Abstract. Novel self-microemulsifying floating tablets were developed to enhance the dissolution and oral absorption of the poorly water-soluble tetrahydrocurcumin (THC). Their physicochemical properties and THC permeability across Caco-2 cell monolayers were assessed. The self-microemulsifying liquid containing THC was adsorbed onto colloidal silicon dioxide, mixed with HPMC, gas-generating agents (sodium bicarbonate and tartaric acid), lactose and silicified-microcrystalline cellulose and transformed into tablets by direct compression. The use of different types/concentrations of HPMC and sodium bicarbonate in tablet formulations had different effects on the floating characteristics and in vitro THC release. The optimum tablet formulation (F2) provided a short floating lag time (∼23 s) together with a prolonged buoyancy (>12 h). About 72% of THC was released in 12 h with an emulsion droplet size in aqueous media of 33.9±1.0 nm while that of a self-microemulsifying liquid was 29.9±0.3 nm. The tablet formulation was stable under intermediate and accelerated storage conditions for up to 6 months. The THC released from the self-microemulsifying liquid and tablet formulations provided an approximately three-to fivefold greater permeability across the Caco-2 cell monolayers than the unformulated THC and indicated an enhanced absorption of THC by the formulations. The self-microemulsifying floating tablet could provide a dosage form with the potential to improve the oral bioavailability of THC and other hydrophobic compounds.
To demonstrate the potential alternative sources of starch used in tablet formulations, starches from taro (TS) and sweet potato (SPS) tubers were prepared with obtained yields of 11.0 and 9.6%, respectively. Both TS and SPS met USP22-NF17 identification and specifications. Their equilibrium moisture contents and gelatinization temperatures were comparable with those of commercial starch, whereas amylose contents of TS and SPS were 21.38% w/w and 41.76% w/w, respectively. Both were found to possess similar flow characteristics. To evaluate TS and SPS as granulating agents and disintegrants, tablets with controlled compression loads were prepared by incorporating a starch candidate with dibasic calcium phosphate in paste and powders forms, respectively. Tablets were then evaluated based on compressibility, friability, and disintegration. It was found that the binding and disintegrating performance of both TS and SPS was similar to that of commercial cornstarch.
The results indicated that the complex of CS-PAA at optimal proportion and amount was a promising polymeric osmogent for a zero-order controlled release from two-layered swellable micro/nanoporous osmotic pump tablets.
Abstract. The objectives of this study were to prepare push-pull osmotic tablets (PPOT) of felodipine using an interpolymer complex of chitosan (CS) and poly(acrylic acid) (PAA) as an osmopolymer, and to study the mechanisms of drug release from these tablets. The interpolymer complexes were prepared with different weight ratios of CS to PAA. Preparation of PPOT involved the fabrication of bilayered tablets with the drug layer, containing felodipine, polyethylene oxide, and the polymeric expansion layer, containing the CS-PAA complex. The effects of polymer ratios, type of plasticizers, and compression forces on release characteristics were investigated. It was found that drug release from PPOT exhibited zero-order kinetics and could be prolonged up to 12 or 24 h depending on the plasticizer used. PPOT using dibutyl sebacate showed a longer lag time and slower drug release than that using polyethylene glycol 400. In the case of polyethylene glycol 400, an increase in the CS proportion resulted in an increase in the drug release rate. The compression force had no effect on drug release from PPOT. Drug release was controlled by two consecutive mechanisms: an osmotic pump effect resulting in the extrusion of the drug layer from the tablet and subsequent erosion and dissolution of the extruded drug layer in the dissolution medium. The mathematical model (zero-order) related to extrusion and erosion rates for describing the mechanism of drug release showed a good correlation between predicted and observed values.
Background and purpose:
Crinum asiaticum
L. has long been used in Thai traditional medicine to treat osteoarthritis and inflammation by placing it on painful areas without further formulation design which is suboptimal for therapeutic use. Thus, this research aims to formulate a topical hydrogel patch containing
C. asiaticum
L. extracts (CAE) for anti-inflammatory effects.
Experimental approach:
The hydrogel patches are made from carrageenan, locust bean gum, with glycerin as a plasticizer and contain CAE formulated by using response surface methodology based on Box-Behnken design for design, determination of the effect of independent factors on the tensile strength, and optimization of the hydrogel patch formulation.
In vitro
release and skin permeation studies using a modified Franz diffusion cell and anti-inflammatory activity were evaluated.
Findings/Results:
The optimized CAE hydrogel patch showed a good correlation between predicted and observed tensile strength values and exerted its maximum cumulative lycorine release and permeation at 69.38 ± 2.78% and 48.51 ± 0.45%, respectively which were fit to Higuchi's kinetic model. The release rates were found to decrease with an increase in the polymer proportion of carrageenan and locust bean gum. In addition, the patch exerted potent
in vitro
anti-inflammatory activity with an IC
50
value of 21.36 ± 0.78 μg/mL.
Conclusion and implication:
The optimized CAE hydrogel patch application was successfully formulated with excellent mechanical properties, cumulative release, permeation, and anti-inflammatory effects. Thus, it has the potential to be further developed as a herbal application to relieve pain and inflammation. The
in vivo
anti-inflammatory effect of this delivery system should be further investigated.
Background and purpose:
Garcinia mangostana
, simply known as mangosteen, has long been used by Thai traditional medicine because of its reported antibacterial and anti-inflammatory activities for the treatment of skin infections. In this study, mangosteen pericarps were developed into a hydrogel patch to eradicate acne-inducing bacteria.
Experimental procedure:
The
G. mangostana
extract was investigated for bactericidal activity. A hydrogel patch containing the extract was examined for mechanical properties, antibacterial activity,
in vitro
release, skin permeation, and a phase I clinical study of skin irritation and allergic testing by a closed patch test.
Finding/Results:
The
G. mangostana
hydrogel patch made from carrageenan and locust bean gum powders was yellow in color, smooth, durable, and flexible. This
G. mangostana
hydrogel patch was effective against
Cutibacterium acnes, Staphylococcus epidermidis
, and
Staphylococcus aureus
. The active ingredient, α-mangostin, was released and permeated from the
G. mangostana
hydrogel patch within the first 30 min at 33.16 ± 0.81% and 32.96± 0.97%, respectively. The
G. mangostana
hydrogel patch showed no irritation in 30 healthy volunteers. However, two volunteers had delayed allergic contact dermatitis to 0.5% (w/w)
G. mangostana
hydrogel patch.
Conclusion and implication:
This hydrogel patch containing
G. mangostana
ethanolic extract is not recommended for patients who have any reaction to mangosteen but has utility as an anti-acne facial mask.
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