Ointments plates

Tablets TLC Shake powder with ethanol (absolute), centrifuge, expose plate to carbon dioside, 2 min Silica Chloroform-acetic acid (4 1) with 0.02% butylated hydroxytoluene 254 nm BP, vol. II. p. 798. for eye ointment, p. 572. EP, pt. 11-9, p. 418 [6] TLC [ 1,8,1041] GC [2,8] HPLC [8.9.10421 HI...

Amin and Jakobs48) dissolve suppositories and ointments, which contain several active ingredients (hydrocortisone or its esters, an antihistaminic, a local anaesthetic and a disinfectant), in chloroform/methanol. They apply the solution directly on a thin-layer plate without freeing it from the suppository or ointment base. After the separation the active ingredients are scanned with variation coefficients of 1.29-3.56%. 

Zinc is also a primary metal in the penny coin, which used to be made of copper. In addition, zinc can be mixed with copper to form brass, which is a very useful alloy because of its durability and hardness. Another useful compound is zinc oxide. Made by burning zinc vapor in air, zinc oxide is used to make white paints. Used as an ointment, zinc oxide makes a good sunscreen because it blocks the Suns harmful ultraviolet rays that damage the skin. Zinc oxide also has another important property it is photoconductive, which means that it conducts electricity better when exposed to light. For example, a photocopier contains a photoconductive plate that is sometimes made with zinc oxide. When this plate is electrically... 

One test deficiency to be aware of is inadequate dis-persement of a cream or ointment on microbial test plates. Firms may claim to follow USP procedures, yet in actual practice they may not disperse product over the test plate, resulting in inhibited growth as a result of concentrated preservative in the nondispersed inoculate. The spread technique is critical, and the firm should document that the personnel performing the technique have been adequately trained and are capable of performing the task. Validation of the spread-plate technique is particularly important when the product has a potential antimicrobial affect. 

The oxychloride BiOCl is utilized in an odd application of bismuth. The compound can be crystallized as small plates with a diameter of less than 10 pm. The small crystals have a very high refractive index and, dispersed in nail varnish or ointment, a pearlescent effect. For that reason, bismuth oxychloride has been an important pigment for cosmetics. Annually more than 500 tonnes of bismuth is used for this purpose. 

Hoebus et al. (1993) used silica gel TLC with various mobile phases to identify corticosteroid hormones available on the European market. Detection was by fluorescence after the plates were sprayed with alcoholic sulfuric acid and heated. Datta and Das (1994) identified and quantified corticosteroids and their esters in pharmaceutical preparations of creams and ointments. The preparations were dissolved in chloroform, centrifuged to remove water and insoluble material, and silica gel TLC with hexane mobile phase was used to wash out base ingredients followed by chloroform-ethyl acetate (1 1) for free steroids or (2 1) for esters and spectrodensitometry at 240 nm recoveries were 99 1% and the agreement of results with the official methods used was excellent. 

The ointments were applied daily for a maximum of 3 weeks, according to summary of product characteristics. After assessment of the infected nail debridement, topical antifxmgal bifonazole cream was applied daily in both groups for 8 weeks. A total of 102 patients were evaluated, i.e. 51 in the 40% urea ointment with plastic dressing group and 51 in the bifonazole urea group. The primary end point was complete removal of the nail plate at day 21. Secondary end points were complete cure and mycological cure evaluated at day 105. Ease of use and local tolerability were also assessed. 

---