Microemulsions serve as ideal candidates as potential drug delivery system due to their specialized qualities of improved solubilisation of drug, extended shelf life and ease of method of preparation and administration to patients. The unique features of microemulsions are thermodynamically stable, clear, colloidal dispersion of water and oil that are stabilized by surfactant and cosurfactant. Microemulsion typically has a droplet diameter of approximately 100 nm or less. Microemulsions have numerous applications in pharmaceutics and many other industries. In the present review we shall discuss about the various aspects of microemulsion with respect to the field of non steroidal anti inflammatory drug, along with its preparation, evaluation and research work carried out in microemulsion.

Sustained release aceclofenac matrix tablets constituting Kollidon sustained release (KSR) (polyvinyl acetate and povidone-based matrix retarding polymer) were developed in this study in an attempt to design a dosage form that manifests desirable release profile and thorough adherence to official monographs. Nine matrix tablet formulations were prepared by dry blending and direct compression method by varying the proportion of KSR and compression load with fixed percentage of aceclofenac. Among this, by comparing response variables of the prepared formulations with that of the marketed product, two formulations (KSR5 and KSR7) were chosen as the optimized formulations. The formulation showed close resemblance to commercial products and compliance with United States Pharmacopoeia USP specification. The exponential model was applied to characterize the drug release behavior from polymeric systems. It was found that non-Fickian release is predominant in tablets containing KSR with a trend toward zero-order kinetics. The study also involves in vivo evaluation of the optimized formulations to find out relevant pharmacokinetic parameters. Correlation of in vitro drug release with that of amount of drug absorbed in vivo has also been performed.

Our present work describes the formulation and evaluation of an ocular deliver system of ofloxacin based on the concept of temperature-and ion-activated in situ gelling system. A combination of Pluronic F-127 and Pluronic F-68 along with chitosan, (pH-sensitive polymer also acts as a permeation enhancer) was used in temperature and pH-triggered in situ gelling systems while gellan alone was used in ion-activated in situ gelling system. The formulation allows its easy instillation into the eye as a liquid (drops), forms transparent gel, and spreads over the corneal surface. At the formulation pH, transcorneal permeation profile of ofloxacin was comparable to that of in vitro release profile. In situ gel-forming ability of the developed systems significantly controls precorneal drainage as studied by gamma scintigraphy. Thus, increased residence time in the eye would help to increase the ocular bioavailability. The formulation was also found to be nonirritant and well tolerable. C_max of in situ gelling formulation was found to be 1.5 times higher than marketed eye drops solution at the similar T_max of 1 h.

Lack of suitable prednisolone formulations for treatment of asthma could limit treatment compliance in pediatric population and hence the aim of this study was to develop prednisolone-polymer complexes with enhanced solubility and to incorporate this complex into orally disintegrating films to enable rapid drug delivery. The prednisolone-polymeric complexes were prepared using solvent evaporation and freeze drying techniques with a drug-polymer ratio of 1:1 using hydroxypropyl β-cyclodextrin (HP β-CD), hydroxypropyl methylcellulose 4 cps, and polyvinylpyrrolidone K-30 as polymeric carriers and the parameters such as an aqueous solubility, dissolution profile, and solid-state characterization using differential scanning calorimetry (DSC) of the complexes determined. The optimized complex was then incorporated into films prepared using solvent casting technique and the weight variation, thickness, solid-state characterization, in vitro disintegration and dissolution profiles of the films were then determined. The highest prednisolone solubility was seen with the prednisolone-HP β-CD complex prepared by freeze drying (1.82 mg/mL) followed by the same complex prepared by solvent evaporation (1.70 mg/mL). The solubility's were significantly higher compared to prednisolone powder (0.2 mg/mL) ( P < 0.05). DSC analysis of complexes revealed a reduction in area of the endothermic peak indicating the presence of amorphous drug while in comparison, the DSC analysis of films did not show endothermic peak showing complete absence of crystalline drug. The film was thin, uniform in weight and thickness, showing rapid disintegration of 55 s with almost complete drug release within 3 min. The study revealed the incorporated drug-polymer complex have maintained the amorphous state and enabled rapid drug release.

The objective of this study was to develop the Verapamil hydrochloride sustained-release floating matrix tablets using gas-generation approach to prolong the gastric residence time. Floating tablets were prepared using hydroxypropyl methylcellulose K4M (HPMC) as hydrophilic gel material, sodium bicarbonate as gas-generating agent and Citric Acid as floating assistant agent. A 3 ² factorial design was used to select the optimized formulation wherein HPMC K4M (X1) and Citric Acid (X2) were taken as independent variables and Floating lag time (FLT), amount of drug release after 24hrs. (Q ₂₄ ) were taken as dependent variables. The release data were evaluated by the model-dependent (curve fitting) method using PCP Disso v2.08 software. Optimisation studies were carried out by using the Design Expert software (version 8.0.1). The floating tablets were evaluated for uniformity of weight, hardness, thickness, swelling index, friability, drug content, FLT, and in vitro release. The in vitro drug release followed Hixson-Crowell model and mechanism of drug release was found to be anomalous or non-fickian type. The optimized formulation was F3 containing HPMC K4M 15%, and Citric acid 3% having minimum FLT and maximum drug release after 24 hrs.

The aim of this investigation was to prepare and characterize mirtazapine microemulsion for intranasal delivery, to determine its brain drug delivery using pharmacokinetic studies, and assess its performance pharmacodynamically for the antidepressant activity. Mirtazapine microemulsion of different compositions were prepared by water titration method and characterized for globule size and zeta potential. Microemulsion with maximum drug solubilization, lowest globule size and lowest zeta potential was considered optimal and taken for further studies with or without addition of chitosan, a mucoadhesive agent. Pharmacokinetics of optimized mirtazapine microemulsion, mucoadhesive microemulsion and mirtazapine solution were studied in brain and blood of male Wistar rats post intranasal and oral administration. Despair Swim test, locomotor activity and plus maze test were carried out in rats in order to compare therapeutic activity of the drug formulation for oral and intranasal route. Brain/blood uptake ratios were found to be highest for mirtazapine mucoadhesive microemulsion (MMME) followed by mirtazapine microemulsion (MME) post-intranasal administration compared to oral delivery of microemulsion. Significant ( P < 0.05) reduction in assessed pharmacodynamic parameters was observed after intranasal administration of MMME against control group. This investigation demonstrates a more rapid and larger extent of transport of mirtazapine into the brain with intranasal MMME, which may prove useful in treating depression.

The work investigates the development and optimization of novel beads of potato starch-alginate blend containing tolbutamide by ionotropic gelation using 3 ² factorial design. The optimized beads exhibited 85.57 ± 3.24% drug encapsulation efficiency and 50.42 ± 2.18% drug release after 8 h. The in vitro drug release followed controlled-release (zero-order) pattern with super case-II transport mechanism over 8 h. The swelling and degradation of the optimized beads were influenced by pH of test mediums. These were also characterized by SEM and FTIR analysis. These newly developed beads are suitable for controlled delivery of tolbutamide for prolonged period.