The transdermal route has numerous advantages over the more traditional drug delivery routes. These include high bioavailability, absence of first pass hepatic metabolism, steady drug plasma concentrations, and the fact that therapy is non-invasive. The main obstacle to permeating drug molecules is the outermost layer of the skin, the stratum corneum. Consequently, research into enhancing transdermal drug delivery (TDD) by overcoming this layer, is an area of prime interest. This review article is written to provide a coverage commentary of the recent advancements in TDD enhancement techniques.

The present research was aimed to formulate and evaluate pH and time-dependent multiparticulate systems for colon-targeted drug delivery of celecoxib (CXB) with maximum drug absorption, reduced peak plasma fluctuations, and minimum potential side effects. Multiple unit delayed release systems of the drug in MCC (Avicel^® PH-102) grade were prepared using polymethacrylate polymers (Eudragit^® L-100 and RSPO) as a granulating binder by the extrusion-spheronization technique and characterized for their shape, size, size distribution, friability, density, and moisture content. In vitro release studies were performed in 0.1N HCl, for first 2 h then further performed in phosphate buffer (pH 6.8) for 24 h. The resulting pellets were prepared by extrusion spheronization using different grades of polymethacrylate polymers as a granulating binder, showing a substantial decrease in drug release in initial 5 h (16.28-16.7%) and releasing most of the drug in 12-24 h. The geometric and arithmetic mean diameter ranged from (490 to 780 ΅m) and (636 to 734 μm), respectively. The minimum to maximum range for circularity, elongation and rectangle were found to be (0.847±0.009 to 0.965±0.078), (1.036±0.057 to 1.185±0.023), and (0.724±0.041 to 0.791±0.047) respectively showing the proper shape and size of the pellets. The content of CXB in the prepared pellets was observed between 98.70 and 99.47% justifying the uniform drug distribution. The in vitro dissolution studies showed that the retardant effect in initial 5 h and most of the drug release in 24 h depended on the ratio and concentration of different grades of methacrylate polymers used in the formulation. CXB-loaded MUPS prepared by the extrusion-spheronization technique using polymethacrylate polymers showed immense potential for colon-specific drug delivery of the drug.

The purpose of this research was to mask the intensely bitter taste of metoclopramide hydrochloride and to formulate a rapid-disintegrating tablet of the taste-masked drug. Taste masking was done by complexing the drug with ion exchange resin, Indion 204 and Indion 214, in different ratios. The complex loading process was optimized for the concentration of resin, swelling time, stirring time, pH, and temperature for maximum drug loading. Drug-resin complexes (DRC) were tested for flow properties, drug content, in-vitro release in simulated salivary fluid, and in simulated gastric fluid (SGF), taste evaluation by the panel method. Taste evaluation of DRC revealed considerable taste masking with the degree of bitterness below threshold value (40 μg/ml) in 0 to 5 min. Complex of both Indion 204 and Indion 214 masked the taste, but on the basis of the comparative study, resin 214 was selected for taste masking property. Disintegrant croscarmellose (5% wt/wt) gave the minimum disintegration time in comparison to crosspovidone and sodium starch glycolate. The batch of tablet containing Pearlitol SD and Avicel (PH102) in the ratio 60:40 and 5% (wt/wt) Croscarmellose showed faster disintegration i.e. 32 s, as compare to marketed tablet. It also revealed rapid drug release (t ₈₀ , 6 min) in SGF compared with marketed formulation (t ₈₀ , 9 min).

The present investigation was aimed at developing and exploring the use of nanoerythrosomes (nEs) for targeted delivery of anti-malarial drug, pyrimethamine (PMA). The formulation was prepared by the extrusion method and drug was conjugated to nEs with the help of gluteraldehyde used as a cross-linking agent. The nEs formulation was optimized for drug concentration, surface morphology, viscosity, and sedimentation volume. The drug-loaded nEs showed delayed in vitro release, good stability at 4±1°C, and controlled in vivo release. Tissue distribution studies showed higher accumulation of drug in liver (17.34±1.3 μg/ml) at 3 h in the case of nEs as compared to free drug (12.82±0.7 μg/ml). A higher amount of drug i.e. 13.14±0.9 μg/ml was found after 24 h in liver in the case of nEs as compared to free drug concentration of 9.72±0.5 μg/ml. Data showed that developed PMA-loaded nEs hold promise for targeting and controlling the release of drug and improve treatment of malaria.

