[Show abstract][Hide abstract] ABSTRACT: To compare the 6-month results of two formulations of Riboflavin provided by Sina Darou, Iran, and Uznach, Switzerland, in corneal collagen cross-linking (CXL) for keratoconus patients.
Considering the results of the previous study about the similarity of the formulations and the active ingredients of the two types of Riboflavin, they were used in the CXL procedure of 60 keratoconic eyes (30 eyes in each group). After 6 months, the mean improvement of UCVA (0.239), BCVA (0.707), and MRSE (0.513) did not differ significantly between the two groups. The mean decrease in max- K (0.731), mean- K (0.264), central corneal thickness (0.759), and Q-value (0.669) did not show any significant difference between the two groups. The two groups had no significant difference in endothelial cell count decrease (0.229). The Sina Darou formulation decreased corneal hysteresis more than the Swiss formulation (P = 0.057) but there were no significant differences in the mean decrease of corneal resistance factor between the two groups (P = 0.117).
Based on the early results, the results of visual acuity, refraction, and corneal topography using Sina Darou and Uznach formulations of Riboflavin showed that both were effective in CXL. However, considering the relatively significant difference in corneal hysteresis changes between the two groups, this study will continue to report the long-term results.
DARU-JOURNAL OF FACULTY OF PHARMACY 04/2014; 22(1):37. · 0.62 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Gastric emptying is a complex and extremely variable process. This causes the unpredictability of the bioavailability of drug delivery systems. Gastro retentive drug delivery systems (GRDDS)s have received significant attention in the past decades primarily due to the fact that they can overcome the limitation of conventional oral controlled release drug delivery systems related to fast gastric emptying time. An optimum GRDDS can be defined as a system which remains in the stomach for a sufficient time interval and releases active ingredients in a controlled manner. This, significantly extends the duration of drug release, prolongs dosing interval and increases bioavailability of drugs and therefore improves compliance of the patients and effectiveness of pharmacotherapy. This article gives an overview of the main concepts used to design pharmaceutical dosage forms with prolonged gastric residence times as well as the parameters-affecting gastric emptying, advantages, shortcomings, formulation considerations and, factors that affect gastro retentive systems. The main emphasis is on the entire classification and different types of GRDDSs. Finally evaluation methods of these systems have been summarized.
[Show abstract][Hide abstract] ABSTRACT: The mesoporous glass-ceramic (GC) was employed as a carrier to investigate its capability for pharmaceutical applications. Piroxicam (PX) as a model drug was loaded in the GC by using of solvent evaporation technique. The physicochemical properties and morphology of the powders were evaluated employing X-ray powder diffractometry (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The drug adsorption isotherms were assessed as well. Drug release profiles were examined by fitting the data to the 10 common kinetic models. The specific surface area, Vm (the volume of the N2 adsorbed on the 1g of the GC when the monolayer is complete) and the average pore diameter of the GC powder before and after loading process were measured by the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analysis benefiting N2 adsorption/desorption isotherms. The ideal loading of PX in the GC was 41.8%. The average pore diameter for the GC was determined to be about 10nm. The Freundlich model was found to be the best adsorption isotherm. Decrease of the GC specific surface area and Vm values were observed after loading process. Drug release data were best fitted to the Weibull model with the shape factor of 0.4-0.7 signifying the Fickian diffusion of PX from the GC. Accordingly, the GC could be considered as a suitable adsorbent to develop an oral drug delivery system.
Colloids and surfaces B: Biointerfaces 02/2014; · 3.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was conducted to investigate the effects of HPMC (K4M and K100M) as well as tragacanth on the drug release rate of diltiazem (DLTZ) from matrix tablets prepared by direct compression method.Mechanism of drug transport through the matrices was studied by fitting the release data to the 10 kinetic models. 3 model independent parameters; i. e., mean dissolution time (MDT), mean release rate (MRR) and release rate efficacy (RE) as well as 5 time point approaches were established to compare the dissolution profiles. To find correlation between fraction of drug released and polymer's molecular weight, dissolution data were fitted into two proposed equations.All polymers could sustain drug release up to 10 h. The release data were fitted best to Peppas and Higuchi square root kinetic models considering squared correlation coefficient and mean percent error (MPE). RE and MRR were decreased when polymer to drug ratio was increased. Conversely, t60% was increased with raising polymer /drug ratio. The fractions of drug released from the formulations prepared with tragacanth were more than those formulated using the same amount of HPMC K4M and HPMC K100M.Preparation of DLTZ matrices applying HPMCK4M, HPMC K100M and tragacanth could effectively extend the drug release.
