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Medicine, Pharmaceutics and Dosage Forms

What is a medicine or drug?

A medicine is a chemical substance which can be defined as an agent intended for use in:

Diagnosis – Identification of the nature of illness or disease in man or animal,
Mitigation – Action of reduction of the severity of disease in man or animal,
Treatment – Manner in which we use the drug or treatment for treating any disease in man or animal,
Cure – Provided relief from a disease in man or animal, or
Prevention – Protects a man or animal from a disease.

What is pharmaceutics?

The science of dosage form design is called pharmaceutics. It is the discipline of pharmacy that directly deals with the process of turning new chemical entities or old dosage forms into a medication that can be safely and effectively used by patients.

The field of Pharmaceutics specifically deals with formulation development, packaging, stability & marketing of the new dosage form. In the development process of a new dosage form, pharmaceutics gives special attention on issues such as how many drugs to be used in creating the new dosage form, the quantities of drug to be used and how much drug will be effective for treating the disease.

Developing a new drug or a new dosage form from an old drug form are also examples of New Chemical Entities. Such New Chemical Entities can be newly synthesized or obtained naturally. Examples of dosage forms include tablets, capsules, powder, granules, pills, syrups etc.

Dosage Forms

Dosage forms are the means by which a drug molecule or an API (Active Pharmaceutical Ingredients) is delivered to the site of action within the body to produce optimum desired effects and minimum adverse effect.

For example, almost everybody knows about a Paracetamol tablet which is commonly used to treat headaches and fever. In a Paracetamol tablet, Paracetamol is the API or the Active Pharmaceutical Ingredient and tablet is the dosage form. To have the right effect and provide the precise pharmacological action, the API which is Paracetamol has to reach the site of action, which is the brain, and then have the exact pharmacological action, and treat the headache. Without a dosage form such as tablet, this whole process would have faced several barriers and its impact on the site of action would have suffered as a result.

What is Dosage form made from?

Dosage form is made from API and Excipients. While APIs (Active Pharmaceutical Ingredient) show the pharmacological action, excipients help in increasing the bulk of the API and provides stability to the API so that the API can cross the barriers and reach the site of action.

All APIs have a pharmacological action which needs to be identified. Depending on the disease the dose of API varies, however the API in itself is not sufficient to reach the site of action and requires additional excipients to create a practical dosage form.

Please note that excipients do not increase or decrease the therapeutic action of any active ingredient. It is interesting to note here that excipients are generally inert in nature and don’t have any pharmacological action.

Examples of excipients include binding agents, sweetening agents, flavoring agents or preserving agents. Acfording to the dosage form the exceipients are selected and converted into a dosage form.

Why are dosage forms required?

Dosage forms are primarily required for 3 main purposes:

Providing a safe and convenient delivery of accurate dosage. For example, tablets, capsules or syrups.
Concealing the bitter taste or odor of the API. For example, Coated tablets or flavored syrups.
Protection of drug substances from atmospheric oxygen or moisture. For example, coated tablets or sealed ampoules.
Ram-Eesh Institute is the best Pharmacy college in Greater Noida, Delhi NCR and Uttar Pradesh.

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What is the importance of accounting?

It is important to keep your financial records updated to ensure smooth functioning of your business.

Helps in evaluating the performance of the business

The financial records give a clear picture of operations as well as the financial position of small business or corporation. It helps in better understanding the financial status of your business. Accounting not only helps you maintain a track of your expenses, gross margin and income but also helps in allocating the budget properly by comparing the previous data.

Ensures statutory compliances

Proper accounting will help maintain statutory compliances when it comes to your business. Liabilities such as GST, income tax, pension funds and others will be properly addressed.

Non-maintenance of books and accounts is an offence punishable by law. If a company fails to abide by the statutory compliances, the company will be liable to a huge penalty.

Creating a proper budget and future projections

A businesses financial record plays a crucial role when it comes to budgeting and futuristic projections. Previous financial data is used to provide the base of business trends. With proper financial records, it is possible to make business decisions concerning budgetary and the onset of future projects.

Filing financial statements

Accounting Services plays a critical role while filing financial statements with the Registrar of companies. Financial statements are required for stock exchange and also for direct and indirect tax filing purposes.

