Increasing the Bioavailability of Eye Drops Essay

When formulated as modified release dosage forms, pellets are less susceptible to dose dumping than the reservoir-type single unit formulations.4 Micropellets technology delivers almost perfectly spherical particles exhibiting a very narrow particle size distribution and excellent flow properties and these are characterized by a smooth surface free of dust and thus provide optimal conditions for subsequent film coating. Controlled release pellets are manufactured either to deliver the bioactive agent at a specific site within the GIT or to sustain the action of drugs over an extended period of time. While these results have been traditionally achieved through the application of a functional coating material, at times the core pellets themselves have been modified to provide the desired effect. This further enhances the role of pellets in oral dosage form

Among other approaches tried by scientists, colloidal systems like liposomes, polymeric nanoparticles etc., have shown promise but not many products have made it to the market (7). Nanoparticulate drug delivery systems are gaining much popularity in recent years. Among these, nanoparticulate drug delivery systems from biodegradable and biocompatible polymer are an interesting option for controlled drug delivery and drug targeting (8). Amongst the various drug-delivery systems, solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLCs) are potentially attractive choices due to their natural components and easily scaled-up formulation processes. In addition, their hydrophobic core provides a suitable environment for entrapment of hydrophobic drugs (9). Among the important technological advantages of nanoparticles as drug carriers are: high stability (i.e. long shelf life), high carrier capacity (i.e. many drug molecules can be incorporated into the particle matrix), feasibility of incorporation of both hydrophilic and hydrophobic substances, and feasibility of variable routes of administration (10). NLCs are kind of lipid-based nanoparticles, which has the advantages of biodegradable, brain targeting, well-recognized safety profile by drastically reducing drug-related toxicities through reduction of nonspecific biodistribution (11). NLCs consist of an unstructured solid lipid

These forms can be classified into nanospheres and nanocapsules. Nanospheres are solid, monolithic spheres made of dense polymer matrix, wherein the active ingredient is dispersed, while nano-capsules creating reservoirs, made of polymer membrane contiguous the drug in solid or liquid form (Bucolo and Salomone, 2012). The drug absorption mechanism from nano-spheres or nano-capsules after their application to conjunctival sac includes dispersion of the drug and degradation of the polymer (Rathore, and Nema, 2009). The advantages of nanoparticles as an ophthalmic dosage form, rise corneal infiltration and a larger dissolution area, which enhances of the drug bioavailability when compared to conventional eye drops (Bucolo, and Salomone,

Accordingly, in vitro release rate of ketoprofen from KPT7 was the most convenient one among the previously studied tablet formulations showing an optimum lag time of 6hrs followed by a drug release after changing pH from1.2 to

The human gastrointestinal track is a complex time, position, patient-dependent absorptive, metabolizing, and excretive organ. Key of physiological factors that control absorption of drugs from the GIT include gastric, fluid and food intake, bulk fluid and luminal pH, gastric and intestinal secretions, absorptive mechanisms, enterocyte-based metabolism and secretion. Properties of a drug, such as its solubility, stability, ionization, and lipophilicity, strongly influence the rate and extent of drug absorption from GI lumen. Critical assessment of fundamental physicochemical properties and consideration of interplay with physiological constraints of the GIT are paramount to successful design of oral drug delivery systems. Ideal oral extended-release systems rely upon dosage form to control the rate of drug release with no effect from the intrinsic properties of the drug or the conditions prevailing within GIT [1].

Type of coating and method of applying coating will determine dominant mechanism of drug release from coated pellets. Release kinetic is predominantly determined by the behavior of coating material under physiological conditions of git. Multiparticulates coated for extended release purpose; release the drug by eighter diffusion or erosion or combination of these mechanisms.

