Ocular diseases require localized administration of drugs to the tissues around the ocular cavity. The existing ocular drug delivery systems are fairly primitive and inefficient. However, the design of ocular system is undergoing gradual transition from an empirical to rational basis. In the recent years, there has been explosion of interest in the polymer based delivery devices. Utilization of the principles of controlled release as embodied by ocular inserts offers an attractive approach to the problem of prolonging pre-corneal drug residence times. In the present update, the authors discuss the basic concept of ocular inserts as drug delivery system and examine the few inserts, which are available in the market or are being developed by pharmaceutical companies for drug delivery. The article discusses soluble ocular drug insert (SODI), Ocusert, Collagen Shields, Ocufit, Minidisc and new ophthalmic delivery system (NODS) with special attention to biological/clinical performances, and potential for future applications and developments.

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Size reduction is a process of reducing large solid unit masses into small unit masses, coarse particles or fine particles. Size reduction process is also termed as comminution or diminution or pulverizations . In addition to the standard adjustments of the milling process (i.e., speed, screen size, design of rotor, load), special techniques of milling may be useful including special atmosphere, temperature control, sonocrystallization, supercritical fluid process. etc. Moreover, some advance technologies of size reduction including Micron Technologies, Gran-U-Lizer™ Technology, Jet-O-Mizer™ and Microfluidics® have been popular. Various application of size reduction concept covers oral delivery of poorly soluble drugs, micronization, nanotechnology (micro- and nano suspensions), etc. This systemic review highlights advantages and disadvantages, mechanisms, theories, techniques, advances, and pharmaceutical applications of size reduction technology.

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A reverse phase high performance liquid chromatography (RP-HPLC) method for the simultaneous estimation of amlodipine and metoprolol in marketed formulation is developed. The determination was carried out on a Kromasil C18 (250 x 4.6 mm, 5 µm) column using a mobile phase of 0.02 M phosphate buffer solution: acetonitrile (70:30v/v, pH 3.0). The flow rate was 1.0ml/min with detection at 221 nm. The retention time for amlodipine was 2.57 min and for metoprolol 4.49 min. Amlodipine and metoprolol showed a linear response in the concentration range of 10-110 µg/ml. The correlation co-efficient (' r ' value) for amlodipine and metoprolol was 0.9991 and 0.9992, respectively. The results of analysis have been validated statistically and by recovery studies. The percentage recoveries obtained for amlodipine and metoprolol ranges from 100.04 to 100.57%.

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Ambroxol hydrochloride (HCL) is a potent mucolytic capable of inducing bronchial secretion. It is used in the treatment of asthma, bronchitis, and cough. But it is a very bitter drug and slightly soluble in water. Thus, in the work under taken, an attempt was made to mask the taste and to formulate into a oro-dispersible tablet by complexation with ion exchange resins, which also acts as super disintegrating agents. Since, these tablets can be swallowed in the form of dispersion, it is suitable dosage form for pediatric and geriatric patients. Cation exchange resins like Indion-204 and Indion-234 were utilized for the sorption of drug. Drug-resinates were prepared in drug to resin ratio of 1:5 and 1:6. The prepared tablets were evaluated for general appearance, content uniformity, hardness, friability, taste evaluation, mouth feel, wetting time, in vitro and in vivo disintegration time, and in vitro dissolution studies. Tablets with both the resins have shown quick disintegrating features, i.e., within 20 s, which is very characteristic of oro-dispersible tablets. Also, the dispersion not showing any bitter taste, indicate the capability of ion exchange resins used, both as taste masking and super disintegrating agents. Almost more than 90 percent of drug was released from both the formulations within 1 h. Further formulations were subjected to stability testing for 3 months at temperatures 25±5ºC/60±5%RH and 40±5ºC/75±5%RH. Both tablets have shown no appreciable changes with respect to taste, disintegration, and dissolution profiles.

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Nasal drug delivery system offers lucrative way of drug delivery of both topical and systemic therapies. The high permeability, high vasculature and low enzymatic environment of nasal cavity are well suitable for systemic delivery of drug molecules via nose. The noninvasiveness and self administrative nature of nasal delivery also attracts the formulation scientists to deliver protein and peptide compounds. Despite of all the advantages of nasal drug delivery, the bioavailability of nasally administered products, especially for protein and peptide molecules, is affected by many barriers such as physiological barriers, physicochemical barriers, and formulation barriers. This review will focus on the various bioavailability barriers in nasal drug delivery and the strategies to improve the bioavailability of nasal dosage forms.

