Tacrolimus (FK 506) is a potent macrolide lactone immunosuppressive agent used for prophylaxis of organ rejection after transplantation and graft-versus-host disease after bone marrow transplantation in patients. Moreover, tacrolimus is a drug of choice in the treatment of atopic dermatitis for decreasing side effects associated with the use of topical corticosteroids. In spite of its success in ensuring graft survival, therapeutic use of tacrolimus is complicated due to its narrow therapeutic index (between 5 and 15 ng/ml). Tacrolimus has a large inter-/intra-patient variability in pharmacokinetics profile and a poor oral bioavailability because of its poor solubility, P-gp efflux, marked pre-systemic metabolism by CYP3A in the enterocytes and liver first pass effect. Several formulation approaches such as oily solution, solid dispersions, complexation with cyclodextrins, liposomes etc., have been investigated to improve oral delivery of FK 506. In this review, we have discussed various formulation approaches that have been undertaken by various researchers to solve the problems related to the drug delivery of tacrolimus.

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Purpose: Niosomes play an increasingly important role in drug delivery as they can reduce toxicity and modify pharmacokinetic and bio-availability. Topically applied niosomes can increase the residence time of drugs in the stratum corneum and epidermis, while reducing the systemic absorption of the drug. It can act as drug containing reservoirs and the modification of the vesicular compositions or surface properties can adjust the drug release rate and the affinity for the target site. Ketoconazole is a broad spectrum Imidazole derivative useful in the treatment of superficial and systemic fungal infections. Materials and Methods: In order to improve the low skin penetration and to minimize the side effects associated with topical conventional drug administration, Ketoconazole niosomes were prepared by a thin film hydration method using different ratios of non-ionic surfactants (Span 40, 60 and Tween 60) along with cholesterol (CHO). The formulations were evaluated for size, shape, entrapment efficiency and in vitro drug release. Results: Niosomes appeared spherical in shape and size range was found to be 4.86 ± 1.24-7.38 ± 3.64 μm. The entrapment efficiency was found in the range of 55.14 ± 2.29-78.63 ± 0.91% and in vitro drug release in the range of 46.63 ± 0.95-72.37 ± 0.59% in 24 h. Ketoconazole niosomes formulated with Span 60 and CHO in the ratio of 1:0.2 were found to be promising and were incorporated into 1% Carbopol gel. The formulated gel was evaluated for various physicochemical parameters and antifungal activity. The in vitro drug release study was carried out using phosphate buffer saline pH 7.4 and was found to be 36.18 ± 1.50% in 12 h. Conclusion: Gel formulation containing niosomes loaded with Ketoconazole showed prolonged action than formulations containing Ketoconazole in non-niosomal form and it can be developed successfully to improve the antifungal activity.

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Purpose: The purpose of this research work was to formulate raft-forming chewable tablets of H ₂ antagonist (Famotidine) using a raft-forming agent along with an antacid- and gas-generating agent. Materials and Methods: Tablets were prepared by wet granulation and evaluated for raft strength, acid neutralisation capacity, weight variation, % drug content, thickness, hardness, friability and in vitro drug release. Various raft-forming agents were used in preliminary screening. A 2 ³ full-factorial design was used in the present study for optimisation. The amount of sodium alginate, amount of calcium carbonate and amount sodium bicarbonate were selected as independent variables. Raft strength, acid neutralisation capacity and drug release at 30 min were selected as responses. Results: Tablets containing sodium alginate were having maximum raft strength as compared with other raft-forming agents. Acid neutralisation capacity and in vitro drug release of all factorial batches were found to be satisfactory. The F ₅ batch was optimised based on maximum raft strength and good acid neutralisation capacity. Drug-excipient compatibility study showed no interaction between the drug and excipients. Stability study of the optimised formulation showed that the tablets were stable at accelerated environmental conditions. Conclusion: It was concluded that raft-forming chewable tablets prepared using an optimum amount of sodium alginate, calcium carbonate and sodium bicarbonate could be an efficient dosage form in the treatment of gastro oesophageal reflux disease.

