Development of Controlled Drug Delivery Systems (CDDS)

Development of Controlled Drug Delivery Systems (CDDS) 1.1 CONTROLLED DRUG DELIVERY SYSTEMS (CDDS) Now a day’s on the development of Novel drug delivery systems (NDDS) marked consideration has been focused. The method of drug delivery to the site of action shows a significant effect on its efficacy. It leads to the development and evolution of novel drug delivery systems that enhanced performance of potential drug molecules. Novel drug delivery systems play a key role in pharmaceutical research and development. Since when compared new chemical moiety the developmental cost and time required for introducing NDDS is relatively low. Oral route remains one of the most ‘natural’ routes of drug administration and has seen remarkable accomplishments in the last couple of decades towards optimization of oral delivery of drug molecules. Oral ingestion is one of the oldest and most extensively used routes of drug administration. They provide an effective method of obtaining systemic and local effects. Drug delivery describes a process whereby a therapeutic agent is administered to the body in a controlled manner. The product’s commercial and clinical value, product differentiation can be improved by developed drug delivery technologies. These advanced technologies serve as an advanced resource to outreach the competition. By simplifying the administration and dosing regimen drug delivery technologies make medicine more acceptable and convenient to a patient. Any drug molecule by using Novel drug delivery system (NDDS) can get a ‘new life,’ and thus improving the competitiveness, patent life and market value. Among different NDDS present in the market, the major share in the market is hold by the oral controlled release systems because of its greater benefits of patient compliance and ease of administration. The development of novel and highly versatile delivery systems and osmotic drug delivery systems are the major contribution in oral NDDS. Basically, there are three novel modes of drug delivery, i.e. Targeted delivery, Modulated release and Controlled release. Targeted delivery refers to the administration of a drug carrier systemically in order to deliver drug to the specific type of cells, tissues or organs. Modulated release implies use of a drug delivery device that releases the drug under controlled environmental conditions, bio feedback, sensor input or an external control device at a variable rate. Controlled release refers to a specific device that delivers the drug at specific release profiles or at a predetermined rate into the patient body. 1.1 CONTROLLED DRUG DELIVERY SYSTEMS (CDDS) The nature of the controlled release dosage form is such that the release is determined by the design of the system and the physiochemical properties of the drug and is independent of the external factors or the microenvironment in which the dosage form is placed. These products typically provide significant benefits over immediate-release conventional dosage formulations. Optimum therapy with repetitive administration of conventional dosage forms (e.g. injectables, liquids or tablets) can classically be pursued by dosage scheduling. The aim of this process is to maintain drug concentration in a therapeutic range, above the minimum effective concentration and below the toxic concentration. Thus CDDS avoids the undesirable saw tooth characteristics of the plasma concentration vs time profiles of the conventional drug products. A diagrammatic illustration of controlled versus conventional dosage delivery is shown in Figure-1. Fig 1.1 Plasma Time profile of controlled drug release and conventional release The plasma concentration of the drug reaches a maximum (crest) with conventional dosage forms and then decrease (trough) at the point where repeated administrations becomes necessary to maintain the plasma drug concentration. Very often the initial concentration is above the therapeutically effective level that may increase the risk of side effects. Conventional dosage forms can thus result in a drug regimen in which the drug concentration oscillates between alternating periods of overdose and inefficiency. The delivery of drug at controlled rate over an extended period of time is represented mathematically: Rate in = Rate out = Ke x Cd x Vd Where Cd is the desired drug level, Vd is the volume of distribution and Ke rate content for drug elimination from the body. Added to this, the high cost of development of new, safe, specific and effective drug molecule is prohibitive and developing nations virtually cannot afford such integrated multi-group cost intensive drug development ventures. Therefore, many pharmaceutical industries and drug research institute oriented their efforts to develop pre-programmed unattended delivery of drug at a rate and for a period to meet and achieve the therapeutic need. These systems are coined as Controlled drug delivery systems Table 1.1 Classification of oral controlled release systems depending on mechanism of Release 3 (vyas etal,2002) 1.1.1. ADVANTAGES OF CONTROLLED RELEASE PRODUCTS 4 As controlled release dosage form are slightly expensive than conventional formulations, they cannot be justified unless they offer come clinical or practical advantages given below: Reduction in dosing frequency More uniform effect Reduced fluctuation in steady levels Increased safety margin of high potency drugs Improved patient convenience and compliance Reduced in total amount of dose administered Avoidance of night time dosing Reducing of GI irritation and other dose related side effects and Reduction in health care cost. 1.1.2.DISADVANTAGES OF CONTROLLED RELEASE PRODUCTS 4 However, controlled drug delivery systems also have some disadvantages. They include, High cost; Poor systemic availability; Unpredictable and often poor invitro-invivo correlation; Possibility of dose dumping; Dosage adjustments potential is reduced; First pass clearance potential is increased; In case