Studies on the Mechanism of Primary Nucleation of Ciprofloxacin Hydrochloride Monohydrate

A general expression for the relationship between induction periodand supersaturation was developed based on polynuclear approach.Different mechanism of primary nucleation in solution can beillustrated by the expression. The results of induction perioddetermined by laser scattering method shows that the crystallizationof ciprofloxacin hydrochloride monohydrate in water/ethanol oraqueous solution is by the mechanism of primary nucleation followedby one-dimensional diffusion growth, and then on-dimensionalcontinuous or 'birth and spread' growth on crystal face. The growthmechanism on the crystal face is affected by temperature and solvent.

Degradation of ciprofloxacin hydrochloride in a multiphase mixed system by subaquatic gas-liquid discharge plasma

In recent years, antibiotic pollution has become a serious threat to human health. In this study, a gas-liquid discharge plasma is developed to degrade ciprofloxacin hydrochloride in a multiphase mixed system containing inorganic and organic impurities. The discharge characteristics are analyzed by diagnosing the applied voltage and discharge current waveforms, as well as the optical emission spectra. The work investigates how degradation efficiency is affected by applied voltage, gas flow rate, treatment time, initial concentration as well as the addition of γ-Al_(2)O_(3) pellets and peanut straw. After 70 min, the degradation efficiency of ciprofloxacin hydrochloride in the multiphase mixed system reached 99.6%. Its removal efficiency increases as the initial concentration decreases and the applied voltage increases. Besides, there is still a good degradation efficiency of ciprofloxacin hydrochloride with the addition of peanut straw.The degradation mechanism of ciprofloxacin hydrochloride is investigated through the analysis of degraded intermediates and reactive species.

Determination of Ciprofloxacin Hydrochloride in Pharmaceutical Preparation and Biological Fluid by Rayleigh Light Scattering Technique

A highly sensitive and simple Rayleigh light scattering （RLS） method for the determination of ciprofloxacin hydrochloride has been developed. Ciprofloxacin hydrochloride （CPFH） reacted with tetraphenylboron sodium（TPB） to form an ion-association complex in pH 5.31 aqueous solution, which resulted in a significant enhancement of the RLS intensity, which was linear with the concentration of CPFH in the range of 12.7-419 ng·mL^-1. The limit of detection for CPFH was 6.99 ng·mL^-1. The method is simple, highly sensitive and selective within a wide linear range. Applying this method for the determination of ciprofloxacin hydrochloride in pharmaceutical preparations and biological fluids obtained satisfactory results.

Simple and cost-effective determination of ciprofloxacin hydrochloride by electrical micro-titration

By employing an electrical micro-titration system, in which a capacitively coupled contactless conductivity detector（C^4D） was used to monitor the reaction process in real time, herein a novel method for determining ciprofloxacin hydrochloride（CIPHCl） was developed for the first time. Mode 1： Standard CIPHCl solutions at different concentrations were loaded into reaction cells, respectively, and were titrated with standard Ag^＋. Upon the titration, the formation of a precipitate alters the number of ions in the solution, raising the change of conductivity, which was monitored by a special C-4 D to construct a titration curve. The endpoint of the titration was located from the peak of the curve. Between the elapsed time and the initial concentration of titrand, a linear relationship was established over the range of2.0–8.0 mmol/L. Mode 2： Standard Fe^3＋ took the place of Ag^＋, and was used as titrant to recognize ciprofloxacin contributed to the formation of complexation, which also resulting a change of solution conductivity. Under optimized conditions, a working range of 1.0–5.0 mmol/L CIPHCl was found. Because the reaction solutions were isolated from the working electrodes, this pioneer work shows significant simplicity and cost-effectiveness, by eliminating the requirements for detector exchange/renewal between different measurements, and by involving no auxiliary chemicals. Both of the two approaches were applied successfully to determine CIPHCl in tablet samples. And the results were in good agreement with those obtained by reference method.

Thermal Behaviour of Some New Polyoxometalate Complexes of Ciprofloxacin with Keggin-type Heteropoly Acids

Four polyoxometalate complexes, (CPFX·HCl)_3H_4SiW_~12 O_~40 , (CPFX·HCl)_3H_3PW_~12 O_~40 , (CPFX·HCl)_3H_3PMo_~12 O_~40 and (CPFX·HCl)_4H_4SiMo_~12 O_~40 , were prepared from ciprofloxacin hydrochloride(CPFX·HCl) reacting with H_nXM_~12 O_~40 ·nH_2O(X=P,Si; M=W,Mo) in an aqueous solution, and characterized by elemental analysis, IR spectrometry and TG-DTA. The IR spectrum confirms the presence of Keggin-type anions of heteropoly acids and the characteristic functional groups of ciprofloxacin. The TG/DTA curves show that their thermal decomposition is a multi-step process including simultaneous collapse of the Keggin-type structure. At first, these compounds had a mass loss of water molecules, then several other mass losses occured due to the decomposition of ciprofloxacin hydrochloride and its fragments with the degradation of Keggin anions. The end product of decomposition is the mixture of WO_3(or MoO_3) and SiO_2(or P_2O_5), identified by X-ray diffraction and IR spectroscopy. The possible thermal decomposition mechanisms of these complexes are proposed. This study exemplified that the thermal stability of the complexes containing tungsten is much better than that of the complexes containing molybdenum.

