Poly (D, L-lactide-co-glycolide) (PLGA) is approved by the Food and Drug Administration for drug delivery use. The polymeric nanoparticles based on PLGA and its co-polymer are designed for controlled and targeted drug delivery. Also, PLGA and its co-polymer are important in designing nanoparticles with desired characteristics such as biocompatibility, biodegradation, particle size, surface properties, drug release and targetability. This review focuses on the polymer literature, methods for preparation of nanoparticles and recent studies on the nanoparticles based on PLGA and its co-polymer for the conventional and targeted delivery of drugs by various routes.

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The purpose of the study was to prolong the gastric residence time of atenolol by designing its floating tablets and to study the influence of different polymers on its release rate. Nine formulations of atenolol containing varying concentrations of polymers were designed by optimization. The floating matrix tablets of atenolol were prepared by direct compression method. The prepared tablets were evaluated for physicochemical parameters such as hardness, floating properties (floating lag time, floating time and matrix integrity), swelling studies and drug content. The physicochemical parameters of formulated tablets were found to be within normal range. A significant difference in drug release (P < 0.0001) and floating lag time ( P < 0.005) at 0.5, one, four and eight hours were observed. The floating lag time of all the formulations was within the prescribed limit (<10 minutes). All the formulations showed good matrix integrity and retarded the release of drug for eight hours. The release pattern of atenolol was fitted to different models based on coefficient of correlation (r). All the formulations, except F2, F3 and F6 showed Korsemeyer-Peppas model as the best fit model. Formulation F2 and F3 showed first order model while F6 showed zero order model. Diffusion exponent (n) value was found in the range of 0.52-0.99 indicating diffusion as a release mechanism. The swelling studies of all the formulations showed that formulations containing Xanthan gum has higher swelling indices than HPMC K100M and HPMC K4M. It can be concluded that formulations with higher swelling indices retarded the release of drugs more than those with lower swelling indices.

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A novel, safe and sensitive method of spectrophotometric estimation in the ultraviolet region has been developed using 1M lignocaine hydrochloride (an economic drug) as a hydrotropic solubilizing agent for the quantitative determination of tinidazole, a sparingly water-soluble antiprotozoal drug in tablet dosage form. Beer's law was obeyed in the concentration range of 5-25 µg/ml. Lignocaine hydrochloride does not interfere above 280 nm. There was more than a six-fold enhancement in aqueous solubility of tinidazole in 1M lignocaine hydrochloride solution as compared with the solubility in distilled water. Commonly used tablet excipients and lignocaine hydrochloride did not interfere in spectrophotometric estimation. Results of the analysis were validated statistically and by recovery studies. The results of analysis obtained by the proposed method were comparable with the results of analysis obtained by the Indian Pharmacopoeial method.

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Rapid and simple reversed phase chromatographic conditions have been developed to separate pharmacologically active components of antihypertensive drug formulations (enalapril maleate + amlodipine besilate and ramipril + hydrochlorothiazide) on high-performance liquid chromatography (HPLC) and thin layer chromatography. The mobile phase consists of methanol-water (60:40 v/v) for reversed-phase thin layer chromatography (RPTLC). Detection was carried out by iodine vapors. The HPLC method was developed on a C-18 column with detection carried out by a UV detector at 215 and 220 nm for enalapril maleate + amlodipine besilate and ramipril+ hydrochlorothiazide, respectively. The HPLC method was validated using data elements specificity, linearity and range, and accuracy and precision.

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The design of effective drug delivery systems has recently become an integral part of the development of new medicines. Hence, research continuously keeps searching for ways to deliver drugs over an extended period of time with a well- controlled release profile. The ionotropic gelation method was used to prepare sweet potato starch-blended controlled release alginate microbeads of ibuprofen. Sweet potato is an important crop in many developing countries. Although sweet potato originated from Central America, its ability to adapt to a wide variety of climatic conditions allows it to grow both in tropical and in moderate temperature regions of Africa, Asia and the Americas. The influence of various formulation factors such as in vitro drug release, entrapment efficiency, swelling study and micrometric properties was investigated. Other variables included sweet potato starch concentration, percentage drug loading, curing time, cross-linking agent and stirring speed during the microencapsulation process. The entrapment efficiencies were found in the range of 71.85 ± 2.04 - 94.53 ± 1.02%. The particle sizes were found in the range of 0.82 ± 0.006 - 1.08 ± 0.009 mm. This suggested that the ionotropic gelation method was successful in producing sweet potato starch-blended alginate microbeads.

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To evaluate the scientific knowledge and attitudes of health professionals in Palestine regarding the advantages of transdermal therapeutic systems (TTSs) over conventional therapy . Data were gathered from a questionnaire that was handed out to community pharmacists and physicians. Pharmaceutical industry decision makers were enrolled in this study. Data were analyzed using the SPSS statistical software program version 10 . 79.5% of pharmacists and 74% of physicians thought that TTSs eliminate variables due to gut absorption. 78.8% of pharmacists and 65.6% of physicians were in agreement regarding the capacity of TTSs to avoid first-pass metabolism. In this study, 83.3% of the physicians and 81.3% pharmacists still agree that TTSs may provide controlled release. 55.8% of pharmacists and only 26% of physicians believed that TTSs eliminate drug-plasma fluctuation. 56.8% of pharmacists and 63.5% of physicians agreed that TTSs can use drugs with low therapeutic indices. 81.3% of pharmacists and 85.4% of physicians believed that TTSs are not invasive and can be removed easily to stop drug administration. 81.3% of physicians and 89.1% of pharmacists thought that TTSs may irritate or sensitize the skin. Eighty-four percent of pharmacists and 75% of physicians recognize that TTSs should contain drugs that must be stable and have correct physicochemical properties. The importance of TTSs is understood and appreciated by Palestinian health personnel. Pharmaceutical industries should pay more attention to the development and production of TTSs due to the valuable advantages of this therapeutic system.