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The present study is aimed towards formulation and evaluation of floating multiparticulate oral drug delivery system of diltiazem hydrochloride, which can provide sustained release. The work also aims to study various parameters affecting the behavior of floating multiparticulate in oral dosage form. Floating microspheres were prepared by non-aqueous emulsification solvent evaporation technique, using ethyl cellulose and Eudragit RS-100 as the rate controlling polymer. The in vitro performance was evaluated by the usual pharmacopoeial and other tests such as drug-polymer compatibility, (%) yield, particle size analysis, drug entrapment efficiency, surface topography, in vitro floatability and release studies. Results show that the mixing ratio of components in the organic phase affected the size, size distribution (199-320 µ m), drug content (59-84%), %yield (57-77%) and drug release of microsphere (45-99% after 12 h) and floating time >12 h. The best results were obtained at the ratio of drug: polymer Eudragit RS-100 (1:3). In most cases, good in vitro floating behavior was observed and broad variety of drug release pattern could be achieved by variation of the polymer ratio, which was optimized to match target release profile. Stability studies showed no significant change in the drug content in the formulation even after 3 months. The data obtained in this study thus suggest that a micro particulate floating dosage form of diltiazem hydrochloride can be successfully designed to give controlled delivery and improved oral bioavailability.

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Delayed release microspheres of aceclofenac were formulated using an enteric polymer, cellulose acetate phthalate (CAP) prepared by solvent evaporation technique. The effects of various other modern enteric polymers such as hydroxyl propyl methyl cellulose phthalate (HPMCP), Eudragit L 100, and Eudragit S -100 on the release of aceclofenac from the CAP microspheres have been evaluated. The microspheres were characterized for particle size, scanning electron microscopy (SEM), percentage yield, drug entrapment, and for in-vitro release kinetics. The shape of microspheres was found to be spherical by SEM. The drug entrapment efficiency of microspheres was found to be ranging from 75.65 to 96.52 %w/w. The study was designed in the form of a factorial design in which the effects of HPMCP, Eudragit L 100, and Eudragit S 100 on the release rate of drug from CAP delayed release microspheres were evaluated. The results revealed that the HPMCP exhibits positive influence whereas Eudragit L 100 and Eudragit S 100 exhibits negative effect on the drug release rate of CAP microspheres. In vitro drug release from all formulations followed the first order release kinetics and erosion plot. Formulation with drug: CAP : HPMCP ratio of 1:8:2 was considered best because it showed delayed release.

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Haloperidol, a butyrophenone, is widely used neuroleptic. Though haloperidol is well absorbed after oral dosing, there is a first pass metabolism leading to a reduced bioavailability of the drug (60-70%). Therefore, the present investigation is concerned with the development of melt-in-mouth tablets of haloperidol. Various formulations were prepared incorporating a combination of superdisintegrants, croscarmellose sodium, sodium starch glycolate, and crospovidone by direct compression method. The formulated melt-in-mouth tablets were evaluated for various physicochemical parameters, disintegration time and for in vitro drug release. All the formulations had disintegration time less than 30 s and release maximum amount of drug by 12 min. Formulation containing higher concentration of crospovidone decreases disintegration time and optimize the drug release. The most satisfactory formulation was found to be stable during the stability studies conducted as per ICH guidelines QIC, as it showed no significant changes ( P <0.05) in the physicochemical properties, disintegration time and in vitro drug release.

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The present work was designed to develop suitable transdermal matrix patches of tramadol hydrochloride, a non-steroidal anti-inflammatory drug, using hydroxy propyl methyl cellulose (HPMC), Eudragit RL-100 and Eudragit RS-100 with triethyl citrate as a plasticizer and dimethyl sulfoxide (DMSO) as a penetration enhancer. Different batches developed using Eudragit RL-100 : HPMC and Eudragit RS-100 : HPMC in ratio of 2 : 8, 4 : 6, 6 : 4, and 8 : 2. Drug - excipients interaction study was further carried out using Fourier transform infrared (FTIR) spectroscopic technique. Physical evaluation was performed such as moisture content, moisture uptake, tensile strength, flatness, and folding endurance. In vitro diffusion studies were performed using cellulose acetate membrane (pore size 0.45 µ ) in a Franz's diffusion cell. The concentration of diffused drug was measured using UV-visible spectrophotometer (Jasco V-530) at l_max 275 nm. The batch containing Eudragit RL-100 : HPMC (8 : 2) showed 79.65% release within 12 h and batch containing Eudragit RL-100 : HPMC (2 : 8) showed only 58.30% release in 12 h. This is because that the Eudragit produce crystallization free patch.

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The aim of this study was to evaluate the effect of increasing crospovidone (superdisintegrant) load on the characteristics of fast-disintegrating tablets for the potential use of the drug for its therapeutic effect. Five tablet formulations, F ₀ , F ₁ , F ₃ , F ₇ , and F ₁₀ containing 0%, 1%, 3%, 7%, and 10% (w/w) of crospovidone, respectively, frusemide and microcrystalline cellulose (PH102), were prepared by direct compression, at a different compression forces. Tablet weight variation, content uniformity, crushing strength, disintegration time, wetting time, and in vitro release were measured for each formulation at each compression force. A linear increase in compression force resulted in an exponential increase in hardness for all formulations, a linear increase in disintegration and wetting times was observed for the formulations F ₀ , F ₁ , F ₃ with the increase in compression force. The tablet formulation F ₇ indicated, there was no effect of compression force on disintegration and wetting time. The in vitro release of the drug was increased with increase in concentration of crospovidone irrespective the compression force. However, storage under high humidity conditions caused the softening of the tablets containing the high amount of crospovidone, leading to softening of tablets. Fast disintegration of the tablets within 1-2 min is prerequisite for improving the dissolution of frusemide, attributed to increase in speed at which maximum surface area of sparingly soluble drug is exposed to the dissolution medium. However, tablet containing high amount of crospovidone must be protected from the atmospheric moisture because storage of these tablets at high humidity led to softening and losing the tablet characteristics.