Transdermal systems are ideally suited for diseases that demand chronic treatment. Hence, an anti-diabetic agent of both therapeutic and prophylactic usage has been subjected to transdermal investigation. Gliclazide, a second-generation hypoglycemic agent, faces problems like its poor solubility, poor oral bioavailability with large individual variation and extensive metabolism. In the present work, transdermal matrix-type patches were prepared by film casting techniques on mercury using polymers like HPMC, Eudragit RL-100, and chitosan. Also an attempt was made to increase the permeation rate of drug by preparing an inclusion complex with hydroxypropyl β-cyclodextrin (HP β-CD). The possibility of a synergistic effect of chemical penetration enhancers (CPE) (propylene glycol and oleic acid) on the transdermal transport of the drug was also studied. Folding endurance was found to be high in patches containing higher amount of the Eudragit. There was increase in tensile strength with an increase in Eudragit in the polymer blend. In vitro drug release profile indicates that the drug release is sustained with increasing the amount of Eudragit in patches. The patches containing inclusion complex of drug showed higher permeation flux compared with patches containing plain drug. The result of the synergistic effect indicates that the HP β- CD in conjunction with other CPE showed a higher permeation flux.

The purpose of this work was to study the film coating potential of okra gum extracted from pods of Abelmoschus esculentus plant using paracetamol as a model drug. Core tablets of paracetamol were obtained from a pharmacy shop in the locality and the physicochemical properties such as weight, hardness, friability, and disintegration time were evaluated. Aqueous coating suspensions of okra gum and hydroxypropylmethylcellulose (0.6%w/v) were prepared and used to coat the tablets in Hi-coater. The coated tablets were evaluated for weight uniformity, diameter, thickness, hardness, friability, disintegration time, and moisture uptake at controlled humidity. The coating remained intact, durable, and resistant to chipping when challenged to catastrophic fall or rubbed on a white paper. The coated tablets had lower friability, increased disintegration time (24 min) compared to the core (3 min) and improved hardness, but there was no difference in the dissolution profile of the samples from the batches containing okra and hydroxypropylmethylcellulose as film formers. Changes were observed in some of the physicochemical properties of the formulations containing okra gum as with the known film former and it was convenient to conclude that these changes were due to the effect of the mechanical properties of the film formers. It was our conclusion that okra gum is a promising natural, biodegradable, cheap and eco-friendly film former in aqueous tablet film coating operation, particularly when masking of taste or objectionable odor in a solid dosage formulation is desired.

Oral mucoadhesive sustained drug delivery systems of salbutamol sulfate were formulated using an isolated natural agent from the seeds of Caesalpinia pulcherrima. The isolated material was evaluated for various parameters, such as, melting point, viscosity, pH, elemental analysis, swelling index, phytochemical constituents, and solubility studies. The mucoadhesive characters of the isolated substance were identified by a comparative study with hydroxyl propyl cellulose and sodium alginate, by various in vitro methods, such as, Shear stress measurement, Wilhelmy's method, Falling sphere method, and Detachment force measurement. Formulation and evaluation of mucoadhesive oral tablets of salbutamol sulfate (100 mg), using isolated natural materials in different proportions, and in vitro release studies, were carried out for three different formulations according to the U.S.P apparatus two (paddle method). Each 100 mg tablet was taken in 900 ml of acid buffer 1.2 and maintained at 37˚C. After two hours the filtrate was collected and replaced in buffer 7.4. In vitro releases of three different formulations for nine hours were studied, which showed the sustained action of drug release with increasing the concentration of the isolated natural mucoadhesive agent in the formulations.

Salbutamol sulfate microcapsules with a coat consisting of sodium alginate and mucoadhesive polymer such as sodium carboxy methyl cellulose (NaCMC), methyl cellulose (MC), carbopol-934, and hydroxy propyl methyl cellulose (HPMC) were prepared by ionotropic gelation technique and were evaluated for morphological characters, drug content, loading efficiency, drug-polymer interactions, swelling ratio, mucoadhesive properties, and in vitro release. The resulting microcapsules were discrete, spherical, and free-flowing, and microencapsulation efficiency was 51.28-96.70%. The microcapsules prepared with alginate alone (A4) have exhibited good mucoadhesive property in the in vitro washoff test. The swelling ratio of microcapsules was enhanced with increased alginate concentration. Salbutamol sulfate release from these mucoadhesive microcapsules was slow and extended over a period of 8 h and depends upon the concentration of the alginate. The drug release from alginate-HPMC/carbopol microcapsules followed diffusion-controlled first-order kinetics. The release rate of alginate-HPMC microcapsules (A4H) was higher than other formulations and comparable with commercially available controlled-release capsules. Microcapsules with alginate alone (A4) followed diffusion mechanism. In conclusion, alginate-HPMC/carbopol mucoadhesive microcapsules could be promising vehicle for oral controlled release of salbutamol sulfate.