of hypersensitivity reactions, toxicity or poisoning drug retrieval is difficult; Effect of oral dose depends on Mean Residence Time. To control or change the drug release from a dosage form there will be a number of design options. Most of the per oral controlled release dosage forms comes under the category of osmotic, matrix or reservoir systems. The polymer matrix contains embedded drug in matrix systems in which the release occurs by partitioning of drug into the release medium and polymer matrix. In case of reservoir systems a rate controlling membrane is surrounded and coated around the drug core. But, drug release from conventional controlled systems i.e., reservoir and matrix systems is affected by various factors like presence of food, pH and different physiological factors. In case of osmotic systems the drug is delivered based on the principles of osmotic pressure. The drug release from this system doesn’t depend on the pH and various physiological parameters and thus by optimizing the drug and systems properties the release characteristics can be modulated. 1.2. OSMOTIC DRUG DELLIVERY SYSTEMS – A REVIEW 1.2.1. HISTORICAL BACKGROUND In 1955 Rose and Nelson utilized the principles of osmotic pressure in drug delivery for the first time. They described two systems; one that delivered 0.02 ml/day for 100 days and another that delivered 0.5 ml/day for 4 days, both for use in Pharmacological research. In the 1970s, Higuchi and Leeper proposed a series of variations of the Rose-Nelson pump5. Theeuwes further modified the Rose-Nelson pump and developed a system. Small osmotic pumps of these forms are sold under the trade name ALZET (Alza Corp., CA). The device has a volume of approximately 170Â µl, and the normal delivery rate is 1Â µl/hr. A major milestone was achieved in 1974 with the description by Theeuwes and Alza’s co-workers of a tablet design composed of a compressed tablet-core surrounded by a semi permeable membrane with a single orifice, so-called Elementary osmotic pump (EOP). This design adaptation for human use was conveniently processable using standard tabletting and coating procedures and equipment. The first two products indomethacin, Osmosin6 and phenylpropanolamine, Acutrim TM6 were launched in the 1980s. Oral osmotic drug delivery system (OODS) development continued with two new OODS designs, the controlled-porosity osmotic pumps (CPOP) and the push-pull osmotic pumps (PPOP). The first of these was the CPOP, which was designed to decrease the risk of extremely localized drug-induced irritation at the site close to the orifice. In the 2000s, a new drug product based on OODS technology was formulated to deliver methylphenidate to children (above the age of 6 years) with attention-deficit hyperactivity disorder (ADHD). These delivery systems were based on a new design, the push-stick osmotic pumps (PSOP), which combined immediate and sustained drug release phases. The drug release from this system doesn’t depend on the pH and various physiological parameters and thus by optimizing the drug and systems properties the release characteristics can be modulated. In the last few years more number of patents are granted on these oral omotic drug delivery systems. These systems has ability to improve therapeutic agents clinical profile and so they are becoming one of the most attractive technologies today. Osmotically controlled oral drug delivery system for the controlled delivery of active agents follows osmotic pressure principle. For the controlled drug delivery osmotic devices are most assured strategy based systems. Among the controlled drug delivery systems these are most reliable systems. Osmotic systems could be used in the form of implantable devices or oral drug delivery systems. Osmotic pump tablet (OPT) generally consists of a core including the drug, an osmotic agent, other excipients and semi-permeable membrane coat. 1.2.2. THEORY Osmosis can be defined as spontaneous movement of a solvent from a solution of lower solute concentration to a solution of higher solute concentration through an ideal semi permeable membrane, which is permeable only to the solvent and impermeable to solute. The pressure applied to the higher-concentration side to inhibit solvent flow is called osmotic pressure8. Osmotic pressure is a colligative property, which depends on concentration of solute that contributes to osmotic pressure. Solutions of different concentrations having the same solute and solvent system exhibit an osmotic pressure proportional to their concentrations. Thus a constant osmotic pressure, and thereby a constant influx of water can be achieved by an osmotic delivery system that results in a constant zero order release rate of drug8. PRINCIPLE OF OSMOSIS An osmotic system releases a therapeutic agent at a predetermined, zero order delivery rate based on the principle of Osmosis, which is movement of a solvent from lower concentration of solute towards higher concentration of solute across a semi-permeable membrane. When osmotic system is administered, from the one or more delivery ports the drug that contain suspension or solutions is pumped out of the core due to the hydrostatic pressure developed by the imbibition of water in to the core osmotically through the semi-permeable membrane. By the water influx through semi-permeable membrane the delivery of drug from this system can be controlled. Osmotic pressure is directly proportional to temperature and concentration and the following equation describes the relation between them: ÃŽ   = ØcRT where OP = osmotic pressure, ÃŽ   = osmotic coefficient, c = molar concentration, R = gas constant, T = Absolute temperature. OSMOTIC PUMPS Osmotic pump is a new delivery device, which delivers drugs or other active agents at a controlled rate by the principle of osmosis. Control resides in the water permeation properties of the formulations Table: 1.2 Examples of some marketed band of Osmotic drug delivery system7 DEPARTMENT OF PHARMACEUTICAL TECHNOLOGY, SVCPPAGE 1