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Introduction: A tablet system consisting of cores coated with two layers of swelling and rupturable coatings was prepared and evaluated as time controlled chronomodulated tablet. Materials and Methods: Cores containing Montelukast sodium as model drug were prepared by direct compression and then coated sequentially with an inner swelling layer containing a HPMC E 5 and an outer rupturable layer of Eudragit RL/RS (1:1). A three-factor, two-level, full factorial design was used to investigate the influence of amount of HPMC E 5 and Eudragit RL/RS (1:1) on the responses, i.e., lag time to release and time required for 80% of drug to releases. The dissolution tests were studied using the USP paddle method at 50 rpm in 0.1 N HCL for 2 hr and than in phosphate buffer pH 6.8. Result: The lag time of the drug release decreased by increasing the inner swelling layer and increased by increasing the rupturing layer level. Conclusion: The results obtain from present study suggest that swelling come reputable coating approach gives desire drug release after lag time.

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Purpose: The purpose of the present investigation was to improve the flow and mechanical properties of racecadotril by a crystallo-co-agglomeration (CCA) technique. Direct tableting is a requirement of pharmaceutical industries. Poor mechanical properties of crystalline drug particles require wet granulation which is uneconomical, laborious, and tedious. Materials and Methods: The objective of this work was to study the influence of various polymers/excipients and processing conditions on the formation of directly compressible agglomerates of the water-insoluble drug, racecadotril, an antidiarrheal agent. The agglomerates of racecadotril were prepared using dichloromethane (DCM)-water as the crystallization system. DCM acted as a good solvent for racecadotril as well as a bridging liquid for the agglomeration of the crystallized drug and water as the nonsolvent. The prepared agglomerates were tested for micromeritic and mechanical properties. Results: The process yielded ~90 to 96% wt/ wt spherical agglomerates containing racecadotril with the diameter between 299 and 521 μ. A higher rotational speed of crystallization system reduces the size of the agglomerates and disturbs the sphericity. Spherical agglomerates were generated with a uniform dispersion of the crystallized drug. CCA showed excellent flowability and crushing strength. Conclusion: Excipients and processing conditions can play a key role in preparing spherical agglomerates of racecadotril by CCA, an excellent alternative to the wet granulation process to prepare intermediates for direct compression.

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Purpose: The demand for melt-in-mouth tablets (MMTs) has been rapidly growing during the last decade, especially for the elderly and children who have swallowing difficulties, to avoid first-pass metabolism and quick drug entry into the systemic circulation. Materials and Methods: In this work, a new approach has been tried to prepare MMTs using a hydrophilic waxy binder [polyethylene glycol (PEG)-6-stearate]. Carvedilol MMTs were prepared by direct compression method using different mucoadhesive polymers such as hydroxypropyl methylcellulose (HPMC), chitosan, and sodium carboxymethyl cellulose (Na-CMC) at various concentrations (range: 0.5-5%) to reduce the flushing action of saliva and to increase mucosal absorption. All the formulations were evaluated for various physiochemical parameters, and the formulations containing the maximum amount of polymer (F4, F7, and F10) were selected for further stability study. Results: The deaggregation time of the tablets was found to be rapid, and the dissolution test revealed that carvedilol was dissolved from the formulation within the compendia limits. This data confirmed that the polymer concentration (0.5-5%) was within acceptable limits. It was also concluded that avicel PH101, pearlitol SD 200, and croscarmellose sodium (CCS) were the appropriate excipients and formulated in the right proportion. Conclusion: As a result, mouth dissolving administration of carvedilol formulated with appropriate excipients and especially with chitosan seems a promising alternative to traditional routes.

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Aim: Prevention of periodontal disease progression is the primary goal of periodontal therapy. When conventional therapy is found to be inadequate in achieving periodontal health in chronic periodontitis, local antimicrobial agents are used as an adjunct to scaling and root planing (SRP), which produces encouraging results. In the present study, an attempt was made to develop a low-dose controlled-release delivery system for the treatment of periodontal infections. A new sustained release drug system of poly e-caprolactone (PCL) nanofibers containing metronidazole (MET) was successfully electrospun and evaluated clinically for periodontal diseases. The retentive nanofibres were shown to provide a controlled delivery of the drugs. Materials and Methods: Nanofibers were prepared with MET in PCL by electrospinning technique. The drug-coated nanofibers provided sustained effect up to a period of 11 days (264 h) and followed first-order release. Forty sites in seven patients (four females and three males) with chronic periodontitis (5-8 mm probing depth) were allocated in two experimental treatment groups: Group A treated with SRP + MET nanofibers and Group B treated with SRP alone (control group). All these patients were evaluated clinically for probing depth (PD), plaque index (PI), and gingival index (GI). Results: Both the treatment groups were found to be efficacious in the treatment of periodontal disease as demonstrated by improvement in PD, PI, and GI. Conclusion: Combination of SRP + MET nanofibers (Group A) resulted in added benefits, compared to the control group.

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