Solidified Reverse Micellar Solution Research Articles

Formulation, in vitro and in vivo Characterisation of Diclofenac Potassium Sustained Release Tablets Based on Solidified Reverse Micellar Solution (SRMS)

Aims: To formulate sustained release diclofenac potassium tablets based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties of the tablets. Study Design: Formulation, in vitro and in vivo evaluation of sustained release diclofenac potassium. Place and Duration of Study: Department of Pharmaceutical Technology and Industrial Pharmacy, University of Nigeria, Nsukka and Department of Pharmaceutics, University of Nigeria, Nsukka 410001, Nigeria. Methodology: SRMS, consisting of mixtures of phospholipid and triglyceride were prepared in the ratios of 1:1, 2:1 and 1:2 (Phospholipon® 90H: Softisan® 154) respectively. SRMS-based tablets containing 100 mg of diclofenac potassium each were prepared using validated plastic mould. The physicochemical properties of the tablet formulations were studied and compared with the market brands of the drug for sustained release properties. In vitro release was carried out in simulated intestinal fluid (SIF, pH 7.5) using the USP paddle method. Anti-inflammatory, analgesic/anti-nociceptive and ulcerogenic properties of the formulated tablets were studied using adult Wistar rats. Results: The results showed that the physicochemical properties of the tablet formulations were significantly affected by the composition/ratio of the lipid matrix (LM) used (p < 0.05). The hardness of the tablets ranged from 4.55 ± 0.50 to 5.10 ± 0.39 kgf for tablets formulated with LM 1:2 and 1:1 (M3 and M1) respectively. Friability results indicated that all the SRMs tablets exhibited friability values less than 1 %. The erosion time ranged from 35.8 ± 1.10 to 120.3 ± 0.32 min. The release profile of the tablets showed maximum release between 8 – 11 h for all the batches. Diclofenac potassium tablets based on SRMS had good anti-inflammatory and analgesic properties and also inhibited the ulcerogenicity of the NSAID by up to 85 %. Conclusion: Diclofenac potassium tablets based on SRMS could be used for once daily administration.

Formulation, in vitro and in vivo Characterisation of Diclofenac Potassium Sustained Release Tablets Based on Solidified Reverse Micellar Solution (SRMS)

Aims: To formulate sustained release diclofenac potassium tablets based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties of the tablets. Study Design: Formulation, in vitro and in vivo evaluation of sustained release diclofenac potassium. Place and Duration of Study: Department of Pharmaceutical Technology and Industrial Pharmacy, University of Nigeria, Nsukka and Department of Pharmaceutics, University of Nigeria, Nsukka 410001, Nigeria. Methodology: SRMS, consisting of mixtures of phospholipid and triglyceride were prepared in the ratios of 1:1, 2:1 and 1:2 (Phospholipon® 90H: Softisan® 154) respectively. SRMS-based tablets containing 100 mg of diclofenac potassium each were prepared using validated plastic mould. The physicochemical properties of the tablet formulations were studied and compared with the market brands of the drug for sustained release properties. In vitro release was carried out in simulated intestinal fluid (SIF, pH 7.5) using the USP paddle method. Anti-inflammatory, analgesic/anti-nociceptive and ulcerogenic properties of the formulated tablets were studied using adult Wistar rats. Results: The results showed that the physicochemical properties of the tablet formulations were significantly affected by the composition/ratio of the lipid matrix (LM) used (p &lt; 0.05). The hardness of the tablets ranged from 4.55 ± 0.50 to 5.10 ± 0.39 kgf for tablets formulated with LM 1:2 and 1:1 (M3 and M1) respectively. Friability results indicated that all the SRMs tablets exhibited friability values less than 1 %. The erosion time ranged from 35.8 ± 1.10 to 120.3 ± 0.32 min. The release profile of the tablets showed maximum release between 8 – 11 h for all the batches. Diclofenac potassium tablets based on SRMS had good anti-inflammatory and analgesic properties and also inhibited the ulcerogenicity of the NSAID by up to 85 %. Conclusion: Diclofenac potassium tablets based on SRMS could be used for once daily administration.

Sustained-release diclofenac potassium-loaded solid lipid microparticle based on solidified reverse micellar solution: in vitro and in vivo evaluation

Objective: To formulate sustained-release diclofenac potassium-loaded solid lipid microparticles (SLMs) based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties.Methods: SRMS consisting of mixtures of Phospholipon® 90H and Softisan® 154 were used to formulate diclofenac potassium-loaded SLMs. Characterization based on the particle size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release was carried out in simulated intestinal fluid (pH 7.5). Anti-inflammatory and ulcerogenic properties were studied using rats.Results: Maximum EE% of 95%, 94% and 93% were obtained for SLMs formulated with SRMS 1:1, 2:1 and 1:2, respectively. In vitro release showed about 85–90% drug release at 13 h. Diclofenac potassium-loaded SLMs showed good anti-inflammatory and gastro-protective properties.Conclusion: Diclofenac potassium-loaded SLMs based on SRMS could be used orally or parenterally under controlled conditions, for once daily administration.

