Studies of pilocarpine:carbomer intermolecular interactions (original) (raw)
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Biopolymers and pilocarpine interaction study for use in drug delivery systems (DDS)
Journal of Thermal Analysis and Calorimetry, 2016
This work aimed at the investigation of pilocarpine's interaction in the association of cashew gum (CG) and chitosan (CH) biopolymers because of mucoadhesive and prolonged release properties of this polymeric system. To elucidate this issue, characterization techniques, such as DSC, TG, XRD, IR, were applied besides DFT B3LYP/6-31??G(d,p) computational calculations. According to this approach, CG interacts with pilocarpine having a protective thermal effect on the drug and CH can reduce its thermal stability. These interactions occur, preferably, between a carbonyl group from pilocarpine and hydroxyl groups from biopolymers in which hydrogen bonds are involved. Thus, this work was able to identify interactions between the drug and the biopolymers and how, in a molecular approach, they occur. These results allow for the full understanding of the influence of each biopolymer for future pilocarpine-release systems.
Colloids and Surfaces B: Biointerfaces, 2013
The ability of anionic polymer sodium carboxymethylcellulose to influence the release of four model cationic drugs (chlorpheniramine maleate, venlafaxine hydrochloride, propranolol hydrochloride and verapamil hydrochloride) from extended release (ER) hydrophilic matrices based on non-ionic polymer polyethylene oxide was investigated by X-ray photoelectron spectroscopy (XPS), isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC). For all studied APIs, a combination of polyethylene oxide with sodium carboxymethylcellulose produced slower drug release compared to the matrices of single polymers. This behaviour was mainly attributed to the interaction of ester/carboxylic acid functionalities to yield H-bonding between the anionic polymer groups and the additionally protonated N-atoms of the active substances. X-ray photoelectron and isothermal titration calorimetry studies confirmed drug-polymer interaction and polymer-polymer interaction (i.e. the PEO binding with negatively charged NaCMC), whilst differential scanning calorimetry indicated the existence of both crystalline and molecularly dispersed active forms in the created complexes. The drug release mechanisms were fitted to various models suggesting diffusion control for the majority of the formulations. The Korsmeyer-Peppas model was found to be the most suitable for description of release profiles of all formulations. The present study showed that XPS and ITC in combination with DSC can be valuable tool to investigate the presence and nature (mechanism) of synergistic interactions between polymers and drugs in extended release matrix tablets.
Polymers, 2018
This work is the continuation of a series of studies focused on establishing the relationship between the surface thermodynamic properties of polyelectrolyte matrix tablets and drug release mechanisms. In this case, two model drugs with different polarity features, such as carbamazepine (non-polar) and metoprolol succinate (polar) were used in combination with polymeric material hydroxypropyl-methyl cellulose (HPMC) and two polyelectrolytes derived from maleic anhydride corresponding to the sodium salts of poly(maleic acid-alt-ethylene) and poly(maleic acid-alt-octadecene) named PAM-0Na and PAM-18Na, respectively. The polymers were obtained and characterized as reported previously. Surface studies were performed by the sessile drop method, whilst the surface free energy was determined through Owens, Wendt, Rable and Kaeble (OWRK) semi-empirical model. By contrast, the drug release studies were performed by in vitro dissolution tests, where data were analyzed through dissolution effi...
Soft Materials, 2020
The objective of this study was to formulate hydrophilic matrices for a controlled delivery of Piroxicam using carboxymethyl xanthan gum derivatives (CMX). CMXs with various degrees of substitution (DS = 0.22, 1.70 and 2.85) were synthesized by an etherification reaction, and their characterization was realized by FT-IR spectroscopy, X-ray diffraction, and scanning electron microscopy. Different tablets were prepared using the direct compression method. The powder mixtures were characterized by the determination of their angle of repose, compressibility index and Hausner ratio, whereas weight uniformity, hardness, friability, drug content, and in-vitro drug dissolution were employed to test the tablets under simulated gastric and intestinal conditions. The obtained results indicated that the drug release rate increases with the CMX ratio. The matrices based on CMX2 (DS = 1.7) were found to be the best candidates in controlling the release profile, where the optimal formulation contains 40% of CMX2 (F9). The dissolution data showed that all matrices fit well with Korsmeyer-Peppas model, whereas the release kinetics of F9 followed non-Fickian type release. The highest mean dissolution time value was obtained for F9. Finally, these results revealed that CMXs are suitable excipients for the sustained release dosage forms for as long as 20 h.
