Solidified Reverse Micellar Solution (SRMS)-Based Indomethacin Sustained-Release Tablets: Formulation and In vitro Evaluation

Purpose: To formulate and evaluate sustained-release indomethacin tablets based on solidified reverse micellar solution (SRMS).Methods: SRMS consisting of mixtures of phospholipid (Phospholipon® 90H) and triglyceride (Softisan® 154) were prepared in the ratios of 1:1, 2:1 and 1:2, respectively. SRMS-based tablets containing 75 mg of indomethacin each were prepared using a validated plastic mould. The physicochemical properties of the tablet formulations were studied. In vitro release study was carried out in simulated intestinal fluid (SIF, pH 7.5).Results: The results showed that the physicochemical properties of the tablet formulations were significantly affected by the composition/ratio of the lipid matrix used (p < 0.05). Tablet hardness ranged from 5.00 ± 0.39 to 5.60 ± 0.36 kgf for tablets formulated with SRMS 1:2 and 2:1 (N3 and N2), respectively. The tablets exhibited friability of < 1 % (p < 0.05). Erosion time in SIF ranged from 124.0 ± 0.5 to 180.0 ± 1.1 min while drug release from the tablets reached a maximum in 8 – 11 h for all thebatches.Conclusion: Indomethacin tablets based on SRMS exhibited good sustained-release properties and can be further developed to achieve once daily administration for improved patient adherence to therapy.Keywords: Solidified reverse micellar solution, Phospholipid, Triglyceride, Indomethacin, Sustained release

Surface modified solid lipid microparticles based on homolipids and Softisan® 142: preliminary characterization.

AbstractObjectiveTo preliminarily investigate three different lipid matrices consisting of two natural homolipids from Capra hircus (goat fat) and Bovine Spp. (tallow fat) and one semi-synthetic lipid (Softisan® 142) separately structured with Phospholipon® 90G (P90G) as potential delivery systems for poorly water soluble drugs.MethodsThe structured lipid matrices were characterized by differential scanning calorimetry (DSC) and employed to prepare solid lipid microparticles (SLMs) by the melt homogenization method using gradient concentrations of polysorbate 80 and at different emulsification times of 2, 5 and 10 min using a Silverson mixer. The SLMs were analyzed for morphology and particle size, thermal properties, stability studies and determination of injectability.ResultsThe results showed that SLM production was optimum at 5 % of lipid matrices, 1.5 % of polysorbate 80 and emulsification time of 5 min. Increase in polysorbate 80 concentrations decreased the particle size of the SLMs. The SLMs were well formed, spherical, smooth and non-porous with particle sizes in the ranges of (13.90 ± 2.10) μm - (0.09 ± 0.01) μm for SLMs produced from the structured - tallow fat; (13.40 ± 1.30) μm - (0.10 ± 0.01) μm for the structured - goat fat and (13.40±2.00) μm - (2.10± 1.00)μm for the structured Softisan® 142 lipid matrices. DSC traces showed that Softisan® 142 was the most crystalline of all three bulk matrices due to its high enthalpy (−7.962 mW/mg) while tallow fat was the least (−5.067 mW/mg) but addition of P90G to the matrices lowered their enthalpies mostly in the structured goat fat matrices. The SLMs when stored at 4-6 ° were most stable and syringeable with 27 G needle.ConclusionsThis suggests that structured goat fat matrices with the enthalpy of −2.813 mW/mg will mostly favour drug loading of some poorly soluble drugs more than tallow fat (−4.892 mW/mg) and Softisan® 142 (−5.501 mW/mg)

In vitro and In vivo Characterisation of Piroxicam-Loaded Dika Wax Lipospheres

Purpose: To formulate piroxicam-loaded lipospheres and evaluate their in vitro and in vivo properties.Method: Piroxicam-loaded lipospheres were prepared by hot  homogenization technique using dika wax and Phospholipon® 90G (1:1, 1:2 and 2:1) as the lipid matrix. Characterisation, based on particle sizeand morphology, pH, drug content and encapsulation efficiency, were carried out on the lipospheres. In vitro release was evaluated in simulated intestinal fluid (pH 7.5). Anti-inflammatory and ulcerogenic properties of the piroxicam-loaded lipospheres were studied using healthy, adult Wistar rats.Result: Photomicrographs revealed spherical particles in the range of 1.66 – 3.56 ìm. The results also indicated that lipospheres formulated with lipid matrix 1:1 and containing 0.25 % piroxicam had the highest encapsulation efficiency of 84 %. In vitro release data showed that lipospheres formulated with lipid matrix having higher concentration of dika wax exhibited the fastest drug release of drug with maximum release time between 60 - 70 min. The lipospheres exhibited good anti-inflammatoryproperties with 58.6 % oedema inhibition at 5 h. Piroxicam-loaded liposheres had an ulcer index of zero while, the reference (plain piroxicam) had an ulcer index of 15.00 ± 1.23 (p < 0.05).Conclusion: Piroxicam lipospheres formulated with a mixture of dika wax and phospholipid exhibited good in vitro and in vivo properties.Keywords: Dika wax, Lipospheres, Piroxicam, Phospholipid, Ulcerogenicity, Anti-inflammator