Interaction of cetyltrimethylammonium bromide with drug in aqueous/electrolyte solution:A combined conductometric and molecular dynamics method study

Interaction between beta-lactum antibiotic drug ciprofloxacin hydrochloride(CFH)and cationic surfactant cetyltrimethylammonium bromide(CTAB)was performed conductometrically in aqueous as well as in the occurrence of different salts(NaCl,KCl as well as NH_4Cl)over the temperature range of 298.15–323.15 K at the regular interval of 5 K.CFH drug has been suggested for the treatment of bacterial infections such as urinary tract infections and acute sinusitis.A clear critical micelle concentration(CMC)was obtained for pure CTAB as well as(CFH+CTAB)mixed systems.The decrease in CMC values of CTAB caused by the addition of CFH reveals the existence of the interaction between the components and therefore it is the indication of micelle formation at lower concentration of CTAB and their CMC values further decrease in attendance of salts.A nonlinear behavior in the CMC versus T plot was observed in all the cases.The ΔG_m^0 values are found to be negative in present study systems demonstrated the stability of the solution.The values of ΔH_m^0 and ΔS_m^0 reveal the existence of hydrophobic and electrostatic interactions between CFH and CTAB.The thermodynamic properties of transfer for the micellization were also evaluated and discussed in detail.Molecular dynamic simulation disclosed that environment of water and salts have impact on the hydrophobic interaction between CFH and CTAB.In water and salts,CTAB adopts spherical micelle in which charged hydrophilic groups are interacted with waters whereas hydrophobic tails form the core of the micelle.This hydrophobic core region is highly conserved and protected.In addition,micelle formation is more favorable in aqueous Na Cl solution than other solutions.

High-throughput measurements of ciprofloxacin, clomipramine and fexofenadine hydrochlorides with an 8-channel electrical titrator

High-throughput measurements of ciprofloxacin, clomipramine and fexofenadine hydrochlorides were performed by employing an automatic 8-channel electrical titrator. Silver nitrate （AgNO3） and sodium tetraphenylborate （NaTPB） were used as titrants. When AgNO3 was used for measuring the drugs in pure form, recoveries were 97.6%-102.0% with RSD values ≤1.0%; for measuring them in pharmaceutical formulations, recoveries were 96.6%-99.1% with RSD values ≤1.0%. Batch samples of eight could be measured simultaneously and maximally 30 measurements per minute could be completed. When NaTPB was used for measuring the drugs in pure form, the recoveries were 96.8%-102.6% with RSD values 〈0.8%; for measuring them in pharmaceutical formulations, the recoveries were 97.5%-102.7% with RSD values ≤0.9%. For all analyses, no auxiliary devices or chemicals were needed and there was no requirement for changing or cleaning working electrodes between measurements. The efficiency, accuracy and precision of the proposed method make it an alternative for routine quality control analyses.

Growth response and toxic effects of three antibiotics on Selenastrum capricornutum evaluated by photosynthetic rate and chlorophyll biosynthesis

The effects of three types of antibiotics （erythromycin,ciprofloxacin and sulfamethoxazole） on the photosynthesis of freshwater algae,Selenastrum capricornutum Printz,were investigated by determining the growth rate,chloroplast pigments content,seven main precursors （including δ-aminolevulinic acid,porphobilinogen,uroporphyrinogen III,coproporphyrinogen III,protoporphyrin IX,Mg-proporphyrin IX and protochlorophyllide）,and photosynthetic rate during chlorophyll biosynthesis.The antibiotics significantly decreased the growth rate,chlorophyll content,and photosynthetic rate.Erythromycin induced a decreasing effect at a concentration of 0.06 mg/L,while ciprofloxacin and sulfamethoxazole achieved the same results at concentrations higher than 1.5 mg/L.Only erythromycin significantly inhibited chlorophyll biosynthesis,which indicated that it was considerably more toxic to S.capricornutum than ciprofloxacin and sulfamethoxazole,and may pose a high potential risk to aquatic ecosystems.