Financial statements build trust in a company. A company’s financial statements act as a base for investors to decide on whether to invest their hard-earned money in the company.

The balance sheet of a company can have a huge impact on the company. The value of assets varies from the time they were purchased. A certain number of revenue earned will be stated by the company. But how much of that amount is actual cash and how much of it amount receivable should be accurately stated.

Conclusion

Proper accounting outsourcing services will help you deal better with financial issues. Accounting requires accuracy and good quality work. When you decide on outsourcing your accounting services, you’ll find more time to work on the growth opportunities of your business.

At Aavana, we have a team of dedicated professionals who will work with your business’s accounting needs. You can count on us to render quality services that will best suit your needs. We also do online accounting services.

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Functions and Classification of Semiconductor Diodes

Diodes play an important role in electronic circuits. To understand the circuits, we must first learn the function of various electronic components in the circuit.

I Classification According to the Structures

Semiconductor diodes mainly rely on PN junctions to work. And according to the characteristics of the surface structure of PN junctions, the semiconductor diodes are divided into the following types

1. Point-contact Diode

The point-contact diode is formed by pressing a metal pin on a single chip of germanium or silicon material and then performing the current method. Therefore, the PN junction has small electrostatic capacitance suitable for high-frequency circuits. However, compared with the junction type, the point contact diode has poor forward and reverse characteristics, which is not suitable for large current and rectification. And as its construction is simple, the price is cheap. Therefore, it is widely used for general purposes such as detection, rectification, modulation, mixing and slicing of small signals.

2. Bond-type Diode

The bond-type diode is formed by fusing a silver filaments on one chip of germanium or silicon. Compared with the point-contact type, although the capacitance of the PN junction in bond-type diode is slightly increased, it has excellent forward characteristic. So it’s usually used for switching and sometimes used for detection and power rectification (no more than 50mA). And bond-type diode fused with golden wires is referred to as golden-bond type diode, and that fused with the silver wire belongs to silver-bond type diode.

3. Alloyed Diode

A PN junction is formed by alloying a indium or aluminum metal on a germanium or silicon single chip of N-type. Its forward voltage drop is small, suitable for large current rectification. Since its PN junction has a large electrostatic capacity when it is reversed, it’s not suitable for high-frequency detection and rectification.

4. Diffused-type Diode

In a high-heat foreign gas of P-type, a N-type single chip of germanium or silicon is heated to make a portion of its surface become P-type, and the PN junction of diffused-type diode is obtained. Due to the small forward voltage drop of its PN junction, it is suitable for heavy current rectification. Recently, the mainstream of large current rectifiers has been transferred from a silicon-alloyed type to a silicon-diffused type.

5. Mesa-type Diode

Its PN junction is made in the same manner as the diffused type, but its unnecessary portions are corroded. Thus the rest of the section is in the shape of a mesa. Initially, the mesa-type diode is made by diffusing the semiconductor materials, so it’s also called diffused mesa type diode. This type is mainly used for small current switches.

6. Planar Diode

On an N-type silicon single chip, a part of P-type foreign gas is diffused through the shielding effect of the oxide film on the surface, thus forming the PN junction of planar diode. Therefore, there is no need for corrosion to adjust the area of PN junction. Further, since the surface of the PN bond is flat and covered by the oxide film, it has good stability and long service life. It’s also called the epitaxial planar type diode at first for the semiconductor material is formed with epitaxial method. Planar diode is also primarily used for for small current switches.

7. Alloy-Diffused Diode

It is a type of alloyed diode. As alloy materials are easily diffused, if we subtly blend the impurities with the materials, then the mixture will diffused with the alloy to obtain an appropriate concentration distribution of the impurities in the formed PN junction. This method is suitable for manufacturing a high- sensitivity varactors.

8. Epitaxial-type Diode

It’s formed by making a PN junction through process of extent the length. It needs superior skills for manufacturing. Since the distribution of different concentrations of impurities can be controlled, it is also suitable for manufacturing a highly-sensitive varactor.