Drug delivery is the method of transporting a pharmaceutical compound to safely achieve its desired therapeutic effect in the body by using approaches, formulations, technologies, and systems. Today these technologies are nanobiomaterials and the use of nanobiomaterials are unprecedentedly increasing in drug delivery thanks to their significant advances in the diagnosis and treatment of disease. The major goals of using nanomaterials are to reduce toxicity, increase biocompatibility, safety, and specific cell targeting. Otherwise, nanoparticle-based vehicles in drug delivery is an important technology because of their small-sizes, easy penetration through cells, increasing cellular uptake, and capacity to carry large amounts of drugs, thus

Liposomal microencapsulation for occular use has been employed to sustain the drug release, and to reduce or eliminate occular irritation. In addition,

About 40 million people in the world are blind and India is home to 1/3 of the world’s blind population. Yet, for many of these cases, it is preventable and treatable. In developing countries, the leading cause of blindness is attributed to cataracts, in which the natural lens of the eye clouds over time. This requires surgical

Various techniques have been used in attempt to improve solubility and dissolution rates of poorly water soluble drugs which include solid dispersion, micronization, lipid based formulations, melt granulation, direct compaction, solvent evaporation, co precipitation, adsorption, ordered mixing, liquisolid compacts, solvent deposition inclusion complexation and steam aided granulation. In these techniques carrier plays an important role in improving solubility and dissolution rate. Polymers, superdisintegrants, surfactants are extensively studied in recent years for dissolution enhancement in drugs.

In many pharmaceutical industries, spray drying is used to create particles that are utilized to form many oral or inhaled drugs. Thus, these particles are designed to be pressed into tablets or dispersed in aerosols. A spray dryer is a processing unit that produces a mist where the solvent is quickly evaporated, leaving particles that are collected in a cyclone. This quick evaporation leaves the molecules fixed in their current positions, preventing the molecules from finding their stable locations and generating a less stable structure. The structure of the active pharmaceutical ingredients (APIs) affects how the pharmaceutical drugs interact with the body (Vicente). Hence, bioavailability is the extent and rate at which an

Despite the tremendous advancement in drug delivery, oral route is the most preferred route to the systemic circulation due to the ease of administration, low cost of drug, patient compliance and flexibility in formulation. About 90% of all drugs used to produce systemic effects are administered by oral route. Of the drugs that are administered orally, solid oral dosage forms represent the preferred class of products. Tablets are the most common type of

In general, the lower the viscosity of the drug, the more comfortable and easy it will be to administer to the patient population. According to the data gathered in Lutz et al, the maximum viscosity is limited to about 30 cP or roughly 100–300gL^(-1) for mAb’s IgG concentration in a prefilled syringe. Viscosities being targeted for use with wearable injectors is between one and 100 cP (Shortall, 2014) Viscosity models and data suggests that temperature increase, altering the amino acid groups determining surface charges and van der Waals forces through molecular engineering, adjusting pH and using excipients can reduce viscosity. The effects of different excipients can vary significantly depending on the protein structure. (Lutz et al) Anion excipients reduce viscosity consistent with the Hofmeister series, while cation excipients provide equivalent viscosity reduction independent of the Hofmeister series. Hydrophobic attraction forces responsible for increased viscosity may be disrupted by hydrophobic excipients to reduce viscosity. Hydrophobic excipients such as sodium camphor-sulfonate, camphor-10-sulfanic acid *L Arginine, and camphor-10-sulfonic acid salt can reduce viscosity 10-fold. (See Lutz, Kanai, Guo, Du for more info) Using high-throughput computational and experimental tools can help estimate

Numerous hydrophilic drug delivery products have been formulated, mainly as matrices, using cellulosic polymers, and they are called "swelling-controlled release systems".

The purpose of writing this review was to investigate, compile, recent, current and past literatures. In recent years several advancements has been made in research and development of oral drug delivery system. Various drugs, which are unstable in alkaline pH, soluble in acidic pH, having narrow absorption window, site of action specific to stomach can be developed by using this technique. Gastro-retentive drug delivery systems (GRDDS) can improve the controlled delivery of drugs that have an absorption window by continuously releasing the drug for a prolonged period of time before it reaches to absorption site. These include floating system, swelling system, expanding system, low density systems, high density system, bioadhesive and mucoadhesive systems etc. In fact the buoyant dosage unit enhances gastric residence time (GRT) without affecting the intrinsic rate of emptying. GRDDS is an approach to prolong gastric residence time, thereby targeting site-specific drug release in upper gastro intestinal tract improving the oral sustained delivery of drug. For minimizing the limitations and achieving better gastric retention various combinational approaches floating and swelling, floating and bio-adhesion, etc., multi-particulate systems, super porous hydrogel etc., have been discussed. The present review addresses briefly about suitable drug candidates, formulation considerations, physiological difficulties and classification, factors effecting gastric retention, merits,