International Journal of Biological Macromolecules, 2015
The study shows development and optimization of modified release interpenetrating polymer network (IPN) macromolecules (beads) of oxcarbazepine using sodium alginate-egg albumin prepared by ionotropic gelation method and CaCl 2 as a cross-linker. Independent variables were identified based on preliminary study of investigation. The effect of amount of both polymers on drug entrapment efficiency (DEE,%), bead size (m) and cumulative drug release at 8 h (Q 8h , %) were optimized using 3 2 factorial design. The DEE, average size and Q 8h were found in the range of 65.08-91.02%, 976-1084 m and 73.50-94.06% respectively. The beads were also characterized by FTIR, DSC, SEM and XRD. The experiential responses were coincided well with predicted values obtained by Design-Expert ® 8.0.6.1 software. The swelling of beads were influenced by the pH of a release medium. The in vitro drug release from IPN beads exhibited sustained release Hixson-Crowell pattern with anomalous non-Fickian diffusion mechanism concluding that the developed sodium alginate-egg albumin IPN composite beads are suitable for sustained delivery of oxcarbazepine for desired period.
European Journal of Pharmaceutics and Biopharmaceutics, 2011
The aim of the study was the formulation of polyelectrolyte complexes composed of poorly water-soluble acid drugs and basic polymethacrylates by hot-melt extrusion enabling a tailor-made release pattern by the addition of inorganic salts. The influence of different electrolytes was analyzed at varying conditions in order to control drug delivery from the complexes. Poorly water-soluble model drugs naproxen and furosemide were applied in their non-ionic form.
BioMed Research International, 2013
Slowly degradable copolymers of L-lactide and -caprolactone can provide long-term delivery and may be interesting as alternative release systems of cyclosporine A (CyA) and rapamycin (sirolimus), in which available dosage forms cause a lot of side effects. The aim of this study was to obtain slowly degradable matrices containing immunosuppressive drug from PLACL initiated by nontoxic Zr[Acac] 4 . Three kinds of poly(L-lactide-co--caprolactone) (PLACL) matrices with different copolymer chain microstructure were used to compare the release process of cyclosporine A and rapamycine. The influence of copolymer chain microstructure on drug release rate and profile was also analyzed. The determined parameters could be used to tailor drug release by synthesis of demanded polymeric drug carrier. The studied copolymers were characterized at the beginning and during the degradation process of the polymeric matrices by NMR spectroscopy, GPC (gel permeation chromatography), and DSC (differential scanning calorimetry). Different drug release profiles have been observed from each kind of copolymer. The correlation between drug release process and changes of copolymer microstructure during degradation process was noticed. It was determined that different copolymer composition (e.g., lower amount of caprolactone units) does not have to influence the drug release, but even small changes in copolymer randomness affect this process.
International Journal of Pharmaceutical Investigation, 2015
Polyelectrolyte complexes (PECs) are the association complexes formed between oppositely charged particles (e.g., polymer-polymer, polymer-drug and polymer-drug-polymer). These are formed due to electrostatic interaction between oppositely charged polyions. Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) advocated in use of painful and inflammatory rheumatic and certain non-rheumatic conditions. The drug has a relatively short elimination half-life, which limits the potential for drug accumulation. As an analgesic, it has a fast onset and long duration of action. Aim: invitro-invivo evaluation of Xanthan gum and Eudragit E100 inter polyelectrolyte complex based sustained release tablet. Materials and Method: Xanthan gum and Eudragit E100 were used as PEC and were prepared using different proportions i.e. in 1:1 to 1:6 ratio. The optimum ratio of E100 and XG was 1:6 used to characterize the IPC and the formulation of tablet. The tablets were prepared by wet granulation using PVP K30 as binder. Results and Discussion: FT-IR and DSC studies confirmed the formation of IPC. Scanning Electron Microscopy (SEM) studies showed highly porous tablet surface. The tablets were evaluated for hardness, weight variation, and drug content, found to be within limits. In vitro and in vivo studies concluded that tablets showed sustained release profile. The short term stability study of the optimized formulation indicated that the formulation was stable. Conclusion: Since the Poly Electrolyte Complex delay the release of the drug, it can be employed in formulating sustained release matrix tablets.
Chemical and Pharmaceutical Bulletin, 1987
Interpolymer complex formation of polyvinylpyrrolidone (PVP) with carboxyvinyl polymer (CP) was examined by turbidity measurement, a binding isotherm study and Fourier-transform infrared spectroscopy. The interpolymer complex of PVP with CP was found to be formed in the unit molecular ratio of 1: 1 under ideal conditions, though the ratio of PVP in the solid complex was lower than 1: 1 under practical conditions. Hydrogen bonding might be the driving force for the complexation, and the degree of hydrogen bonding was calculated to be about 40 to 50%. The slowest dissolution rate of chlorpheniramine maleate from tablets, which consisted of a blend of PVP and CP was observed when the polymer combination ratio was 1: 1. In the case of indomethacin, the longest lag time for the dissolution was observed at the polymer ratio of 1: 1. Therefore, the drug dissolution behavior from PVP/CP tablets is dependent on the complex formation of PVP and CP.