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Two simple, rapid, and precise methods - linear regression equation (LRE) and standard absorptivity - were developed and validated for the estimation of pioglitazone hydrochloride in tablet dosage form. The maximum absorbance (l_max ) of pioglitazone hydrochloride was found to be 269.8 nm in methanol:water:hydrochloric acid (250:250:1). Beer-Lambert law was obeyed in the concentration range of 10-50 µg/ml, and the standard absorptivity was found to be 253.97 dl/g/cm. Both the methods were validated for linearity, accuracy, precision (days, analysts, and instrument variation), and robustness (solvent composition). The numerical values for all parameters lie within the acceptable limits. Pioglitazone hydrochloride was estimated in the range of 99.58-99.97% by LRE method and 100.25-100.75% by standard absorptivity method. At 99% confidence limit, the F-test value for the methods was found to be 1.8767.

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A multiparticulate system combining pH-sensitive property and specific biodegradability for colon targeted delivery of 5-fluorouracil (5-FU) was examined. The purpose of this study was to prepare and evaluate the colon-specific alginate beads of 5-FU for the treatment of colon cancer. Calcium alginate beads were prepared by extruding 5-FU loaded alginate solution to calcium chloride solution, and gelled spheres were formed instantaneously by ionotropic gelation reaction using different ratios of FU and alginate, alginate and calcium chloride, stirring speeds (500-1500 rpm), and reaction time. The core beads were coated with Eudragit S-100 to prevent drug release in the stomach and provide controlled dissolution of enteric coat in the small intestine and maximum drug release in the colon. Morphology and surface characteristics of the formulation were determined by scanning electron microscopy. In vitro drug release studies were performed in conditions simulating stomach to colon transit. No significant release was observed at acidic pH, however, when it reached the pH where Eudragit S-100 starts to dissolve, drug release was observed. Also, release of drug was found to be higher in presence of rat caecal content.

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Forskolin, a diterpene obtained from natural roots of Coleus forskohlii (wild) Briq. (family: Lamiaceae ), reduces intraocular pressure (IOP) by 23-28%, which is a desirable feature for an antiglaucoma therapy. Polyvinyl alcohol-14000 based ophthalmic inserts of pure forskolin (PVA-OIF) were prepared as matrix drug delivery with the aim of achieving once a day administration. Ophthalmic inserts were prepared using polymer PVA in various concentrations. The ophthalmic inserts were evaluated for evaluation parameters and in vitro drug release. One-way ANOVA tested in vitro release characteristics statistically. The in vitro release data was treated according to diffusion model proposed by Higuchi and Peppas in order to access the mechanism of drug release. The batch formulated with PVA-14000 (1.5%), showed sustained drug release behavior over a period of 6 hrs.

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The purpose of the present investigation was to compare the characteristics of the microspheres of chitosan prepared using two different cross-linking agents: viz. formaldehyde and glutaraldehyde and by simple heat treatment. Chitosan microspheres were prepared by emulsification cross-linking method. Microspheres were characterized for entrapment efficiency, particle size, in-vitro drug release and surface morphology was studied by scanning electron microscopy. The entrapment efficiency of the glutaraldehyde and formaldehyde cross-linked microspheres was significantly higher ( P <0.05) than the heat-cross-linked microspheres. In-vitro drug release studies indicated that the microspheres cross-linked using glutaraldehyde showed slower release rate than those cross-linked with formaldehyde while the heat cross-linked microspheres showed the fastest release.

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Smoking is a practice where a substance, most commonly tobacco as dried or curled leaves is burned and the smoke is tasted or inhaled. This is primarily done as a recreational activity. But, owing to the chemicals present in tobacco, it slowly becomes addictive in nature. Few smokers use effective smoking cessation aids when trying to stop smoking. Smoking is the most important single cause of morbidity and mortality in under developed, developing and developed countries. Because smoking prevention will not affect tobacco-related mortality, quitting by current smokers is the main way to achieve positive effects on mortality. Many smokers are interested in quitting. Most of the smokers try to quit smoking at least once in their lifetime. To support smokers in their quit attempts, a wide range of smoking cessation aids is available. These comprise methods and products to assist smokers in quitting through coping with psychological or physical aspects of nicotine dependence. Meta-analyses have shown that smoking cessation courses, nicotine replacement therapy, and bupropion can significantly increase success rates in quitting. Even minimal interventions such as self-help materials have a small effect when compared with no intervention.

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