We focused on qualitatively exploring the basic mechanisms involved in the Ionic gelation (IG) process, a method quite frequently used for synthesis of chitosan (CS) microparticles (MPs) and nanoparticles (NPs). We synthesized CS MPs and NPs using the Ionic gelation and microemulsion methods, and characterized the CS NPs and MPs at different stages of formulation using scanning electron microscopy (SEM) and fluorescence microscopy. Fourier Transform Infrared (FTIR) analysis was carried out to confirm effective cross-linking. Moreover, for the first time, we reported the mechanisms of IG technique for CS NP and MP synthesis with qualitative proof: (1) Complex formation of long chain oligomers with polyanions (long beaded structures) (2) cleavages at weak sites on addition of acid (HCl) (3) formation of CS NPs on chain scission. The versatility of IG for the synthesis of CS MPs and NPs was proved and compared with the microemulsion technique, thereby enhancing the wide spectrum of its use in therapeutics and biomedical applications.

In view of good skin tolerability, glycofurol was used as a vehicle-based gel and its effect on the topical penetration of Naproxen (NAP) was investigated. The aim of this study was to develop a suitable gel with bioadhesive property, spreadability, and viscosity for a topical anti-inflammatory effect. Three gelling agents were examined: Carbopol 974P, Gantrez AN 119, and Polyvinylpyrroloidone PVP K30. Skin permeation rates and lag times of NAP were evaluated using the Franz-type diffusion cell, in order to optimize gel formulation. The permeation rate of the NAP-based gel across excised rat skin was investigated. A significant increase in permeability parameters such as steady-state flux (Jss), permeability coefficient (Kp), and penetration index (PI) were observed in the optimized formulation containing 2% Transcutol as a permeation enhancer. From the skin irritation test, it was concluded that the optimized novel tetraglycol-based gel formulation was safe to be used for transdermal drug delivery. The developed naproxen / glycofurol-based gel appeared promising for dermal and transdermal delivery of naproxen and could be applicable with water-insoluble drugs, which would circumvent most of the problems associated with drug therapy.

Floating beads are often used for controlled drug release as they have a gastroretentive property without affecting the gastric emptying rate. In the present study mosapride-controlled release beads were prepared with the help of the ionotropic gelation method, using sodium alginate containing KHCO ₃ as the gas-forming agent. The physical characterization of the mosapride beads was examined by SEM. The results showed that the shape and texture of the beads were uniform before and after dissolution. The percentage of mosapride drug entrapment efficiency ranged from 97.4 ± 0.08 to 99.1 ± 0.04. The percentage of mosapride content from the beads was determined by high-performance liquid chromatography (HPLC) and ranged from 97.9 ± 0.08 to 99.6 ± 0.01. The in-vitro percentage release of mosapride from the beads at the end of 14 hours ranged from 90.0 ± 0.2 to 99.5 ± 0.12. The formulated beads in formulations 1 and 3 were sealed in vials and kept for 90 days at 40°C / 75% RH. After 90 days of exposure the percentage drug content was found to be 99.2 ± 0.04. The Floating beads designed for the gastroretentive dosage form could be suitable for controlled drug delivery.

Pioglitazone HCl is an antidiabetic agent with poor aqueous solubility. Inclusion complexes of pioglitazone HCl were prepared with β-cyclodextrin using various methods (physical mixing, kneading method, co-precipitation). The main aim of the present invention is to study the effect of the method of preparation on the dissolution profiles of pioglitazone HCl-β-Cyclodextrin inclusion complexes . The phase solubility profile of pioglitazone HCl with β-cyclodextrin was classified as AL-type and stability constant with 1:1 molar ratio was 115.45, calculated from the phase solubility diagram. Formation of the inclusion complex between pioglitazone HCl and β-cyclodextrin was confirmed by the Fourier Transform Infrared (FT-IR) spectroscopy. The dissolution profile of inclusion complexes were determined and compared with those of pioglitazone HCl alone and its physical mixtures. The dissolution rate of the pioglitazone HCl-β-cyclodextrin inclusion complex prepared by the co-precipitation method was six times higher when compared with the pure drug. The method of complexation of pioglitazone HCl in β-CD increased the dissolution rate of the drug in the following order: Coppt > KM > PM >Drug.