Novel Approches about Semisolid Dosage Forms  

The new access in semisolid dosage forms by adding or applying some new approaches to improve them from bioavailability, efficacy, drug dosing  cost etc and  also techniques which may be launched recently, but not widely used.  

Article developed by S. J. Daharwal, Ekta Verma and R. B. Saudagar
Institute of Pharmacy, Pt. Ravishankar Shukla University, Raipur

SEMISOLID DOSAGE FORMS:

Semisolids constitute a significant proportion of pharmaceutical dosage forms They serve as carriers for drugs that are topically delivered by way of the skin, cornea, rectal tissue, nasal mucosa, vagina, buccal tissue, urethral membrane, and external ear lining, A wide range of raw materials is available for the preparation of a semisolid dosage form. Apart from the usual pharmaceutical ingredients such as preservatives, antioxidants, and solubilizers, the basic constituents of a semisolid dosage form are unique to its composition the choice of suitable raw materials for a formulation development is made on the basis of the drug delivery requirements and the particular need to impart sufficient emolliency or other quasi-medicinal qualities in the formulation. Because of their peculiar theological behavior, semisolids can adhere to the application surface for sufficiently long periods before they are washed off. This property helps prolong drug delivery at the application site. A semisolid dosage form is advantageous in terms of its easy application, rapid formulation, and ability to topically deliver a wide variety of drug molecules. Semisolid dosage forms usually are intended for localized drug delivery. In the past few years, however, these forms also have been explored for the systemic delivery of various drug

 Ointments: are semisolid preparations for external application to skin or mucous membranes. Their composition softens but does not melt upon application to the skin. Therapeutically, ointments function as skin protective and emollients, but they are used primarily as vehicles for the topical application of drug substances.

 Creams: are semisolid dosage forms that contain one or more drug substancesDissolved or dispersed in a suitable base, usually oil in- water emulsion or aqueous microcrystalline dispersion oflong-chain fatty acids or alcohols that are water-washable and are cosmetically and aesthetically acceptable.

 Gels: are semisolid systems that consist of either suspensions of small inorganic particles or large organic molecules interpenetrated by a liquid.Gels can be either water based (aqueous gels) or organic solvent based (organogels).

 Pastes: are semisolid dosage forms that contain one or more drug substances incorporated in a base with large proportions of finely dispersed solids, are intended for external application to skin, but very thick & stiff.

 Jellies: are transparent, non-greasy, semisolid prepration for external applications to skin & mucous membrane.

 Poultices: are soft, viscous wet masses of solid substances applied to skin & now outdated.

 Suppositories: are intended in other than oral cavity i.e., vaginal, nasal cavity. generally introduced in systemic.

 Percutaneous drug absorption: Semisolid dosage forms for dermatological drug therapy are intended to produce desired action at specific sites in the epidermal tissue. A drug’s ability to penetrate the skin’s epidermis, dermis and subcutaneous fat layers depends on the properties of the drug and the carrier base. Although drug and the carrier base. Although drug and the carrier base. Although area for most dermatological disorders lies in the viable epidermis or upper dermis. Hence, a drug’s diffusive penetration of the skin — percutaneous absorption— is an important aspect of drug therapy. The main portals of drug entry are the follicular region, the sweat ducts or the unbroken stratum corneum between the appendages. A substance’s particular route mainly depends on the physicochemical properties of the drug and the condition of the skin.