[Show abstract][Hide abstract] ABSTRACT: The rapidly growing applications of antibody-based therapeutics requires novel approaches to develop efficient drug delivery systems in which biodegradable polymeric nanoparticles are amongst the best candidates. In the present study bevacizumab loaded PLGA nanoparticles were formulated by water-in-oil-in-water emulsion method. Protein inactivation and aggregation are the major drawbacks of this technique. Therefore protective ability of various stabilizers was studied during entrapment process. Probable changes in VEGF165 binding capability of bevacizumab was assayed by ELISA which portrays the antibody's bio-efficiency. Probable breakage of bevacizumab and its secondary and tertiary structural integrity upon entrapment were analyzed by SDS-PAGE and circular dichroism spectroscopy, respectively. In vitro and ex vivo released bevacizumab from the prepared nanoparticles was also investigated. Results revealed that the protein interfacial adsorption is the foremost destabilizing factor in the double emulsion method and incorporation of appropriate concentrations of albumin could protect bevacizumab against entrapment stress. Ex vivo release results, in rabbit vitreous, indicated the ability of prepared nanoparticles in prolonged release of the active antibody. Consequently this approach was an attempt to achieve sustained release PLGA nanoparticle formulation with the aim of protecting integrity and performance of entrapped bevacizumab.
European journal of pharmaceutical sciences: official journal of the European Federation for Pharmaceutical Sciences 08/2013; · 2.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Results of previous studies on the benefits of ocular drug delivery using polymeric mucoadhesive nanoparticles suggested longer presence and better penetration of nanoparticles, and thus, increased effect and bioavailability of drugs entrapped in nanoparticles. In this study, a novel polymer, poly β-amino ester, was used for the preparation of triamcinolone acetonide loaded nanoparticles using a modified emulsification/solvent diffusion method.
Mucoadhesiveness studies, in vitro drug release, X-ray powder diffraction, differential scanning calorimetry, and scanning electron microscopy were used for physicochemical characterization of nanoparticles. Thirty six hours after inducing uveitis by intra vitreal injection of a lipopolysaccharide, sampling from the aqueous humor was done and inflammatory factors such as cell, protein, nitric oxide, and prostaglandin E2 were compared. Results: Nanoparticles with a mean size of 178 nm and drug loading of 5.3% were prepared and used for in vivo studies in rabbits with uveitis. Higher anti-inflammatory effect was observed for polymeric nanoparticles of triamcinolone acetonide compared to microparticles of prednisolone acetate and triamcinolone acetonide, and an equal effect compared to subconjunctival injection of triamcinolone acetonide in terms of inhibiting inflammation and inflammatory mediators.
It can be concluded that polymeric nanoparticles of triamcinolone acetonide will provide as good anti-inflammatory effects as subconjunctival injection method and are better compared to other drug delivery systems.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this work was to improve the efficacy of triamcinolone acetonide (TA) in the treatment of endotoxin-induced uveitis (EIU) using a polymeric nanoparticulate drug delivery system. Poly (d,l-lactide-co-glycolide) (PLGA) nanoparticles were prepared using a modified emulsification/solvent diffusion method. Processing factors affecting loading and size were also studied. After physicochemical studies including in vitro release, X-ray powder diffraction, differential scanning calorimetry and scanning electron microscopy, in vivo studies were conducted using nanoparticles sized 195 nm with 3.16% drug loading. Inflammatory factors such as flare, cell and fibrin were studied in rabbit's eye over 96 hours period, using laser flare meter and slit lamp examination. Inflammatory mediators such as NO, PGE2, cell and protein were measured quantitatively 36 hours after intravitreal injection of endotoxin in aqueous humor, and the therapeutic effects were compared in different groups. Results indicated statistically significant differences between the effect of nanoparticles in the treatment of EIU compared to microparticles of TA and prednisolone acetate (PA). There were no significant differences between the effects of TA injection and TA nanoparticles. In conclusion, sustain release biodegradable TA nanoparticles are potential new topical treatment options which can provide better patient compliance.
European journal of pharmaceutics and biopharmaceutics: official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V 01/2013; · 3.15 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Naproxen is a non-steroidal anti-inflammatory drug which can be used for the treatment of inflammatory disorders like uveitis and arthirit rheumatoid. The aim of the present study was to investigate the physicochemical characteristics of naproxen-PLGA nanoparticles. The nanoparticles of naproxen with PLGA were formulated using the solvent evaporation/extraction technique (the single emulsion technique). Several process parameters i.e., drug/polymer ratio, aqueous phase volume and speed of homogenization were considered with the aim of achieve optimal preparation conditions. The physicochemical characteristics of nanoparticles were studied applying particle size analysis, differential scanning calorimetry, X-ray crystallography, Fourier transform infrared spectroscopy and scanning electron microscopy. The release rate of naproxen from various drug/polymer nanoparticles was investigated as well. All the prepared formulations using PLGA resulted in nano-range size particles (352-571 nm) with spherical smooth morphology. The nanoparticles of naproxen-PLGA displayed lower crystallinity with no chemical interactions between the drug and polymer molecules. The nanoparticles exhibited the slower release of drug in comparison with the intact drug and the physical mixtures. According of these findings, formulation of the naproxen-PLGA nanoparticles was able to improve the physicochemical characteristics of the drug and possibly will increase the anti-inflammatory effects of drug following its ocular or intra-joint administration.