9. Schottky Diode

Basic principle of Schottky diode is to block the reverse voltage with the formed Schottky on the contact surface of the metal (for example, lead) and the semiconductor (N-type silicon chip). Its pressure resistance is only about 40V. As the switching speed is very fast, and the reverse recovery time trr is particularly short. Therefore, a switching diode and a low-voltage high-current rectifier diode can be fabricated.

II Classification according to the Purpose

1. Detection Diode

In principle, the process of taking modulation signal from the input signal is a detection. In the detection diode, working frequency of germanium point-contact type diode is up to 400MHz, with small forward voltage drop, small junction capacity, high detection efficiency and good frequency characteristics. A diode for detection like point-contact type can be used for circuits such as amplitude limiting, clipping, modulation, mixing, and switching. There are also two diode assemblies with consistent characteristics specifically for frequency detection.

2. Rectifier Diode

In principle, the DC output taken from the input AC is rectification. Taking the magnitude of the rectified current (100 mA) as the boundary, the output current greater than 100 mA is called rectification. It can subdivided into three types: silicon -semiconductor rectifier diode of 2CZ type, 2 silicon bridge rectifier of QL type, 2CLG-type rectifier diode used for high-voltage silicon stack for TV with working frequency of nearly 100KHz.

3. Amplitude-limiting Diode

Most diodes can be used for amplitude limiting. There are also dedicated amplitude-limiting diodes like the high-frequency Zeners. In order to make these diodes have a particularly strong effect of limiting the sharp amplitude, they are usually made of silicon materials.There are also such components that a number of necessary rectifier diodes are connected in series to form a single unit according to the needs of limiting voltage.

4. Modulation Diode

It’s usually referred to as a dedicated diode for ring modulation, which is a combination of four diodes with consistent forward characteristics. They are usually directly used for frequency modulation.

5. Mixing Diode

When the mixing method of diode is used, Schottky type and point-contact type diodes are often used in the frequency range of 500 to 10,000 Hz.

6. Amplifying Diode

Usually, amplifying with diodes are indicating the amplification of the negative-resistance devices such as tunnel diodes and bulk-effect diodes, as well as the parametric amplification with varactors. Therefore, the diode for amplification generally refers to tunnel diode, bulk effect diode, and varactor diode.

7. Switching Diode

There is switching diode used for logic operations at low currents (such as 10 mA), and the switching diode used for magnetic core excitation at hundreds of milliamps. Low-current switching diode has point-contact type and bond type, and silicon-diffused type, mesa type and planar diode can work at high temperatures. Switching diode has fast switching speed. And schottky diode has an extremely short switching time, which makes it an ideal switching diode. Point-contact diode of 2AK type is often used for switching circuits at medium speed, while 2CK-type planar diode is used for high-speed switching circuits.

8. Varactor Diode

Small power diodes for automatic frequency control (AFC) and tuning are called varactor diodes. The electrostatic capacitance of its PN junction is changed by applying a reverse voltage. Therefore, it is widely used for automatic frequency control, scanning oscillation, frequency modulation, and tuning. Generally, a silicon diffused diode is used, but diodes of alloy diffused type, epitaxial type, or double diffused type can also be used because they have a particularly large changing rate of electrostatic capacitance in terms of the voltage.

9. Frequency Multiplication Diode

There is a frequency multiplication with the varactor and a frequency multiplication by the snap-off diode. The varactor diode for frequency multiplication is called a variable reactor. Although the variable reactor works the same as the varactor diode for automatic frequency control, its structure can withstand higher power. The snap-off diode is also called a step recovery diode, and its reverse recovery time from on to off is remarkably short. Therefore, if a sine wave is applied to the snap-off diode, the output waveform is suddenly pinched off, so that many high-frequency harmonics can be generated.

10. Zener Diode

Zener Diode is usually made into diffused type or alloyed type of silicon, with a curve of reverse breakdown changing rapidly, used for control voltage and standard voltage. The terminal voltage (also known as Zener voltage) when the diode is working is from about 3V to 150V, and can be divided into many grades. In terms of power, there are also products ranging from 200mW to more than 100W. Generally 2CW-type zenzer diode works in the reverse breakdown state with a small dynamic resistance. And 2DW-type zener diode is the two complementary diodes reversely connected in series for reducing the temperature coefficient.

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