Sustained release indomethacin-loaded solid lipid microparticles based on solidified reverse micellar solution (SRMS): in vitro and in vivo evaluation

Abstract Solidified reverse micellar solutions (SRMS) were formulated using phospholipid (Phospholipon 90H) and triglyceride (Softisan 154) in the ratios of 1:1, 2:1 and 1:2, respectively. SLMs were prepared by melt homogenization technique. Characterization based on yield, mean particle diameter and morphology, pH, thermal analysis and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release was carried out in simulated intestinal fluid (SIF, pH 7.5), while the anti-inflammatory and ulcerogenic properties were studied using rats. From the results, the mean particle diameter of SLMs ranged from 2.19 ± 0.05 μm to 20.77 ± 0.03 μm. Maximum EE% of 96, 93 and 94 % were obtained and showed significant variation within the batches (p

Drug release and permeation studies of nanosuspensions based on solidified reverse micellar solutions (SRMS)

Solidified reverse micellar solutions (SRMS), i.e. mixtures of lecithin and triglycerides, offer high solubilisation capacities for different types of drugs in contrast to simple triglyceride systems [Friedrich, I., Müller-Goymann, C.C., 2003. Characterisation of SRMS and production development of SRMS-based nanosuspensions. Eur. J. Pharm. Biopharm. 56, 111–119]. Nanosuspensions based on SRMS were prepared by homogenisation close to the melting point of the SRMS matrix. In a first step the SRMS matrices of 1:1 (w/w) ratios of lecithin and triglycerides were loaded with 17β-estradiol-hemihydrate (EST), hydrocortisone (HC) or pilocarpine base (PB), respectively, and subsequently ground in liquid nitrogen to minimise drug diffusion later on. The powder was then dispersed in a polysorbate 80 solution using high pressure homogenisation. The drug loading capacities of the nanosuspensions were very high in the case of poorly water-soluble EST (99% of total 0.1%, w/w, EST) and HC (97% of total 0.5%, w/w, HC) but not sufficient with the more hydrophilic PB (37–40% of total 1.0%, w/w, PB). These findings suggest SRMS-based nanosuspensions to be promising aqueous drug carrier systems for poorly soluble drugs like EST and HC. Furthermore, in vitro drug permeation from the different drug-loaded nanosuspensions was performed across human cornea construct (HCC) as an organotypical cell culture model. PB permeation did not differ from the nanosuspension and an aqueous solution whereas the permeation coefficients of HC-loaded nanosuspensions were reduced in comparison to aqueous and oily solutions of HC. However, the permeated amount was higher from the nanosuspensions due to a much lower HC concentration in the solution than that in the nanosuspension (solution 0.02%, w/w, versus nanosuspension 0.5%, w/w). The high drug load of the nanoparticles provides prolonged HC release. Permeated amounts of EST were reduced in comparison to HC and only detectable with an ELISA technique. The EST release from nanosuspensions and different EST-loaded systems revealed a prolonged EST release from the nanoparticulate systems in contrast to a faster release of an oily solution of an equal EST concentration. With regard to an aqueous EST suspension of similar concentration which represents a depot system the release rate from the nanosuspensions revealed the same order of magnitude which points again to a prolonged release potential of the nanosuspensions.

Characterization of solidified reverse micellar solutions (SRMS) and production development of SRMS-based nanosuspensions

Solidified reverse micellar solutions (SRMS), i.e. binary mixtures of 30–60% (w/w) lecithin and two different hard fats, were investigated regarding their physicochemical properties and the influence of lecithin on solid lipids. For this purpose, the systems were characterized with X-ray and thermal analysis, transmission electron microscopy (TEM) and photon correlation spectroscopy. The melting point (m.p.) of the solid lipids, which is a crucial parameter of the solid state, was not altered up to a lecithin concentration of 50% whereas reverse micelles were likely to be frozen still in the solid state. In addition, solubilities of 17β-oestradiol-hemihydrate, pilocarpine base and hydrochloride in the SRMS melt were studied for evaluation of the drug carrier potency. Drug solubilization in the SRMS melt increased linearly with rising amount of lecithin. SRMS-based nanosuspensions were developed with a given lecithin/hard fat ratio of 1:1 (w/w). High-pressure homogenization was applied on cold to avoid lecithin loss. Optimization of the systems in terms of a variation of the homogenizing parameters such as pressure, number of cycles and temperature resulted in nanoparticulate systems with a polysorbate 80/SRMS ratio of 1:5 (w/w), and a total amount of 5 and 15% (w/w) SRMS, respectively. Production temperatures near the lipid m.p. proved best to be maintained by varying the pressure, yielding small nanoparticles with a narrow particle size distribution. The solid lipid nanoparticles were characterized with X-ray and thermal analysis as well as TEM. The crystalline particles (β modification) are of anisometrical shape and have transition temperatures far below the bulk m.p. due to the colloidal character of the systems.