In-vitro evaluation of bioadhesive and release properties of thiamine hydrochloride formulation from Gelatin, Gellan as their admixtures

This study was aimed at determining the effect of gelatin on the bioadhesive strength and release properties of gelatin gum. Bioadhesive strength determination was carried out using tensiometric methods. Thiamine tablets was prepared by wet granulation method and used for the study. Tablets properties evaluated include: weight uniformity, friability, disintegration time test and release studies in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). The study showed that the gelatin alone had the highest bioadhesive strength, while gellan had the least. Admixture of both gelatin and gellan showed values that were intermediate to those obtained for the two polymers differently. The release study showed a better release with batch A (1:1) highest in SIF, followed by F (0:1), and the reverse was the case in SGF

Formulation and Release Characteristics of Zidovudine-Loaded Solidified Lipid Microparticles

Purpose: To formulate and determine the release profile of zidovudine (AZT)-loaded solidified lipid microparticles (SLMs).Methods: Different concentrations (0, 1, 2, 3 and 5 %w/w) of zidovudine (AZT) were formulated into microparticles in melt dispersion of Phospholipon® 90H and goat fat in the ratio 1:1, 2:1, 2:3 and 1:3 followed by lyophilization. They were characterized for particle size, yield, entrapment efficiency (EE) and loading capacity (LC). In vitro release kinetics and mechanism of release were assessed sequentially in simulated gastric fluid (SGF, pH 1.2)and simulated intestinal fluid (SIF, pH 7.2).Results: The ratio 1: 1 formulation was the most stable in terms of physical observation.. Particle size analysis indicated that the particles were irregular in shape with size ranging from 5.10 ± 0.10 to 13.40 ± 2.20 μm. Yield decreased with increase in drug concentrations in the SLMs formulations. EE data showed that the microparticles containing 1 % w/w of AZT had the highest entrapment efficiency of 74.0 ± 0.03 %. LC also decreased with increase in concentration of AZT. AZT tablet released most of its content within 5 min with a sharp decrease in the concentration but the SLMs maintained its release for 8 to 12 h in different batchesConclusion: The results show that drug content has influence on drug release from the SLMs, but not on the mechanism of release. Furthermore, dose dumping was avoided and drug release mechanism was mostly non-Fickian while for the reference (commercial) tablet, it was Fickian.Keywords: Phospholipon® 90H, Solidified lipid microparticles, Solidified reverse micellar microparticle, Zidovudine

Use of trona as a permeation enhancer for ointments prepared with beeswax extracted from native honeycombs

This work studied the effect of trona on the release and permeation of salicylic acid from ointments formulated with beeswax processed from native honeycombs. Pure trona was obtained by re-crystallisation. The test (extracted) beeswax was characterized using standard physicochemical procedures. Trona was incorporated into salicylic acid ointment at concentrations of 0.5 - 2.0 %w/w and the ointments evaluated. Consistencies of the ointments were determined bypenetrometry while release studies were carried out by studying diffusion of salicylic acid from the ointments on ferric chloride agar. The permeation of salicylic acid from optimised ointments was also studied. Results obtained indicated that the physicochemical properties of the beeswax processed from native honeycombs compared favourably with the standard beeswax. Release enhancement by trona was in the order: 0.5 %w/w > 1.0 %w/w > 1.5 %w/w > 2.0 %w/w while in the permeation experiment, enhancement was mostly observed at trona concentrations of 1.5 %w/w and 2.0 %w/w. Trona could be used as a release and permeation enhancer in salicylic acid ointments

The mechanism of diclofenac sodium release from non-disintegrating bioadhesive tablets

The mechanism of diclofenac sodium release from non-disintegrating bioadhesive tablets was studied. Diclofenac sodium was embedded in Carbopol 941 to produce bioadhesive granules, which were later, incorporated into a structure-forming material, paraffin wax. The tablets were formulated by pour moulding in a well-lubricated plastic mould. The tablets were thereafter evaluated as compressed uncoated tablets using the following parameters: weight uniformity, friability, hardness, thickness, absolute drug content and release studies. The release study was undertaken in simulated intestinal fluid (SIF) without pancreatin. The result of the study showed that the release of diclofenac sodium was extended in all the tablets. The tablets conformed to pharmacopoeia specification as applied to uncoated compressed tablets. The mechanism of release of diclofenac sodium appeared to have followed different release models. Key words: Diclofenac sodium, bioadhesive tablets, non-disintegrating tablets, release mechanism. Journal of Pharmaceutical and Allied Sciences Vol.2(2) 2005: 202-20

In Vitro Availability of Naproxen from Liquid Self-Emulsifying Systems

No Abstract Available Discovery and Innovation Vol.16(1&2) 2004: 22-2

THE PHYSICOCHEMICAL PROPERTIES OF STARCH DERIVED FROM TACCA INVOLUCRATA

Tacca starch was extracted from the root tubers of Tacca involucrata. The starch granules are predominantly oval with single, double or triple cleft helium. It gelatinizes at 52-65oC and has an amylose content of 36%. Key Words: Physicochemical properties, starch, Tacca involucrata, Taccaceae Nig. J. Nat Prod. And Med. Vol.3 1999: 71-7