Evaluating Employees with Ease Essay

Performance evaluations are a critical component of human resource management in any organization. In â€Å"Evaluating Employees with Ease† Sharon LaBuke gives useful tips designed to help nursing employers conduct evaluations that translate into a positive experience for their employees. In LaDuke’s view, the first priority is to strategize the process. A good place to start is the examination of the evaluation document that forms â€Å"a common frame of reference for both manager and employee† (LaDuke, n.d., p. 49). It is noteworthy that the author places cultural issues at the top of the list of priorities, suggesting that employers thoroughly evaluate the culture of their facility to see whether the process is consistent with the culture. Relationships with the people evaluated and finding the right language are also at the top of the list, since these issues help set the right kind of atmosphere for the evaluation process, suggesting that people will feel better if they know the employer has the right kind of attitude. The second set of suggestions involves more organizational aspects. For example, LaDuke suggests that people will feel the evaluation is more objective when they know that they are being evaluated on an ongoing basis, with feedback offered throughout the year. To help make assessments more detailed and grounded in facts, employers can log important events and try to address them in a timely fashion. The creation of a personal plan for improvement is also a useful idea. Created with staff input, this plan can serve as a roadmap for individual development, helping the person to focus on the right areas. Constantly following up on the progress with the plan, the manager can create an ongoing dialogue with the employee concerning personal needs. The author effectively captures the most important points in the evaluation process. It is helpful that the focus is on the personal development of the employee, not on evaluation per se. the nurturing nature of such evaluation clearly has the potential to contribute to the employees’ development and foster adequate atmosphere in the organization. Reference LaDuke, S. (n.d.). Evaluating Employees with Ease.

