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1.
The polyethylene glycol (PEG) treatment of ciprofloxacin-Indion 234 complex was aimed to retard rapid ion exchange drug release
at gastric pH. Ciprofloxacin loading on Indion 234 was performed in a batch process, and the amount of K+ in Indion 234 displaced by drug with time was studied as equilibrium constant KDM. Drug-resin complex (DRC) was treated with aqueous PEG solution (0.5%–2% wt/vol) of different molecular weights (MWs) for
2 to 30 minutes. The PEG-treated ciprofloxacin-Indion 234 complex was evaluated for particle size, water absorption time,
and drug release at gastric pH. During drug loading on Indion 234, the equilibrium constant (KDM) increased rapidly up to 20 minutes with efficient drug loading. Increased time of immersion of the drug resinate in PEG
solutions significantly retained higher size particles upon dehydration. The larger DRC particles showed longer water absorption
times owing to compromised hydrating power. The untreated DRC showed insignificant drug release in deionized water; while
at gastric pH, ciprofloxacin release was complete in 90 minutes. A trend of increased residual particle size, proportionate
increase in water absorption time, and hence the retardation of release with time of immersion was evident in PEG-treated
DRC. The time of immersion of DRC in PEG-treated DRC. The time of immersion of DRC in PEG solution had predominant release
retardant effect, while the effect of molecular weight of PEG was insignificant. Thus, PEG treatment of DRC successfully retards
ciprofloxacin ion exchange release in acidic pH. 相似文献
2.
The purpose of this research was to obtain directly compressible agglomerates of ibuprofen-paracetamol containing a desired
ratio of drugs using a crystallo-co-agglomeration technique. Crystallo-co-agglomeration is an extension of the spherical crystallization
technique, which enables simultaneous crystallization and agglomeration of 2 or more drugs or crystallization of a drug and
its simultaneous agglomeration with another drug or excipient. Dichloromethane (DCM)-water system containing polyethylene
glycol (PEG) 6000, polyvinyl pyrollidone, and ethylcellulose was used as the crystallization system. DCM acted as a good solvent
for ibuprofen and bridging liquid for agglomeration. The process was performed at pH 5, considering the low solubility of
ibuprofen and the stability of paracetamol. Loss of paracetamol was reduced by maintaining a low process temperature and by
the addition of dextrose as a solubility suppressant. The agglomerates were characterized by differential scanning calorimetry,
powder x-ray diffraction (PXRD), and scanning electron microscopy and were evaluated for tableting properties. The spherical
agglomerates contained an ibuprofen-paracetamol ratio in the range of 1.23 to 1.36. Micromeritic, mechanical, and compressional
properties of the agglomerates were affected by incorporated polymer. The PXRD data showed reduction in intensities owing
to dilution and reduced crystallinity. Thermal data showed interaction between components at higher temperature. Ethylcellulose
imparted mechanical strength to the agglomerates as well as compacts. The agglomerates containing PEG have better comparessibility
but drug release in the initial stages was affected owing to asperity melting, yielding harder compacts. The agglomeration
and properties of agglomerates were influenced by the nature of polymer. 相似文献
3.
Conclusion Hydrolyzed gelatins (Byco-A, Byco-O and Byco-C), when used as binders, yielded soft, uniform granules with good flow properties.
As the molecular weight and viscosity of hydrolyzed gelatins increased, the compressibility of granules decreased and their
compactability increased. The balance between compressibility and compactability of granules may be achieved by careful monitoring
of the molecular weight of hydrolyzed gelatins that can serve as potential binders. 相似文献
4.
Shelke SM Bhosale SH Dash RC Suryawanshi MR Mahadik KR 《Bioorganic & medicinal chemistry letters》2011,21(8):2419-2424
Monoamine oxidase-A (MAO-A) inhibitors are of particular importance in the treatment of depressive disorders. Herein described is pharmacophore generation and atom-based 3D-QSAR analysis of previously reported pyrrole based MAO-A inhibitors in order to get insight into their structural requirements responsible for high affinity. The best pharmacophore model generated consisted of four features DHHR: a hydrogen bond donor (D), two hydrophobic groups (H) and an aromatic ring (R). Based on model generated, a statistically valid 3D-QSAR with good predictability was developed. Derived pharmacophore was used as a query to search Zinc ‘clean drug-like’ database. Hits retrieved were passed progressively through filters like fitness score, predicted activity and docking scores. The survived hits present new scaffolds with a potential for MAO-A inhibition. 相似文献
5.
The purpose of this research was to evaluate in vitro transnasal sustained-release ability of sorbitan monostearate (SMS)
organogels in isopropyl myristate (IM). Organogels were prepared containing SMS (2.5%–20%) and water (5%–25%) in IM and analyzed
microscopically for phase behavior. The effect of Tween surfactants on gel strength and in vitro nasal diffusion of propranolol
is reported. The in vitro nasal release retardant effect of SMS and Tween 20 was investigated using factorial design. The
microscopic changes in structure of organogel during in vitro nasal diffusion were studied. The water-holding capacity of
SMS organogels in IM increased with SMS concentration. The release retardant effect with incorportation of cosurfactant was
of the order of Tween 80> Tween 60> Tween 20. Gel strengthening and increased viscosity were evident with increased concentration
of SMS and Tween 20. The 3-dimensional network of SMS molecules controls the diffusional drug release. The organogel system
on nasal mucosa during diffusion is dynamic in nature and changes continuously with the time of diffusion. The water penetration
in the organogel network results in percolation and emulsification of organogel, thus affecting the release. Organogels provided
an effective barrier for diffusion of propranolol. The surface epithelium lining and the granular cellular structure of treated
nasal mucosa were intact. 相似文献
6.
