“Pharmacy is the branch of health sciences that deals with the preparation and dispensing of drugs. Its aim is to ensure the safe and effective use of pharmaceutical drugs”. Pharmacists are the experts and health professionals who have done their studies in medicines. They can use their knowledge of medicines for the benefit of patients.
Pharmaceutics is the discipline of pharmacy that deals with the process of turning a new chemical entity (NCE) or old drugs into a medication to be used safely and effectively by patients. It is also called the science of dosage form design.
The Need For Dosage Forms:
- Accurate dose.
- Protection e.g. coated tablets, sealed ampoules.
- Protection from gastric juice.
- Masking taste and odour.
- Placement of drugs within body tissues.
- Sustained release medication.
- Controlled release medication.
- Optimal drug action.
- Insertion of drugs into body cavities (rectal, vaginal).
- Use of desired vehicle for insoluble drugs.
Types of Pharmaceutical Dosage Forms: Dosage forms are the means by which drug molecules are delivered to sites of action within the body.
Pharmaceutical Tablets: A tablet is a hard, compressed medication in round, oval or square shape. Solid dosage form containing unit dose of one or more medicament. Tablets constitute approximately 90% of all dosage forms clinically used to provide systemic administration of therapeutic agents. This widespread use of tablets has been achieved as a result of their convenience and also the diversity of tablet types.
Tablets are prepared primarily by compression of granules or powder blends, with a limited number prepared by molding. Most tablets are used in the oral administration of drugs. Many of these are prepared with colorants and coatings of various types. Other tablets, such as sublingual, buccal, or vaginal tablets, are prepared to have features most applicable to their particular route of administration.
General Properties of Tablets:
- A tablet must be strong and hard to withstand mechanical shock during manufacturing, packing, shipping, dispensing and use.
- The drug content of the tablet must be bio-available, that is, the tablet must be able to release its content in a predictable and reproducible manner.
- The tablet must be chemically and physically stable to maintain its chemical and physical attributes during manufacture, storage, and use.
- The tablet should have an elegant product identity which is free from any tablet defect.
- Tablets must be uniform in weight and in drug content.
The various tablet types are described as follows:
• Compressed tablets: Compressed tablets represent a significant proportion of tablets that are clinically used to provide systemic administration of therapeutic agents either in a uncoated state (i.e., in their simplest form) or in a coated state. These tablets are designed to provide rapid disintegration in the gastric fluid following ingestion hence, allowing rapid release of the drug and, ultimately, systemic absorption of the dosage form.
• Sugar-coated Tablets: These are compressed tablets that have been coated with concentrated sugar solution to improve patient’s compliance, increase aesthetic appeal, mask objectionable tastes or odors, increase stability and/or modify the release of therapeutic agent(s). Sugarcoating was once quite common but lost commercial appeal due to the time and expertise required in the coating process, the increase in size and weight of coated tablets, high cost of process validation and shipping.
• Film-Coated Tablets: Film-coated tablets are conventional tablets coated with a thin layer of polymer (e.g., hydroxypropyl methylcellulose, hydroxypropyl cellulose) or a mixture of polymers (e.g., Eudragit E100) capable of forming a skin-like film. The film is usually colored and also impacts the same general characteristics as sugar coating with the added advantage of being more durable, less bulky, and less time-consuming to apply. By its composition, the coating is designed to break and expose the core tablet at the desired location in the gastrointestinal tract.
• Effervescent Tablets: Effervescent tablets are uncoated tablets that generally contain organic acids (such as tartaric or citric acid) and sodium bicarbonate in addition to the medicinal substance or API. They react rapidly in the presence of water by releasing carbon dioxide which acts as a disintegrator to produce either a drug suspension or an aqueous solution. These tablets are prepared by compressing granular effervescent salts (organic acid and bicarbonate) with the medicinal substances.
• Enteric-coated Tablets: Enteric-coated tablets are compressed tablets that have delayed-release properties. They are coated with polymeric substances (such as cellulose acetate phthalate/cellulose acetate butyrate; hydroxypropylmethylcellulose succinate; and methacrylic acid copolymers) that resist solution in gastric fluid but disintegrate and allow drug dissolution and absorption in the intestine.
• Chewable Tablets: Chewable tablets are big sized tablets which are difficult to swallow and thus, are chewed within the buccal cavity prior to swallowing. They are especially useful for administration of large tablets to children and adults who have difficulty swallowing conventional tablets or antacid formulations in which the size of the tablet is normally large and the neutralization efficacy of the tablet is related to particle size within the stomach. Chewable tablets are not conventionally used if the drug has issues regarding taste acceptability.
• Buccal and Sublingual Tablets: Buccal and sublingual tablets are small, flat, oval tablets that are intended to be dissolved in the buccal pouch (buccal tablets) or beneath the tongue (sublingual tablets) for absorption through the oral mucosa to produce a systemic effect. These tablets are employed to achieve either rapid absorption into the systemic circulation e.g. glyceryl trinitrate sublingual tablets or, alternatively, to enable oral absorption of drugs that are destroyed by the gastric juice and/or are poorly absorbed from the gastrointestinal tract.
• Lozenges or Troches: These are disc-shaped solid preparations containing medicinal agents and generally a flavoring substance in a hard candy or sugar base. They are intended to be slowly dissolved in the oral cavity, usually for local effects.
