Considering the advantageous for the rectal administration of non-steroidal anti-inflammatory drugs, the objective of this study was to formulate and evaluate rectal mucoadhesive hydrogels loaded with diclofenac-sodium chitosan (DFS-CS) microspheres. Hydroxypropyl methylcellulose (HPMC; 5%, 6%, and 7% w/w) and Carbopol 934 (1% w/w) hydrogels containing DFS-CS microspheres equivalent to 1% w/w active drug were prepared. The physicochemical characterization revealed that all hydrogels had a suitable pH for rectal application (6.5-7.4). The consistency of HPMC hydrogels showed direct proportionality to the concentration of the gelling agent, while carbopol 934 gel showed its difficulty for rectal administration. Farrow's constant for all hydrogels were greater than one indicating pseudoplastic flow. In vitro drug release from the mucoadhesive hydrogel formulations showed a controlled drug release pattern, reaching 34.6-39.7% after 6 h. The kinetic analysis of the release data revealed that zero-order was the prominent release mechanism. The mucoadhesion time of 7% w/w HPMC hydrogel was 330 min, allowing the loaded microspheres to be attached to the surface of rectal mucosa. Histopathological examination demonstrated the lowest irritant response to the hydrogel loaded with DFS-CS microspheres in response to other forms of the drug.

Coenzyme Q10 (CoQ10) is an insoluble, poorly permeable antioxidant with great biological value which acts as anti-aging and anti-wrinkle agent. To improve its permeability through topical application, the current study aimed at formulating oil/water (o/w) nanoemulsion (NE) as an efficient vehicle for delivering (CoQ10) through the skin barriers. The solubility of (CoQ10) was tested for various oils, surfactants (S), and co-surfactants (CoS). The NE region was determined by constructing pseudoternary phase diagrams. NE formulae containing 1, 2, and 3% w/w drug have been subjected to thermodynamic stability test. The formulae that passed thermodynamic stability tests were characterized by physical properties as pH, viscosity, refractive index, droplet size, zeta-potential, TEM, electroconductivity, in vitro release, and ex vivo permeation. The formula 'F2' containing 10% w/w isopropyl myristate (oil phase), 60% w/w of Tween 80: Transcutol HP mixture (S/CoS) at ratio 2:1, 30% w/w water and 2% w/w drug was evaluated for its anti-wrinkle efficiency using an animal model. The 'F2' formula showed 11.76 ± 1.1 nm droplet size, 1.4260 ± 0.0016 refractive index, 0.228 PDI, -14.7 ± 1.23 mv zeta potential, 7.06 ± 0.051 pH, 199.05 ± 0.35 cp viscosity, and the highest percentage of drug release in the selected dissolution media. About 47.21% of the drug was released in phosphate buffer 7.4 containing 5% w/v Labrasol and 5% w/v isopropyl alcohol through 24 h. It also showed the highest drug flux (J = 3.164 µg/cm/h), enhancement ratio (E = 8.32), and permeability coefficient (K = 22.14 × 10 cm/h). CoQ10 NE reduced the skin wrinkles and gave the skin smooth appearance. Our investigation suggests the potential use of NE as a vehicle for enhancing solubility and permeability of CoQ10 and thus improving its anti-wrinkle efficiency.

Nanoemulsions were investigated as transdermal delivery systems for indomethacin. Six formulae were prepared using Triacetin, capryol 90 and labrafil as oils; Tween 80 and pluronic F127 as surfactants and transcutol and propylene glycol as co-surfactants. The continuous phase was that one with the larger volume fraction regardless of the hydrophile-lipophile balance of the surfactant/co-surfactant mixture. Surfactant type had significant effects on particle size and rheological properties of the nanoemulsions. Pluronicbased formulae recorded the lowest particle sizes and the highest viscosities. The prepared nanoemulsions increased drug solubility up to 610-fold compared with water. Refractive index measurements proved the compatibility between indomethacin and the used nanoemulsion components. Indomethacin was almost completely ionized at the pH values of the prepared nanoemulsions, suggesting drug absorption via the hydrophilic pathway of the skin upon topical application. Nanoemulsions controlled indomethacin release through semipermeable membrane and enhanced its permeation through excised newly born albino rat skin. The formulae were stable for six months at ambient conditions. Transdermal single application of selected formulae resulted in effective plasma levels up to 32 h in rats. Nanoemulsions were significantly superior to other investigated transdermal approaches at solubilizing indomethacin and achieving higher plasma levels.

High amylose corn starch was used to obtain substituted amylose (SA) polymers by chemically modifying hydroxyl groups by an etherification process using 1,2-epoxypropanol. Tablets for drug-controlled release were prepared by direct compression and their release properties assessed by an in vitro dissolution test (USP XXIII no 2). The polymer swelling was characterized by measuring gravimetrically the water uptake ability of polymer tablets. SA hydrophilic matrix tablets present sequentially a burst effect, typical of hydrophilic matrices, and a near constant release, typical of reservoir systems. After the burst effect, surface pores disappear progressively by molecular association of amylose chains; this allows the creation of a polymer layer acting as a diffusion barrier and explains the peculiar behaviour of SA polymers. Several formulation parameters such as compression force, drug loading, tablet weight and insoluble diluent concentration were investigated. On the other hand, tablet thickness, scanning electron microscope analysis and mercury intrusion porosimetry showed that the high crushing strength values observed for SA tablets were due to an unusual melting process occurring during tabletting although the tablet external layer went only through densification, deformation and partial melting. In contrast, HPMC tablets did not show any traces of a melting process.