Samrat Chakraborty Abhijit Khopade Chandrakant Kokare Kakasaheb Mahadik Balasaheb Chopade 《Journal of Molecular Catalysis .B, Enzymatic》2009,58(1-4):17-23
In this study, we have reported novel α-amylase enzyme from less extensively studied marine Streptomyces sp. D1. Enzyme production was determined by using media containing 2% sucrose, 0.35% peptone and 0.15% of malt extract. Optimum temperature for enzyme production and activity was found to be 45 °C and enzyme retained almost 50% of its activity at 85 °C. Enzyme activity was also retained in presence of commercially available detergent and oxidizing agents. The partially purified enzyme from strain D1 exhibited specific activity of 113.64 U/mg protein that corresponds to 2.8-fold purification. SDS-PAGE and zymogram activity staining showed a single band equal to molecular mass of 66 kDa. The reported enzyme may have wide spread application for detergent and pharmaceutical industry. 相似文献
7.
A new methodology based on a metabolic control analysis (MCA) approach is developed for the optimization of continuous cascade bioreactor system. A general framework for representation of a cascade bioreactor system consisting of a large number of reactors as a single network is proposed. The kinetic and transport processes occurring in the system are represented as a reaction network with appropriate stoichiometry. Such representation of the bioreactor systems makes it amenable to the direct application of the MCA approach. The process sensitivity information is extracted using MCA methodology in the form of flux and concentration control coefficients. The process sensitivity information is shown to be a useful guide for determining the choice of decision variables for the purpose of optimization. A generalized problem of optimization of the bioreactor is formulated in which the decision variables are the operating conditions and kinetic parameters. The gradient of the objective function to be maximized with respect to all decision variables is obtained in the form of response coefficients. This gradient information can be used in any gradient-based optimization algorithm. The efficiency of the proposed technique is demonstrated with two examples taken from literature: biotransformation of crotonobetaine and alcohol fermentation in cascade bioreactor system. 相似文献
8.
Sharvil S. Patil Edakkal Venugopal Suresh Bhat Kakasaheb R. Mahadik Anant R. Paradkar 《AAPS PharmSciTech》2015,16(5):1153-1159
The present work explores inner structuration of in situ gelling system consisting of glyceryl monooleate (GMO) and oleic acid (OA). The system under study involves investigation of microstructural changes which are believed to govern the pharmaceutical performance of final formulation. The changes which are often termed mesophasic transformation were analysed by small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), rheology and plane polarised light (PPL) microscopy. The current work revealed transformation of blank system from W/O emulsion to reverse hexagonal structure upon addition of structural analogues of ibuprofen. Such transformations are believed to occur due to increased hydrophobic volume within system as probed by SAXS analysis. The findings of SAXS studies were well supported by DSC, rheology and PPL microscopy. The study established inverse relationship between log P value of structural analogues of ibuprofen and the degree of binding of water molecules to surfactant chains. Such relationship had pronounced effect on sol–gel transformation process. The prepared in situ gelling system showed sustained drug release which followed Higuchi model.KEY WORDS: flurbiprofen, hexagonal phase, ibuprofen, ketoprofen, liquid crystal, sustained drug release 相似文献
9.
The purpose of this research work was to obtain directly compressible agglomerates of ibuprofen with talc by a novel crystallo-co-agglomeration
(CCA) technique, which is an extension of spherical crystallization. Ibuprofen-talc agglomerates were prepared using dichloromethane
(DCM)-water as the crystallization system. DCM acted as a good solvent for ibuprofen as well as a bridging liquid for agglomeration
of crystallized drug with talc. The agglomerates were characterized by differential scanning calorimetry, powder X-ray diffraction,
and scanning electron microscopy and were evaluated for tableting properties and for drug release. The process yielded spherical
agglomerates containing ∼95% to 96% wt/wt of ibuprofen. Agglomerates containing talc showed uniform distribution of hydroxypropylmethylcellulose
and decreased crystallinity, and deformed under pressure. The miniscular form of ibuprofen and the hydrophobicity of talc
governed the drug release rate. The batch containing a higher proportion of talc showed zeroorder kinetics and drug release
was extended up to 13 hours. The CCA technique developed in this study is suitable for obtaining agglomerates of drug with
talc as an excipient. 相似文献
10.
Conclusion The results of this investigation showed that spray drying of CH and HG resulted in free-flowing powder, which exhibited improved
compressibility and compactibility, thereby suggesting the potential of such spray-dried mixtures of CH and HG as binder in
tablets. Optimization of CH:HG ratio needs to be undertaken on a case basis, depending on the presence of other excipients
in the formulation.
Published: October 22, 2005 相似文献