• Tablet Triturates: Tablet triturates are small, usually cylindrical, moulded, or compressed tablets containing small amounts of usually potent drugs mixed with a combination of sucrose and lactose or any suitable diluent. They are prepared from moist material, using a triturate mould that gives them the shape of cut sections of a cylinder.
• Hypodermic Tablets: Hypodermic tablets are soft, readily soluble tablets that were originally used by physicians in extemporaneous preparation of parenteral solutions. These tablets are dissolved in a suitable vehicle (water for injections) and administered by parenteral route.
• Dispensing Tablets: Dispensing tablets also referred to as compounding tablets are tablets supplied primarily as a convenience for extemporaneous compounding. These tablets contain large amounts of highly potent APIs, and thus are used by a pharmacist to compound prescriptions that can be incorporated readily into powders and liquids, thus, circumventing the necessity to weigh small quantities of these potent drug substances.
• Gelatin-Coated Tablets: Gelatin-coated tablets are compressed tablets coated with either one or two-toned color gelatin. The gelatin coating impacts the same general characteristics as sugar coating and film coating with the added advantage of improving the stability of photosensitive APIs. The gelatin coating also facilitates swallowing, enables custom branding, and prevents counterfeit since they are more tamper-evident than unsealed capsules. Gelatin-coated tablets are also ideal for double-blind clinical studies, or for drug substances that can irritate the esophageal mucosa when they are incorporated in an immediate-release tablet such as bisphosphonates.
• Multiple Compressed Tablets/ Multi-compressed Tablets: Multiple compressed tablets, also called multi-compressed tablets are tablets that are composed of two or more layers. These tablets are prepared by subjecting the fill material to more than one compression cycle.
• Rapid-release Tablets: Rapid-release tablets, also called rapidly dissolving tablets, rapidly disintegrating tablets, orally-dispersible tablets, quick disintegrating tablets, mouth dissolving tablets, fast disintegrating tablets, fast-dissolving tablets, rapid-dissolving tablets, or porous tablets are characterized by disintegrating or dissolving in the mouth within 1 minute, some within 10 seconds, leaving an easy-to-swallow residue.
• Vaginal Tablets/ Vaginal Inserts: Vaginal tablets are uncoated, bullet-shaped, or ovoid tablets designed for vaginal administration. They are prepared by compression and are shaped to fit tightly on plastic inserter devices that accompany the product.
• Immediate-Release Tablets: Immediate-release tablets are tablets designed to disintegrate and release their medication with no special rate-controlling features, such as special coatings and other techniques. This is the most common type of tablet and examples include, chewable, effervescent, sublingual and buccal tablets.
• Implantation Tablets/ Implants: These are long-acting sterile tablets designed to provide continuous release of drugs, often over a period of months or a year. They are placed subcutaneously for systemic or local delivery.
Implants are mainly used for the administration of hormones such as testosterone steroids for contraception. They usually contain rate-controlling excipients in addition to the active ingredient.
Advantages of Tablets:
- Tablets are elegant in appearance and convenient to use.
- They are superior to other dosage forms with respect to chemical, physical and microbiological stability.
- Tablets provide stable and an accurately measured dosage of drug substance to patients.
- Tablets can be formulated to protect unstable drug substances or disguise unpalatable excipients.
- Tablets are generally inexpensive to manufacture.
- It is easier to mask the unpleasant taste of some APIs in tablets thus improving patient acceptability.
- Tablets may be formulated to contain two or more drug substances (even if they are physically or chemically incompatible), thus reducing multiple tablet use.
- Tablets may be easily manufactured to show product identification using colored coatings, embossed markings, and printing.
- Tablets may be designed to release their active substance at a particular site within the gastrointestinal tract to reduce side effects, promote absorption at that site or provide a local effect (e.g. ulcerative colitis).
- With the exception of proteins which are denatured in the gastrointestinal tract, all classes of therapeutic agents may be administered orally in the form of tablets.
Tablets remain popular as a dosage form, due to the various advantages afforded both to the manufacturer and to the patient. Although the basic mechanical approach for most tablet manufacture has remained the same, efforts are continuously made to understand more clearly the physical characteristics of powder compaction and the factors affecting the availability of the drug substance from the dosage form after oral administration.
Career Scope & Job Opportunities in the Pharmacy field are huge. Due to the opening of large pharmaceutical companies, the future in the field of pharmacy is bright.
Numerous jobs are available for pharmacists in government as well as private organizations. After completing your studies, you can easily find jobs in pharmaceutical industries, government departments, colleges and universities, hospitals, investigation and research institutes etc.
Pharmacists can practice in community pharmacies, hospitals, clinics, extended care facilities, psychiatric hospitals, and regulatory agencies. The Sales & Marketing job sector also hires the maximum number of pharmacy graduates.One can also work in retail stores of medicines. After registering with the state Pharmacy Council, you can open a chemist/drug shop and sell medicines as per Doctor’s prescription.
Pharmacists play a vital role in improving patient care through the medicine and information they provide. In addition, pharmacy has excellent earning potential and is consistently ranked as one of the most highly trusted professions due to the care and service pharmacists provide.
About The Author:
Dr. Ashish Acharya
[Principal]
Website: Corporate Institute of Pharmacy, Bhopal
Email Id : Prof.acharya1@gmail.com
Phone : 9425024469
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