History DBQ

Ancient World: Civilizations and Religion Thousands of years ago, Ancient River Civilizations were thriving. At the time, they were like Paris, France, London, England or New York, New York; they were the places everyone wanted to be. These river civilizations established farming, formal religious rituals, governments, and writing and with all of these put together, they eventually became popular cities that created technology that made life much easier. You might have heard of many of these well known ancient civilizations such as: Mesopotamia,Egypt, India, and China. None of these civilizations would have been known if they hadn't made use of the technology and ways of living they developed. Ancient Mesopotamia, located between the Tigris and Euphrates rivers, is one of the many well known river civilizations. Ancient Mesopotamia consisted of city states including Assyria, Babylon, and many others. According to Document #1 , at around BBC, Assyrian physicians came up with the brill iant idea of using bandages to reduce swelling and to heal wounds. Might this be where the creation of â€Å"Band-Aids† started?It's always a possibility; the Ancient Mesopotamia created this thousands of years ago and we kept the invention growing because it worked. With the creation of the bandage, the Mesopotamia gained some thrill points in the area of medicine. The idea that was probably thought of as absurd eventually ended up being a technology that everybody uses to prevent wounds from becoming worse than what they start as. Bandages are still being used and updated in the 21st century. Imagine bandages in the next hundred years! Bandages weren't the only things Mesopotamia could boast about creating! Document #3 mentions that inBabylon, between 600 and BBC, Manipulators, king of Babylon, started developing the building of the Great Ramparts of Babylon. However, by the time Unpopularity's reign was ending, he had not yet finished the Great Ramparts. So his eldest son, Nebuchadnezzar, finished the Ramparts for his father. The finished Ramparts had a moat, 2 strong walls made of burnt brick circling the area, and fences 2. These Ramparts provided a type of safety barrier for the Babylonians. It protected them from the outside world; it was almost impossible from anyone to get in, and unless you knew a passageway, it was hard to get out.The next River civilization is Ancient Egypt. Egypt, located near the Nile River, was well known for many things. These things included their new means of travel, their process of mummification, their pyramids, and many more! If you've read the Kane Chronicles Series by Rick Ordain, you would already have some background information in mind about Ancient Egypt. However, in case you haven't read the book, the picture in Document #2 shows that when it came to transportation across the Nile, navigation was tough.Not many people were able to get through the Niles cataracts, rocks, rapids and waterfalls and hill they wer e traveling across the Nile, things happened and they were never seen again. So, the Egyptians created a boat called a Baroque. The Baroque helped travel across the Nile become easier. Baroque's were stronger than most other boats, so crashing into a rock once or twice didn't cause much damage. The Ancient Egyptians were also huge on domesticating plants and animals. They domesticated as much as cows down to the papyrus plant that they used to draw this primary source!The domesticated animals mainly helped with transportation on land and with food. The animals with higher populations could easily be killed to make food the same way we kill pigs, chicken, and cows to eat. The bigger animals such as cows could help carry things necessary to make even the smallest voyage into the desert. That's not the only thing Egyptians are known for! While the creation of the baroque bought Egypt thrill points in travel and the domestication of plants and animals bought the same in farming, the Anc ient civilization's most known skill was mummification.Document #4 describes the process of mummification. First, the embalmers, also known as the people who mummify the body, take out all of the body's organs and store them in separate Jars. Each lung gets a big Jar, the heart gets a medium sized Jar, the eyes are removed and put in smaller Jars, so on and so forth. The embalmers then slice open the corpse and fill the stomach with spices and herbs to make sure the body doesn't smell extremely bad after time. They then sew the body back together and put the body in salt for 70 days to mummify.After the 70 days, they wrap the corpse in bandages bonded by gum and put the body in a caskets. This entire process was done to King Tutu, and other pharaohs of the time. The mummification process bought experience to the Ancient Egyptians on medicine and preservation. Ancient India is another river civilization that advanced over the creation and use of new technologies. Located in the Indus River Valley, India created very unique towns in comparison to most other river civilizations.As shown in Document #6, Ancient India was an urban area with lots of streets and houses. Ancient India back then was similar to the Urbana of New York currently. There were houses from 1 story to 3 stories made of bricks, and these houses all had yards, Just like most houses in neighborhoods do. Each house was circled by a fence and right out of those fences we streets that led to other houses or other places. The ancient Indus civilization also had drainage systems in every house that led to the main street where there was lots of room to store the civilization's waste.I personally believe that the Indus River civilization was the most similar to America today because of the fact that their cities were so urbanize. Ancient China, located between the Yanking and Yellow rivers is the last major Ancient River civilization. China is well known today for exporting the majority of America's go ods. However, according to Document #7, during the 1 lath century BC, China was big with silk. If you've read Project Mulberry by Linda Sue Park, it tells a story of a young Chinese girl that does a project relating to the silk creating rates of silkworms in Mulberry trees.This was called sericulture. In Ancient China, Chinese people domesticated silkworms to create tons of silk. They eventually ended up weaving that silk into clothing and embroidery and the Chinese Civilization started trading the silk the same way they trade goods today. The trading of the silk clothing ended up making the civilization richer and richer day by day! Silk wasn't the only thing China had! According to Document #5, in the bronze age, the Chinese River Civilization suddenly doubled in strength.During this time, they created horse drawn chariots, a new form of writing, their own calendar, and social classes. With all of these elements, China finally became a full civilization with technologies supportin g it. To conclude, the four Ancient River Valleys started off as nothing, but eventually, with the help of technology, Mesopotamia, Egypt, India and China all ended up being lots more than what they started off as. The increase of the usage of cosmologies in the civilizations really helped them thrive as a whole and become the civilizations we know them as today.

Greek Philosophies Impact On The Early Development Of...

Christianity belief is seen more as a theology while Greek thinking or Hellenism is seen more as a philosophy. All theologists are philosophers but not all philosophers are theologists. Greek philosophies had great impact on the early development of Christian thought. Much of the elements in the early Greek philosopher’s theories regarding the soul, creation, and salvation were reflected in the development of early Christian thought. The Greeks were tenacious in asking why and how questions concerning those and things around them, and even about themselves. The main purpose behind theology is to understand and follow God’s divine revelation. Philosophy tends to arrive to general principles through consideration of what is perceived by the sense, which is then rationally evaluated. Theologists like Augustine and Thomas Aquinas both discovered the use of Aristotle in the formation of the Christian mind. Aristotle, a Greek philosopher, believed that all humans had a purpose and that the purpose was for the greater good. However, the good life or the blessed life for Aquinas and Augustine was heaven. For Greek thinkers like Aristotle or even Plato, human actions derived from reason, rationality, and intellect. Christian thinkers like Augustine saw philosophical reflection as a complement to theology. Those philosophical reflections were based off of the underlying intellectual commitment of the Christian Faith. The thoughts of both Augustine and Thomas AquinasShow MoreRelatedGender, Or Race, And Many Christians Essay1074 Words   |  5 Pagesgender, or race, and many Christians did not believe in killing. The apologies demonstrated the fallacy of pagan religions and Christianity. The importance of Christian history provides an example of those who took their faith seriously in the early church. 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