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Leflunomide, an immune modulatory prodrug that is rapidly converted to its active metabolite possibly in the gut wall, plasma and in the liver was microencapsulated by the solvent evaporation technique using a nonaqueous solution of polymethacrylate polymer to achieve its release from the microcapsules at a slower rate. At the optimal condition of process variables such as stirring speed, temperature of the medium, drug polymer ratio and ratio of light liquid paraffin and heavy liquid paraffin, maximum encapsulation efficiency was obtained. These microspheres were free-flowing in nature, discrete and uniform spherical in size, as evident by scanning electron microscopy. The in vitro release experiments were carried out in the simulated intestinal fluid (pH 7.2 phosphate buffer) using united States Pharmacopoeia (USP) XXII apparatus II. The data obtained from the dissolution profiles were compared using different kinetics models and the regression coefficients were compared.

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Levofloxacin is a fluoroquinolone antibacterial drug effective in the treatment of bacterial conjunctivitis. The objective of the present work was to develop ocular inserts of levofloxacin and evaluate their potential for sustained ocular delivery. Conventional ophthalmic solution shows the poor bioavailability and therapeutic response due to many pre - corneal constraints. These constrains necessitate the controlled and sustained drug delivery to become a standard one in the modern pharmaceutical era. Matrix-type ocular inserts were prepared by the film-casting technique in Teflon-coated Petri dishes and characterized in vitro by drug release studies using a flow-through apparatus that simulated the eye conditions. Nine formulations were developed, which differed in the ratio of polymers polyethylene oxide (PEO), hydroxypropyl cellulose (HPC) and ethyl cellulose (EC). All the formulations were subjected to evaluation of thickness, weight variation, folding endurance and drug content uniformity and in vitro release study. On the basis of in vitro drug release studies, the formulation with PEO/EC (F9) was found to be better than the other formulations (release of 101.35% within 24 hrs) and it was selected as an optimized formulation, which was further subjected to in vivo studies and ageing studies. The in vitro result revealed that formulation F9 followed a perfect zero-order kinetics release (n = 1.03) and the rest of the formulations released the drug by super case II kinetics (n > 1). It was also observed that increasing the proportion of PEO and HPC to EC increases the rate of release of Levofloxacin. On the basis of in vitro and in vivo correlation stability studies, it can be concluded that this ocular inserts formulation can be a promising once-a-day controlled release formulation.

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Sustained release tablet of Verapamil hydrochloride (VPH) was prepared by using Precirol ATO 5 (PREC) by direct compression of matrices prepared by using the melt granulation technique. The effect of different concentrations of PREC on the in-vitro drug release of VPH was studied by comparing it with the marketed formulation and percent release given in USP for VPH extended release tablets. Effect of release enhancers such as microcrystalline cellulose (MCC) and lactose on in-vitro drug release was also studied. Biopharmaceutical evaluation of the satisfactory formulation was also performed in order to estimate the maximum concentration of drug in plasma (C _max ), time required to reach maximum concentration (t _max ), elimination rate constant (k), elimination rate constant (t _1/2 ), area under curve (AUC _(0-t) and AUC _(02a), apparent volume of distribution (V _d ) and mean residence time. The results showed that PREC can be utilized as the matrix forming agent to sustain the release of VPH. The results of biopharmaceutical evaluation showed that the rate of absorption appeared to be more sustained, resulting in a more uniform plasma concentration profile of VPH. More bioavailability was noted with the sustained release formulation even though the drug has substantial first pass metabolism. The results indicated that it is possible to make once-a-day sustained-release tablet of VPH by using the melt granulation technique.

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The aim of this study was to develop ambroxol hydrochloride sustained release pellets by an extrusion-spheronization technique and subsequent coating with acrylic polymers. Acrylic polymers like Eudragit RL 30 D, Eudragit RS 30 D and Eudragit NE 30 D were used as release retarding coating polymers. The release retarding capability of these polymers was also investigated. In each case, 10% polymer on dry basis was loaded. The flow property, surface roughness as well as the drug release behavior of the pellets was found to be the subject of types of polymers. About 35% drug was released at the first hour in 0.1N HCl media (pH 1.2) from Eudragit RL 30 D-coated pellets but from Eudragit RS 30 D and Eudragit NE 30 D-coated pellets, only 13.75 and 2.43% drug was released, respectively. In buffer media (pH 6.8), about 54% drug was released at the first hour from Eudragit RL 30 D-coated pellets but only 64% drug was released at 10 h. From Eudragit RL 30 D- and Eudragit NE 30 D-coated pellets only 7.28 and 1.14% drug was released at 1 h, respectively, but about 5.14 and 5.86 h was required for 50% drug release from these two polymers and about 80% drug was released at 10 h. The functional groups present in the polymeric films played a significant role on in vitro release kinetics of the drug from the coated pellets. Different kinetic models like zero order, first order and Higuchi were used for fitting the drug release pattern. The Higuchi model was the best fitted for ambroxol release from the coated pellets. The drug release mechanism was derived with Korsmeyer equation.

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