysis employing commercially available TiO₂ Degussa P25 catalyst. The process of direct photolysis and photocatalytic degradation were investigated under different type of lights. Detailed insights into the reactive properties of HCTZ and ABSA have been obtained by density functional theory calculations and molecular dynamics simulations. Specifically, preference of HCTZ towards hydrolysis was confirmed experimentally and explained using computational study. Results obtained in this study indicate very limited efficiency of hydrolytic and photolytic degradation in the case of ABSA, while photocatalytic degradation demonstrated great potential. Namely, after 240 min of photocatalytic degradation, 65% of ABSA was mineralizated in water/TiO₂ suspension under SSI, while the nitrogen was predominantly present as NH₄⁺. Reaction intermediates were studied and a number of them were detected using LC-ESI-MS/MS. This study also involves toxicity assessment of HCTZ, ABSA, and their mixtures formed during the degradation processes towards mammalian cell lines (rat hepatoma, H-4-II-E, human colon adenocarcinoma, HT-29, and human fetal lung, MRC-5). Toxicity assessments showed that intermediates formed during the process of photocatalysis exerted only mild cell growth effects in selected cell lines, while direct photolysis did not affect cell growth.

A validated stability-indicating LC method for simultaneous determination of quinapril and hydrochlorothiazide in pharmaceutical samples

A stability-indicating liquid chromatographic method was developed and validated for simultaneous determination of quinapril and hydrochlorothiazide in drug substances and dosage forms. Chromatographic separation of quinapril, hydrochlorothiazide and its degradation products was achieved on a RP-18 column, using acetonitrile and phosphate buffer (pH 4.6) as mobile phase in a gradient mode and detection at 216 nm. Stress testing was performed under hydrolytic, oxidative, thermal and photolytic conditions. The degradation products were well resolved from main peaks, proving the stability-indicating power of the method. The assay was linear for quinapril and hydrochlorothiazide concentrations of 40–200 µg mL−1 and 25–125 µg mL−1, respectively. The developed method was selective, accurate and precise for quinapril and hydrochlorothiazide determination. This method was used to quantify both drugs in combined commercial tablets. The results showed that the proposed method was found to be suitable for quantitative determination and the stability study of quinapril and hydrochlorothiazide in pharmaceutical samples.